JP3231870B2 - DC power supply - Google Patents

Abstract

PURPOSE:To allow the collection of energy higher than that limited by the allowable charging current and charging voltage of a battery by charging a series circuit of the battery and a capacitor with energy collected at the time of deceleration. CONSTITUTION:When all switching elements 51, 54, 56 are turned OFF, charging current flows through a path of terminal P-a capacitor 52-a diode 53-a battery 1-terminal N thus charging the capacitor 52 and the battery 1. When the series circuit of the battery 1 and the capacitor 52 is charged with energy collected at the time of deceleration, energy higher than the level limited by the allowable charging current and voltage of the battery can be collected and restarting battery current can be reduced by feeding the auxiliary driving energy from the series circuit of the battery 1 and the capacitor 52 at the time of next and subsequent auxiliary driving. Furthermore, when the energy is collected sufficiently for the capacitor 52, only the capacitor 52 can be operated as a DC power supply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply capable of improving the performance of a drive system by replacing a battery in a drive system using a battery such as an electric vehicle or a diesel electric hybrid system. Related to the device.

[0002]

2. Description of the Related Art Regarding diesel-electric hybrid systems, see "Development of diesel-electric hybrid engines for large vehicles" (Atsuomi Obata et al., Toshiba Review-1991 V
OL.46NNO.8). Induction motors are controlled by inverters, and the brake energy, which was previously discarded as heat in diesel engines, is converted into electric power and stored in a DC power source, which is reused during operation to reduce fuel consumption. By sharing torque between the diesel engine and the induction machine during acceleration, the output of the engine alone is reduced while maintaining the total output, reducing NOx and black smoke in exhaust gas.
With such performance, it is possible to reduce pollution and save energy of large vehicles. Because city buses frequently start and stop repeatedly, the diesel-electric hybrid system is highly effective. Conventionally, a battery was used as a DC power supply for storing braking energy of this system. FIG. 5 shows a configuration of a conventional diesel-electric hybrid system using a battery as a DC power supply.

[0005] In FIG. 5, reference numeral 1 denotes a battery;
A diesel engine, 3 is an induction machine directly connected to the diesel engine 2, and 4 is an inverter for controlling the induction machine 3 at a variable speed.
Reference numeral 6 denotes a smoothing capacitor, and reference numeral 6 denotes a DC / DC converter for converting a DC voltage of the inverter 4 into a voltage suitable for the vehicle-mounted device 7. Numeral 8 denotes a discharge circuit for flowing the current through a resistor when the braking energy cannot be received by the battery 1. The resistor 9 includes a resistor 9, a self-extinguishing element 10, and a diode 1.
1 and 12. 13 to 16 are current detectors for detecting a current flowing through the battery 2. 13 and 14 are induction machines 3
, The phase currents i1u and i1w of the inverter 4 are detected.
Is detected. Reference numeral 16 detects the sum of currents flowing through the battery 1 and the vehicle-mounted device 7. 17 is an output signal of an accelerator sensor, 18 is a retarder (electric auxiliary brake of a diesel electric hybrid system, hereinafter referred to as a retarder).
The output signal of the retarder lever for the driver to control the braking force of the induction motor 3 is controlled by the accelerator sensor output signal 17 and the retarder lever output signal 18. Is a function control circuit that determines In an automobile, the driving force changes depending on the rotation speed of the engine even with the same accelerator depression amount. Further, in the diesel-electric hybrid system, the induction machine 3 may be controlled to the power generation side even when the engine is driven, which is also a function of the engine speed. Therefore, the function control circuit 1
An output signal of a speed detector 20 for detecting the rotational speed of the diesel engine 2 is input to 9. The function control circuit 19 receives the input accelerator sensor output signal 17,
From the Dalebar output signal 18 and the speed signal output from the speed detector 20, the induction motor can be selected from the three modes of auxiliary driving, retarder, and power generation of the diesel-electric hybrid system. 3 to operate, and the mode
The mode selection signal is output to the inverter control circuit 21 together with the reference signal in that mode. The reference value output from the function control circuit 19 is a positive torque reference value in the auxiliary drive mode, a braking power reference value in the retarder mode, and a charging current maximum value in the power generation mode. In the auxiliary drive mode, the inverter control circuit 21 controls the inverter 4 so that the induction machine 3 outputs a torque equal to the torque command value given from the function control circuit 19. In the retarder mode, the induction machine 3 generates electric power equal to the braking electric power reference value.
The generated power is calculated from the inverter DC voltage, that is, the battery voltage detected by the voltage detector 22, and the inverter DC current detected by the current detector 15, and the closed loop control is performed. At this time, the battery current is detected by the current detector 16, and the difference between the inverter DC current and the battery current is consumed by the resistor 9, so that the predetermined braking power is obtained regardless of the charging rate of the battery 1. The induction machine 3 can generate power. In the power generation mode, the induction machine 3 is controlled so that the battery voltage detected by the voltage detector 22 becomes equal to the preset battery charge voltage command value. When the battery voltage is less than the charge voltage command value, constant current control is performed so that the battery current detected by the current detector 16 becomes equal to the maximum charge current supplied from the function control circuit 19. To be precise, what is detected by the current detector 16 is the sum of the battery current and the input current of the DC / DC converter 6, and not the battery current itself, but the DC / D
The input current of the C converter 6 is so small that it can be neglected as compared with the battery current at the time of auxiliary driving and at the time of retarding. Car driving mode (start, acceleration, steady running, deceleration, stop)
FIG. 6 shows the relationship between the operation of the conventional diesel-electric hybrid system. There are no gear changes for simplicity. When the accelerator is fully depressed from the stop state of the vehicle, the function control circuit 19 notifies the inverter control circuit 21 of the auxiliary drive mode by the mode selection signal and outputs the acceleration torque reference value. I do.

[0004] An inverter control circuit 21 controls the inverter 4 so that the induction machine 3 outputs an acceleration torque corresponding to a given torque reference value. Since the engine has poor exhaust gas characteristics at low rotational speeds, the auxiliary drive torque is increased to reduce the load on the engine. However, as the rotational speed increases, the auxiliary drive torque may be very small. For this reason, the discharge power of the battery 1 at the time of start / acceleration decreases with the rotation speed as shown in FIG.

When the accelerator pedal depression amount becomes equal to or less than a predetermined value, the function control circuit 19 notifies the inverter control circuit 21 of the change to the power generation mode by the mode selection signal, and the charging current maximum value and the generation voltage command value. Is output. The detected value of the battery current is fed back to the inverter control circuit 21 by the current detector 16 and the detected value of the DC voltage is fed back by the voltage detector 22. The induction machine 3 generates electric power based on the charging voltage command value. The inverter 4 is controlled to operate as a machine. The output of the engine 2 is also reduced by the control of the automobile, and the automobile shifts to a steady running.

When the input of the retard lever is given by the retard lever output signal 18, the function control circuit 19 changes to the inverter control circuit 21 to be in the retard mode by the mode selection signal. And a braking power reference is output. The inverter control circuit 21 controls the inverter 4 so that the induction machine 3 generates electric power corresponding to the braking electric power reference value. Under the control of the vehicle, the torque of the engine 2 is zero, the braking torque is obtained by the power generation of the induction machine 3, and the vehicle decelerates.

When the vehicle is stopped and neither the accelerator sensor output signal 17 nor the reducer lever output signal 18 is present, the function control circuit 19 sets the power generation mode to the inverter control circuit 21 as in the case of steady running. Outputs the voltage command value. If the voltage of the battery 1 is low and power generation is required, the engine is operated even when the battery 1 is stopped, and power is generated by the induction machine 3.
During steady-state running and when stopped, power generation is not always performed. The DC power is discharged by the auxiliary drive and the power consumed by the on-vehicle equipment 7, and the battery voltage detected by the voltage detector 22 decreases, and power generation is performed for charging only when it can be considered that the predetermined discharge rate is exceeded. . If the DC power supply has sufficient energy, the induction machine 3 has stopped.

[0008] In the battery voltage waveform, a dotted line indicates a voltage reference value for charge control by power generation. In the battery current waveform, the dotted line has a current value of zero. The battery voltage at the time of starting acceleration decreases due to the discharge by the auxiliary drive. As the battery current becomes higher, the auxiliary driving power becomes smaller as the rotation speed becomes higher.
Decreases with increasing rotation speed. In power generation during steady running, constant voltage control is performed at the value determined as the maximum current during power generation while the voltage is lower than the reference value, and when the voltage reaches the reference value, constant voltage control at the reference voltage is performed. As a result, the current is reduced. At the time of deceleration, both the voltage reference value and the maximum current are set to values larger than those at the time of power generation, so that the torque required for braking is obtained and the battery 1 is charged with high power. When the battery voltage reaches the maximum allowable charging voltage, the battery current must be reduced. However, when the braking torque is reduced, the operation is hindered. Therefore, the discharging circuit 8 supplies the resistor 9 with a current corresponding to the reduced battery current. The braking torque is constant. As shown by the thick solid line in FIG. 6, the battery current decreases, but the sum with the consumption of the resistor 9 (the portion shaded by a vertical line) is constant. When the battery voltage is going to rise even when all the resistors are turned on, the constant voltage control is performed for the first time, and the direct current is reduced. Battery 1
When the charging rate of the battery is low, it takes time to increase the battery voltage. If the time required for deceleration is shorter than that, there is no need to supply a current to the resistor 9 and the entire braking energy can be charged. In this case, the battery current is a constant current equal to the DC current.

[0009]

Since the charging current and the charging voltage greatly affect the life of the battery 1, the battery 1 must be used so that the charging current and the charging voltage do not exceed allowable values.

In the diesel-engine hybrid system, the braking force is obtained by converting the kinetic energy of a large vehicle into electric energy. The current value may be exceeded. Even if the battery 1 is discharged and can be charged by charging over a long period of time with a small current, the charging current may exceed an allowable value because a large amount of power is used for a short time during rapid braking. . The excess current must be consumed by the resistor 9.
Further, when the charging rate of the battery 1 increases, the voltage rapidly rises even with a small battery current. Therefore, in this case, the battery voltage does not exceed the charging allowable voltage and the predetermined braking force is maintained. The braking energy must be consumed by the resistor 9. Further, when the required energy at the time of starting acceleration is larger than the recovered energy at the time of deceleration, the power must be generated during steady running. In addition, as shown in FIG. 6, the auxiliary braking is not always performed after deceleration.
For example, after the auxiliary drive is performed by starting acceleration, when the vehicle goes uphill, the auxiliary drive is required again. For this reason, the charging voltage command at the time of steady driving is determined so as to quickly recover the energy required for the auxiliary driving again. Cannot be recovered.

The diesel-electric hybrid system aims to reduce fuel consumption and pollution by supplying the recovered braking energy to power supply to the vehicle-mounted device 7 and auxiliary driving. In addition, the amount of power recovered during braking is restricted. In addition, there is also a problem that the use of a battery having a large charge / discharge current affects its life, and the battery must be replaced in a short time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a DC power supply capable of recovering braking energy exceeding the above-described conventional battery limitation and extending the life of the battery.

[0013]

In order to achieve the above object, a DC power supply according to the present invention comprises a first switching element connected in series to a positive electrode of a battery with a polarity enabling discharge of the battery. And a second switching element connected in parallel to the series circuit and with a polarity enabling charging of the battery.
, A capacitor connected in parallel with the first diode, and a capacitor connected in parallel with the series circuit of the battery and the first switching element and with a polarity enabling charging of the capacitor. A third switching element, a third diode connected with a polarity enabling discharge, and a fourth diode connected in anti-parallel to the first switching element. It is a feature.

[0014]

The power supply device 50 of the present invention shown in FIG. 1 is most suitable for a power supply of a drive device that repeats power generation and regeneration. By controlling switching elements, a series circuit of a capacitor 52 and a battery 1 and only a capacitor 52 are provided. And the battery 1 alone.

When charging the series circuit of the battery 1 and the capacitor 52, the switching elements 51, 54, 56
Turn off all of. When all the switching elements are turned off, the charging current flows through the path of the terminal P → the capacitor 52 → the diode 53 → the battery 1 → the terminal N, and both the capacitor 52 and the battery 1 are charged. Of course, for charging, the voltage applied between the terminals P and N
2 and the voltage of the battery 1. When the applied voltage is low, the DC power supply 50 is cut off from the load by the diode 53.

When discharging from the series circuit of the battery 1 and the capacitor 52, only the switching element 51 is turned on. The discharge current flows through the path of the terminal N → the switching element 51 → (the capacitor 52 or the diode 58) → the terminal P. Energy is stored in the capacitor 52,
Discharge current flows through capacitor 52 while diode 58 is reverse biased. That is, it is discharged from the series circuit of the battery 1 and the capacitor 52. Capacitor 52
Is discharged, only the battery 1 is discharged via the diode 58.

When charging only the capacitor 52,
Only the switching element 56 is turned on, and the switching element 5
1, 54 are turned off. The charging current flows through the path of the terminal P → the capacitor 52 → the switching element 56 → the terminal N,
Only the capacitor 52 can be charged. In this case, even if the capacitor voltage is higher than the battery voltage, the battery 1 is disconnected from the terminal P by turning off the switching element 54, and the negative side of the capacitor 52 is connected to the terminal N by turning on the switching element 56. Then, the battery 1 is disconnected from the negative side of the capacitor 52 by the reverse bias of the diode 53, so that only the capacitor 52 can be charged.

When discharging only from the capacitor 52, the switching elements 51 and 54 are turned off. The switching element 56 may be either on / off. A discharge current flows through the path from the terminal N → the diode 57 → the capacitor 52 → the terminal P, and the discharge can be performed only from the capacitor 52.
Due to the reverse bias of the diodes 53 and 55, the battery 1 is disconnected from the discharge path even if the voltage of the terminal P becomes lower than the battery voltage.

When charging only the battery 1,
The switching element 54 is turned on, and the switching element 5
1, 56 are turned off. Terminal P → Switching element 5
The charging current flows through the path of 4 → diode 55 → battery 1 → terminal N, and only the battery 1 can be charged regardless of the presence or absence of energy stored in the capacitor 52.

As described above, the control of the switching element is the same as that of the discharge from the series circuit of the capacitor 52 and the battery 1 as described above. That is, when the regenerative energy is stored in the capacitor 52, it is not possible to discharge only from the battery 1 while leaving the energy in the capacitor 52. First, the battery is discharged from the series circuit of the capacitor 52 and the battery 1. When the energy of the capacitor 52 is used up, the battery 1 is discharged. As a practical matter, there is no need to discharge only from the battery 1 while leaving energy in the capacitor 52.

[0021]

1 is a block diagram of a DC power supply device 50 according to the present invention. The DC power supply device 50 shown in FIG. 1 is connected in series to the positive electrode side of a battery 1 with a polarity enabling discharge of the battery 1. The first switching element 51 and the first diode
A series circuit of a second switching element 54 and a second diode 55 connected in parallel with the series circuit and with a polarity enabling charging of the battery 1; And a third switching element connected in parallel with the series circuit of the battery 1 and the first switching element 51 and with a polarity enabling charging of the capacitor 52. 56, a third diode 57 connected with a polarity enabling discharge, and a fourth diode 53 connected in anti-parallel to the first switching element 51. FIG. 2 shows a configuration diagram of an embodiment in which the DC power supply device 50 of the present invention is applied to a hybrid system of a prime mover 2 such as a diesel engine and an induction machine 3.

When applied to a hybrid system, a capacitor (several hundred volts, several farads to several tens of farads) required for a capacitor used in a DC power supply is required to recover braking energy of a large vehicle. For example, if a double-layer capacitor that has recently been used and has a very large capacity and can be rapidly charged and discharged is used, the DC power supply device 50 of the present invention can be configured in a size that can be mounted on a vehicle.

In FIG. 2, reference numeral 50 denotes a DC power supply of the present invention; 61, a voltage detector for detecting a battery voltage; 62, a voltage detector for detecting the positive voltage of the capacitor 52; From output signal to voltage detector 6
4 is a subtractor that subtracts the output signal of No. 4 and outputs a voltage applied across the capacitor 52, that is, a detection signal of the capacitor voltage. A comparator 64 compares the output signal of the subtractor 63 with the set value of the constant setter 65, and outputs the result as a logical value. If the capacitor voltage exceeds the set value of the constant setter 65, the logical value is "1", otherwise it is "0". The output of the comparator 64 is input to the power supply control circuit 66. The output of the subtractor 63 is also input to the power supply control circuit 66 in order to control the power supply based on the magnitude relationship between the inverter DC voltage and the battery voltage. The power control circuit 66
The mode selection signal, which is sent directly from the function control circuit 19 to the inverter control circuit 21 in the conventional example, and each mode
The reference signal at the input is also input. The power supply control circuit 66 supplies a switching signal for instructing on / off of the switching elements 51, 54, 56 to an on-delay circuit 6 in accordance with the state of charge of the capacitor 52, which can be determined from the output signal of the comparator 64.
7, 68, and 69, and if necessary at the time of switching the on / off state of the switching element, a mode selection signal and a reference in each mode are sent to an inverter control circuit 21 provided from a function control circuit 19. The signal is changed and output to the inverter control circuit 21. The switching element 54 and the on-delay circuit 6 are output by the output signal of the on-delay circuit 67.
The on / off state of the switching element 56 is determined by the output signal of the switching element 51 and the output signal of the on-delay circuit 69 by the output signal 8. When the switching signal output from the power supply control circuit 66 changes from the logical value “1” to “0”, the on-delay circuits 67, 68, and 69 immediately output the switching signal, but the switching signal changes from “0” to “1”. Changes from "0" to "1" after a predetermined delay time.
It is a circuit to change to. Next, the operation of FIG. 2 configured as described above will be described.

FIGS. 3 and 4 are explanatory diagrams of the operation of the diesel electric hybrid system using the DC power supply device 50 of the present invention. It shows speed, induction motor power, inverter DC voltage, battery voltage, capacitor voltage, battery current, and capacitor current. The dotted line of the voltage waveform indicates zero volt. When the vehicle starts running for the first time, no energy is stored in the condenser 52.

The first starting acceleration from time t0 in FIG. 3 shows this case. Since the capacitor voltage is zero, the output of the comparator 64 is zero. When the auxiliary control mode is given as the mode selection signal from the function control circuit 19 and the output of the comparator 64 is zero, the power supply control circuit 66 turns on the switching element 51 and turns off the switching elements 54 and 56. Is output. On delay circuits 67, 68,
The switching elements 51, 54, 56 are turned on and off via 69 in accordance with the switching signal. The start / acceleration energy is calculated from terminal N → battery 1 → switching element 5
It is supplied from the battery 1 through a path of 1 → diode 58 → terminal P. Therefore, at this time, the inverter DC voltage is equal to the battery voltage.

When the accelerator depression amount decreases at time t1, the function control circuit 19 selects the power generation mode. The vehicle runs normally. When the output signal of the comparator 64 is zero in the power generation mode, the power supply control circuit 66 turns off the switching elements 51 and 56 and turns off the switching element 54.
Output a switching signal so that is turned on. Since the power generated by the induction machine 3 is controlled by the inverter control circuit 21, the generated power is supplied from the terminal P to the switching element 54.
→ flow through diode 55 → battery 1 → terminal N,
Only the battery 1 is charged. Therefore, also at this time, the inverter DC voltage is equal to the battery voltage. At time t2, the DC voltage reaches the charging voltage command value, and the generated power becomes zero.

At time t3, a deceleration command is given, and the function control circuit 19 selects the retard mode. If the output of the comparator 64 is zero in the retard mode, the power supply control circuit 66 outputs a switching signal that turns off all of the switching elements 51, 54, and 56. By controlling the induction machine 3 to generate large electric power for obtaining a retarder torque, the braking electric power is charged in the smoothing capacitor 5 of the inverter DC part, and the DC voltage rises rapidly, and the braking electric power is increased. If the sum of the voltages of the capacitors 52 is to be exceeded, a charging current flows through the DC power supply device 50 in a path of terminal P → capacitor 52 → diode 53 → battery 1 → terminal N, and a series circuit of the capacitor 52 and battery 1 Will be charged.

As shown in FIG. 3, a certain retarder power
If so, the battery current decreases as the voltage of the capacitor 52 increases. Further, since the DC voltage can be made higher than that of the conventional system using only the battery, the braking power itself can be made larger than that of the conventional system. The car stops at time t4 and restarts at time t5. At this time, the capacitor 5
2, the deceleration energy is charged and the capacitor voltage rises. If this voltage is lower than the set voltage 65, the output of the comparator 64 is zero, and the switching element 51 is turned on and the switching elements 54 and 56 are turned off. Output a switching signal to The switching signal is the same as that between the times t0 and t1, but since energy is accumulated in the capacitor 52, the discharge current from the DC power supply 50 is changed from the terminal N → the battery 1 → the switching element 51 → the capacitor 52 → the terminal P flows in the path of P, and the energy of the auxiliary drive is
And a battery 1 from a series circuit. At time t0, the battery current is reduced by the amount corresponding to the increase in the DC voltage as compared with the case of the auxiliary drive.

At time t6, the accelerator depression amount decreases, and the function control circuit 19 switches the mode from auxiliary driving to power generation. Whether or not energy remains in the capacitor 52 at the end of the acceleration depends on the driving pattern, but FIG. 3 illustrates that energy is left in the capacitor 52. When all the energy of the capacitor 52 is released, the operation is the same as that between the times t1 and t3. Time t
Since the battery is discharged from the battery 1 during the auxiliary drive between 5 and t6 and the charging rate is lowered, the battery 1 must be charged if the charging rate is lower than a predetermined value during steady running. At this time, when the series circuit of the battery 1 and the capacitor 52 is charged, the capacitor voltage rises, and there is less room for recovering the retarder energy, so that only the battery 1 is charged. For this purpose, the switching element 54 must be turned on, and the switches 51 and 56 must be turned off. However, if energy remains in the capacitor 52 at the end of the auxiliary driving, the switching element 5
Even after 1 is turned off, the inverter DC voltage is higher than the battery voltage due to the electric charge accumulated in the smoothing capacitor 5 in the inverter DC section. Therefore, at the moment when the switching element 54 is turned on, the smoothing capacitor 5 of the inverter DC section → the terminal P → the switching element 54 → the diode
There is a danger that the charge accumulated in the smoothing capacitor 5 is discharged through the path of the capacitor 55 → the battery 1 → the terminal N → the smoothing capacitor 5 and the switching element 54 is destroyed by an overcurrent. To avoid this, it is necessary to lower the DC voltage to the battery voltage, then end the auxiliary drive, and shift to the power generation mode. Conventionally, the inverter control circuit 2 which directly outputs from the function control circuit 19 to the inverter control circuit 21
The mode selection signal to 1 and the reference signal in each mode are
By giving the signal to the inverter control circuit 21 through the power supply control circuit 66, even if the mode selection signal output from the function control circuit 19 changes from auxiliary drive to power generation at time t6, the power supply control circuit 669 sends the signal to the inverter. It is not output to the data control circuit 21 immediately, but is left in the auxiliary drive state, and only the switching element 51 is turned off. Thereby, the battery 1,
It becomes impossible to discharge from any of the capacitors 52, and the energy of the auxiliary drive is supplied from the smoothing capacitor 5 of the inverter DC section. Since the capacity of the smoothing capacitor 5 is small, the inverter DC voltage drops rapidly, and at time t7, the inverter DC voltage becomes lower than the battery voltage. When the inverter DC voltage becomes lower than the battery voltage, the switching element 54 may be turned on. At time t7, the power supply control circuit 66 outputs to the inverter control circuit 21 the power generation mode selection signal and the reference value in the power generation mode which have been held. Further, the switching element 54 is turned on. At the start of the power generation operation of the induction machine 3, since the DC voltage is lower than the battery voltage, a reverse voltage is applied between the terminal P and the battery 1 by the diode 55, and the DC power supply 50
Is separated from the inverter 4. Since the load of power generation is only the smoothing capacitor 5 in the inverter DC section, the inverter
The DC voltage rises rapidly. When the DC voltage becomes higher than the battery voltage, the diode 55 conducts and the terminal P →
Switching element 54 → diode 55 → battery 1 →
Only the battery 1 is charged through the path of the terminal N.
Since the auxiliary driving between the times t5 and t6 is performed by the series circuit of the capacitor 52 and the battery 1, the discharged power of the battery 1 is smaller than in the conventional case, and the amount of power generation during steady running is smaller than in the conventional case. Therefore, the time t7 to t8 until the battery voltage reaches the charge voltage command value becomes shorter than the time t2 t3.

The same is repeated hereafter. In operation for a long time, the amount of energy released during auxiliary driving is larger than the amount of energy recovered during deceleration. Will be combined. However, due to road conditions,
If only a certain period is taken, the energy recovered during deceleration may increase. Such as when going downhill. Thus, when the capacitor voltage becomes sufficiently high, the battery 1 can be disconnected from the inverter 4 and can be operated with only the capacitor 52. At time t11 in FIG. 4, the amount of depression of the accelerator that has been fully depressed until then becomes small. At this time, the capacitor 52 has recovered enough energy to have a voltage sufficient to recover the retarder energy from the induction machine 3. That is, the output of the comparator 64 is “1”.

At time t11, the power generation mode is selected by the function control circuit 19. In the power supply control circuit 66, the comparator 6
4 is "1", the switching element 51 is turned off. However, the inverter control circuit 21 continues to be off during the conventional auxiliary driving. Are turned off.
As a result, the inverter DC voltage drops rapidly, and when the inverter DC voltage becomes lower than the capacitor voltage at time t12, the diode 57 conducts, and the terminal N of the DC power supply device 50 switches from the terminal N to the diode. In the path from 57 to the capacitor 52 to the terminal P, the capacitor 52 discharges, and the invert DC voltage becomes equal to the voltage of the capacitor 52. If only the switching element 56 is turned on after this time t12,
Charge and discharge can be performed only by the capacitor 52.

Further, the battery 1 does not need to be charged during steady running. This is because the fact that sufficient energy has been stored in the capacitor 52 means that the battery 1 that has been charged in the series circuit has been sufficiently charged. If the auxiliary drive is performed only with the energy of the capacitor 52, the load of the battery 1 is reduced. Is only the in-vehicle device 7. Since the capacity of the battery 1 is selected in consideration of auxiliary driving and charging / discharging at the time of the retarder, if the load is only the vehicle-mounted device 7, the battery 1 has a considerable time without supplementary charging. If charging of the battery 1 is unnecessary, power and regeneration can be freely performed using the capacitor 52 as a power source thereafter. Terminal P during regeneration
It is charged through the path of → the capacitor 52 → the switching element 56 → the terminal N.

By repeating the pattern operation using only the capacitor 52 as a power source, the voltage of the capacitor 52 falls,
When the output of the comparator 64 becomes zero, the switching element 56 is turned off at the time of shifting from steady running to deceleration, so that the deceleration energy is recovered to the series circuit of the capacitor 52 and the battery 1 again.

[0034]

As described above, according to the present invention, when no energy is stored in the capacitor 52,
The driving energy can be supplied only from the battery. By charging the recovered energy at the time of deceleration to the series circuit of the battery and the capacitor 52, it is possible to recover more energy than was previously restricted from the allowable values of the charging current and the charging voltage of the battery, and the battery was charged from the next auxiliary drive And capacitor 52
By supplying auxiliary driving energy from the series circuit of the above, the battery current at the time of restarting, which was conventionally the largest in the battery current, can be reduced. Furthermore, when a large amount of energy is recovered during operation and sufficient energy is recovered in the capacitor 52, the battery can be disconnected from the inverter, and the operation using only the capacitor 52 as a DC power supply is possible. Thereby, the stress of the battery is remarkably reduced as compared with the related art, and the life of the battery can be extended.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a DC power supply device of the present invention.

FIG. 2 is a configuration diagram of a first embodiment of a drive system to which the DC power supply device of the present invention is applied.

FIG. 3 is a waveform chart for explaining the operation of the drive system shown in FIG. 2;

FIG. 4 is a waveform chart for explaining the operation of the drive system shown in FIG. 2;

FIG. 5 is a configuration diagram of a drive system using a conventional DC power supply device.

FIG. 6 is a waveform chart for explaining the operation of the conventional drive system of FIG. 5;

[Description of Signs] 1... Battery 2... Engine 3... Induction machine 4... Inverter 5... ... Resistance 10 ... Self-extinguishing element 11,12 ... Diode 13-16 ... Current detector 17 ... Accelerator sensor 18 ... Retarder lever Output signal Output signal 19 ... Function control circuit 20 ... ... speed detector 21 ... inverter control circuit 22 ... voltage detector 50 ... DC power supply device 51, 54 ... switching element 56 ... switching element 52 ... condensers 53, 55 ... diode 57, 58 Diodes 61, 62 Voltage detector 63 Subtractor 64 Comparator 65 Constant setting device 66 Power supply control circuit 67-69 On-delay circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 1/00-1/16 H02J ⁷ /00-7/36 B60L 11/18

Claims (1)

(57) [Claims] A first switching element and a first diode connected in series to a positive electrode of the battery with a polarity enabling discharge of the battery; a series circuit of the first switching element and the first diode; A series circuit of a second switching element and a second diode connected with a polarity enabling charging of the battery, a capacitor connected in parallel to the first diode, and a first switching element connected to the battery. A third switching element connected in parallel to a series circuit of elements and with a polarity enabling the charging of the capacitor, a third diode connected with a polarity enabling the discharging, and A DC power supply device comprising a fourth diode connected in anti-parallel to the switching element.