JP2011024298A - Charging/discharging equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obviate the need for resistance for resonance prevention and reduce loss by carrying out control mainly based on a current control loop. <P>SOLUTION: A PID amplifier 34 compares a half-bridge output current I<SB>1</SB>with a reference current I<SB>R</SB>and amplifies and inputs the result of comparison to a PWM circuit 10. The PWM circuit 10 compares the output of the PID amplifier 34 with the output of a PWM carrier generator 38 and generates PWM signals G<SB>1</SB>, G<SB>2</SB>to drive switching elements 11, 12. A PID amplifier 35 compares a half-bridge output current I<SB>3</SB>with the sum of the reference current I<SB>R</SB>and the output V<SB>36</SB>of a PID amplifier 36 from an integrated control unit 28 and amplifies the result of comparison. At a PWM circuit 27, the output of the PID amplifier 35 is compared with the output of the PWM carrier generator 38 and PWM signals G<SB>3</SB>, G<SB>4</SB>are generated to drive switching elements 23, 24. The voltage of a capacitor 19 that provides a bias power supply is controlled by driving the switching elements 23, 24. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charge / discharge device for testing a charge characteristic and a discharge characteristic by passing a current through a battery, an electric double layer capacitor and the like (hereinafter collectively referred to as a battery under test including claims).

  Conventionally, as such an apparatus, for example, one as shown in Patent Document 1 is known. In the technique described in Patent Document 1, a low-voltage regenerative DC power supply 50 is configured from an AC power supply 1 via an AC power supply regenerative DC power supply 2 as shown in FIG. A charging / discharging device 60 to which the present invention belongs is connected downstream. In Patent Document 1, only the charge / discharge device 60 is described.

The low-voltage regenerative DC power supply 50 is connected to the output voltage of the DC / DC converter composed of the reactor 5, the current detector 6 and the capacitor 7 from the output side of the half bridge composed of the switching elements 3 and 4. To detect. The output of the current detector 6 and the output of the voltage detector 8 are input to the control amplifier 9, and the output of the control amplifier 9 is supplied to the switching element 3 and the switching element 4 via the PWM circuit 10. Drive (G ₅ ), 4 (G ₆ ).

The charging / discharging device 60 includes a first half bridge including a first switching element 11 (G ₁ ) and a second switching element 12 (G ₂ ), a third switching element 23 (G ₃ ), and a fourth switching element 23 (G ₃ ). A second half bridge composed of the switching element 24 (G ₄ ) is provided. A battery under test 17 is connected between the two half bridges via a reactor 13 and a current detector 14. A reactor 22 and a capacitor 19 serving as a bias power source are connected between the battery under test 17 and the two half bridges. A resistor 15 and a capacitor 16 connected in series are connected to both ends of the battery under test 17 so as to prevent a ripple current accompanying switching from flowing through the battery under test 17.

The output of the reactor 22 has a filter effect by connecting a resistor 18 in series with the capacitor 19 and suppresses the ripple voltage of the bias power source. Discharge current, and a current reference I _R that is output from the output integrated control circuit 28 of the current detector 14 compares amplified by the amplifier 20, converted into a PWM signal inputted to the PWM circuit 21. The PWM circuit 21 controls the current of the battery under test 17 by driving the switching elements 11 and 12 (G ₁ and G ₂ ) based on the PWM signal.

On the other hand, this charging / discharging device is provided with a bias power source. This bias power source is for allowing the switching element to be conductive even when the voltage of the battery under test 17 is lowered so that the test of the battery under test 17 can be performed. It can be discharged. In this prior art, the bias supply voltage, compares and amplifies the voltage reference V _R, which is output from the voltage detector 25 detects the voltage at the integrated control circuit 28 in the comparison amplifier 26 through the PWM control circuit 27 switching The elements 23 and 24 (G ₂ and G ₃ ) are driven and controlled.

  In the prior art having such a configuration, the second half bridge converts the DC voltage of the smoothing capacitor 7 connected to the output terminal of the low-voltage regenerative DC power supply 50 into a pulse, so that the capacitor 19 has a desired stable voltage. Since it accumulates between terminals, there exists an advantage which does not require another power supply for bias.

Japanese Patent Laid-Open No. 2005-20858

  In the prior art as described above, since the output circuit from the switching elements 11 and 12 to the reactor 13 and the capacitor 16 forms an LC resonance circuit, when the switching element is driven in the voltage mode as shown in this circuit, the output Vibration occurs. Therefore, the resistor 15 is connected in series with the capacitor 16 to provide a damping effect. However, in a test apparatus with a large charge / discharge current, the loss of the resistor 15 is considerably large, which is contrary to energy saving. In particular, recent automobile batteries perform a charge / discharge test at about 60 to 300 A, so that the loss of resistance is considerably increased.

  Similarly, since the series resistance 18 of the bias power supply capacitor 19 is also controlled in the voltage mode, it is for vibration prevention and is contrary to energy saving. Further, since the charging current flows into the bias power source through the battery under test 17, this energy is regenerated to the DC power source via the reactor 22 → the switching element 23, and the resistance loss and switching loss of this circuit are considerable. Amount. In addition, since the ripple current of the DC power source is also proportional to the battery current, there are many inconveniences such as the need to significantly increase the ripple current tolerance of the capacitor 7 of the low voltage regenerative DC power source 50 in the case of a low voltage and large current.

  The present invention has been proposed to solve the above-described problems of the prior art. That is, the object of the present invention is to eliminate the need for the resistor 15 connected in series with the capacitor 16 or the resistor 18 connected in series with the bias power supply capacitor 19 in order to prevent a ripple current accompanying switching from flowing through the battery under test. In order to reduce the loss caused by these resistors 15 and 18 and the loss caused by other switching, an energy saving, small and economical charging / discharging device is provided.

  The charging / discharging device of the present invention includes a first half bridge in which a first switching element and a second switching element are connected in series, and a second half bridge in which a third switching element and a fourth switching element are connected in series. And a control circuit for controlling on / off of each switching element, a battery under test to be charged / discharged is connected to the output side of the first half bridge via a first reactor, and the second A bias power source comprising a second reactor and a capacitor is connected to the output side of the half bridge, and the battery under test and the bias power source are connected in series.

In particular, in the present invention, the control circuit is
(1) a PWM circuit for controlling the first and second switching elements of the first half bridge according to the first reactor current I ₁ , the current reference I _R , and the PWM carrier frequency;
(2) an amplifier for obtaining a current reference V ₃₆ corrected based on the bias power supply voltage V ₁ and the voltage reference VR _;
(3) a PWM circuit for controlling the third and fourth switching elements of the second half bridge according to the corrected current reference V ₃₆ obtained by this amplifier and the current I ₃ of the second reactor;
It is characterized by having.

  According to the present invention, since the bias power source is controlled mainly by the current control loop, a resistance for preventing resonance is not required, and the loss is reduced. Further, the bias voltage control is easy to perform in parallel operation by adopting a configuration in which the current reference is corrected with the bias voltage while the current control based on the current reference is used as a reference. Further, when the PWM carrier of the charge / discharge current and the carrier phase for the bias power supply are set to 180 °, the bias power supply ripple can be reduced and the apparatus can be miniaturized.

  Further, when the units are arranged in parallel, by adjusting the frequency phase of the PWM carrier for each unit, the power ripple can be significantly reduced and the capacitor can be made small. If the bias power supply is not operated when the voltage of the battery is high, a loss can be reduced and a more efficient charging / discharging device can be configured.

1 is a circuit diagram showing a configuration of Embodiment 1 of the present invention. 3 is a timing chart showing the operation of the first embodiment. The circuit diagram which shows the structure of Example 2 of this invention. The timing chart which shows the operation | movement of Example 3 of this invention. The circuit diagram which shows an example of a prior art. The circuit diagram which shows the structure of the charging / discharging apparatus for the conventional parallel operation.

  Hereinafter, embodiments of a charge / discharge device according to the present invention will be described with reference to the drawings. In the embodiments, the same or similar components are denoted by common reference numerals, and redundant description is omitted.

[Constitution]
FIG. 1 is a circuit diagram illustrating a configuration of the first embodiment. In FIG. 1, the voltage detector 8, the control amplifier 9, and the PWM circuit 10 that are control circuits of the low-voltage regenerative DC power supply 50 illustrated in FIG. 5 are not shown.

  The structural feature of the first embodiment is that the filter capacitor 16 connected in parallel with the battery under test 17 does not have the vibration preventing resistor connected in the prior art of FIG. Further, there is no resistor 18 connected in series with the capacitor 19 serving as a bias power source in the prior art. Therefore, in the first embodiment, the following configuration is adopted.

The first half-bridge output current I ₁ is detected by the current detector 31 and input to the PID amplifier 34. In the PID amplifier 34, and a current reference _{I R} output from the half-bridge output current _{I 1} and the comprehensive controller 28 compares and amplifies, and inputs to the PWM circuit 10. The PWM circuit 10 compares the output of the PID amplifier 34 with the output of the PWM carrier generator 38 to generate PWM signals G ₁ and G ₂ and drive the switching elements 11 and 12 of the first half bridge. To do.

The second half-bridge output current I ₃ of the bias power supply is detected by the current detector 32 and input to the second PID amplifier 35. In the second of the PID amplifier 35, the sum this with the half bridge output current _{I 3,} obtained by adding the current reference _{I R} and an output _{V 36} of the third PID amplifier 36 from the comprehensive controller 28 by the adder 39 _{(I R} + V ₃₆ ). The output of the second PID amplifier 35 is compared with the inverted output of the PWM carrier generator 38 in the PWM circuit 27 to generate PWM signals G ₃ and G ₄ , and the second half-bridge switching element 23, 24 is driven. In this case, the PWM carrier frequency input to the PWM circuit 27 is inverted by the inverting amplifier 37, and the first half-bridge PWM circuit 10 and the second half-bridge PWM circuit 27 are shifted in phase by 180 °. PWM control is performed.

The voltage V ₁ of the bias capacitor 19 is detected by the voltage detector 25 and input to the third PID amplifier 36. In the third PID amplifier 36, compares and amplifies the voltage reference _{V R} output from the general control circuit 28 the output voltages _{V 1} of the capacitor 19, to correct the current reference _{I R} by adder 39 and the output _{V 36} .

The current I ₂ flowing into the battery under test 17 is measured with high accuracy by the current detector 14 and input to the general controller 28. The general control unit 28, in order to control the current with high accuracy, and fine adjustment of the current reference I _R by flowing current I ₂ of the tested battery 17. Voltage V ₂ of the test battery 17 detected by the voltage detector 33, this on the basis of the output voltage V ₂ of the test battery 17, to determine the general control unit in the 28 charge stop or discharge completion, the current reference I _R Turn on / off or adjust. The current reference I _R is input to the first PID amplifier 34 as described above, by comparing the first half-bridge output currents I ₁ and to adjust the half-bridge output current I ₁ is controlled by the PWM circuit 10 .

[Action]
As shown in FIG. 1, in the first embodiment, the first half-bridge chopper output current I ₁ is controlled by using a PID amplifier 34 to form a current control loop that operates at higher speed than voltage control. is doing. Therefore, the voltage of the capacitor 16 becomes an integral of the current and becomes a first order lag, so there is no concern that the LC resonance circuit including the reactor 13 and the capacitor 16 will vibrate. Therefore, it is not necessary to insert the resistor 15 for suppressing vibration in series with the capacitor 16 as in the prior art. The same can be said for the capacitor 19 of the bias power source.

Thus, charge and discharge current I ₁ and the bias current I ₃ of the power supply, because it is PID controlled both at the same current reference I _R, is basically the direct current of the capacitor 19 is zero, the bias supply voltage It does not change. However, due to drift, such as a current detector, since slightly bias voltage V ₁ is varied, in Embodiment 1, and V ₃₆ amplifies an error between the voltage reference V _R by the third PID amplifier 36, current by correcting the reference I _R minutely, and keeping the bias power supply voltage stably.

  Further, in the first embodiment, the ripple current flowing through the capacitor 19 is reduced to make the capacitor smaller, so that the first half bridge and the second half bridge for the bias power supply are polarized with the inverting amplifier 37 in the polarity of the carrier frequency. Is inverted to generate a PWM signal whose phase is shifted by 180 °. This will be described with reference to FIGS. 2D is an equivalent circuit diagram of the first embodiment, and FIGS. 2A to 2C are waveform diagrams of the carrier frequency of each part, the driving signal of the switching element, and the charging current in the equivalent circuit diagram.

2A shows the waveforms of the drive signals G ₁ and G _{2 of} the first half-bridge element and the charging current i ₁ of FIG. 2D, and the ripple of this waveform flows to the capacitor 19. FIG. 2B shows the waveform of i ₂ when the carrier frequencies of the first half bridge and the second half bridge are in phase. Since the phase of the ripple of i _{1 and} the ripple of i ₂ are 180 ° different, a large ripple current flows through the capacitor 19.

FIG. 2 (c) shows the waveform of i ₂ when the carrier frequency is shifted by 180 °. It is ideal when V ₁ : V ₂ : V ₃ = 3: 2: 1. In this case, as shown in FIG. 2 (c), the ripple phases of i ₁ and i ₂ are in phase. No ripple current flows through the capacitor 19. However, this is an ideal case. In other cases, the ripple current increases than in the case of FIG. 2C, but decreases compared to the case where the carrier frequency is the same phase. In the first embodiment, the carrier frequency is shifted by 180 °. However, the carrier frequency is the same phase, and the same effect can be obtained even if the polarity of the output side of the PID amplifier is reversed. As a result, the carrier frequency is reversed. A phase PWM signal is obtained.

  Next, a second embodiment of the present invention will be described. The maximum capacity of one charging / discharging device as shown in FIG. 5 and the first embodiment of the present invention is generally about 5V60A. Therefore, when further increasing the capacity, it is conceivable to connect a plurality of these chargers / dischargers in parallel.

In FIG. 6, a plurality of conventional charge / discharge devices based on voltage control are connected in parallel to one general control unit 28 and the battery under test 17. In this prior art, the master unit, in the case of voltage control their second half-bridge with a reference voltage V _R from the output voltages V ₁ and the comprehensive controller 28 of the capacitor 19 for biasing the PID amplifier 36 Compare. The output of the PID amplifier 36 is used as a current reference, the switch 40 is switched to the parent device side, and the second PID amplifier 35 compares and amplifies the half-bridge output current I ₃ and the output of the third PID amplifier 36. Thus, voltage control and current control are performed.

Slave unit switches the switch 40 to the slave unit side, got a current reference from the PID amplifier 36 of the master unit, in the second PID amplifier 35, a half-bridge output current _{I 3} and the output of the third PID amplifier 36 By comparing and amplifying the voltage, voltage control and current control are performed.

  In this prior art, the current reference from the PID amplifier 36 of the parent device is switched between the parent device and the child device by the changeover switch 40, so that the current balance between the parent device and the child device is very good. In other words, even when a capacitor serving as a bias power source for the parent device and the child device is connected in parallel to the battery under test 17, both capacitors 19 are balanced, so that the bias current flows evenly. is there. However, this conventional technique has a disadvantage that one wiring is required between the parent device and the child device, and a changeover switch is required.

  On the other hand, in Example 2 of the present invention, as shown in FIG. 3, a plurality of charge / discharge devices of FIG. 1 are connected in parallel to the general control unit 28 and the battery under test 17. In the second embodiment, the control for each charging / discharging device is mainly current control as in the first embodiment, and the voltage control is controlled so as to correct this current reference. For this reason, there is no distinction between the master unit and the slave unit, and the number of wirings is small.

  In the second embodiment, as shown in FIG. 6, a plurality of charging / discharging devices are simply connected in parallel to the battery under test 17 without providing a changeover switch between the parent device and the child device. In this case, since the capacitor 19 serving as a bias power source for each charging / discharging device is a common power source, when the balance between the plurality of capacitors 19 is lost, only the current from one capacitor 19 flows and the current of the other capacitor 19 flows. Will not flow.

Therefore, in order to improve the current balance among the plurality of charging / discharging devices, the gain of the third PID amplifier 36 is not infinite, and the voltage drops with respect to the output V ₃₆ of the PID amplifier 36. For example, the output _{V 36} saturated at about 5% of the current reference _{I R,} a gain as the voltage _{V 1} of the bias power at this time is changed 5% to 10%. In general, the accuracy of the bias power supply voltages V ₁ is not severe, because the battery discharge is sufficient if possible to zero voltage is sufficient at 5% to 10% voltage accuracy.

In Example 2 of this configuration, the voltage to the output V ₃₆ of the PID amplifier 36 has a characteristic to droop, that correction of significant current reference I _R is performed between a plurality of discharge device for parallel operation Absent. As a result, the current balance at the time of parallel operation is improved, and there is no problem that only the current from one capacitor 19 flows and the current of the other capacitor 19 does not flow even if a changeover switch is not provided.

Next, Embodiment 3 of the present invention will be described. In Example 3, the general control unit 28 monitors the voltage of the output voltage V ₁ of the output voltage V ₂ or bias power source and comprising a capacitor 19 of the test battery 17. When the voltage V ₂ or V ₁ is the monitoring is higher than the set value, and controls the voltage reference V _R to be output from the general control unit 28 of the embodiment 1, comprising a bias voltage below zero voltage As described above, the fourth switching element 24 is forcibly turned on and the third switching element 23 is turned off. In this case, in addition to turning on and off the switching elements 23 and 24 themselves, the gate of the switching element 24 may be forcibly turned on and the gate of the switching element 23 may be forcibly turned off.

The operation of the third embodiment will be described with reference to FIGS. 4D is an equivalent circuit diagram of the third embodiment, and FIGS. 4A to 4C are PWM carrier frequencies, drive signals G ₁ and G _{4 for the} switching elements 11 and 24, and an equivalent circuit. is a timing chart showing the relationship of the bus current i _D from the DC power source 50.

FIG. 4A shows the current i _D of the DC bus when the bias power supply is always controlled. The bus current i _D flows from the time t _{1 to} t ₂ into the capacitor 19 through the first half-bridge chopper. On the other hand, the energy of the capacitor 19 between times _t 3 ~t ₄ is flowing at the negative polarity of the DC bus _{i D.} For this reason, the efficiency decreases due to the wide current-carrying width and the increase in resistance loss and the occurrence of switching loss in the switching elements 23 and 24.

In Example 2, when the battery voltage V ₂ is higher than the set value, since the bias voltage is not required, it is controlled to be a bias voltage below zero voltage. That is, since are to leave the switching elements 24 turned on, the energization widths of the bus current i _D becomes narrower, because the regenerative also eliminated, a high-efficiency charge and discharge. In addition, when the load to be tested is a battery, the voltage decreases (1 to 1.5 V or less) in a very short time. This state is shown in FIG.

If up the current capacity of the rechargeable device with parallel, changing the phase of the carrier frequency of the PWM for each charge and discharge device, the ripple of the bus current i _D, as shown in FIG. 4 (c), it is less. FIG. 4C shows a ripple state when two charging / discharging devices are connected in parallel. As a result, the ripple current of the DC power supply 50 can be reduced and the capacitance of the capacitor can be reduced, so that the power supply can be reduced in size and at the same time the loss can be reduced, thus saving energy and improving efficiency. . When four charging / discharging devices are connected in parallel, ripples can be further reduced by giving a 90 ° phase difference to the PWM carrier frequency of each charging / discharging device.

DESCRIPTION OF SYMBOLS 1 ... AC power source 2 ... AC power source Regenerative type DC power source 50 ... Regenerative type AC power source 60 ... Charge / discharge device 11, 12 ... Switching element 13, 22 ... Reactor 14 ... Current detector 15, 18 ... Resistance 17 ... Test battery 16 , 19, capacitors 23, 24, switching elements 21, 27, PWM circuits 20, 26, amplifier 28, general control units 31, 32, current detectors 25, 33, voltage detectors 34, 35, 36, PID amplifier 37,. Inversion circuit 38 ... PWM carrier generator 39 ... adder 40 ... switch

Claims (6)

A first half bridge in which a first switching element and a second switching element are connected in series; a second half bridge in which a third switching element and a fourth switching element are connected in series; It has a control circuit to control off,
A battery under test to be charged and discharged is connected to the output side of the first half bridge via a first reactor, and a bias consisting of a second reactor and a capacitor is connected to the output side of the second half bridge. In a charge / discharge device in which a power source is connected and the battery under test and a bias power source are connected in series,
The control circuit includes:
(1) a PWM circuit for controlling the first and second switching elements of the first half bridge according to the first reactor current I ₁ , the current reference I _R , and the PWM carrier frequency;
(2) an amplifier for obtaining a current reference V ₃₆ corrected based on the bias power supply voltage V ₁ and the voltage reference VR _;
(3) in accordance with the current I ₃ of the sum and the second reactor with the corrected current reference V ₃₆ and current reference I _R obtained by the amplifier, the second half-bridge the third and fourth switching PWM circuit for controlling the element,
A charge / discharge device comprising: The corrected amplifier to obtain a current reference V ₃₆ was the charge and discharge device according to claim 1, characterized in that it has a characteristic that the voltage droops as the current correction. Equipped with a battery voltage detector
When the voltage obtained by the voltage detector is higher than the set value, the fourth on the switching element in accordance with the voltage reference V _R, as an off-the third switching element, characterized in that the switching operation and stopped The charge / discharge device according to claim 1. Equipped with a battery voltage detector
When the voltage obtained by the voltage detector is higher than the set value, forcibly turning on the gate of the fourth switching element in accordance with the voltage reference V _R, as force off the gate of the third switching element, The charging / discharging device according to claim 1, wherein the switching operation is stopped.   The charge / discharge device according to claim 1, wherein a phase difference between the PWM carrier frequencies of the first and second switching elements and the PWM carrier frequency of the third and fourth switching elements is 180 °.   A plurality of the charge / discharge devices of claim 1 are connected in parallel to the battery under test and the bias power source, and the PWM carrier frequency of the switching element in each device has a phase difference between the charge / discharge devices of claim 1 in parallel. A charge / discharge device characterized by the above.

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