JP4838008B2 - Power supply device and control method thereof - Google Patents

Description

  The present invention relates to a power supply device used in a battery charge / discharge device and a control method thereof.

Conventionally, in the evaluation of a secondary battery used in a hybrid vehicle or the like, functions such as high-speed charge / discharge and alternating current superposition to the battery are required. In such a test apparatus for evaluating a secondary battery, it is necessary to improve response characteristics, and various power supply apparatuses are considered.
A general power supply device has a charging period in which a three-phase alternating current is charged to a secondary battery, and a discharging period in which the secondary battery returns to a three-phase alternating current. FIG. 5 shows a chopper control circuit of a general power supply apparatus. The chopper control circuit 500 compares the monitor voltage 501 of the secondary battery with the reference voltage 116 by the control amplifier 115 and outputs the output voltage Aout. The triangular wave generation control unit 117 outputs a triangular wave Ta during charging and a triangular wave Tb2 during discharging, and compares the output voltage Aout with an operational amplifier 118 that outputs a charging chopper signal and an operational amplifier 119 that outputs a discharging chopper signal. Then, the charging chopper signal Sa and the discharging chopper signal Sb2 are output to the charging / discharging step-up / down chopper circuit.

  When charging the secondary battery with the power output from the three-phase AC regenerative converter, the regenerative power is down-converted to a voltage suitable for charging the secondary battery using the charging chopper signal Sa, and the secondary battery is recharged. Charge the battery. Conversely, when discharging from the secondary battery to the three-phase AC regenerative converter, the voltage of the secondary battery is up-converted (boosted) to the voltage of the AC regenerative converter using the discharge chopper signal Sb2.

FIG. 6 shows operation waveforms of such a conventional chopper control circuit 500. FIG. 6A shows the relationship between the voltage waveform of the charging triangular wave and the voltage waveform of the discharging triangular wave with the output voltage Aout of the control amplifier 115 as the center.
The charging chopper signal Sa is in a conductive state during a period when the voltage of the charging triangular wave Ta is lower than the output voltage Aout of the control amplifier 115. For example, since the voltage of the charging triangular wave Ta is lower than the output voltage Aout of the control amplifier 115 during the period indicated by the dotted line 201 and the dotted line 202, the charging chopper signal Sa for switching the step-down chopper circuit when charging the secondary battery. Is turned on (high level).

  Conversely, the discharging chopper signal Sb2 for switching the boosting chopper circuit when discharging from the secondary battery is in a conductive state during a period in which the voltage of the discharging triangular wave Tb2 is higher than the output voltage Aout of the control amplifier 115. For example, during the period indicated by the dotted line 203 and the dotted line 204, the voltage of the discharge triangular wave Tb2 is higher than the output voltage Aout of the control amplifier 115, so Sb2 is in the on state (high level). Va represents the offset voltage of the charging triangular wave Ta, and Vb2 represents the offset voltage of the discharging triangular wave Tb2.

  In the first half of the charging period in which the charging chopper signal Sa is turned on, the charging triangular wave Ta and the output voltage Aout of the control amplifier 115 greatly cross each other, and the charging chopper signal Sa has a long on period. As the output voltage Aout of the control amplifier 115 gradually decreases, the ON period of the charging chopper signal Sa becomes shorter, and the OFF state continues. Thereafter, an off period in which the pulse 205 of the charging chopper signal Sa and the pulse 206 of the discharging chopper signal Sb2 are not output occurs in the portion of the dashed-dotted line circle 601. This is because the operational amplifiers 118 and 119 cannot follow the on / off change because they operate in the saturation region.

  Thereafter, the pulse width of the discharge chopper signal Sb2 is gradually widened and outputted, and the second half of the discharge period starts. At the beginning of the discharge period, the cross period of the discharge triangular wave Tb2 and the output voltage Aout of the control amplifier 115 is small, and the on period of the discharge chopper signal Sb2 is short. As the output voltage Aout of the control amplifier 115 further decreases, the ON period of the discharge chopper signal Sb2 becomes longer.

  After that, contrary to the above, the output voltage Aout of the control amplifier 115 gradually increases, the ON period of the discharge chopper signal Sb2 is gradually shortened to enter the OFF state, and the discharge period ends. Further, when the discharging period ends, the charging period starts, the ON period of the charging chopper signal Sa becomes gradually longer, and the output voltage Aout of the control amplifier 115 returns to the initial state on the left side of FIG. Thereafter, such PWM operation is repeated, and charging and discharging are alternately performed between the AC regenerative converter and the secondary battery.

As described above, in the conventional charging / discharging operation, charging and discharging are alternately performed in sequence. That is, after the charging operation is stopped, the discharging operation is performed, and after the discharging operation is stopped, the charging operation is performed again.
Further, as a conventional technology for a converter that performs step-up and step-down, a step-up / step-down chopper circuit is described in “Semiconductor power converter” of Patent Document 1.
JP 2000-156971 A

In the prior art, as shown in FIG. 6, the charging operation and the discharging operation are alternately performed. On the other hand, the operational amplifiers 118 and 119 for comparing the output voltage Aout of the control amplifier 115 with the triangular wave for charging / discharging outputs the charging / discharging chopper signals Sa and Sb2 when the output is saturated to either plus or minus. It was like that.
Therefore, for example, when the output of the operational amplifier 118 that generates a pulse for turning on the charging chopper signal Sa changes from plus to minus, or when it changes from minus to plus, it takes time to shift from the saturated state to the feedback region. . That is, it takes time until the charging operation is performed after the discharging operation is stopped, or until the discharging operation is performed after the charging operation is stopped, as shown by a one-dot chain line 601 in FIG. There is an off period in which the pulse 205 of the chopper signal Sa and the pulse 206 of the discharging chopper signal Sb2 are not output. As a result, there is a problem that the current during charging / discharging cannot be continuously transferred, and the charging / discharging waveform is distorted during the switching period of charging / discharging.

Moreover, since the technique described in Patent Document 1 shares the current smoothing reactor of the boost converter and the step-down converter, there is a problem that the boost and the step-down cannot be operated simultaneously.
In view of the above problems, an object of the present invention is to improve a response characteristic in a power supply device used for a battery charging / discharging device, and smoothly shift a charging / discharging sequence without interrupting a discharging operation and a charging operation. An object of the present invention is to provide a power supply apparatus and a control method thereof.

A power supply device according to claim 1 includes a regenerative converter, a secondary battery, a step-down converter that steps down the output of the regenerative converter by a charging switch means and charges the secondary battery, and outputs the secondary battery. A boost converter that boosts the voltage by a discharge switch and discharges it to the regenerative converter; and a control that always operates the charge switch and the discharge switch to overlap each other.

And , when charging and discharging a predetermined current between the regenerative converter and the secondary battery, the control means is configured such that the step-down converter including the charging switch means causes a charging current to flow, and the discharging switch means A discharge current is caused to flow from the step-up converter, and the difference between the charging current and the discharging current is controlled to be equal to the predetermined current.

The control method of the power supply device according to claim 2 includes a regenerative converter, a secondary battery, a step-down converter that charges the secondary battery by stepping down the output of the regenerative converter by a charging switch means, and the secondary battery. outputting a boost converter which boosts the discharge switch means discharging to the regenerative converter of a control method of a power supply device and a control means for driving and said charge switch means and said discharge switch means, the regeneration When charging / discharging a predetermined current between the converter and the secondary battery, the control means always overlaps the switching operation of the charging switch means and the discharging switch means.

The control means is configured such that the step-down converter comprising the charging switch means causes a charging current to flow, and the discharging current is caused to flow from the step-up converter comprising the discharging switch means. The difference between the charging current and the discharging current The current is controlled to be equal to the current.

  Thus, in this invention, in the power supply device which charges / discharges between a regenerative converter and a secondary battery, discharge operation and charging operation can be performed continuously without interruption. As a result, a smooth charge / discharge current without distortion can be obtained.

(First embodiment)
A first embodiment of a power supply device and a control method thereof according to the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a power supply apparatus 101, where 102 is a three-phase AC power source, 103 is a secondary battery, 104 is an AC regenerative converter, 105 is a switch for charging with a MOSFET, 106 is a choke coil, 107 is a diode, and 108 is a capacitor. 109 and 110 are terminals, 111 is a discharging switch by MOSFET, 112 is a choke coil, 113 is a diode, and 114 is a current probe. In addition, since 115 thru | or 119 are the same as FIG. 5, description is abbreviate | omitted.

  The electric power input from the three-phase AC power source 102 is converted into DC via the AC regenerative converter 104 and output to the secondary battery side. First, the operation when charging the secondary battery 103 will be described. The direct current output from the AC regenerative converter 104 is switched by the charging switch 105, stepped down by a step-down chopper circuit composed of a diode 107, a choke coil 106 and a capacitor 108, and connected to terminals 109 and 110. 103 is charged.

  Next, the operation when discharging from the secondary battery 103 to the three-phase AC power source 102 will be described. The direct current output from the secondary battery 103 is boosted by a boost chopper circuit including a capacitor 108, a choke coil 112, and a diode 113 and output to the AC regenerative converter 104. The AC regenerative converter 104 converts the boosted DC into a three-phase AC and outputs it to the three-phase AC power source 102. As described above, the power supply circuit according to the present invention is provided with the step-down circuit during charging and the step-up circuit during discharging.

  Next, a chopper control circuit that controls the charging switch 105 and the discharging switch 111 will be described. The chopper control circuit includes a control amplifier 115 that outputs a differential voltage between the voltage of the sensor 114 that detects and monitors the charge / discharge current to the secondary battery 103 and the voltage of the reference voltage 116, the charging triangular wave Ta, and the discharging voltage. A triangular wave generation control unit 117 that generates a triangular wave Tb1 in a preset sequence, and a charging chopper signal Sa that turns on and off the charging switch 105 by comparing the output voltage Aout of the control amplifier 115 and the charging triangular wave Ta are generated. And an operational amplifier 119 that compares the output voltage Aout of the control amplifier 115 and the discharge triangular wave Tb1 to generate the discharge chopper signal Sb1 for turning on and off the discharge switch 111. This configuration itself is the same as the chopper control circuit 500 described in the prior art of FIG.

  Next, operation waveforms during charging / discharging of the power supply apparatus 101 of FIG. 1 will be described. FIG. 2A shows an output voltage Aout of the control amplifier 115 and voltage waveforms of the charging triangular wave Ta and the discharging triangular wave Tb1. FIG. 2B is a diagram depicting the charging chopper signal Sa and the discharging chopper signal Sb1 on the same time axis as the output waveforms Ta and Tb1 of the triangular wave generation control unit 117 of FIG.

  Here, Va in FIG. 2A indicates the offset voltage of the charging triangular wave Ta, Vb1 indicates the offset voltage of the discharging triangular wave Tb1, and for example, the charging triangular wave Ta is the circuit shown in FIG. 2C. appear. The output of the integrating circuit composed of the operational amplifier 251, the capacitor 253, and the resistor 254 is input to the comparator 252 and compared with the offset voltage Va. The rectangular wave output of the comparator 252 is input to the resistor 254 constituting the integrating circuit, and the charging triangular wave Ta charged / discharged by the integrating circuit is output. Similarly, the discharge triangular wave Tb1 can be generated by setting the offset voltage Va of the comparator 252 to Vb1.

  2A and 2B, the charging chopper signal Sa is in a conductive state during a period in which the voltage of the charging triangular wave Ta is lower than the output voltage Aout of the control amplifier 115, as in FIG. For example, during the period indicated by the dotted line 201 and the dotted line 202, the voltage of the charging triangular wave Ta is lower than the output voltage Aout of the control amplifier 115, so Sa is turned on (high level).

On the contrary, the discharge chopper signal Sb1 becomes conductive in a period in which the voltage of the discharge triangular wave Tb1 is higher than the output voltage Aout of the control amplifier 115. For example, during the period indicated by the dotted line 203 and the dotted line 204, the voltage of the discharge triangular wave Tb1 is higher than the output voltage Aout of the control amplifier 115, so Sb1 is in the on state (high level).
In the first half of the charging period when the charging chopper signal Sa is turned on, the charging triangular wave Ta and the output voltage Aout of the control amplifier 115 greatly cross each other, and the charging chopper signal Sa has a long on period. As the output voltage Aout of the control amplifier 115 gradually decreases, the ON period of the charging chopper signal Sa becomes shorter, and the OFF state continues for a while.

  However, in the portion indicated by the one-dot chain line circle 207 in FIG. 2B, the discharging chopper signal Sb1 is turned on before the charging chopper signal Sa is turned off. This is because the offset voltage Vb1 of the discharge triangular wave Tb1 is higher than the offset voltage Vb2 of the conventional discharge triangular wave Tb2 of FIG. Thus, before the charging chopper signal Sa is turned off, the on state of the discharging chopper signal Sb1 is started, and the charging operation and the discharging operation overlap at a portion indicated by a one-dot chain line circle 207, When switching from the charging operation to the discharging operation or from the discharging operation to the charging operation, there is no period during which charging / discharging is not performed, and distortion generated in the charging / discharging waveform can be reduced. Even if a problem due to the saturation operation of the operational amplifiers 118 and 119, that is, the pulse 205 in which the charging chopper signal Sa is not output or the pulse 206 in which the discharging chopper signal Sb1 is not output occurs as in the prior art of FIG. The discharge operation is performed continuously without interruption.

  In addition, it is difficult to realize such overlapping of the charging operation and the discharging operation with a conventional power supply circuit in which the charging circuit and the discharging circuit are combined, but the power supply circuit 101 according to the present invention is Since two systems of the charging circuit including the charging switch 105 and the discharging circuit including the discharging switch 111 are provided, the charging operation and the discharging operation can be overlapped.

  Here, the simulation waveform at the time of charging / discharging by the conventional technology and the simulation waveform at the time of charging / discharging by the power supply circuit 101 of this embodiment are compared. FIG. 3A is a waveform in the case of the prior art, and 301 indicates a charge / discharge command value. When swinging to the plus side, the charging operation is performed, and when swinging to the minus side, the discharging operation is performed. 302 is a charging / discharging waveform slightly delayed from the command value 301, and the charging / discharging waveform is distorted in the dotted circle 303 at the switching portion from the discharging operation to the charging operation and the dotted circle 304 at the switching portion from the charging operation to the discharging operation. You can see that

On the other hand, in the charge / discharge waveform according to the present embodiment of FIG. 3B, the charge / discharge command value 305 and the charge / discharge waveform 306 slightly delayed from the command value 305 have substantially the same shape. There is no distortion in the charging / discharging waveform at the switching portion from the discharging operation to the discharging operation and at the switching portion from the discharging operation to the charging operation.
Thus, by operating the discharge operation and the charge operation in an overlapping manner, the charge / discharge current operates continuously without interruption, and a distortion / discharge waveform without distortion can be realized.

(Second Embodiment)
A second embodiment of the power supply apparatus and control method thereof according to the present invention will be described with reference to FIG. FIG. 4 differs from the power supply device 101 of the first embodiment in the method of generating the charging chopper signal Sa3 and the discharging chopper signal Sb3. Unlike the prior art of FIG. 6 and the first embodiment of FIG. 2, the charging chopper signal Sa3 and the discharging chopper signal Sb3 of the present embodiment are not continuously turned off, and are always In this state, a short charging chopper signal Sa3 and a discharging chopper signal Sb3 are output. That is, the charging operation and the discharging operation are always performed in parallel.

  A circuit diagram of the chopper control circuit 403 that realizes such an operation is shown in FIG. A clipper circuit 404 is provided between the output voltage Aout of the control amplifier 115 and the operational amplifiers 118 and 119. As shown in FIG. 4A, the clipper circuit 404 clips the lower voltage of the output voltage Aout so that the output voltage Aout1 does not become the predetermined voltage Vc1 or less, and outputs it to the charging operational amplifier 118. The output voltage Aout is clipped so that the output voltage Aout2 does not exceed the predetermined voltage Vc2, and is output to the discharge operational amplifier 119. The clipper circuit 404 that clips the voltage can be realized by a simple circuit that cuts a predetermined voltage or more with a Zener diode, for example. On the contrary, when the voltage below a certain voltage is cut, it is possible to invert with an inverting amplifier.

In this way, by inputting the charging triangular wave Ta of the triangular wave generation control unit 117 and the output voltage Aout1 of the clipper circuit 404 to the operational amplifier 118, the charging chopper signal Sa3 output from the operational amplifier 118 is one point in FIG. As indicated by a chain line circle 401, the battery is not continuously turned off, and a weak charging operation is always performed.
Similarly, by inputting the charging triangular wave Tb2 and the output voltage Aout2 of the clipper circuit to the operational amplifier 119, the discharging chopper signal Sb3 output from the operational amplifier 119 is as shown by a one-dot chain line 402 in FIG. There is no continuous off state, and a weak discharge operation is always performed.

  In this embodiment, for example, when the charging current required to charge the secondary battery is 100 A, if the discharging current due to the discharging operation that is always operating is 1 A, the charging current is 101 A. Thus, the charging condition of 100A can be satisfied. Similarly, when the discharge condition is 100 A and the charging current by the charging operation that is always operating is 1 A, the discharge condition of 100 A can be satisfied by setting the discharge current to 101 A. That is, the control may be performed so that the difference between the charging current and the discharging current becomes equal to a predetermined current value. Further, even if the charging switch 105 and the discharging switch 111 are configured by switches other than MOSFETs, they can be realized in the same manner, and the effect does not change.

  As described above, since the discharge operation and the charge operation always operate in an overlapping manner, the charge / discharge current is continuously operated without interruption, and a distortion-free charge / discharge waveform can be realized.

It is a circuit diagram of the power supply device concerning the present invention. It is explanatory drawing of the charging / discharging sequence of 1st Embodiment. It is a simulation waveform figure at the time of charging / discharging. It is explanatory drawing of the charging / discharging sequence of 2nd Embodiment. It is a control circuit diagram of a prior art. It is explanatory drawing of the charging / discharging sequence of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Power supply device 103 ... Secondary battery 104 ... AC regeneration converter 105 ... Charging switch 111 ... Discharge switch 107, 113 ... Diode 106, 112 ... Choke coil 108 ... Capacitors 109, 110 ... Terminal 115 ... Control amplifier 117 ... Triangle wave generation control unit 118,119 ... Operational amplifier 403 ... Chopper control circuit 404 ... Clipper circuit

Claims (2)

A regenerative converter;
A secondary battery,
A step-down converter for stepping down the output of the regenerative converter with charging switch means to charge the secondary battery;
A boost converter that boosts the output of the secondary battery by a discharge switch means and discharges it to the regenerative converter;
Have a control means for always operate overlap and said discharge switch means and the charging switch means,
When charging and discharging a predetermined current between the regenerative converter and the secondary battery,
The control means causes a charging current to flow by a step-down converter comprising the charging switch means, and causes a discharging current to flow by a step-up converter comprising the discharging switch means, and the difference between the charging current and the discharging current is the predetermined current. To be equal to
A power supply device characterized by that . A regenerative converter, a secondary battery, a step-down converter for stepping down the output of the regenerative converter with charging switch means to charge the secondary battery, and boosting the output of the secondary battery with discharge switch means; In a control method of a power supply device comprising a boost converter for discharging to a regenerative converter, and a control means for driving the charge switch means and the discharge switch means,
When charging and discharging a predetermined current between the regenerative converter and the secondary battery,
The control means always overlaps the switching operation of the charging switch means and the discharging switch means , and causes a charging current to flow by the step-down converter comprising the charging switch means, and from the discharging switch means the boost converter by flowing a discharge current, a control method of a power supply device the difference between the charging current and the discharge current is equal to or that control to be equal to said predetermined current composed.

Images