JP2011109815A - Power supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply apparatus that can reduce ripple current over a wide operating range while assuring the control range of voltage conversion ratio. <P>SOLUTION: The power supply apparatus 100 includes a normal converter 110 and a polyphase converter 120 connected in parallel. The polyphase converter 120 has a plurality of chopper circuits 121-1 and 121-2 which are connected in parallel and operate at prescribed phase shifted (180 degrees) timings. The reactors L1 and L2 of the chopper circuits 121-1 and 121-2 are coupled magnetically. A control circuit 120 operates one converter having a relatively small current ripple selectively according to predetermined characteristics of ripple currents for the duty ratios of the normal converter 110 and polyphase converter 120 and based on the ratio of the voltage command value VHr of high voltage side voltage VH and the low voltage side voltage VL. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device, and more particularly to a power supply device having a DC voltage conversion function.

  Conventionally, various configurations of power supply devices for performing DC voltage conversion have been proposed. For example, in a motor drive device, a configuration in which a DC voltage obtained by boosting the output of a low-voltage power supply by a boost converter is converted into an AC voltage by an inverter and used for motor driving is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-112904 (Patent Document 1). Are listed. In particular, Patent Document 1 discloses a reactor, a configuration of a boost chopper including power semiconductor switching elements of upper and lower arms and respective antiparallel diodes, and a reactor chopper in order to reduce the influence of dead time in the boost chopper. It is described that the switching frequency is lowered according to the current range.

  Further, as another circuit configuration of the boost converter, a multi-phase converter that operates a plurality of converters connected in parallel with their phases shifted from each other is configured using a magnetically coupled reactor. (Patent Document 2) and JP-A-2003-304681 (Patent Document 3). According to the boost converter described in Patent Documents 2 and 3, the ripple current of the smoothing capacitor can be reduced.

JP 2004-112904 A JP 2006-262601 A JP 2003-304681 A

  In the step-up chopper, since the reactor current is switched, a ripple component (hereinafter also simply referred to as “ripple current”) is inevitably generated in the current. When the ripple current increases, the smoothing capacitor provided in the converter increases in heat generation and the maximum current value of the power semiconductor switching element increases, which may adversely affect the life of the circuit element.

  However, in the step-up chopper described in Patent Document 1, there is a concern that the ripple current increases when the step-up ratio is increased, but this problem is not particularly taken into consideration.

  Further, in the multiphase converter using the magnetically coupled reactor described in Patent Documents 2 and 3, it is expected that the ripple current characteristics are different from those of the normal boost chopper described in Patent Document 1. However, Patent Documents 2 and 3 describe that the ripple current can be reduced, but do not describe how the ripple current changes depending on the operation region of the converter.

  As described above, the ripple current characteristics of the boost converter vary depending on the circuit configuration. Therefore, in applications that require a wide voltage range corresponding to the operating range of the load, a wide voltage conversion ratio (high voltage / low voltage) In general, it is difficult to suppress the ripple current of the boost converter.

  The present invention has been made to solve such problems, and the object of the present invention is to ensure a wide operating range (range of voltage conversion ratio) and to suppress ripple current. Is to provide a simple power supply.

  The power supply device according to the present invention includes a first converter (110), a second converter, and a control circuit. The first converter includes at least one switching element in order to perform DC power conversion between a power supply wiring connected to a load and a DC power supply. The second converter is configured to include at least one switching element connected in parallel with the first converter between the DC power supply and the power supply wiring. The control circuit is configured to control the first and second converters. Each of the first and second converters is configured such that a voltage conversion ratio that is a ratio of the voltage of the power supply wiring to the output voltage of the DC power supply changes according to the duty ratio in the on / off control of the switching element, and The ripple current characteristics with respect to the duty ratio are different between the first and second converters. The control circuit includes a characteristic storage unit and a converter selection unit. The characteristic storage unit is configured to store information on the ripple current characteristic obtained in advance. The converter selection unit calculates a necessary voltage conversion ratio based on the voltage command value of the power supply wiring and the output voltage of the DC power supply, and from the first and second converters according to the information stored in the characteristic storage unit, One converter having a smaller ripple current at the calculated voltage conversion ratio is configured to selectively operate.

  Preferably, the first converter includes a first chopper circuit. The first chopper circuit has at least one first switching element that is controlled to be turned on and off by the control circuit, and a first reactor that is arranged so that a current switched by the first switching element passes therethrough. . The second converter includes a plurality of second chopper circuits connected in parallel. Each of the plurality of second chopper circuits includes at least one second switching element that is controlled to be turned on and off by the control circuit, and a second circuit that is arranged so that a current switched by the second switching element passes therethrough. And a reactor. The second reactors of the respective second chopper circuits are arranged so as to be magnetically coupled to each other, and the respective second chopper circuits are shifted in timing by a predetermined phase from each other among the plurality of second chopper circuits. On / off of the second switching element of the circuit is controlled.

  More preferably, each second reactor of the plurality of second chopper circuits includes coil windings wound around different portions of the common core.

  Preferably, the control circuit further includes a first converter control unit and a second converter control unit. The first converter control unit fixes the switching element of the second converter to OFF when the first converter is selected, while controlling the voltage of the power supply wiring to the voltage command value. The duty ratio of the switching element of the converter is configured to be controlled. The second converter control unit fixes the switching element of the first converter to OFF when the second converter is selected, while controlling the voltage of the power supply wiring to the voltage command value. The duty ratio of the switching element of the converter is configured to be controlled.

  Alternatively, preferably, the power supply device further includes a first switch connected between the DC power supply and the first converter, and a second switch connected between the DC power supply and the second converter. . When the first converter is selected by the converter selection unit, the first switch is turned on, while the second switch is turned off. When the second converter is selected by the converter selection unit, While the second switch is turned on, the first switch is turned off.

  Preferably, the characteristic storage unit stores a characteristic of current ripple with respect to the duty ratio in each of the first and second converters. Then, the converter selection unit calculates a duty ratio in each of the first and second inverters for realizing the calculated voltage conversion ratio, and current ripples of the first and second converters in the calculated duty ratio. Based on the comparison, one converter is selected.

  According to the present invention, it is possible to secure a wide operating range (voltage conversion ratio range) and to suppress the ripple current over a wide operating range.

It is a circuit diagram explaining the structure of the power supply device by embodiment of this invention. It is a circuit diagram which shows the structural example of a magnetic coupling type reactor. It is a graph which compares the characteristic of the ripple current with respect to a duty ratio. It is a functional block diagram explaining the control structure of the power supply device by embodiment of this invention. It is a wave form diagram explaining switching control when a normal converter is selected. It is a wave form diagram explaining switching control when a multiphase converter is selected. It is a flowchart explaining the control processing of the power supply device by embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a circuit diagram illustrating a configuration of a power supply device according to an embodiment of the present invention.
Referring to FIG. 1, power supply apparatus 100 according to an embodiment of the present invention includes smoothing capacitors C0 and C1, relays RL0 and RL1, and a normal boost chopper type converter 110 (hereinafter also referred to as “normal converter”). And a multiphase converter 120 configured to include a magnetically coupled reactor. Power supply device 100 performs DC power conversion between power supply wiring PL connected to load 220 and DC power supply B1.

  The DC power supply B1 outputs a DC voltage. The DC power supply B1 is typically composed of a secondary battery such as nickel metal hydride or lithium ion.

  Smoothing capacitor C0 is connected between node Na electrically connected to the positive electrode of DC power supply B1 and ground wiring GL. Smoothing capacitor C0 smoothes the output voltage of DC power supply B1 corresponding to low-voltage side voltage VL of power supply device 100.

  Smoothing capacitor C1 is connected between power supply line PL and ground line GL, and smoothes high-voltage side voltage VH of power supply device 100. Load 200 is connected to power supply line PL and ground line GL.

  As load 200, for example, an AC motor driven through an inverter circuit is applied. Application to a hybrid vehicle that travels by engine output and / or motor output, an electric vehicle that travels only by motor output, and the like can be given as typical application examples of the DC-DC converter according to the embodiment of the present invention. In this case, for example, the output voltage (voltage VL) of the DC power supply B1 is set to about 200V, while the voltage VH to be supplied to the load 200 is set to about 200V to 650V.

  Normal converter 110 and multiphase converter 120 are connected in parallel with each other between power supply line PL and ground line GL, and each is configured to perform DC power conversion between power supply line PL and DC power supply B1. .

  Relay RL0 is arranged between node Na and normal converter 110, and relay RL1 is arranged between node Na and multiphase converter 120. On / off of each of the relays RL0 and RL1 is controlled by the control circuit 210. Relays RL0 and RL1 are shown as representative examples of “switches”. That is, any element can be used in place of relays RL0 and RL1 as long as it is an element that can be controlled by control circuit 120 to interrupt and form the current path.

  The normal converter 110 is configured by a chopper circuit. Specifically, normal converter 110 includes power semiconductor switching elements (hereinafter simply referred to as “switching elements”) Q01 and Q02, diodes D01 and D02, and a reactor L0. Switching elements Q01 and Q02 are connected in series between power supply line PL and ground line GL. Reactor L0 is electrically connected between node N0, which is a connection node of switching elements Q01 and Q02, and relay RL0. Diodes D01 and D02 are connected in antiparallel to switching elements Q11 and Q12, respectively.

  In this embodiment, an IGBT (Insulated Gate Bipolar Transistor) is exemplified as the switching element. However, as long as the switching element can control turn-on and turn-off by driving control of a control electrode (gate or base), voltage-driven switching is possible. Elements (MOS-FET, IGBT, etc.), current-driven switching elements (bipolar transistors, etc.), and various switching elements can be arbitrarily applied.

  Multiphase converter 120 has a plurality of chopper circuits 121-1 and 121-2 connected in parallel. The chopper circuits 121-1 and 121-2 have the same configuration as the chopper circuit constituting the normal converter 110, except that the reactors L <b> 1 and L <b> 2 are arranged so as to be magnetically coupled to each other. And different. That is, multiphase converter 120 is a multiphase converter including a magnetically coupled reactor.

  Specifically, chopper circuit 121-1 includes switching elements Q11 and Q12, diodes D11 and D12, and a reactor L1. Switching elements Q11 and Q12 are connected in series between power supply line PL and ground line GL. Reactor L1 is electrically connected between node N1, which is a connection node of switching elements Q11 and Q12, and DC power supply B1. Diodes D11 and D12 are connected in antiparallel to switching elements Q11 and Q12, respectively.

  Similarly, chopper circuit 121-2 is configured similarly to chopper circuit 121-1, and includes switching elements Q21 and Q22, diodes D21 and D22, and a reactor L2. Reactor L2 is electrically connected between a node N2, which is a connection node of switching elements Q21 and Q22, and DC power supply B1.

In the configuration of FIG. 1, the normal converter 110 corresponds to a “first converter” and a “first chopper circuit”, and the multiphase converter 120 corresponds to a “second converter”.
The chopper circuits 121-1 and 121-2 correspond to “a plurality of second chopper circuits”. Reactor L0 corresponds to “first reactor”, and reactors L1 and L2 correspond to “second reactor”. Further, the relay RL0 corresponds to a “first switch”, and the relay RL1 corresponds to a “second switch”.

  As described above, reactors L1 and L2 are provided to constitute a magnetically coupled reactor. FIG. 2 shows a configuration example of a magnetically coupled reactor.

  Referring to FIG. 2, the magnetically coupled reactor includes a core 250 and coil windings 241 and 242 wound around the core 250. The core 250 includes outer leg portions 251a and 251b and a central leg portion 252 arranged so as to face each other with the gap 253 interposed therebetween.

  The coil winding 241 constituting the reactor L1 is wound around the outer leg portion 251a. The coil winding 242 constituting the reactor L2 is wound around the outer leg portion 251b. Here, when the cross-sectional area of the outer legs 251a and 251b is S1 and the length is LN1, the magnetic resistance R1 of the outer legs 251a and 251b is expressed by the following equation (1). Similarly, when the cross-sectional area of the center leg 252 is S2, the length is LN2, and the gap length is d, the magnetic resistance R2 of the center leg 252 is expressed by the following equation (2). In the equations (1) and (2), μ represents the magnetic permeability of the core 250, and μ0 represents the magnetic permeability in the air in the gap.

R1≈ (1 / μ) · (LN1 / S1) (1)
R2≈ (1 / μ) · 2 · (LN2 / S2) + 1 / μ0 · (d / S2) (2)
In the present embodiment, the constants S1, LN1, S2, LN2, and d of the magnetically coupled reactor are set so that R2 >> R1 according to the expressions (1) and (2).

  By setting in this way, most of the magnetic flux generated by the passing current of the coil winding 241 is linked to the coil winding 242 and most of the magnetic flux generated by the passing current of the coil winding 242 is almost all the coil winding 241. And become interlinked. As a result, in FIG. 1, counter electromotive forces in the opposite directions to the electromotive forces generated in reactors L1 and L2, respectively, are generated in reactors L2 and L1, respectively.

  The shape of the core 250 is not limited to the example of FIG. 2 and can be arbitrarily set as long as the equivalent circuit described in FIG. 1 can be configured. For example, you may use the shape shown by FIG.5, 6 etc. of Unexamined-Japanese-Patent No. 2003-304681 (patent document 3).

  Voltage sensor 20 detects DC voltage VL on the low voltage side of multiphase converter 120, which corresponds to the output voltage of DC power supply B1. Voltage sensor 22 detects the voltage of power supply line PL, that is, DC voltage VH on the high voltage side of multiphase converter 120. Detection values VL and VH detected by the voltage sensors 20 and 22 are input to the control circuit 210.

  The control circuit 210 includes a CPU (Central Processing Unit) (not shown) and an electronic control unit (ECU: Electronic Control Unit) with a built-in memory, and performs predetermined arithmetic processing based on a map and a program stored in the memory. Configured to run. Alternatively, at least a part of the ECU may be configured to execute predetermined numerical / logical operation processing by hardware such as an electronic circuit.

  Control circuit 210 is a signal PWM0 that controls on / off of switching elements Q01 and Q02 of normal converter 110 so that DC voltage VH of power supply line PL matches voltage command value VHr based on the detection values of the respective sensors described above. And signals PWM1 and PWM2 for controlling on / off of switching elements Q11, Q12, Q21, and Q22 of multiphase converter 120 are generated.

  Each of normal converter 110 and chopper circuits 121-1 and 121-2 causes switching currents to pass through reactors L 0, L 1, and L 2 by turning on and off switching elements Q 02, Q 12, and Q 22 in the lower arm. A DC voltage VH obtained by boosting the DC voltage VL on the low voltage side can be generated in the power supply wiring PL using the current path formed by the upper arm diodes D01, D11, and D21.

  Conversely, normal converter 110 and chopper circuits 121-1 and 121-2 each turn on and off switching elements Q01, Q11, and Q21 of the upper arm to pass the switched current to reactors L0, L1, and L2. As a result, the DC power supply B1 can be charged by the DC voltage VL obtained by stepping down the DC voltage VH on the high voltage side through the current path formed by the lower arm diodes D02, D12, D22 (during regeneration).

  In each of normal converter 110 and chopper circuits 121-1 and 121-2, switching elements Q 01, Q 11, and Q 21 of the upper arm can be fixed off during power running, and switching elements Q 02, Q 12, Q of the lower arm can be fixed during regeneration. It is also possible to fix Q22 off. However, the upper arm switching elements Q11 and Q21 and the lower arm switching elements Q02, Q12, and Q22 are complementary in each switching period in order to continuously cope with regeneration and power running without switching control depending on the current direction. May be turned on and off.

  Hereinafter, in the present embodiment, the ratio of the ON period of the switching element of the lower arm to the switching cycle is defined as the duty ratio DT.

  The relationship between the duty ratio DT and voltage conversion in each of the normal converter 110 and the chopper circuits 121-1 and 121-2 is expressed by the following equation (3). By modifying equation (3), voltage VH on the high voltage side is expressed by equation (4).

DT = 1.0− (VL / VH) (3)
VH = VL / (1.0-VL) (4)
From the equations (3) and (4), when the lower arm switching elements Q02, Q12, and Q22 are fixed off (DT = 0.0), VH = VL, and the voltage VH increases as the duty ratio DT increases. It is understood that it rises. That is, control circuit 210 can control voltage VH of power supply line PL for each of normal converter 110 and chopper circuits 121-1 and 121-2 by controlling duty ratio DT.

  The two chopper circuits 121-1 and 121-2 constituting the multiphase converter 120 operate with a phase difference of 180 (360/2) degrees, that is, a half cycle with respect to the switching cycle. Therefore, the phases of signals PWM1 and PWM2 are shifted by 180 degrees.

  Furthermore, in multiphase converter 120, magnetically coupled reactors L1 and L2 act so that the influences of the ripple components of reactor currents I1 and I2 cancel each other between chopper circuits 121-1 and 121-2. Therefore, the characteristics of the ripple current with respect to the duty ratio differ between the normal converter 110 and the multiphase converter 120 as shown in FIG.

  Referring to FIG. 3, characteristic line 260 corresponds to a plot of ripple current characteristics versus duty ratio in normal converter 110. In converter 110 that is a normal step-up chopper, the longer the ON period of switching element Q02 in the lower arm, the greater the accumulated energy in reactor L0 and the current change when switching element in the lower arm is OFF. The ripple current increases monotonously with the increase of.

  On the other hand, in the multiphase converter 120 provided with the magnetic coupling type reactor, since the electromotive force acts in the reverse direction between the reactors L1 and L2, the chopper circuits 121-1 and 121-2 are shifted in phase by 180 degrees. In the meantime, in the situation where the switching elements Q12 and Q22 of the lower arm are complementarily turned on / off, the ripple current suppressing effect is maximized. That is, in characteristic line 270 indicating the characteristic of ripple current with respect to the duty ratio of multiphase converter 120, there is a minimum point of ripple current at a specific duty ratio (DT = 0.5 in multiphase converter 120 of FIG. 1). . Also, in the region close to DT = 0, current switching is hardly performed, so that the ripple current naturally becomes small.

  As a result, in the specific duty ratio range (D1 <DT <D2 in FIG. 3), the polyphase converter 120 has a smaller ripple current than the normal converter 110.

  On the other hand, the multiphase converter 120 has a problem when it is used in a wide voltage range because the ripple current becomes larger due to the interaction between the reactors in the duty ratio range other than the above.

  As described above, since the ripple current characteristics with respect to the duty ratio are different between the normal converter 110 and the multiphase converter 120, the ripple current I1 in the normal converter 110 and the ripple in the multiphase converter 120 are different for each duty ratio. The current I2 is different. Further, there is a duty ratio region in which the ripple current is smaller when using the normal converter 110 (I2> I1) and a duty ratio region where the ripple current is smaller when using the multiphase converter 120 (I1> I2). To be understood.

  FIG. 4 is a functional block diagram illustrating a control configuration of the power supply device according to the embodiment of the present invention. 4 may be realized by software processing by the control circuit 210, or may be realized by configuring the control circuit 210 with an electronic circuit (hardware) that realizes the function.

  Referring to FIG. 4, control circuit 210 includes a converter selection unit 300, a ripple characteristic storage unit 310, a normal converter control unit 320, and a multiphase converter control unit 330.

  The ripple characteristic storage unit 310 stores information indicating the ripple current characteristic with respect to the duty ratio shown in FIG. Specifically, according to the characteristic lines 260 and 270 (FIG. 3) obtained in advance by analysis, operation experiment, etc., the ripple current I1 of the normal converter 110 and the ripple current I2 of the multiphase converter 120 corresponding to each duty ratio. Are mapped and stored.

  The converter selection unit 300 calculates a necessary voltage conversion ratio (VHr / VL) based on the voltage command value VHr of the power supply device 100 and the low voltage VL, and sets the reciprocal of the voltage conversion ratio to the above (3 The corresponding duty ratio is calculated by substituting it into the formula.

  Then, converter selection unit 300 reads ripple currents I 1 and I 2 at the duty ratio thus calculated from ripple characteristic storage unit 310. Furthermore, converter selection unit 300 selects one converter having a lower ripple current at the assumed duty ratio. That is, when I1> I2, multiphase converter 120 is selected, while when I2> I1, normal converter 110 is selected.

  When converter selection unit 300 selects normal converter 110, normal converter control unit 320 generates signals PWM0, PWM1, and PWM2, as shown in FIG.

  Referring to FIG. 5, normal converter control unit 320 controls the duty ratio of normal converter 110 based on voltage command value VHr and voltages VH and / or VL detected by the voltage sensor. For example, the duty ratio of normal converter 110 is set by correcting the duty ratio corresponding to the theoretical voltage conversion ratio determined by voltage command value VHr and voltage VL by the deviation of voltage VH from voltage command value VHr. The

  Normal converter control unit 320 generates signal PWM0 so as to on / off control switching elements Q01 and Q02 of normal converter 110 according to the duty ratio set in this way. On the other hand, normal converter control unit 320 generates signals PWM1 and PWM2 so that switching elements Q11, Q12, Q21, and Q22 of multiphase converter 120 are fixed off.

  Further, normal converter control unit 320 turns on relay RL0 while turning on relay RL0. Thereby, when normal converter 110 is selected, current input / output between DC power supply B1 and multiphase converter 120 can be cut off.

  On the other hand, when converter selection unit 300 selects multiphase converter 120, multiphase converter control unit 330 generates signals PWM0, PWM1, and PWM2, as shown in FIG.

  Referring to FIG. 6, multiphase converter control unit 330 controls the duty ratio of multiphase converter 120 based on voltage command value VHr and voltages VH and / or VL detected by the voltage sensor. Then, the signals PWM1 and PWM2 are generated in accordance with the controlled duty ratio and so that the phase is shifted by 180 degrees (half the switching period) between the chopper circuits 121-1 and 121-2. On the other hand, multiphase converter control unit 330 generates signal PWM0 so that switching elements Q01 and Q02 of normal converter 110 are fixed off.

  The duty ratio in polyphase converter 120 may be controlled in common between chopper circuits 121-1 and 121-2 based only on voltage information (voltage command value VHr and voltages VL and / or VH). Good. For example, the duty ratio of each of the chopper circuits 121-1 and 121-2 can be set to a common value by the same control as the normal converter 110. Alternatively, by arranging a current sensor (not shown) for detecting the reactor currents I1 and I2, the chopper circuits 121-1 and 121-2 are configured so as to perform the reactor current control independently. The duty ratio of converter 120 may be controlled. In this case, voltage VH of power supply wiring PL can be controlled by adjusting the command value for reactor current control in accordance with the deviation between voltage command value VHr and voltage VH.

  Furthermore, multiphase converter control unit 330 turns on relay RL0 while turning on relay RL1. Thereby, when the multiphase converter 120 is selected, current input / output between the normal converter 110 and the DC power supply B1 can be cut off.

  In the configuration of FIG. 4, the normal converter control unit 320 corresponds to a “first converter control unit”, and the multiphase converter control unit 330 corresponds to a “second converter control unit”.

  FIG. 7 is a flowchart for explaining a series of control processes by the control circuit 210 for realizing the control configuration shown in FIG. Each step of the flowchart is basically realized by software processing by the control circuit 210, but may be realized by hardware processing. The control process shown in FIG. 7 is started at a predetermined cycle.

Referring to FIG. 7, control circuit 210 obtains voltage command value VHr and voltage VL detected by voltage sensor 20 in step S100. Then, the control circuit 210
In step S110, a duty ratio corresponding to the voltage conversion ratio VHr / VL is calculated according to equation (3).

  Further, in step S120, control circuit 210 reads ripple current characteristics based on the converted duty ratio to obtain ripple current I1 in normal converter 110 and ripple current I2 in multiphase converter 120 at the duty ratio. Ask. In step S130, the control circuit 210 compares the ripple currents I1 and I2 by determining whether or not I1> I2. When I1> I2 (YES in S130), control circuit 210 proceeds to step S140, and control circuit 210 stops switching of normal converter 110. In accordance with this, the relay RL0 may be controlled to be turned off.

  Further, in step S150, control circuit 210 controls voltage VH of power supply line PL to voltage command value VHr by duty control of multiphase converter 120. That is, the processing in steps S140 and S150 is the same as the generation of signals PWM0, PWM1, and PWM2 (FIG. 6) and control of relays RL0 and RL1 by multiphase converter control unit 330 in FIG.

  On the other hand, when I1 <I2 (NO determination in S130), control circuit 210 proceeds to step S160 and stops switching of multiphase converter 120. In accordance with this, the relay RL1 may be controlled to be turned off.

  Further, in step S170, control circuit 210 controls voltage VH to voltage command value VHr by duty control of normal converter 110. That is, the processing in steps S160 and S170 is the same as the generation of signals PWM0, PWM1, and PWM2 (FIG. 6) and control of relays RL0 and RL1 by normal converter control unit 320 in FIG.

  As described above, in the power supply device according to the present embodiment, the normal step-up chopper type converter 110 and the multiphase converter 120 including the magnetically coupled reactor are connected in parallel, and the respective converters are relative to each other. The operation can be limited to the operation region where the ripple current is small. As a result, it is possible to secure a wide operating range (voltage conversion ratio range) and suppress ripple current. As a result, heat generation of the smoothing capacitor and the switching element can be suppressed, and the efficiency of the power supply device 100 can be increased and the life of the circuit element can be extended.

  For each chopper circuit 110, 121-1, 121-2, not only the configuration example of FIG. 1 in which switching elements are provided in both the upper arm and the lower arm, but also switching elements (Q02, Q12, Q22) in the lower arm. And a circuit configuration (only for powering) in which diodes (D01, D11, D21) are provided on the upper arm, or switching elements (Q01, Q11, Q21) are provided on the upper arm and diodes (D02, D12 are provided on the lower arm) , D22) may be arranged (regeneration only). Also in this case, the normal converter 110 and the multiphase converter 120 can be similarly selected by obtaining the characteristic lines 260 and 270 in advance.

  In FIG. 1, the multiphase converter 120 is configured by two chopper circuits connected in parallel. However, as shown in FIGS. 7 and 10 of Japanese Patent Laid-Open No. 2003-304681 (Patent Document 2), a plurality of three or more The polyphase converter 12 may be configured by parallel connection of N (N) chopper circuits. In this case, the N chopper circuits are ON / OFF controlled at a timing at which the phases are shifted by (360 / N) degrees. However, even in such a multiphase converter, the ripple current characteristic (characteristic line 270 in FIG. 3) with respect to the duty ratio can be obtained in advance by analysis or experiment.

  Alternatively, in the present embodiment, a configuration example in which a converter (normal converter 110) configured by a normal boost chopper and a multiphase converter (multiphase converter 120) including a magnetically coupled reactor is connected in parallel has been described. The application of the present invention is not limited to such a configuration. That is, for a power supply device configured by connecting a plurality of converters having different ripple currents (or 3 or more converters) in parallel, a converter having a relatively low ripple current at the current operating point is provided as in the present embodiment. It is possible to operate selectively.

  Further, in the present embodiment, the AC motor and the inverter circuit mounted on the hybrid vehicle or the electric vehicle are exemplified for the load 200 of the power supply device 100, but the application of the present invention is not limited to this. That is, the point that the present invention can be applied without particularly limiting the load 200 will be described in a confirming manner.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be applied to a power supply device for performing DC voltage conversion.

  20, 22 Voltage sensor, 100 Power supply device, 110 Normal converter, 120 Multi-phase converter, 121-1, 121-2 Chopper circuit, 200 Load, 210 Control circuit (ECU), 241, 242 Coil winding, 250 core, 251a 251b Outer leg part, 252 Central leg part, 253 Gap, 260 Characteristic line (normal converter), 270 Characteristic line (polyphase converter), 300 Converter selection part, 310 Ripple characteristic memory part, 320 Normal converter control part, 330 Phase converter controller, B1 DC power supply, C0, C1 smoothing capacitor, D01, D02, D11, D12, D21, D22 diode, DT duty ratio, GL ground wiring, I1 ripple current (normal converter), I2 ripple current (multiphase) Converter), L0 rear Kutor, L1, L2 reactor (magnetic coupling type), N0, N1, N2, Na node, PL power supply wiring, PWM0 signal (normal converter), PWM1, PWM2 signal (multi-phase converter), Q01, Q02, Q11, Q12, Q21, Q22 Switching element, RL0, RL1 relay, VH DC voltage (high voltage side), VHr voltage command value, VL DC voltage (low voltage side).

Claims (6)

A first converter configured to include at least one switching element for performing DC power conversion between a power supply wiring connected to a load and a DC power supply;
A second converter configured to include at least one switching element connected in parallel with the first converter between the DC power supply and the power supply wiring;
A control circuit for controlling the first and second converters,
Each of the first and second converters is configured such that a voltage conversion ratio that is a ratio of a voltage of the power supply wiring to an output voltage of the DC power supply changes according to a duty ratio in the on / off control of the switching element,
A ripple current characteristic with respect to the duty ratio is different between the first and second converters,
The control circuit includes:
A characteristic storage unit for storing information on the ripple current characteristic obtained in advance;
While calculating the necessary voltage conversion ratio based on the voltage command value of the power supply wiring and the output voltage of the DC power supply, from the first and second converters according to the information stored in the characteristic storage unit, And a converter selecting section for selectively operating one converter having a smaller ripple current at the calculated voltage conversion ratio. The first converter includes:
A first chopper circuit having at least one first switching element controlled to be turned on and off by the control circuit, and a first reactor arranged so that a current switched by the first switching element passes therethrough. Including
The second converter is:
A plurality of second chopper circuits connected in parallel;
Each of the plurality of second chopper circuits is
At least one second switching element that is on / off controlled by the control circuit;
A second reactor arranged to pass a current switched by the second switching element;
The second reactors of each second chopper circuit are arranged to be magnetically coupled to each other;
2. The power supply device according to claim 1, wherein on / off of the second switching element of each of the second chopper circuits is controlled so that timings of the plurality of second chopper circuits are shifted from each other by a predetermined phase.   3. The power supply device according to claim 2, wherein each of the second reactors of the plurality of second chopper circuits includes coil windings wound around different portions of a common core. The control circuit includes:
When the first converter is selected, the switching element of the second converter is fixed to be off while the voltage of the power supply wiring is controlled to the voltage command value to control the voltage of the first converter. A first converter control unit for controlling a duty ratio of the switching element;
When the second converter is selected, the switching element of the first converter is fixed to be off while the voltage of the power supply wiring is controlled to the voltage command value to control the voltage of the second converter. The power supply device according to claim 1, further comprising: a second converter control unit for controlling a duty ratio of the switching element. A first switch connected between the DC power source and the first converter;
A second switch connected between the DC power source and the second converter;
When the first converter is selected by the converter selection unit, the first switch is turned on, while the second switch is turned off,
5. The device according to claim 1, wherein when the second converter is selected by the converter selection unit, the second switch is turned on while the first switch is turned off. The power supply described. The characteristic storage unit stores a characteristic of the current ripple with respect to the duty ratio in each of the first and second converters,
The converter selection unit calculates a duty ratio in each of the first and second converters for realizing the calculated voltage conversion ratio, and currents of the first and second converters in the calculated duty ratio The power supply device according to claim 1, wherein the one converter is selected based on a comparison of ripples.

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