JP2011109869A - Power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely make ripple current to be lower than a prescribed level in a power supply having a polyphase converter having a magnetic coupling-type reactor element. <P>SOLUTION: A regular step-up chopper circuit shows a ripple current characteristic 102 that the ripple current monotonously increases in accordance with rise of a duty ratio. In a ripple current characteristic 101 of the magnetic coupling-type polyphase converter, minimal points of the ripple current exist to a change of the duty ratio. Since a duty ratio range where the ripple current becomes a prescribed level or below can previously be defined, a voltage command value to the converter is set by limiting it to a voltage range corresponding to such a duty ratio range. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device, and more particularly to a power supply device including a multiphase converter including a magnetically coupled reactor.

  A so-called multiphase converter is known which is composed of a plurality of converters connected in parallel and configured to operate these converters with a phase shift. For example, Japanese Patent Application Laid-Open No. 2006-262601 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2003-304681 (Patent Document 2) reduce the size by combining such a multiphase converter and a magnetically coupled reactor. A DC-DC converter capable of reducing the ripple current of the smoothing capacitor with the circuit configuration described is described.

JP 2006-262601 A JP 2003-304681 A

  As described in Patent Documents 1 and 2, in a multiphase converter in which a reactor is magnetically coupled between a plurality of converters connected in parallel, the ripple component of the reactor current (hereinafter referred to as ripple current) is reduced. The ripple current characteristics are different from those of a normal step-up chopper type converter.

  However, Patent Documents 1 and 2 do not describe any control of a multiphase converter using a magnetically coupled reactor as a circuit element in consideration of ripple current characteristics. For this reason, although it is possible to qualitatively suppress the temperature rise due to the decrease in the ripple current, there is a possibility that the effect of the ripple current reduction cannot be maximized in designing the circuit elements of the converter.

  The present invention has been made to solve such a problem, and an object of the present invention is to ensure that a ripple current is at a predetermined level in a power supply device including a multiphase converter having a magnetically coupled reactor element. By making the following, the effect of reducing the ripple current can be enjoyed to the fullest by suppressing the rating in the circuit element design.

  A power supply device according to the present invention includes a multiphase converter and a control circuit. The multiphase converter includes a plurality of chopper circuits connected in parallel between a power supply wiring connected to a load and a DC power supply. The control circuit controls operations of the plurality of chopper circuits. Each of the plurality of chopper circuits includes at least one switching element that is controlled to be turned on / off by a control circuit, and a reactor that is arranged so that a current switched by the switching element passes therethrough. The reactors of the chopper circuits are arranged so as to be magnetically coupled to each other. The control circuit includes a voltage command value setting unit, a duty ratio control unit, and a switching control unit. The voltage command value setting unit is configured to set the voltage command value of the power supply wiring according to the voltage request value of the power supply wiring based on the operating state of the load. The duty ratio control unit is configured to control the duty ratio of the switching element based on the voltage command value and the detected voltage of the power supply wiring. The switching control unit is configured to control on / off of the switching elements of each chopper circuit in accordance with the controlled duty ratio and so that the timing is shifted by a predetermined phase between the plurality of chopper circuits. Furthermore, the voltage command value setting unit limits the operation region of the multiphase converter in accordance with the range of the duty ratio in which the ripple current is smaller than a predetermined level in accordance with the characteristic of the ripple current with respect to the duty ratio of the multiphase converter obtained in advance. Set the voltage command value to

  Preferably, the voltage command value setting unit sets a settable range of the voltage command value in advance according to a predetermined duty ratio and a voltage detection value of the DC power source set in advance corresponding to an operation region in which the ripple current is smaller than a predetermined level. In addition, when the required voltage value is outside the settable range, the voltage command value is set to the minimum value within the voltage range higher than the required voltage value within the settable range.

  More preferably, each chopper circuit includes first and second switching elements connected in series between the ground wiring and the power supply wiring. The reactor has a coil winding connected between the connection point of the first and second switching elements and the DC power source. The coil winding of each chopper circuit is wound around different parts of the common core.

  More preferably, the duty ratio control unit includes a current command value setting unit and a plurality of current control units provided corresponding to each of the plurality of chopper circuits. The current command value setting is configured to set the current command value of each of the plurality of chopper circuits based on the voltage command value and the detected voltage. Each of the plurality of current control units is configured to independently set the duty ratio of the corresponding chopper circuit according to the passing current and current command value of the corresponding chopper circuit among the plurality of chopper circuits.

  Preferably, the load includes a permanent magnet type motor generator and an inverter configured to perform bidirectional power conversion between the motor generator and the power supply wiring. The induced voltage at the rated maximum rotational speed of the motor generator is applied to the motor generator at the highest value of the voltage of the power supply wiring by the multiphase converter corresponding to the duty ratio limitedly set by the voltage command value setting unit. Lower than voltage.

  According to the present invention, in a power supply device equipped with a multiphase converter including a magnetically coupled reactor element, the ripple current is surely set to a predetermined level or less, thereby reducing the ripple current by suppressing the rating in the circuit element design. You can enjoy it to the fullest.

It is a circuit diagram which shows the structure of the motor drive device 200 provided with 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. 2 is a graph showing a characteristic of a ripple current with respect to a duty ratio in the multiphase converter shown in FIG. 1. It is a functional block diagram explaining the control structure of the multiphase converter 12 in the power supply device by embodiment of this invention. It is a conceptual diagram explaining the setting of the voltage command value by the voltage command setting part shown in FIG. It is a conceptual diagram explaining the modification of the setting of the setting range of a duty ratio. It is a conceptual diagram explaining the modification of the setting of a voltage command value.

  Embodiments of the present invention will be described below 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 in principle.

  FIG. 1 is a circuit diagram showing a configuration of a motor drive device 200 including a power supply device according to an embodiment of the present invention.

  Referring to FIG. 1, motor drive device 200 includes DC power supply B <b> 1, magnetic coupling type multiphase converter 12, smoothing capacitor C <b> 1, control circuit 210, and load 220. The polyphase converter 12 and the control circuit 210 constitute a power supply device according to the embodiment of the present invention.

  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.

  Multiphase converter 12 includes a smoothing capacitor C0 and chopper circuits 13-1 and 13-2 connected in parallel. Chopper circuit 13-1 includes power semiconductor switching elements (hereinafter simply referred to as “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. Smoothing capacitor C0 smoothes the DC voltage on the low voltage side of multiphase converter 12, which is the output voltage of DC power supply B1.

  Similarly, chopper circuit 13-2 is configured similarly to chopper circuit 13-1, 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 multiphase converter 12, reactors L1 and L2 are arranged to be magnetically coupled to each other. That is, reactors L1 and L2 are provided so as 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 2).

  Referring to FIG. 1 again, smoothing capacitor C1 is connected between power supply line PL and ground line GL. Load 220 includes inverter 14 connected to power supply line PL and ground line GL, and AC motor M1 connected to inverter 14.

  Inverter 14 performs bidirectional power conversion between DC power on power supply wiring PL and AC power input / output to / from AC motor M1. AC motor M1 is driven by AC power input / output by inverter 14, and generates positive or negative torque.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are provided in parallel between power supply line PL and ground line GL. U-phase arm 15 includes switching elements Q5 and Q6, V-phase arm 16 includes switching elements Q7 and Q8, and U-phase arm 17 includes switching elements Q9 and Q10. Diodes D5 to D10 are connected in antiparallel with switching elements Q5 to Q10, respectively. An intermediate node of each of U-phase arm 15, V-phase arm 16, and W-phase arm 17 is connected to one end of a U-phase, V-phase, and W-phase stator winding of AC motor M1. The other ends of these stator windings are connected at a neutral point.

  AC motor M1 is configured, for example, by a permanent magnet type synchronous motor that operates as a motor generator. AC motor M1 is a drive motor for generating drive torque of drive wheels of an electric vehicle such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. That is, motor drive device 200 is typically mounted on an electric vehicle. AC motor M1 performs regenerative power generation by the rotational force of the driving force during regenerative braking of the electric vehicle.

  Alternatively, this AC motor M1 has a function of a generator driven by an engine, and operates as an electric motor for the engine, and is incorporated in a hybrid vehicle so that, for example, the engine can be started. You may do it.

  Voltage sensor 20 detects DC voltage VL on the low voltage side of multiphase converter 12 corresponding 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 12.

  Current sensor 24 detects a motor current MCRT of each phase flowing between inverter 14 and AC motor M1. Since the sum of the instantaneous values of the three-phase phase currents is always zero, the current sensor 24 is arranged only in two of the three phases, and the motor current of the phase in which the current sensor 24 is not arranged is calculated. It is also possible to ask for it. Current sensor 25 detects reactor current I1 that passes through reactor L1, and current sensor 26 detects reactor current I2 that passes through reactor L2. Detection values VL and VH detected by voltage sensors 20 and 22, detection values I 1 and I 2 detected by current sensors 25 and 26, and detection value MCRT detected by current sensor 24 are input to 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.

  The control circuit 210 is configured so that the AC motor M1 operates in accordance with the operation command based on the detection values obtained by the sensors, the rotational speed MRN of the AC motor M1, and the torque command value TR. The on / off (switching) of switching elements Q11, Q11, Q21, Q22, Q5 to Q10 is controlled. Specifically, control circuit 210 generates signals PWM1 and PWM2 for controlling on / off of switching elements Q11, Q12, Q21, and Q22 in order to control the voltage of power supply line PL to a desired voltage. Further, the control circuit 210 controls the switching element Q5 to control the amplitude and / or phase of the pseudo AC voltage applied to the AC motor M1 in order to control the output torque of the AC motor M1 according to the torque command value TR. A signal PWMI for controlling on / off of Q10 is generated.

  Each of the chopper circuits 13-1 and 13-2 turns on and off the switching elements Q12 and Q22 of the lower arm to pass the switched current through the reactors L1 and L2, thereby causing the diodes D11 and D21 of the upper arm to Using the current path, a DC voltage VH obtained by boosting the low-voltage side DC voltage VL can be generated in the power supply wiring PL (powering, I1> 0, I2> 0).

  On the other hand, each of the chopper circuits 13-1 and 13-2 turns on and off the switching elements Q11 and Q21 of the upper arm to pass the switched current to the reactors L1 and L2, thereby causing the lower arm diode D12. , D22 can be used to charge the DC power supply B1 with the DC voltage VL obtained by stepping down the DC voltage VH on the high voltage side (I1 <0, I2 <0 during regeneration).

  In each chopper circuit 13-1, 13-2, the switching elements Q11, Q21 of the upper arm can be fixed off during power running, and the switching elements Q12, Q22 of the lower arm can be fixed off during regeneration. is there. However, the switching elements Q11 and Q21 of the upper arm and the switching elements Q12 and Q22 of the lower arm are complementarily turned on and off within each switching period in order to continuously cope with regeneration and power running without switching the control depending on the current direction. You may let them.

  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. That is, the on-period ratio of the upper arm element is represented by (1.0−DT). From the general characteristics of the chopper circuit, the relationship between the duty ratio DT and the voltage conversion in the chopper circuits 13-1 and 13-2 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 expressions (3) and (4), when the lower-arm switching elements 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 is, the control circuit 210 can control the voltage VH of the power supply wiring PL by controlling the duty ratio DT in the chopper circuits 13-1 and 13-2. Details of such converter control will be described later in detail.

  The two chopper circuits 13-1 and 13-2 constituting the multiphase converter 12 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.

  Further, in the multiphase converter 12, the effect of the ripple components of the reactor currents I1 and I2 is canceled between the chopper circuits 13-1 and 13-2 by the magnetically coupled reactor. Therefore, the ripple current characteristic with respect to the duty ratio in the multiphase converter 12 of FIG. 1 is different from that of a normal chopper circuit as shown in FIG.

  Referring to FIG. 3, characteristic line 102 shows a ripple with respect to the duty ratio in a normal chopper circuit in which reactors L1 and L2 in each of chopper circuits 13-1 and 13-2 are replaced with normal (not magnetically coupled) reactors. This corresponds to a plot of current characteristics. In a normal chopper circuit, the longer the on-period of the lower arm switching element, the larger the accumulated energy in the reactor and the current change when the lower arm switching element is off, so the ripple current increases monotonously.

  On the other hand, in the multiphase converter 12 including the magnetically coupled reactor, the electromotive force acts in the reverse direction between the reactors L1 and L2, and therefore the chopper circuits 13-1 and 13-2 whose phases are shifted by 180 degrees are provided. 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 the characteristic line 101 indicating the ripple current characteristic with respect to the duty ratio of the multiphase converter 12, there is a minimum point of the ripple current in the vicinity of DT = 0.5. Also, in the region close to DT = 0, current switching is hardly performed, so that the ripple current naturally becomes small.

  The ripple current of the multiphase converter 12 can be quantitatively grasped by obtaining the characteristic line 101 in advance by analysis, operation experiment, or the like. By limiting to 120, for example, by limiting the duty ratio to 0 and D0 (D0 = 0.5 in the configuration example of FIG. 1), the ripple current can be reliably lowered below a predetermined level.

  FIG. 4 is a functional block diagram illustrating a control configuration of multiphase converter 12 in 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 shown in FIG. 1 includes voltage command setting unit 300, subtraction unit 310, control operation unit 320, multiplication unit 325, current control units 330 and 335, and modulation unit. 350, 355.

  The voltage command setting unit 300 performs the ripple current characteristics shown in FIG. 3 according to the required voltage VHsys set based on the operating state of the load 220, specifically, the rotational speed (MRN) and torque (TR) of the AC motor M1. The voltage command value VHr is set in consideration of the above.

  Here, the setting of the voltage command value by the voltage command setting unit 300 will be described in detail with reference to FIG.

  Referring to FIG. 5, required voltage VHsys is variably set based on the operating state of AC motor M1, which is a load, that is, based on rotational speed (MRN) and torque (TR). The required voltage VHsys is a power supply in which the amplitude of the AC voltage (applied voltage to the AC motor M1) generated by the inverter 14 is larger than at least the amplitude of the induced voltage generated in the stator winding of the AC motor M1. It is necessary to set the voltage VH of the wiring PL.

  Referring to FIG. 5, in the power supply device according to the embodiment of the present invention, voltage command value VHr is limitedly set to a voltage range corresponding to two of duty ratio = 0 and D0 shown in FIG. 5. . That is, according to the equation (4), only two values VHr = VL corresponding to DT = 0 and VHr = V0 = VL / (1-D0) corresponding to DT = D0 are set in a limited manner. When VHsys ≦ VL, VHr = VL is set. On the other hand, when VHsys> VL, VHr = V0. Note that V0 = VL / (1-D0) needs to be designed to be greater than or equal to the maximum value of the required voltage VHsys that is variably set. For example, as described above, the voltage applied to the AC motor 14 by the inverter 14 at the voltage V0 needs to be designed to be larger than the induced voltage when the AC motor M1 operates at the rated maximum rotational speed. There is.

  Furthermore, in order to prevent the voltage command value VHr from being frequently switched when the required voltage VHsys changes in the vicinity of the voltage VL, the voltage command value VHr is increased from VL to V0. A hysteresis dV may be provided between the time when the voltage is lowered to VL.

  In this way, voltage command value VHr is set so that voltage command value VHr of multiphase converter 12 is limited to duty ratio regions 110 and 120 in which the ripple current is reliably below a predetermined level. .

  Referring to FIG. 4 again, subtraction unit 310 calculates voltage deviation ΔVH by subtracting voltage VH detected by voltage sensor 22 from voltage command value VHr set by voltage command setting unit 300. The control calculation unit 320 typically sets the current command value Ir so as to bring the voltage deviation ΔVH close to zero according to PI control (proportional integration) calculation. Qualitatively, when ΔVH increases (changes in the positive direction), the current command value Ir increases, and when ΔVH decreases (changes in the negative direction), the current command value Ir decreases.

  Multiplier 325 calculates current command value Ir # of each chopper circuit 13-1, 13-2 by multiplying current command value Ir in multiphase converter 12 by 0.5 (Ir # = Ir). / 2).

  Current control unit 330 sets duty command value Id1 according to a control calculation (such as a PI control calculation) based on a current deviation between reactor current I1 detected by current sensor 25 and current command value Ir #. Similarly, current control unit 335 sets duty command value Id2 in accordance with a control calculation (PI control calculation or the like) based on a current deviation between reactor current I2 detected by current sensor 26 and current command value Ir #.

  The duty command values Id1, Id2 are set in a range of 0.0 ≦ Id1, Id2 <1.0. Current control units 330 and 335 increase the duty ratio when increasing reactor currents I1 and I2 with respect to current command value Ir #, while decreasing the duty ratio when decreasing reactor currents I1 and I2. Duty command values Id1 and Id2 are set.

  Modulator 350 generates signal PWM1 for controlling chopper circuit 13-1 in accordance with voltage comparison between carrier wave CW, which is a triangular wave or sawtooth wave of a predetermined frequency, and duty command value Id1. The frequency of the carrier wave CW corresponds to the switching frequency of the chopper circuits 13-1 and 13-2. Further, the peak-peak voltage of the carrier wave CW corresponds to the range of 0 to 1.0 of the duty ratio indicated by the duty command value Id1. The modulation unit 350 generates the signal PWM1 so that the lower arm switching element Q12 is turned on during the period of Id1> CW and the lower arm switching element Q12 is turned off during the period of CW> Id1.

  As described above, when the voltage VH is lower than the voltage command value VHr, the duty command value Id1 is set in the direction in which the duty ratio of the lower arm is increased, so that the reactor current I1 is increased. 13-1 is controlled by pulse width modulation (PWM). On the contrary, when the voltage VH is higher than the voltage command value VHr, the duty command value Id1 is set in the direction in which the duty ratio of the lower arm is decreased, so that the reactor current I1 is decreased. 1 is controlled by pulse width modulation (PWM).

  The modulation unit 355 has the same function as that of the modulation unit 350. According to the voltage comparison between the inverted signal of the carrier wave CW, that is, a signal whose phase is shifted by 180 degrees from the carrier wave CW, and the duty command value Id2, the chopper circuit 13 -2 is generated to control -2. Thereby, in the chopper circuits 13-1 and 13-2, after switching the phase of the switching control by 180 degrees, the switching control (duty ratio control) for controlling the voltage VH to the voltage command value VHr is executed independently. Is done. As described above, the switching elements Q11 and Q21 of the upper arm element may be turned on during the off period of the switching elements Q12 and Q22 of the lower arm.

  As described above, according to the control configuration shown in FIG. 4, in the multiphase converter 12, the two chopper circuits 13-1 and 13-2 connected in parallel operate so that their phases are shifted by an electrical angle of 180 °. In each of circuits 13-1 and 13-2, reactor currents I1 and I2 for controlling voltage VH to voltage command VHr are independently controlled.

  That is, according to the configuration of FIG. 4, the “duty control unit” according to the present invention is configured by the subtraction unit 310, the control calculation unit 320, the multiplication unit 325, and the current control units 330 and 335, and the modulation units 350 and 355 A “switching control unit” is configured. In particular, the “current command value setting unit” of the present invention is configured by the subtraction unit 310, the control calculation unit 320, and the multiplication unit 325.

  Next, a modified example of setting the voltage command value VHr by the voltage command setting unit 300 will be described with reference to FIGS. 6 and 7.

  Referring to FIG. 6, in the modification, the design upper limit value I0 of the ripple current is set, and as a boundary value of the operation region where the ripple current is lower than I0 with respect to the same characteristic line 101 as FIG. Duty ratios D1 and D2 are determined. Compared with FIG. 3, D1 <D0 (FIG. 3) <D2.

  In light of equation (4), voltages V1 and V2 corresponding to voltage VH at duty ratios D1 and D2 are determined by equations (5) and (6) below.

V1 = 1 / (1-D1) · VL (5)
V2 = 1 / (1-D2) · VL (6)
Referring to FIG. 7, voltage command setting unit 300 sets VHr = VL when VHsys ≦ VL, while setting VHr = V1 in the range of VL <VHsys ≦ V1, and in the range of VHsys ≧ V2. Set VHsys = V2. In the range of V1 <VHsys <V2, VHr = VHsys is set. Compared with FIG. 5, it is understood that V1 <V0 <V2. Further, V2 needs to be designed to be greater than or equal to the maximum value of the required voltage VHsys that is variably set.

  In this way, according to FIG. 5 or FIG. 7, voltage command setting unit 300 previously sets the settable range of voltage command value VHr in correspondence with the limited application range of the duty ratio in light of ripple current characteristics (FIG. 3). In addition, when the required voltage VHsys is outside the settable range, the voltage command value VHr is set to the minimum value within the settable range that is higher than the required voltage VHsys.

  Further, in the vicinity of VHsys = VL, a hysteresis dV similar to that shown in FIG. 5 may be provided. In other words, it is more practical to provide such hysteresis than to set the duty ratio D3 in FIG. 6 for DT = 0.0 and set VHr in the vicinity of VHsys = VL continuously. Is preferred.

  As described above, in the power supply device according to the present embodiment, paying attention to the characteristic ripple current characteristic of the multiphase converter including the magnetically coupled reactor, the operation region (duty duty) in which the ripple current is surely below a predetermined level is ensured. The multiphase converter 12 can be operated in a limited manner. Therefore, the heat generation level due to the ripple current can be predicted more reliably, and the maximum current value including the ripple current can be estimated more reliably. As a result, the design of the rated values of the circuit elements such as the switching elements Q11, Q12, Q21, Q22 and the smoothing capacitors C0, C1 constituting the multiphase converter becomes more reliable, and the cost can be reduced by suppressing the ratings. . That is, the effect of reducing the ripple current can be maximized.

  In FIG. 4, the configuration in which duty control for current control is independently performed in each of the chopper circuits 13-1 and 13-2 is illustrated. However, as a simpler control configuration, a control calculation result for the voltage deviation ΔVH is illustrated. Accordingly, the duty ratios of the chopper circuits 13-1 and 13-2 can be set in common. However, in the configuration of FIG. 4, by directly controlling the currents passing through the chopper circuits 13-1 and 13-2, an unbalanced operation due to variations in circuit constant differences between the chopper circuits can be eliminated. . As a result, the multiphase converter can be operated more stably. In particular, since the current variation between the converters can be suppressed, the reliability of the rated value design of the circuit element can be improved.

  In FIG. 1, the multiphase converter 12 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, in such a multi-phase converter, the ripple current characteristic with respect to the duty ratio (FIG. 3) also changes. Therefore, the ripple current characteristic is obtained in advance, and the duty for ensuring that the ripple current is lower than a predetermined level according to the characteristic. It is necessary to determine the range of the ratio and the range of the voltage command value VHr corresponding thereto.

  For each chopper circuit, 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 (Q12, Q22) are provided in the lower arm and diodes (D11, D21) are provided in the upper arm. ) Or a circuit configuration in which switching elements (Q11, Q21) are provided on the upper arm and diodes (D12, D22) are provided on the lower arm. Also in this case, the range of the duty ratio for ensuring that the ripple current is lower than a predetermined level in correspondence with the characteristic of the ripple current with respect to the duty ratio that can be grasped in advance, and the range of the voltage command value VHr corresponding thereto Can be decided.

  In the present embodiment, the load 220 is exemplified by the AC motor M1 and the inverter 14 mounted on a hybrid vehicle or an electric vehicle. However, 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 220 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 control of a multiphase converter including a magnetically coupled reactor.

  12 multi-phase converter, 13-1, 13-2 chopper circuit, 14 inverter, 15-17 each phase arm (inverter), 20, 22 voltage sensor, 24, 25, 26 current sensor, 101 characteristic line (normal converter), 102 characteristic line (magnetic coupling type multi-phase converter), 110, 120 duty ratio region (small ripple current), 200 motor drive device, 210 control circuit (ECU), 220 load, 241, 242 coil winding, 250 core, 251a 251b Outer leg, 252 Central leg, 253 Gap, 300 Voltage command setting unit, 310 Subtraction unit, 320 Control operation unit, 325 Multiply unit, 330, 335 Current control unit, 350, 355 Modulation unit, B1 DC power supply, C0, C1 smoothing capacitor, CW carrier wave, DT, D0, D1, D2 due Ratio, D11, D21, D12, D22 diode (converter), D5 to D10 diode (inverter), d gap length, dV hysteresis, GL ground wiring, I0 design upper limit (ripple current), I1, I2 reactor current, Id1 , Id2 Duty command value, Ir current command value, L1, L2 reactor, M1 AC motor, MCRT motor current, MRN speed, N1, N2 node, PL power supply wiring, PWM1, PWM2 signal (converter control), PWMI signal (inverter) Control), Q11, Q11, Q21, Q22 switching element (converter), Q5 to Q10 switching element (inverter), S1, S2 cross section, TR torque command value, VH DC voltage (converter high voltage side), VHr voltage command, VHsysDetermined voltage, VHr voltage command value, VL DC voltage (converter low voltage side), .DELTA.VH voltage deviation.

Claims (5)

A multiphase converter including a plurality of chopper circuits connected in parallel between a power supply wiring connected to a load and a DC power supply;
A control circuit for controlling operations of the plurality of chopper circuits,
Each of the plurality of chopper circuits is
At least one switching element that is on / off controlled by the control circuit;
Including a reactor arranged to pass a current switched by the switching element,
The reactors of each of the chopper circuits are arranged to be magnetically coupled to each other;
The control circuit includes:
A voltage command value setting unit for setting a voltage command value of the power supply wiring according to a voltage request value of the power supply wiring based on the operating state of the load;
A duty ratio controller for controlling a duty ratio of the switching element in order to control the voltage of the power supply wiring to the voltage command value;
A switching control unit for controlling on / off of the switching element of each chopper circuit according to the controlled duty ratio and so that the timing is shifted by a predetermined phase between the plurality of chopper circuits,
The voltage command value setting unit corresponds to a range of the duty ratio in which the ripple current is smaller than a predetermined level according to a characteristic of a ripple current with respect to the duty ratio of the multiphase converter obtained in advance. A power supply apparatus that sets the voltage command value so that an operation region is limited.   The voltage command value setting unit sets a settable range of the voltage command value according to a duty ratio range set in advance corresponding to an operation region in which the ripple current is smaller than a predetermined level and a voltage detection value of the DC power supply. 2. The voltage command value is set to a minimum value within a voltage range that is higher than the voltage request value in the settable range when the voltage request value is outside the settable range and is determined in advance. Power supply. Each chopper circuit is
First and second switching elements connected in series between a ground wiring and the power supply wiring;
The reactor has a coil winding connected between a connection point of the first and second switching elements and the DC power source,
The power supply device according to claim 1 or 2, wherein the coil winding of each chopper circuit is wound around a different part of a common core. The duty ratio controller is
Based on the voltage command value and the detected voltage, a current command value setting unit for setting a current command value of each of the plurality of chopper circuits,
A plurality of current control units provided corresponding to each of the plurality of chopper circuits,
Each of the plurality of current control units is configured to independently set the duty ratio of the corresponding chopper circuit according to the passing current of the corresponding chopper circuit and the current command value among the plurality of chopper circuits. The power supply device according to any one of claims 1 to 3. The load is
A permanent magnet type motor generator;
An inverter configured to perform bidirectional power conversion between the motor generator and the power supply wiring,
The induced voltage at the rated maximum rotational speed of the motor generator is the motor generator at the highest value among the voltages of the power supply wiring by the multiphase converter corresponding to the duty ratio limitedly set by the voltage command value setting unit. The power supply device of any one of Claims 1-4 lower than the applied voltage to.

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