JP6427448B2 - POWER SUPPLY DEVICE AND POWER SUPPLY CONTROL METHOD - Google Patents

Description

  The present invention relates to a power supply device and a power control method.

  In recent years, a DC / DC converter that is switched on / off controlled by a current mode control method (hereinafter referred to as current mode control) that is supplied with power from a three-phase alternating current so that peak values of input current of each phase become equal. There is known a power supply device including the following.

Unexamined-Japanese-Patent No. 11-113256

  However, in the power supply apparatus described above, it is difficult to perform current mode control when, for example, a full bridge type DC / DC converter (hereinafter referred to as a full bridge converter) is used, and a power supply including a full bridge converter In the apparatus, it has been common to perform phase shift control. Therefore, in the power supply apparatus provided with the full bridge converter, the peak value of the input current of each converter in each phase supplied from the multiphase alternating current can not be made uniform, and the conversion efficiency of the power supply may be lowered. Further, when the secondary side is synchronously rectified, in the above-described power supply device, there is a case where a regenerative current is generated on the primary side at the time of light load, and a current waveform for current control can not be obtained.

  The present invention has been made to solve the above problems, and an object thereof is to improve the conversion efficiency of a power supply, and also to provide a power supply device capable of performing current mode control at light load when synchronous rectification is performed on the secondary side. And providing a power control method.

In order to solve the above problems, one aspect of the present invention is a power supply device including a DC / DC converter, wherein the DC / DC converter is a bridge circuit having a switching element, and the bridge circuit is direct or indirect. , A synchronous rectifier circuit connected to the secondary coil, and a switching element included in the bridge circuit. A transformer having a primary coil connected to each other, a secondary coil insulated from the primary coil, a synchronous rectification circuit connected to the secondary coil, and Control unit that controls on / off of the current coil by a current mode control method, and a current detection unit that detects a current flowing through the primary coil, and the switching element includes a first end of the primary coil of the transformer A first end side switching element connected to the second end side switching element connected to the second end of the primary coil of the transformer; Included, the control unit is a positive going timing voltage of the primary coil is determined by the state of the switching device of the first end side is negative, on the primary side coil which is detected by the current detection unit It switches to the primary side current which is a flowing current, and switches to the reversal current which reversed the said primary side current at the timing from which the voltage of the said primary side coil judged from the state of the switching element of the said 1st end becomes negative. Control waveform is generated, and based on the generated control waveform, the switching element at the second end is turned on at the switching timing between the primary current and the reverse current, and the control waveform has a predetermined value. so as to turn off the switching element at the reach timing, controls the on-off switching element of the second end side in the current mode control system A power supply device according to claim Rukoto.

Further, according to one aspect of the present invention, in the power supply device described above, the control unit generates the control waveform by switching between the primary current and the reverse current at least when the load is light.

Further, according to one aspect of the present invention, in the power supply device described above, the control unit alternately switches the primary current and the reverse current each time the switching element on the first end side is switched. Generating the control waveform.

Another embodiment of the present invention, in the power supply, the control unit may start the rise of the primary current, or, at the timing of the start of falling, switching the primary current and said inverted current And generating the control waveform.

Another embodiment of the present invention, in the power supply, the bridge circuit includes a first switching element and second switching element is a switching element of the first end side, in the switching elements of the second end side and a certain third switching element 及 beauty fourth switching elements, the four switching elements constituted by bridge connection, wherein the control unit is connected to a first end of the primary coil of the transformer Controlling the first switching element and the second switching element with a predetermined fixed duty, and controlling the third switching element and the fourth switching element connected to the second end of the primary coil It is characterized in that it is controlled by a current mode control method by pulse width modulation.

  Further, according to one aspect of the present invention, in the power supply device described above, a plurality of the DC / DC converters are provided, and the plurality of DC / DC converters are current peak values of all the control waveforms in the plurality of DC / DC converters. Are controlled to coincide with each other.

Further, one aspect of the present invention is a power supply control method of a power supply apparatus including a DC / DC converter, wherein the DC / DC converter is a bridge circuit having a switching element, and the bridge circuit directly or indirectly. A transformer having a primary side coil to be connected and a secondary side coil insulated from the primary side coil, a synchronous rectification circuit connected to the secondary side coil, and an on state of a switching element of the bridge circuit · A control unit that controls off by a current mode control method, and a current detection unit that detects a current flowing through the primary coil, the switching element being connected to the first end of the primary coil of the transformer Switching element on the first end side, and switching element on the second end side connected to the second end of the primary coil of the transformer , The control section, the voltage of the primary coil is determined by the state of the first end side of the switching element at the positive going timing negative, the current flowing through the primary coil which is detected by the current detection unit Control to the primary side current, and control is made to switch to the reverse current obtained by inverting the primary side current at the timing when the voltage of the primary side coil determined from the state of the switching element on the first end becomes positive to negative A waveform is generated, and based on the generated control waveform, the switching element on the second end is turned on at the switching timing of the primary current and the reverse current, and the control waveform reaches a predetermined value. so as to turn off the switching element at a timing, the current mode control system controls the on-off of the switching elements of the second end side with child Which is a power control method characterized.

  According to the present invention, even when a regenerative current is generated on the primary side, control of the current mode control system can be easily performed. In addition, since the phase currents are balanced, the conversion efficiency of the power supply can be improved.

It is a block diagram showing an example of the power supply device by this embodiment. It is a block diagram which shows an example of the DC / DC converter by this embodiment. It is a block diagram showing an example of a control part by this embodiment. It is a time chart which shows an example of control of a DC / DC converter by this embodiment. It is a time chart which shows an example of current mode control at the time of light load by this embodiment. It is a time chart which shows an example of current mode control of three phases by this embodiment. It is a block diagram which shows an example of three-phase package control by this embodiment.

Hereinafter, a power supply device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of a power supply device 1 according to the present embodiment.
As shown to this figure, the power supply device 1 outputs a predetermined | prescribed DC voltage from three-phase alternating current power supply (R, S, T). The power supply device 1 includes PFC (Power Factor Correction: power factor correction) units 2-1 to 2-3 and DC / DC converters 10-1 to 10-3.

The PFC unit 2-1 is a U-phase PFC circuit, the PFC unit 2-2 is a V-phase PFC circuit, and the PFC unit 2-3 is a W-phase PFC circuit. In addition, in this figure, when the PFC part 2-1, the PFC part 2-2, and the PFC part 2-3 are the same structures and show the arbitrary PFC part with which the power supply device 1 is equipped, or when it does not distinguish in particular Will be described as the PFC unit 2.
The PFC unit 2 is a power factor correction circuit, removes high frequency current components, converts input AC power into DC power, and outputs the DC power.

The DC / DC converter 10-1 converts the DC power converted from the U-phase supplied from the PFC unit 2-1 into a predetermined DC voltage and outputs the DC voltage. Further, the DC / DC converter 10-2 converts the DC power converted from the V phase supplied from the PFC unit 2-2 into a predetermined DC voltage and outputs it. Further, the DC / DC converter 10-3 converts the DC power converted from the W phase supplied from the PFC unit 2-3 into a predetermined DC voltage and outputs it.
In this figure, DC / DC converter 10-1, DC / DC converter 10-2, and DC / DC converter 10-3 have the same configuration, and any DC / DC converter included in power supply apparatus 1 is The DC / DC converter 10 will be described as it is or in the case where it is not particularly distinguished.

  The DC / DC converter 10 is, for example, a DC-DC conversion circuit that converts DC power supplied from the PFC unit 2 into a predetermined DC voltage. The DC / DC converter 10 is, for example, a full bridge DC / DC converter. Here, with reference to FIG. 2, a configuration example of the DC / DC converter 10 will be described.

FIG. 2 is a block diagram showing an example of the DC / DC converter 10 according to the present embodiment.
As shown in FIG. 2, the DC / DC converter 10 includes a current detection unit 11, a voltage detection unit 12, a control unit 13, a full bridge circuit 20, a driver unit 40, and smoothing capacitors (Ci and Co). , A resonant capacitor C5, a series reactor L1, diodes (D5, D6), a synchronous rectification circuit 30, and a choke coil L2.

The smoothing capacitor Ci is connected between the input power supply line VI (first power supply line) and the power supply line GND1 (second power supply line) to smooth the input voltage.
The full bridge circuit 20 includes switching elements Q1 to Q4, parasitic capacitances C1 to C4, and body diodes D1 to D4. That is, the full bridge circuit 20 includes the switching element Q1, the switching element Q2, the switching element Q3, and the switching element Q4, and is configured by bridge-connecting the four switching elements Q1 to Q4.

  In the switching element Q1 (an example of a first switching element), the drain terminal is connected to the power supply line VI, the source terminal is connected to the node N1, and the gate terminal is connected to the signal line of the drive signal G1. That is, the switching element Q1 is connected between the power supply line VI and the first end of the primary coil TL11 described later via the resonant capacitor C5. The switching element Q1 also has a parasitic capacitance C1 and a body diode D1 between the drain terminal and the source terminal.

  In the switching element Q2 (an example of a second switching element), the drain terminal is connected to the node N1, the source terminal is connected to the power supply line GND1, and the gate terminal is connected to the signal line of the drive signal G2. That is, the switching element Q2 is connected between the power supply line GND1 and the first end of the primary coil TL11 described later. The switching element Q2 also has a parasitic capacitance C2 and a body diode D2 between the drain terminal and the source terminal via the resonant capacitor C5.

  In the switching element Q3 (an example of a third switching element), the drain terminal is connected to the power supply line VI, the source terminal is connected to the node N2, and the gate terminal is connected to the signal line of the drive signal G3. That is, switching element Q3 is connected between power supply line VI and the second end (node N3) of primary coil TL11 described later via series reactor L1. The switching element Q3 has a parasitic capacitance C3 and a body diode D3 between the drain terminal and the source terminal.

  In the switching element Q4 (an example of a fourth switching element), the drain terminal is connected to the node N2, the source terminal is connected to the power supply line GND1, and the gate terminal is connected to the signal line of the drive signal G4. That is, switching element Q4 is connected between power supply line GND1 and the second end (node N3) of primary coil TL11 described later via series reactor L1. The switching element Q4 also has a parasitic capacitance C4 and a body diode D4 between the drain terminal and the source terminal.

The transformer TL1 has a primary side coil TL11 and a secondary side coil (TL12, TL13) with a center tap, and converts the power supplied to the primary side coil TL11 to convert the secondary side coil (TL12, TL13) Output to
The primary coil TL11 is connected to the full bridge circuit 20. For example, the first end of the primary coil TL11 is connected to the switching element Q1 and the switching element Q2 via a resonant capacitor C5. That is, the first end of the primary coil TL11 is connected to the node N1 via the resonant capacitor C5. The second end of the primary coil TL11 is connected to the node N3 and is connected to the switching element Q3 and the switching element Q4 via the series reactor L1. That is, the second end of the primary coil TL11 is connected to the node N2 via the series reactor L1.

In the present embodiment, an example in which the primary coil TL11 is indirectly connected to the full bridge circuit 20 via the resonant capacitor C5 will be described as an example, but the primary coil TL11 is directly connected without the resonant capacitor C5. It may be connected to the full bridge circuit 20.
The series reactor L1 is connected in series to the primary side coil TL11, and realizes the ZVS (Zero Voltage Switching) operation of the switching elements Q1 to Q4 by resonance with the parasitic capacitances C1 to C4 and the wiring capacitance.

  The secondary coil (TL12, TL13) is insulated from the primary coil TL11, and the first end of the secondary coil TL13 is at the node N4 and the second end is at the first end of the secondary coil TL12. The second ends of the secondary side coil TL12 are connected to the node N5. Also, the secondary side coil (TL12, TL13) has a center tap (the second end of the secondary side coil TL13 and the first end of the secondary side coil TL12), and the center tap is connected to the node N6 . The center tap is connected to the choke coil L2. The secondary coils (TL12 and TL13) are connected to a synchronous rectification circuit 30 described later.

The diode D5 has an anode terminal connected to the node N3 which is the first end of the primary coil TL11, and a cathode terminal connected to the power supply line VI. The diode D5 functions as a clamp diode.
The anode terminal of the diode D6 is connected to the power supply line GND1, and the cathode terminal is connected to a node N3 which is a first end of the primary coil TL11. The diode D5 functions as a clamp diode.

The synchronous rectification circuit 30 includes switching elements (Q5, Q6), parasitic capacitances (C6, C7), and body diodes (D7, D8).
The switching element Q5 (an example of a fifth switching element) has a drain terminal connected to the node N4 which is the first end of the secondary coil TL13, a source terminal connected to the output power supply line GND2, and a gate terminal connected to the drive signal G5. Each is connected to a line. That is, switching element Q5 is connected between power supply line GND2 and the first end (node N4) of secondary coil TL13. The switching element Q5 has a parasitic capacitance C6 and a body diode D7 between the drain terminal and the source terminal.

  The switching element Q6 (an example of a sixth switching element) has a drain terminal connected to the node N5 which is the second end of the secondary coil TL12, a source terminal connected to the output power supply line GND2, and a gate terminal connected to the driving signal G6. Each is connected to a line. That is, switching element Q6 is connected between power supply line GND2 and the second end (node N5) of secondary coil TL12. The switching element Q6 has a parasitic capacitance C7 and a body diode D8 between the drain terminal and the source terminal.

The choke coil L2 has a first end connected to the node N6 connected to the center tap of the secondary coil (TL12, TL13), and a second end connected to the output power supply line VO. The choke coil L2 is used for smoothing of the DC power output from the DC / DC converter 10 together with a smoothing capacitor Co described later.
The smoothing capacitor Co is connected between the output power supply line VO and the power supply line GND2 to smooth the output voltage.
Here, the load RL indicates a load that consumes DC power output from the DC / DC converter 10.

The current detection unit 11 detects a current flowing through the primary coil TL11 (primary side current Ict flowing through the current transformer CT). The current detection unit 11 outputs the detected current to the control unit 13 as a signal Vict converted into a voltage.
The voltage detection unit 12 performs level conversion of the output voltage of the DC / DC converter 10 to compare with the reference voltage Vref, and outputs a signal Vo to the control unit 13.

  The control unit 13 is a processor including, for example, a central processing unit (CPU) and a digital signal processor (DSP), and the switching element Q1, the switching element Q2, the switching element Q3 and the switching element Q4 included in the full bridge circuit 20. The switching element Q5 and the switching element Q6 included in the synchronous rectification circuit 30 are controlled to be in the on (on) state (conductive state) and the off (off) state (nonconductive state). The control unit 13 controls, for example, on / off of switching elements (Q1 to Q4) of the full bridge circuit 20 and switching elements (Q5, Q6) of the synchronous rectification circuit 30 (current mode control). Do.

  The control unit 13 controls the voltages of the switching element Q1, the switching element Q2, the switching element Q3, the switching element Q4, the switching element Q5, and the gate terminal of the switching element Q6, the driving signal G2, the driving signal G2, and the driving signal G3. The drive signal G4, the drive signal G5, and the drive signal G6 are output through the driver unit 40. The control unit 13 controls the switching element Q1 and the switching element Q2 with a predetermined fixed duty (for example, a duty of 50%), and controls the switching element Q3 and the switching element Q4 by PWM (pulse width modulation). Control.

The control unit 13 switches, for example, the primary side current (Ict) when the voltage of the primary side coil TL11 changes from negative to positive, and the primary side current (when the voltage of the primary side coil TL11 changes from positive to negative) It switches to the inversion current (Inct) which inverted Ict), and generates a control waveform based on the primary side current (Ict) and the inversion current (Inct). The control unit 13 controls on / off of the switching elements Q1 to Q4 by the current mode control method based on the generated control waveform. That is, the control unit 13 switches the primary side current (Ict) and the inversion current (Inct) alternately each time the switching elements (Q1 to Q4) are switched to generate a control waveform. Specifically, the control unit 13 switches to the reverse current (Inct) at the rising edge of the drive signal G1 of the switching element Q1, and generates a control waveform based on the reverse current (Inct). The control unit 13 switches to the primary current (Ict) at the rising edge of the drive signal G2 of the switching element Q2, and generates a control waveform based on the primary current (Ict).
The details of control of the switching element Q1, the switching element Q2, the switching element Q3, and the switching element Q4 by the control unit 13 will be described later.

  The driver unit 40 controls the switching element Q1, the switching element Q2, the switching element Q3, the switching element Q4, the switching element Q5, and the switching element Q6 output from the control unit 13 to drive each switching element. It converts to a voltage and supplies it to the gate terminal of each switching element. The driver unit 40 includes, for example, drivers 41 to 46. Since the DC / DC converter 10 of the present embodiment is isolated by the transformer TL1, it is necessary to be isolated by the control unit 13 or the driver unit 40.

The driver 41 supplies the drive signal G1 for driving the switching element Q1 to the gate signal of the switching element Q1 based on the control signal of the switching element Q1 output from the control unit 13.
The driver 42 supplies the drive signal G2 for driving the switching element Q2 to the gate signal of the switching element Q2 based on the control signal of the switching element Q2 output from the control unit 13.
The driver 43 supplies the drive signal G3 for driving the switching element Q3 to the gate signal of the switching element Q3 based on the control signal of the switching element Q3 output from the control unit 13.

The driver 44 supplies the drive signal G4 for driving the switching element Q4 to the gate signal of the switching element Q4 based on the control signal of the switching element Q4 output from the control unit 13.
The driver 45 supplies the drive signal G5 for driving the switching element Q5 to the gate signal of the switching element Q5 based on the control signal of the switching element Q5 output from the control unit 13.
The driver 46 supplies the drive signal G6 for driving the switching element Q6 to the gate signal of the switching element Q6 based on the control signal of the switching element Q6 output from the control unit 13.

Next, a configuration example of the control unit 13 will be described with reference to FIG.
FIG. 3 is a block diagram showing an example of the control unit 13 according to the present embodiment.
As shown in FIG. 3, the control unit 13 includes a control waveform generation unit 130, a control signal generation unit 140, a comparator 136, and RS flip flops (137, 138).

The control signal generation unit 140 generates various control signals for controlling the drive signals G1 to G6. The control signal generation unit 140 generates, for example, a carrier signal of a predetermined frequency serving as a reference internally, and generates various control signals based on the carrier signal.
The control signal generation unit 140 generates, for example, a signal S1 for generating the drive signal G1 and a signal S2 for generating the drive signal G2. Here, the signal S1 and the signal S2 are signals of a predetermined duty (for example, a duty of 50%). The control signal generator 140 outputs the signal S1 to the driver 41, and the driver 41 outputs the drive signal G1. Further, the control signal generation unit 140 outputs the signal S2 to the driver 42, and the driver 42 outputs the drive signal G2.

  The control signal generation unit 140 generates, for example, a signal S3 for generating the drive signal G3 and a signal S4 for generating the drive signal G4. Here, the signal S3 is a signal for controlling the rising timing of the drive signal G3, and the control signal generation unit 140 outputs the generated signal S3 to the S terminal (set terminal) of the RS flip flop 137. Further, the signal S4 is a signal for controlling the rising timing of the drive signal G4, and the control signal generation unit 140 outputs the generated signal S4 to the S terminal (set terminal) of the RS flip flop 138.

  The control signal generation unit 140 also generates, for example, a signal S5 for generating the drive signal G5 and a signal S6 for generating the drive signal G6. Here, the signal S5 is, for example, an inverted signal of the signal S1, and the signal S6 is, for example, an inverted signal of the signal S2. The control signal generator 140 outputs the signal S5 to the driver 45, and the driver 45 outputs the drive signal G5. Further, the control signal generation unit 140 outputs the signal S6 to the driver 46, and the driver 46 outputs the drive signal G6.

The control signal generation unit 140 also generates a control voltage Ver for current mode control based on, for example, the reference voltage Vref and the signal Vo which is a feedback voltage signal. The control signal generation unit 140 generates the control voltage Ver based on, for example, PID (Proportional-Integral-Derivative) control. The control signal generation unit 140 changes the voltage value of the control voltage Ver so that the signal Vo matches the reference voltage Vref. The control signal generation unit 140 outputs the generated control voltage Ver as an input signal of the comparator 136 (− input signal of the input terminal).
Further, the control signal generation unit 140 generates, for example, the signal SLOP as a slope signal for performing slope compensation for current mode control, and outputs the signal SLOP to the control waveform generation unit 130.

The control waveform generation unit 130 switches to the primary side current (Ict) when the voltage of the primary side coil TL11 changes from negative to positive, and the primary side current (when the voltage of the primary side coil TL11 changes from positive to negative) It switches to the inversion current (Inct) which inverted Ict), and generates a control waveform based on the primary side current (Ict) and the inversion current (Inct). The control waveform generation unit 130 is, for example, a positive phase signal obtained by multiplying the signal Vict obtained by converting the current (primary side current Ict flowing through the current transformer CT) flowing through the primary coil TL11 into voltage by +1 by the current detection unit 11 A signal VIPt is multiplied by “−1” to generate an inverted signal VIN. The control waveform generation unit 130 generates the control waveform (VICON) by switching the generated positive phase signal VIP and the inverted signal VIN between the rising of the drive signal G1 (signal S1) and the rising of the drive signal G2 (signal S2). Do.
The control waveform generation unit 130 includes a buffer unit 131, an inversion unit 132, a switching determination unit 133, a selection output unit 134, and an addition unit 135.

The buffer unit 131 is, for example, a positive phase amplification circuit using an operational amplifier or the like, and outputs a positive phase signal VIP obtained by multiplying the input signal Vict by “+1”.
The inverting unit 132 is, for example, an inverting amplification circuit using an operational amplifier or the like, and outputs an inverted signal VIN obtained by multiplying the input signal Vict by “−1”.

  The switching determination unit 133 determines the positive phase signal VIP and the inverted signal VIN based on the rising of the signal S1 (corresponding to the rising of the driving signal G1) and the rising of the signal S2 (corresponding to the rising of the driving signal G2). The signal SEL is generated as a selection signal for switching. The switching determination unit 133 sets the signal SEL to H (High: high) state when the signal S 1 rises, and changes the signal SEL to L (Low: low) state when the signal S 2 rises. The switching determination unit 133 outputs the generated signal SEL to the selection output unit 134.

  The selection output unit 134 switches the positive phase signal VIP output from the buffer unit 131 and the inversion signal VIN output from the inversion unit 132 based on the signal SEL output from the switching determination unit 133 and outputs the signal as a signal SELO. . For example, when the signal SEL is in the H state, the selection output unit 134 outputs the positive phase signal VIP to the signal SELO. Also, for example, when the signal SEL is in the L state, the selection output unit 134 outputs the inverted signal VIN to the signal SELO.

  The addition unit 135 adds the signal SELO output from the selection output unit 134 and the signal SLOP generated by the control signal generation unit 140 to generate a signal VICON serving as a control waveform for current mode control by PWM. The addition unit 135 outputs the generated signal VICON as an input signal (input signal of the + input terminal) of the comparator 136.

  In the comparator 136, the-input terminal is connected to the signal line of the control voltage Ver described above, and the + input terminal is connected to the signal line of the signal VICON of the control waveform described above. The comparator 136 compares the voltage value of the signal VICON with the voltage value of the control voltage Ver, and outputs an L state when the voltage value of the signal VICON is less than the voltage value of the control voltage Ver. The comparator 136 outputs the H state when the voltage value of the signal VICON is equal to or higher than the voltage value of the control voltage Ver.

  When the signal S3 is in the H state, the RS flip flop 137 changes the output signal Q to the H state, and holds the output signal Q in the H state until the R terminal is in the H state. Further, when the output signal of the comparator 136 is in the H state, the RS flip flop 137 changes the output signal Q to the L state, and holds the output signal Q in the L state until the S terminal is in the H state. An output signal Q of the RS flip flop 137 is output as a drive signal G3 through the driver 43.

  When the signal S4 is in the H state, the RS flip flop 138 changes the output signal Q to the H state, and holds the output signal Q in the H state until the R terminal is in the H state. Further, when the output signal of the comparator 136 is in the H state, the RS flip flop 138 changes the output signal Q to the L state, and holds the output signal Q in the L state until the S terminal is in the H state. The output signal Q of the RS flip flop 138 is output as a drive signal G4 through the driver 44.

Next, the operation of the power supply device 1 according to the present embodiment will be described with reference to the drawings.
First, with reference to FIG. 4, control of switching element Q1, switching element Q2, switching element Q3, switching element Q4, switching element Q5, and switching element Q6 by control unit 13 of DC / DC converter 10 according to the present embodiment explain.
FIG. 4 is a time chart showing an example of control of the DC / DC converter 10 according to the present embodiment.
In this figure, the respective waveforms of the waveforms W1 to W6 indicate voltage waveforms of the drive signals G1 to G6 in order from the top. Also, in this figure, the horizontal axis indicates time, and the vertical axis indicates logic level.

  At time T1, first, the control unit 13 sets the drive signal G1 of the switching element Q1, the drive signal G4 of the switching element Q4, and the drive signal G6 of the switching element Q6 to the H state. In this case, control unit 13 maintains drive signal G2 for switching element Q2, drive signal G3 for switching element Q3, and drive signal G5 for switching element Q5 in the L state. Thereby, the switching element Q1, the switching element Q4, and the switching element Q6 are turned on, and the switching element Q2, the switching element Q3, and the switching element Q5 are turned off. As a result, current flows from the power supply line VI through the path of the switching element Q1, the resonant capacitor C5, the primary coil TL11, the series reactor L1, and the switching element Q4. As a result, power is generated from the primary coil TL11 to the secondary coil TL12. The synchronous rectification circuit 30 connected to the secondary coil TL12 rectifies this power via the switching element Q6 and smoothes the DC voltage smoothed via the choke coil L2 and the smoothing capacitor Co. Output to VO.

  The control unit 13 controls the voltage of the control waveform generated by the control waveform generation unit 130 based on the current value detected by the current detection unit 11 so that the output signal Vo of the voltage detection unit 12 matches the reference voltage Vref. The switching element Q4 is maintained in the ON state until the) reaches a predetermined value. Further, the control unit 13 maintains the ON state of the switching element Q1 so that the ON period (turn-on period) of the switching element Q1 has a predetermined duty (a predetermined fixed duty).

  At time T2, the voltage (VICON) of the control waveform generated by the control waveform generation unit 130 reaches a predetermined value, and the control unit 13 sets the drive signal G4 to the L state and sets the switching element Q4 to the OFF state. The period DT2 of the ON state of the switching element Q4 is changed by the consumption current of the output signal Vo and the load RL. That is, the control unit 13 performs PWM (pulse width modulation) by current mode control to control the period DT2 of the ON state of the switching element Q4.

  Further, at time T3, the ON period of the switching element Q1 reaches a predetermined duty, and the control unit 13 turns the drive signal G1 and the drive signal G6 to the L state, and turns the switching element Q1 and the switching element Q6 to the OFF state. Do. Here, the predetermined duty is, for example, a ratio (for example, 50%, etc.) of the period DT1 in the ON state in the period TT1, and the conduction time (period DT1) per one predetermined period (period TT1). It is a duty ratio which shows a ratio (DT1 / TT1x100). In the present embodiment, this predetermined duty is described as about 50%. Further, the control unit 13 sets the drive signal G2, the drive signal G3, and the drive signal G5 to the H state, and turns the switching element Q2, the switching element Q3, and the switching element Q5 to the ON state.

  The control unit 13 controls the voltage of the control waveform generated by the control waveform generation unit 130 based on the current value detected by the current detection unit 11 so that the output signal Vo of the voltage detection unit 12 matches the reference voltage Vref. The switching element Q3 is maintained in the ON state until the) reaches a predetermined value. Further, the control unit 13 maintains the ON state of the switching element Q2 such that the ON state period (turn-on period) of the switching element Q2 has a predetermined duty (a predetermined fixed duty).

  At time T4, the voltage (VICON) of the control waveform generated by the control waveform generation unit 130 reaches a predetermined value, and the control unit 13 sets the drive signal G3 to the L state to set the switching element Q3 to the OFF state. The period DT4 of the ON state of the switching element Q3 changes due to the consumption current of the output signal Vo and the load RL. That is, the control unit 13 performs PWM (pulse width modulation) by current mode control to control the period DT4 of the ON state of the switching element Q3.

Further, at time T5, the ON period of the switching element Q2 reaches a predetermined duty, and the control unit 13 sets the drive signal G2 to the L state, and turns the switching element Q2 to the OFF state. The control unit 13 sets the drive signal G2 and the drive signal G5 to the L state, and sets the switching element Q2 and the switching element Q5 to the OFF state. Further, the control unit 13 sets the drive signal G1, the drive signal G4, and the drive signal G6 to the H state, and turns the switching element Q1, the switching element Q4, and the switching element Q6 to the ON state.
Thus, in the second period (for example, period DT3), the control unit 13 controls the switching element Q2 to the ON state with a predetermined duty, and controls the switching element Q3 to the ON state by current mode control.

The subsequent processing from time T5 to time T9 is the same as the processing from time T1 to time T5 described above, and thus the description thereof is omitted here. As described above, the control unit 13 alternately repeats the process of the first period (period DT1) and the process of the second period (period DT3) to switch the switching element Q1 and the switching element Q2 included in the full bridge circuit 20. Control ON and OFF states of the switching element Q3 and the switching element Q4.
In FIG. 4, switching elements Q1 to Q4 perform ZVS operation, for example, due to resonance between series reactor L1, parasitic capacitances C1 to C4, and wiring capacitance.

Next, the operation of current mode control in control unit 13 shown in FIG. 3 will be described with reference to FIG.
FIG. 5 is a time chart showing an example of current mode control at light load according to the present embodiment.

  In this figure, each signal is, in order from the top, the output current Io of DC / DC converter 10, carrier signal, drive signal G1, drive signal G2, signal Vict, signal SEL, signal SELO, signal SLOP, input signal of comparator 136 (VICON, Ver), the output signal of the comparator 136, the signal S3, the drive signal G3, the signal S4, and the drive signal G4 are shown. Here, the signal Vict is a signal obtained by converting the primary current Ict into a voltage by the current detection unit 11, and corresponds to the primary current Ict. Further, the signal SEL is a selection signal generated by the switching determination unit 133 described above, and the signal SELO is an output signal of the selection output unit 134 switched by the signal SEL.

  A waveform W11 indicates the waveform of the output current Io. Waveforms W12 to W24 respectively indicate the carrier signal, drive signal G1, drive signal G2, signal Vict, signal SEL, signal SELO, signal SLOP, signal VICON, output signal of comparator 136, signal S3, drive signal G3, signal The voltage waveform of S4 and the drive signal G4 is shown.

In this figure, the horizontal axis represents time, and the vertical axis represents the output current Io representing the current, the signal Vict, the signal SELO, the signal SLOP, and the input signal (VICON, Ver) representing the voltage, and the other signals It shows the logic level. Further, in this figure, period TRA of the carrier signal corresponds to period DT1 in FIG. 4, and period TRB corresponds to period DT3 in FIG.
Further, since the example shown in FIG. 5 is at the time of light load, a regenerative current is generated periodically, and a period of negative current such as the period TRC exists in the output current Io (see waveform W11). .

  At time T11, first, the control unit 13 sets the drive signal G1 to the H state (see the waveform W13), and sets the drive signal G2 to the L state (see the waveform W14). That is, the control signal generation unit 140 of the control unit 13 sets the signal S1 to the H state, sets the drive signal G1 to the H state through the driver 41, and sets the signal S2 to the L state, and sets the signal S2 to the L state. , And sets the drive signal G2 to the L state. When the drive signal G1 is in the H state, the switching determination unit 133 outputs the L state to the signal SEL (see the waveform W16). Thereby, the selection output unit 134 outputs the inverted signal VIN output from the inverting unit 132 to the signal SELO (see the waveform W17). As a result, the adding unit 135 outputs a signal VICON obtained by adding the signal SLOP and the signal SELO (inverted signal VIN) to the comparator 136 (see the waveform W19).

  On the other hand, at time T11, the control signal generation unit 140 sets the signal S4 to the H state (see the waveform W23). As a result, the RS flip flop 138 is set, and the control unit 13 sets the drive signal G4 to the H state (see the waveform W24).

  Next, when the voltage of the signal VICON increases and reaches the control voltage Ver at the time T12 (see the waveform W19), the comparator 136 outputs the H state (see the waveform W20). As a result, the RS flip flop 138 is reset, and the control unit 13 sets the drive signal G4 to the L state (see the waveform W24).

  Next, at time T13, the signal SLOP switches from rising to falling (see the waveform W18), whereby the signal VICON obtained by the addition unit 135 adding the signal SLOP and the signal SELO (inverted signal VIN) falls rapidly. (See waveform W19).

  Next, at time T14, the control unit 13 sets the drive signal G1 to the L state (see the waveform W13) and sets the drive signal G2 to the H state (see the waveform W14). That is, the control signal generation unit 140 of the control unit 13 sets the signal S1 to the L state, sets the drive signal G1 to the L state via the driver 41, and sets the signal S2 to the H state, and via the driver 42. , And sets the drive signal G2 to the H state. In addition, when the drive signal G2 is in the H state, the switching determination unit 133 outputs the L state to the signal SEL (see the waveform W16). Thus, the selection output unit 134 outputs the positive phase signal VIP output from the buffer unit 131 to the signal SELO (see the waveform W17). As a result, the adding unit 135 outputs a signal VICON obtained by adding the signal SLOP and the signal SELO (positive phase signal VIP) to the comparator 136 (see the waveform W19).

  On the other hand, at time T14, the control signal generation unit 140 sets the signal S3 to the H state (see the waveform W21). As a result, the RS flip flop 137 is set, and the control unit 13 sets the drive signal G3 to the H state (see the waveform W22).

  Next, when the voltage of the signal VICON increases and reaches the control voltage Ver at time T15 (see the waveform W19), the comparator 136 outputs the H state (see the waveform W20). As a result, the RS flip flop 137 is reset, and the control unit 13 sets the drive signal G3 to the L state (see the waveform W22).

  Next, at time T16, the signal SLOP switches from rising to falling (see the waveform W18), whereby the signal VICON obtained by the addition unit 135 adding the signal SLOP and the signal SELO (positive phase signal VIP) sharply It descends (see waveform W19).

Next, at time T17, the control unit 13 sets the drive signal G1 to the H state (see the waveform W13) and sets the drive signal G2 to the L state (see the waveform W14) as in the above-described time T11.
The subsequent operations of times T17 to T23 and times T23 to T29 are the same as the operations of times T11 to T17 described above, and thus the description thereof is omitted here.

As described above, even when a regenerative current is generated as shown by the waveform W11 at the time of light load, the DC / DC converter 10 of the present embodiment can perform current mode control by PWM.
As shown in FIG. 5 described above, the controller 13 controls the primary current (corresponding to the positive phase signal VIP) and the reverse current at the rising or falling timing of the primary current Ict (corresponding to the voltage Vict). (Corresponding to the inverted signal VIN) to generate a control waveform (waveform of the signal VICON).

Next, current mode control under normal load in the control unit 13 according to the present embodiment will be described.
Here, the normal load state is a state in which the load is larger than the light load state, and the regenerative current is not generated as in the light load state.

  Since the load is large at the time of normal load, a point at which a regenerative current is not generated in the output current Io is different from that at the time of light load described above. Therefore, although the waveforms of the signal Vict, the signal SELO, and the signal VICON are different from those in the normal load shown in FIG. 5, the operation of the control unit 13 is the same as that in the normal load shown in FIG. That is, the current mode control operation of control unit 13 at the time of normal load is the same as the operation at time T11 to T29 shown in FIG. 5 described above, although the waveforms of signal Vict, signal SELO and signal VICON are different.

  As described above, the control unit 13 according to the present embodiment can implement current mode control by the same control method without the need to change the control method between light load and normal load.

  As described above, the control unit 13 according to the present embodiment executes current mode control by the same control method at light load and normal load, but at light load and normal load. Different control methods may be switched and executed depending on the control method. However, in this case, the control unit 13 executes current mode control according to the control method shown in FIG. 5 at least at light load. That is, the control unit 13 generates a control waveform (VICON) based on the primary side current or the reverse current at least at light load. Then, the control unit 13 controls on / off of the switching elements (Q1 to Q4) by the current mode control method based on the generated control waveform (VICON).

Next, three-phase current mode control according to the present embodiment will be described with reference to FIG.
FIG. 6 is a time chart showing an example of three-phase current mode control according to the present embodiment.
In this figure, each signal shows the input signal (VICON, Ver) of the comparator 136 for three phases and the drive signal G4 (U phase, V phase, W phase) sequentially from the top. A waveform W50 indicates the waveform of the control voltage Ver, and a waveform W51 indicates the waveform of the U-phase signal VICON (the signal VICON of the DC / DC converter 10-1). A waveform W52 shows a waveform of a V-phase signal VICON (signal VICON of the DC / DC converter 10-2), and a waveform W53 shows a W-phase signal VICON (signal VICON of the DC / DC converter 10-3). The waveform is shown. A waveform W54 indicates a U-phase drive signal G4 (U), a waveform W55 indicates a V-phase drive signal G4 (V), and a waveform W56 indicates a W-phase drive signal G4 (W). There is.

Also, in this figure, the horizontal axis shows time, the vertical axis shows the voltage of the input signal (VICON, Ver), and the other signals show logic levels.
Note that although the example shown in this figure describes an example of the drive signal G4 for the sake of explanation, basically the same applies to the drive signal G3, and the description thereof is omitted here.

At time T51, control signal generation unit 140 of each DC / DC converter 10 sets signal S4 to the H state for a predetermined period. As a result, each RS flip flop 138 outputs the H state, and each driver 44 outputs each drive signal G4 (drive signal G4 (U), drive signal G4 (V), and so on) as shown by waveforms W54 to W56. The drive signal G4 (W) is set to the H state.
As a result, the switching element Q4 of each DC / DC converter 10 is turned ON, and each signal VICON rises as shown by the waveforms W51 to W53. Here, since the phases of the three-phase alternating current are different in the U phase, the V phase, and the W phase, the rising waveforms of the respective signals VICON are different. Here, the voltage values of the control voltage Ver are equal and the same voltage value in each DC / DC converter 10 as shown by the waveform W50.

  Next, at time T52, when the voltage value of the U-phase signal VICON reaches the control voltage Ver, the U-phase comparator 136 outputs the H state, and the driver 44 outputs a drive signal as shown by the waveform W54. Set G4 (U) to the L state. Thereby, the switching element Q4 of the U-phase DC / DC converter 10-1 is turned off by the current mode control.

  Also, at time T53, when the voltage value of V-phase signal VICON reaches control voltage Ver, V-phase comparator 136 outputs an H state, and driver 44 produces drive signal G4, as shown by waveform W55. Set (V) to the L state. Thus, the switching element Q4 of the V-phase DC / DC converter 10-2 is turned off by the current mode control.

  Also, at time T54, when the voltage value of the W-phase signal VICON reaches the control voltage Ver, the W-phase comparator 136 outputs the H state, and the driver 44 outputs the drive signal G4, as shown by the waveform W56. Set (W) to L state. Thus, the switching element Q4 of the W-phase DC / DC converter 10-3 is turned off by the current mode control.

  Thus, in the case of three-phase current mode control according to the present embodiment, the DC / DC converters 10 (10-1, 10-2, 10-3) have current peak values of control waveforms of the respective DC / DC converters 10. (Here, the peak values of the signal VICON correspond to each other) are controlled to match. That is, in the DC / DC converter 10 (10-1, 10-2, 10-3), the switching element Q3 and the switching element are arranged such that the current peak values of the current waveform flowing through the primary coil TL11 coincide in three phases. Control Q4 in current mode. In other words, DC / DC converters 10 (10-1, 10-2, 10-3) are current peak values of all control waveforms in DC / DC converter 10 (10-1, 10-2, 10-3). Control to match.

  In the example of the above-described embodiment, the three-phase DC / DC converter 10 includes the control unit 13. However, in the present embodiment, the control unit 13 is partially shared. It is possible to control the phases collectively. Here, with reference to FIG. 8, an example in the case of collectively controlling three phases according to the present embodiment will be described.

FIG. 7 is a block diagram showing an example of three-phase collective control according to the present embodiment.
The control unit 13a shown in this figure includes a control signal generation unit 140, control waveform generation units (130-1, 130-2, 130-3), and comparators (136-1, 136-2, 136-3). , RS flip-flops (138-1, 138-2, 138-3).
In the example shown in this figure, the drive signal G4 for driving the switching element Q4 of each DC / DC converter 10 is described, and the other parts are omitted.

  The control signal generation unit 140 shares processing with the three-phase DC / DC converter 10, and generates the generated signal S1, signal S2, signal S4, signal SLOP, and signal Ver into the three-phase DC / DC converter 10. Supply. Also, the signal Vict (U), the signal Vict (V), and the signal Vict (W) are the signal Vict detected in each of the three-phase DC / DC converters 10.

  Further, in the control waveform generation units (130-1, 130-2, and 130-3), each of the DC / DC converters 10 includes the signal S1, the signal S2, and the signal SLOP generated collectively by the control signal generation unit 140. The signal VICON of each phase is generated based on the detected signal Vict (U), the signal Vict (V), and the signal Vict (W). The configuration of each of the control waveform generation units (130-1, 130-2, 130-3) is the same as that of the control waveform generation unit 130 described above.

  The comparators (136-1, 136-2, and 136-3) control voltage generation unit (130-1, 130- 2, and 130-3) compare the signal VICON of each phase generated. The configuration of each of the comparators (136-1, 136-2, 136-3) is the same as the comparator 136 described above.

  The configuration of each of the RS flip flops (138-1, 138-2, 138-3) is the same as the RS flip flop 138 described above. The RS flip flop 138-1 outputs the U phase drive signal G4 (U) through the driver 44-1, and the RS flip flop 138-2 outputs the V phase drive signal through the driver 44-2. Output G4 (V). Also, the RS flip flop 138-3 outputs the W phase drive signal G4 (W) through the driver 44-3.

The configuration of each of the drivers (44-1, 44-2, 44-3) is the same as that of the driver 44 described above.
Further, in the example shown in FIG. 8, the drive signal G3 for driving the switching element Q3 of the DC / DC converter 10 is omitted for the sake of description, but the drive signal G3 is also similar to the drive signal G4.

  As described above, in the present embodiment, as in the control signal generation unit 140 described above, the configuration of the control unit 13 can be simplified by sharing control signals in the plurality of DC / DC converters 10.

  As described above, the power supply device 1 according to the present embodiment includes the DC / DC converter 10. The DC / DC converter 10 includes a full bridge circuit 20 (bridge circuit), a transformer TL1, a synchronous rectification circuit 30, and a control unit 13. The full bridge circuit 20 has switching elements (Q1 to Q4). The transformer TL1 has a primary coil TL11 to which the full bridge circuit 20 is directly or indirectly connected, and a secondary coil (TL12, TL13) insulated from the primary coil TL11. The synchronous rectification circuit 30 is connected to the secondary side coils (TL12, TL13), and the control unit 13 controls on / off of the switching elements (Q1 to Q4) of the full bridge circuit 20 by a current mode control method. Furthermore, the control unit 13 switches to the primary side current (for example, the positive phase signal VIP) when the voltage of the primary side coil TL11 changes from negative to positive, and when the voltage of the primary side coil TL11 changes from positive to negative. The primary side current is switched to the inverted current (for example, the inversion signal VIN), and a control waveform (for example, the signal VICON) is generated based on the primary side current and the inversion current. Then, the control unit 13 controls on / off of the switching elements (Q1 to Q4) by the current mode control method based on the generated control waveform.

As a result, the power supply device 1 according to the present embodiment switches the primary side current and the inversion current to generate a control waveform (for example, the signal VICON), so that a control waveform suitable for current mode control can be generated. it can. Therefore, the power supply device 1 according to the present embodiment can easily perform control of the current mode control method even when, for example, a regenerative current is generated on the primary side. Therefore, the power supply device 1 according to the present embodiment can improve the conversion efficiency of the power supply and can perform current mode control at the time of light load when performing synchronous rectification on the secondary side.
Further, the power supply device 1 according to the present embodiment can improve the conversion efficiency of the power supply and can improve the response of the switching elements (Q1 to Q4) since the balance of each phase current can be improved.

Further, in the present embodiment, the control unit 13 generates a control waveform based on the primary side current or the reverse current at least at light load.
Thus, the power supply device 1 according to the present embodiment executes a control method of generating a control waveform based on the primary current or the reverse current at least at light load, for example, at light load (except for normal load), for example. It becomes possible to appropriately use in combination with other control methods with good conversion efficiency and response speed. Therefore, the power supply device 1 according to the present embodiment can perform current mode control at light load while further improving the conversion efficiency and the reaction speed of the power supply.

Further, in the present embodiment, the control unit 13 alternately switches the primary side current and the inversion current each time the switching elements (Q1 to Q4) are switched to generate a control waveform.
As a result, the power supply device 1 according to the present embodiment can switch between the primary current and the reversal current by more simple means, and can appropriately generate a control waveform for current mode control.

Further, in the present embodiment, the control unit 13 switches the primary current and the inversion current at the rise or fall timing of the primary current to generate a control waveform.
As a result, the power supply device 1 according to the present embodiment can switch between the primary current and the reversal current by more simple means, and can appropriately generate a control waveform for current mode control.

Further, in the present embodiment, the full bridge circuit 20 includes the switching element Q1 (first switching element), the switching element Q2 (second switching element), the switching element Q3 (third switching element), and the switching element Q4. (The fourth switching element), and the four switching elements (Q1 to Q4) are bridge-connected. The control unit 13 controls the switching element Q1 and the switching element Q2 connected to the first end of the primary coil TL11 of the transformer TL1 with a predetermined fixed duty, and is connected to the second end of the primary coil TL11. The switching element Q3 and the switching element Q4 are controlled by PWM (pulse width modulation) in a current mode control system.
Thus, since the power supply device 1 according to the present embodiment is controlled by PWM (pulse width modulation), current mode control can be performed with a simpler configuration.

Further, the power supply device 1 according to the present embodiment includes a plurality of (for example, three) DC / DC converters 10, and in the plurality of DC / DC converters 10, the current peak values of the control waveforms of the respective DC / DC converters 10 coincide. Control to do so. That is, the plurality of DC / DC converters 10 are controlled such that the current peak values of all the control waveforms in the plurality of DC / DC converters 10 coincide with each other.
As a result, the power supply device 1 according to the present embodiment performs current mode control such that all current peak values match even when AC power of multiple phases is input, so that the balance of each phase current can be reduced. Since it can be taken out, the conversion efficiency of the power supply can be easily improved.

Further, in the present embodiment, the DC / DC converter 10 includes the series reactor L1 connected in series with the primary coil TL11.
Thereby, the power supply device 1 according to the present embodiment can perform the ZVS operation on the switching elements Q1 to Q6 by the resonance of the series reactor L1, the parasitic capacitances (C1 to C4, C6, C7), and the wiring capacitance. By this, since the power supply device 1 according to the present embodiment can reduce the switching loss, it is possible to further improve the conversion efficiency of the power supply.

The power supply control method according to the present embodiment is the power supply control method of the power supply device 1 including the DC / DC converter 10 described above, and at a timing when the control unit 13 changes the voltage of the primary coil TL11 from negative to positive. Switch to the primary side current, switch to the reverse current which reversed the primary side current at the timing when the voltage of the primary side coil TL11 becomes positive to negative, generate a control waveform based on the primary side current and the reverse current, and generate Based on the said control waveform, ON / OFF of a switching element (Q1-Q4) is controlled by a current mode control system.
Thus, the power supply control method according to the present embodiment can improve the conversion efficiency of the power supply, and can perform current mode control at light load when the secondary side is synchronously rectified.

In addition, this invention is not limited to said each embodiment, It can change in the range which does not deviate from the meaning of this invention.
For example, although the configurations of the power supply device 1 shown in FIG. 1 and the DC / DC converter 10 shown in FIG. 2 have been described as an example of the present embodiment, the present invention is not limited to these. For example, the power supply device 1 may be configured to be compatible with a multi-phase AC power supply including three or more DC / DC converters 10, or may be configured not to include the PFC unit 2.
In addition, the DC / DC converter 10 may not include a part or all of the series reactor L1, the resonance capacitor C5, and the diodes (D5, D6).

Moreover, although the transformer TL1 demonstrated the example provided with the secondary side coil (TL12, TL13) with a center tap, you may not have a center tap.
In addition, although the synchronous rectification circuit 30 has been described as an example in which both wave rectification circuits are used, the present invention is not limited to this and may be a full wave rectification circuit such as a full bridge.
Further, in the above embodiment, although the example in which the DC / DC converter 10 includes the full bridge circuit 20 has been described, a half bridge circuit may be provided instead of the full bridge circuit 20.

In the above embodiment, the control unit 13 controls the switching element Q1 and the switching element Q2 with a fixed duty of 50%. However, the present invention is not limited to this. You may do it.
Further, in the above embodiment, although the example in which the switching determination unit 133 switches the positive phase signal VIP and the inversion signal VIN at the rising timing of the drive signal G1 and the drive signal G2 has been described, the present invention is limited thereto. It is not a thing. For example, switching may be performed between the period of the H state (period TRA) of the carrier signal and the period of the L state (period TRB), and the rising period and falling period of the primary side current Ict (corresponding to the voltage Vict). You may switch between

  In the above embodiment, the control unit 13 generates the drive signal G5 as the inverted signal of the drive signal G1 and generates the drive signal G6 as the inverted signal of the drive signal G2. It is not a thing. For example, the control unit 13 may generate the drive signal G5 as an inverted signal of the drive signal G4, and generate the drive signal G6 as an inverted signal of the drive signal G3.

In the above embodiment, the switching element Q1 and the switching element Q2 are described as the first switching element and the second switching element, but the switching element Q3 and the switching element Q4 are described as the first switching element and the second switching It may be an element. Although the switching element Q3 and the switching element Q4 have been described as the third switching element and the fourth switching element, the switching element Q1 and the switching element Q2 may be replaced by the third switching element and the fourth switching element.
Although the control signal generation unit 140 has described the example of generating the control voltage Ver based on PID control, the control voltage Ver may be generated by another control method.

The control unit 13 described above is not limited to the circuit configuration shown in FIG. 3 and may be realized by another circuit configuration. For example, in the comparator 136 (136-1, 136-2, 136-3), an example is described in which the-input terminal is connected to the signal line of the control voltage Ver and the + input terminal is connected to the signal line of the signal VICON However, the − input terminal may be connected to the signal line of the signal VICON, and the + input terminal may be connected to the signal line of the control voltage Ver. Also, in this case, a negative logic reset RS flip flop in which the R terminal is reset in the L state is applied to the RS flip flop 137 and the RS flip flops 138 (138-1, 138-2, 138-3).
Further, in the above embodiment, the processing of each part of the control unit 13 (13a) may be realized by dedicated hardware such as an IC (Integrated Circuit) or may be realized by software processing.

  The above-described power supply device 1 internally includes a computer system. The process of the control unit 13 (13a) described above is stored in a computer readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory or the like. Alternatively, the computer program may be distributed to a computer through a communication line, and the computer that has received the distribution may execute the program.

DESCRIPTION OF SYMBOLS 1 power supply device 2, 2-1, 2-2, 2-3 PFC part 10, 10-1, 10-2, 10-3 DC / DC converter 11 electric current detection part 12 voltage detection part 13, 13a control part 20 full Bridge circuit 30 Synchronous rectification circuit 40 Driver section 41, 42, 43, 44, 44-1, 44-2, 44-3, 45, 46 Driver 130, 130-1, 130-2, 130-3 Control waveform generation section 131 buffer unit 132 inversion unit 133 switching determination unit 134 selection output unit 135 addition unit 136, 136-1, 136-2, 136-3 comparator 137, 138, 138-1, 138-2, 138-3 RS flip flop 140 Control signal generator C1, C2, C3, C4, C6, C7 Parasitic capacitance C5 Resonant capacitor Ci, Co Smoothing capacitor D1, D2, D , D4, D7, D8 body diode D5, D6 diode L1 series reactor L2 choke coil Q1, Q2, Q3, Q4, Q5, Q6 switching element TL1 transformer TL11 primary coil TL12, TL13 secondary coil RL load

Claims (7)

A power supply device comprising a DC / DC converter, comprising:
The DC / DC converter is
A bridge circuit having a switching element;
A transformer having a primary coil to which the bridge circuit is directly or indirectly connected, and a secondary coil insulated from the primary coil;
A synchronous rectifier circuit connected to the secondary coil;
A control unit that controls on / off of a switching element of the bridge circuit by a current mode control method;
A current detection unit that detects a current flowing through the primary coil;
The switching element includes a switching element on a first end side connected to a first end of the primary coil of the transformer, and a second end side connected to a second end of the primary coil of the transformer. And switching elements,
The control unit
Primary side current which is a current flowing through the primary side coil detected by the current detection unit at a timing when the voltage of the primary side coil determined from the state of the switching element on the first end side changes from negative to positive The control waveform is generated by switching to the inversion current obtained by inverting the primary side current at the timing when the voltage of the primary side coil becomes positive to negative as determined by the state of the switching element on the first end side. The switching element on the second end side is turned on at the switching timing of the primary side current and the reverse current based on the control waveform, and the switching element is turned on at the timing when the control waveform reaches a predetermined value. A power supply characterized by controlling on / off of the switching element on the second end side by the current mode control method so as to turn off. apparatus. The power supply device according to claim 1, wherein the control unit switches the primary current and the inversion current at least at light load to generate the control waveform. The control unit
The primary side current and the reverse current are alternately switched each time the switching element on the first end side is switched to generate the control waveform. Power supply. The control unit
The control waveform is generated by switching between the primary side current and the inversion current at the timing of the start of the rise of the primary side current or the start of the fall of the primary side current. The power supply device according to any one of the above. It said bridge circuit includes a first switching element and second switching element is a switching element of the first end side, and a third switching element 及 beauty fourth switching element is a switching element of the second end side Having the four switching elements in a bridge connection,
The control unit
The first switching element and the second switching element connected to the first end of the primary coil of the transformer are controlled by a predetermined fixed duty and connected to the second end of the primary coil. The power supply device according to any one of claims 1 to 4, wherein the third switching element and the fourth switching element are controlled by pulse width modulation in a current mode control system. A plurality of the DC / DC converters,
The plurality of DC / DC converters are controlled such that the current peak values of all the control waveforms in the plurality of DC / DC converters coincide with each other. Power supply as described in. It is a power supply control method of a power supply apparatus provided with a DC / DC converter, comprising:
The DC / DC converter is
A bridge circuit having a switching element;
A transformer having a primary coil to which the bridge circuit is directly or indirectly connected, and a secondary coil insulated from the primary coil;
A synchronous rectifier circuit connected to the secondary coil;
A control unit that controls on / off of a switching element of the bridge circuit by a current mode control method;
A current detection unit that detects a current flowing through the primary coil;
The switching element includes a switching element on a first end side connected to a first end of the primary coil of the transformer, and a second end side connected to a second end of the primary coil of the transformer. And switching elements,
The control unit
Primary side current which is a current flowing through the primary side coil detected by the current detection unit at a timing when the voltage of the primary side coil determined from the state of the switching element on the first end side changes from negative to positive The control waveform is generated by switching to the inversion current obtained by inverting the primary side current at the timing when the voltage of the primary side coil becomes positive to negative as determined by the state of the switching element on the first end side. The switching element on the second end side is turned on at the switching timing of the primary side current and the reverse current based on the control waveform, and the switching element is turned on at the timing when the control waveform reaches a predetermined value. A power supply characterized by controlling on / off of the switching element on the second end side by the current mode control method so as to turn off. Control method.

Images