JP4570559B2 - Charge / discharge circuit - Google Patents

Description

  The present invention relates to an improvement of a charge / discharge circuit that can be charged and is particularly optimal for a power source that supplies power to an inductive load.

  As this kind of charge / discharge circuit, for example, one of the two capacitors is connected depending on the direction of regenerative current generated between the two capacitors, which are the power source, and the DC motor, which is the inductive load. A charging circuit for charging and a discharging circuit capable of supplying electric power from one of the two capacitors to the DC motor according to the driving direction of the DC motor are provided.

In the charging circuit, a boost chopper for boosting the electromotive force of the DC motor is provided so that the capacitor can be charged even when the electromotive force of the DC motor is lower than the voltage of the capacitor. The discharge circuit is configured to directly connect the capacitor and the DC motor by operating the switch when the DC motor must actively generate torque (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-309961 (FIG. 1)

  However, in the conventional charge / discharge circuit described above, the power source can be charged by boosting the electromotive force of the DC motor, so that energy regeneration can be performed efficiently. However, whether or not the power source is charged or discharged depends on whether or not the power source is charged. Since it is uniquely determined by the relationship between the motor speed and torque, and no consideration is given to the voltage drop due to the discharge of the power supply or aging deterioration, there is a risk that sufficient power supply to the inductive load may not be possible due to the voltage drop Even if the power supply should be charged by energy regeneration due to the voltage drop of the power supply, the power supply is in a mode for supplying power from the power supply to the inductive load, and the power supply can be charged efficiently. There is a fear that it cannot be done.

  Furthermore, in the mode in which power is supplied from the power source to the inductive load, the charging circuit and the discharging circuit are arranged in parallel between the power source and the inductive load, and the power output from the discharging circuit is not limited to the inductive load. There is a risk that it will also be consumed by the charging circuit.

  Therefore, the present invention was devised to improve the above-mentioned problems, and the object of the present invention is to provide a charge / discharge circuit that can efficiently charge a power source with an electromotive force of an inductive load. is there.

In order to achieve the above object, the problem solving means of the present invention is provided between a rechargeable power source and an inductive load, and supplies the power from the power source to the inductive load and the inductive load is generated. A discharge circuit that makes it possible to charge the power source by electromotive force, transforms the voltage of the power source and outputs it to the inductive load, a charging circuit that charges at least a constant current of the power source by the electromotive force of the inductive load, and the inductive load and the charging circuit In the charge / discharge circuit that connects the inductive load and the charging circuit only when the power source can be charged by the electromotive force of the inductive load. And the voltage output from the discharge circuit, the switch is closed when the electromotive force of the inductive load is higher than the voltage output from the discharge circuit .

According to the present invention, as a result of comparison , only when the electromotive force of the inductive load exceeds the output voltage of the discharge circuit, the switch is closed and the power source is charged via the charging circuit. Since the inductive load and the charging circuit are connected only when charging is possible by the electromotive force of the inductive load, there is no fear that the power output from the discharging circuit is consumed by the charging circuit.

  Therefore, when the power source can be charged with the electromotive force of the inductive load, the power source can be reliably charged, and the power of the power source is not wasted. It becomes possible to charge.

  In addition, when the power source is charged by the electromotive force of the inductive load, the power source is always supplied via the charging circuit, so that the power source can be efficiently charged in a short time.

  In addition, since it has a discharge circuit that transforms and outputs a predetermined voltage even when the voltage of the power supply drops, it can supply sufficient power to the inductive load, and the entire system including the power supply and the inductive load Improved reliability and practicality.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a configuration diagram of a charge / discharge circuit according to an embodiment. FIG. 2 is a configuration diagram of a charge / discharge circuit in a modification of the embodiment. FIG. 3 is a configuration diagram of a charge / discharge circuit according to another embodiment.

As shown in FIG. 1, the charging / discharging circuit C1 in one embodiment is provided between a rechargeable power source E and an inductive load M, and transforms the voltage v of the power source E to generate the inductive load M. The discharge circuit 1 that outputs to the power source E, the diode 2 that is provided between the discharge circuit 1 and the inductive load M and prevents the backflow of the current output from the discharge circuit 1, and the electromotive force e of the inductive load M Is provided with a charging circuit 3 for charging at least a constant current, and a switch 4 provided between the inductive load M and the charging circuit 3, and power can be supplied from the power source E to the inductive load M. In addition, as a result of comparison, when the electromotive force e of the inductive load M is higher than the voltage output from the discharge circuit, the switch is closed, that is, the power source E can be charged only when the power source E can be charged. It can be done.

  In more detail, the power source E and the inductive load M are connected to the discharge line 10 via the charge line 11, and the discharge circuit 1 and the diode 2 are arranged in the middle of the discharge line 10 from the power source E side. A resistor 7 having an extremely low resistance value is provided in series so that no current flows from the inductive load M through the discharge line 10. Further, in the middle of the other charging line 11, the switch 4 and the charging circuit 3 are provided in series in order from the inductive load M side, and one end of the charging line 11 is connected to the power source E of the discharging line 10 and the discharging circuit 1. The other end is connected between the diode 2 and the resistor 7 in the middle of the discharge line 10.

The power source E is a secondary battery that can be repeatedly charged and discharged, and specifically, for example, a lead storage battery, a nickel-cadmium battery, a nickel-hydrogen battery, a lithium ion battery, or the like.

The discharge circuit 1 may be any circuit that can transform the voltage of the power source E to a predetermined voltage and supply power to the inductive load M. Specifically, for example, a DC-DC converter or the like may be used. Therefore, even when the power supply E discharges and the voltage drops, the voltage can be boosted by the discharge circuit 1 and power can be stably supplied to the inductive load M. It has become.

  Subsequently, the charging circuit 3 can be charged at least with a constant current. Specifically, for example, a chopper type switching converter or the like can be used, and the power source E can be charged with a constant current. E can be charged. Further, when the charging circuit 3 is a circuit that can charge the power source E with constant current and constant voltage with the electromotive force e generated in the inductive load M, the time required until the power source E is fully charged. Can be shortened.

  Further, the switch 4 is controlled by the control unit 5 so as to be closed only when the electromotive force e of the inductive load M exceeds the output voltage v ′ of the discharge circuit 1. The control unit 5 receives voltage signals from a voltage sensor 6 a that detects the electromotive force e of the inductive load M and a voltage sensor 6 b that detects the output voltage v ′ of the discharge circuit 1, and receives the electromotive force e and the discharge circuit 1. The output voltage v ′ is monitored and compared. Basically, when the electromotive force e exceeds the output voltage v ′ of the discharge circuit 1, the switch 4 is controlled to be closed. When the output voltage is less than 1 output voltage v ′, the switch 4 is opened.

  In addition, the control unit 5 monitors the voltage detected by the voltage sensor 6b and controls the discharge circuit 1 so that a stable voltage can be supplied to the inductive load M, and the charging circuit 3 is configured so that the power source E can be effectively charged. Control.

  The voltage sensors 6a and 6b are specifically provided so as to sandwich the resistor 7 in the middle of the discharge line 10, and the voltage sensor 6a is provided in the vicinity of the inductive load M on the discharge line 10. The voltage sensor 6b is provided in the middle of the charging line 11 and at a portion on the discharge circuit 1 side with a space from the voltage sensor 6a. By detecting the voltage at the connection site to the charging line 11, the electromotive force e of the inductive load M and the output voltage v ′ of the discharge circuit 1 are detected.

  The inductive load M is a motor, a solenoid, a relay, or the like. For example, in the case where the inductive load M is a motor or a solenoid, a drive circuit is included in the inductive load M if necessary for driving the motor or the like.

  Next, the operation of the charging / discharging circuit C1 configured as described above will be described. When power is supplied from the power source E to the inductive load M, the power of the power source E is transformed from the voltage v to the voltage v ′ by the discharging circuit 1. And supplied to the inductive load M.

  At this time, if the electromotive force e of the inductive load M does not exceed the output voltage v ′ of the discharge circuit 1, the control unit 5 keeps the switch 4 open, and the power source E is inductive. The power supply to the sexual load M is continued.

  Conversely, an electromotive force e generated in the inductive load M due to a surge or the like, or when the inductive load M is a motor, an electromotive force generated in the inductive load M when the inductive load M is driven by an external force or the like. When e becomes higher than the output voltage v ′ of the discharge circuit 1, the control unit 5 closes the switch 4 and charges the power source E with the electromotive force e via the charging circuit 3 provided in the middle of the charging line 11. Can do.

  That is, in the charging / discharging circuit C1 in the embodiment, the power source E is charged via the charging circuit 3 only when the electromotive force e of the inductive load M exceeds the output voltage v ′ of the discharging circuit 1. That is, since the inductive load M and the charging circuit 3 are connected only when the power source E can be charged by the electromotive force e of the inductive load M, the power output from the discharge circuit 1 is charged. There is no risk of being consumed by the circuit 3.

  Therefore, when the power source E can be charged with the electromotive force e of the inductive load M, the power source E can be reliably charged, and the power of the power source E is not wasted. It becomes possible to charge the power supply E efficiently by e.

  In addition, when the power source E is charged with the electromotive force e of the inductive load M, the power source E is always supplied via the charging circuit 3, so that the power source E can be efficiently charged in a short time.

  Further, since the discharge circuit 1 that transforms and outputs the predetermined voltage v ′ even if the voltage v of the power source E decreases, the power supply to the inductive load M can be sufficiently supplied. The reliability and practicality of the entire system including the sexual load M are improved.

  Further, the inductive load M is a motor, and in particular, the motor that is the inductive load M is provided to an electric power steering device or an electromagnetic suspension that exhibits a damping force by the torque of the motor. Even when the motor is forcibly driven by an external force to generate a large electromotive force e, the power source E is always charged through the charging circuit 3 when the supply is performed. There is no fear of charging with an overvoltage or overcurrent that is undesirable for the power supply E.

  When the inductive load M is a motor such as an electric power steering device or an electromagnetic suspension and the power source E is a battery mounted on the vehicle as described above, the charge / discharge circuit C1 uses the power source E. Since it is possible to charge efficiently, the occurrence of a situation where the battery rises can be effectively suppressed.

  As shown in FIG. 2, if the charging line 11 is connected between the resistor 7 of the discharge line 10 and the inductive load M, the power source E is charged by the electromotive force e of the inductive load M. In this case, power is not consumed by the resistor 7 and the power source E can be charged with the inductive load M without waste. In this case, a diode can be used in place of the resistor 7.

  Next, the charging / discharging circuit C2 of another embodiment shown in FIG. 3 will be described. In addition, about the part similar to the charging / discharging circuit C1 in one Embodiment, suppose that the detailed description is abbreviate | omitted only by attaching | subjecting the same code | symbol, and will explain in detail about a different part.

  This charging / discharging circuit C2 inducts a capacitor 8 that is grounded between the diode 2 and the inductive load M in the middle of the discharging line 10 with respect to the configuration of the charging / discharging circuit C1 of the above-described embodiment. In addition to being connected in parallel with the load M, the controller 5 in this embodiment monitors the voltage at both ends of the resistor 7 to monitor the electromotive force e of the inductive load M and the output voltage v of the discharge circuit 1. Is not controlled to open / close the switch 4, but the resistor 7 is abolished and the non-contact type current sensor is used as a current detecting means for detecting the direction of the current in the portion of the discharge line 10 where the resistor 7 is provided. 9, and the switch 4 is controlled to be opened and closed by determining whether or not the electromotive force e exceeds the output voltage v ′ of the discharge circuit 1 according to the direction of the current detected by the current sensor 9.

  In addition, the voltage sensor 12 that detects the voltage of the site on the inductive load M side that is upstream from the site where the charging circuit 3 of the charging line 11 is provided, even if the power source E is discharged and the voltage decreases, It is provided to control the discharge circuit 1 so that a stable voltage can be supplied to the inductive load M.

  In the charge / discharge circuit C2 configured as described above, when the electromotive force e of the inductive load M is equal to or lower than the output voltage v ′ of the discharge circuit 1, the current flows in the direction of flowing into the inductive load M. When the electromotive force e of the inductive load M exceeds the output voltage v ′ of the discharge circuit 1, the voltage of the capacitor 8 also becomes the output voltage v ′. On the contrary, current flows from the inductive load M side to the capacitor 8 side.

  Therefore, it can be determined whether or not the electromotive force e is equal to or higher than the output voltage v ′ of the discharge circuit 1 based on the direction of the current in the portion of the discharge line 10 where the current sensor 9 is provided. Thus, it can be determined whether or not the power source E can be charged.

  Therefore, when the direction of the current detected by the current sensor 9 is the direction from the power source E side to the inductive load M side, the control unit 5 generates the electromotive force e of the inductive load M of the discharge circuit 1. Since the power supply E cannot be charged by the electromotive force e because the output voltage is less than v ′, the switch 4 is opened. Conversely, the direction of the current detected by the current sensor 9 changes from the inductive load M side to the power supply E side. When the direction is directed to the direction, since the electromotive force e of the inductive load M exceeds the output voltage v ′ of the discharge circuit 1, the switch 4 is closed because the power source E can be charged by the electromotive force e. So as to control.

  Therefore, also in this embodiment, similarly to the charge / discharge circuit C1 in the embodiment, the inductive load M and the charging circuit 3 are connected only when the power source E can be charged by the electromotive force e of the inductive load M. Since the connection is made, there is no fear that the power output from the discharge circuit 1 is consumed by the charging circuit 3.

  That is, when the power source E can be charged with the electromotive force e of the inductive load M, the power source E can be reliably charged, and the power of the power source E is not wasted. It becomes possible to charge the power supply E efficiently by e.

  In addition, when the power source E is charged with the electromotive force e of the inductive load M, the power source E is always supplied via the charging circuit 3, so that the power source E can be efficiently charged in a short time.

  Further, since the discharge circuit 1 that transforms and outputs the predetermined voltage v ′ even if the voltage v of the power source E decreases, the power supply to the inductive load M can be sufficiently supplied. The reliability and practicality of the entire system including the sexual load M are improved.

  Further, in the charge / discharge circuit C2 of this other embodiment, the resistor 7 can be eliminated, so that there is no power consumption by the resistor 7, and the inductive load M is caused by fluctuations in the current consumption of the inductive load M. This has the advantage of preventing fluctuations in the voltage supplied to.

  Furthermore, since the capacitor 8 is provided, even if the power supply from the power source E is interrupted, there is an advantage that power can be supplied to the inductive load M by the discharge from the capacitor 8.

  The inductive load M is a motor. In particular, when the motor that is the inductive load M is used for an electric power steering apparatus or an electromagnetic suspension that exhibits a damping force by the torque of the motor, this charge is required. Even in the discharge circuit C2, the same effects as the charge / discharge circuit C1 in the above-described embodiment can be achieved.

  The control unit 5 may have any configuration as long as it can perform the operations in the above-described embodiments. For example, the control unit 5 includes an arithmetic processing device and a storage device, and a program is stored in the arithmetic processing device. The above-described operation may be realized by executing the above, or may be realized by an electronic circuit.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a block diagram of the charging / discharging circuit in one embodiment. It is a block diagram of the charging / discharging circuit in the modification of one Embodiment. It is a block diagram of the charging / discharging circuit in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge circuit 2 Diode which is a rectifier 3 Charging circuit 4 Switch 5 Control part 6a, 6b, 12 Voltage sensor
7 Resistance 8 Capacitor 9 Current sensor 10 as current detection means Discharge line 11 Charging line C1, C2 Charge / discharge circuit E Power supply M Inductive load

Claims (4)

Provided between the rechargeable power supply and the inductive load, supplying power from the power supply to the inductive load, enabling the power supply to be charged with the electromotive force generated by the inductive load , and transforming the voltage of the power supply A discharge circuit that outputs to the inductive load; a charging circuit that charges at least a constant current with the electromotive force of the inductive load; and a switch provided between the inductive load and the charging circuit. In a charge / discharge circuit that connects an inductive load and a charging circuit only when charging is possible by the electromotive force of the inductive load, the electromotive force of the inductive load is compared with the voltage output from the discharge circuit. A charge / discharge circuit , wherein a switch is closed when an electromotive force of a load is higher than a voltage output from the discharge circuit. The current detection means for detecting the current flowing from the inductive load to the discharge circuit side is provided, and the switch is closed when the current detection means detects the current flowing from the inductive load to the discharge circuit side. The charge / discharge circuit according to 1. The charge / discharge circuit according to claim 1, wherein a capacitor parallel to the inductive load is provided between the discharge circuit and the inductive load . The charge / discharge circuit according to claim 3, wherein the current detection means detects a current between the capacitor and the inductive load .

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