Power supply device and control device and control method thereof

Abstract

To provide a power supply device in which an auxiliary converter is used.SOLUTION: A power supply device 1 according to the present invention includes: a DC / DC converter 11 having first and second phases, which are first and second legs of a full-bridge circuit, respectively; an auxiliary converter 12A and a reactor LA inserted in series between the output end of the first phase and a node n1; an auxiliary converter 12B and a reactor LB inserted in series between the output end of the second phase and the node n1; and a switch 13 inserted between the node n1 and a load 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply device, as well as a control device and a control method thereof.

Background Art

[0002] In recent years, the spread of devices using rechargeable batteries, such as electric vehicles, renewable energy power generation, and mobile devices, has been rapidly progressing. Along with this, the level of performance required for power supply devices for rechargeable battery tests is becoming higher. Examples of such performance include high voltage compatibility, large power capacity, high speed response, low output ripple, high efficiency, and low cost.

[0003] Non-Patent Document 1 discloses the configuration of a typical power supply device for rechargeable battery tests. As shown in FIG. 1 of the same document, the power supply device for rechargeable battery tests has a configuration in which a PWM (Pulse Width Modulation) rectifier, an isolated DC / DC converter, and a non-isolated DC / DC converter (main converter) are connected in series between an AC power supply and a load (the rechargeable battery to be tested).

[0004] Non-Patent Document 2 discloses a technique for reducing the output ripple of a non-isolated DC / DC converter connected between a high-voltage side power supply and a low-voltage side power supply. An auxiliary converter composed of a full-bridge cell is inserted between the output terminal of the bidirectional chopper constituting the main converter of the non-isolated DC / DC converter and the low-voltage side power supply. This auxiliary converter is configured to have a full-bridge circuit and a capacitor connected in parallel to the full-bridge circuit.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

[0006] The inventors of the present application have been considering applying an auxiliary converter as described in Non-Patent Document 2 to a power supply device in order to reduce the output ripple of the power supply device as described in Non-Patent Document 1. Specifically, they have been considering inserting an auxiliary converter between the output end of the main converter of the power supply device and the load. However, in the course of their consideration, they have found that a configuration in which an auxiliary converter is applied to a power supply device has a problem in that the auxiliary converter cannot be initially charged.

[0007] Specifically, in order to use an auxiliary converter, it is necessary to charge the capacitor therein (initial charge) before starting. In the configuration of Non-Patent Document 2 with power supplies on both sides, if it is allowed to pass current through the power supplies on both sides during the initial charge, this initial charge can be completed without any particular problem by passing current between the power supplies. However, when applying an auxiliary converter to a power supply device, in order to pass the same current, it is necessary to pass current through the battery under test. Since passing such current through the battery before the start of the test is prohibited, it is impossible to pass the current for initial charge through the auxiliary converter, and as a result, it has conventionally been impossible to apply an auxiliary converter to a power supply device.

[0008] Therefore, one of the objects of the present invention is to provide a power supply device to which an auxiliary converter is applied.

[0009] By the way, the control of the auxiliary converter is executed based on the comparison result between a carrier signal and a voltage signal generated from the output voltage of the main converter. Conventionally, during this control, the phase of the triangular-wave carrier signal was maintained at a constant value. However, in order to achieve the above object, when providing a first phase and a second phase in the main converter of the power supply device and installing an auxiliary converter in each, if the phase of the carrier signal is maintained at a constant value, the phase of the output voltage of one auxiliary converter and the phase of the output voltage of the other auxiliary converter may coincide, and as a result, the effect of reducing the output ripple may not be obtained.

[0010] Therefore, another object of the present invention is to provide a control device and a control method for a power supply device that can obtain the effect of reducing the output ripple even when a first phase and a second phase are provided in the main converter and an auxiliary converter is installed in each.

Means for Solving the Problems

[0011] The power supply device according to the present invention includes a DC / DC converter having a first phase and a second phase that are the first leg and the second leg of a full-bridge circuit, respectively, a first auxiliary converter and a first reactor serially inserted between an output terminal of the first phase and an output node, a second auxiliary converter and a second reactor serially inserted between an output terminal of the second phase and the output node, and a switch inserted between the output node and a load.

[0012] The control device of the power supply device according to the present invention is a control device of a power supply device including a DC / DC converter having a first phase and a second phase that are the first leg and the second leg of a full-bridge circuit, respectively, a first auxiliary converter and a first reactor serially inserted between an output terminal of the first phase and an output node, a second auxiliary converter and a second reactor serially inserted between an output terminal of the second phase and the output node, and a switch inserted between the output node and a load. The control device controls the operation of the DC / DC converter so that each of a first output voltage output from the output terminal of the first phase and a second output voltage output from the output terminal of the second phase changes according to a predetermined duty ratio, controls the operation of the first auxiliary converter based on a first carrier signal and a first command value that changes in synchronization with an AC component of the first output voltage, controls the operation of the second auxiliary converter based on a second carrier signal and a second command value that changes in synchronization with an AC component of the second output voltage, and generates the first carrier signal and the second carrier signal based on a predetermined carrier signal so that a phase difference between the first carrier signal and the second carrier signal is different in a first period in which the first command value and the second command value are different from each other and in a second period in which the first command value and the second command value are the same as each other.

[0013] The control method of the power supply device according to the present invention is a DC / DC converter having a first phase and a second phase which are the first leg and the second leg of a full-bridge circuit respectively, a first auxiliary converter and a first reactor inserted in series between the output terminal of the first phase and the output node, a second auxiliary converter and a second reactor inserted in series between the output terminal of the second phase and the output node, and a switch inserted between the output node and the load. The control method of the power supply device includes controlling the operation of the DC / DC converter such that each of a first output voltage output from the output terminal of the first phase and a second output voltage output from the output terminal of the second phase changes according to a predetermined duty ratio, controlling the operation of the first auxiliary converter based on a first carrier signal and a first command value that changes in synchronization with an AC component of the first output voltage, controlling the operation of the second auxiliary converter based on a second carrier signal and a second command value that changes in synchronization with an AC component of the second output voltage, and generating the first carrier signal and the second carrier signal based on a predetermined carrier signal such that a phase difference between the first carrier signal and the second carrier signal is different in a first period in which the first command value and the second command value are different from each other and in a second period in which the first command value and the second command value are the same as each other.

Advantages of the Invention

[0014] According to the power supply device of the present invention, since a current path can be formed from the output terminal of the first phase to the output terminal of the second phase through the first auxiliary converter, the output node, and the second auxiliary converter, the first auxiliary converter and the second auxiliary converter can be charged without flowing a current to the load. Therefore, it becomes possible to provide a power supply device to which an auxiliary converter is applied.

[0015] According to the control device and control method of the power supply device according to the present invention, in both the case where the first output voltage and the second output voltage are the same value and the case where the first output voltage and the second output voltage are different values, the phase of the output voltage of one auxiliary converter and the phase of the output voltage of the other auxiliary converter can be made different. Therefore, even when the main converter is provided with a first phase and a second phase and an auxiliary converter is installed in each, it is possible to obtain an effect of reducing the output ripple.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] FIG. 1 is a diagram showing the configuration of the power supply device 1 and its control device 2 according to the present embodiment. As shown in the figure, the power supply device 1 according to the present embodiment is a power supply device for battery test connected between a DC power supply 3 that outputs a DC voltage Vdc (>0) and a load 4 that is a storage battery. Hereinafter, an example in which the power supply device 1 is a power supply device for battery test will be taken to describe the embodiments of the present invention, but the present invention is widely applicable to various power supply devices (including power supply circuits, power conversion devices, and power converters) including power supplies for battery test.

[0019] Inside the power supply device 1, a non-insulated DC / DC converter 11 (main converter), auxiliary converters 12A, 12B, reactors LA, LB, and a switch 13 are arranged. The DC power supply 3 may have a configuration including an AC power supply, a PWM rectifier, and an insulated DC / DC converter as described in, for example, Non-Patent Document 1.

[0020] The control device 2 is a computer that controls the operation of the power supply device 1, and is configured to operate based on command values Da, Db and carrier signals carrier1, carrier2 supplied from an external computer (not shown). The command values Da, Db are each a constant voltage value, and usually have the same value. The carrier signal carrier1 is a triangular wave signal that oscillates at a constant period T in a voltage range of 0 or more, and the carrier signal carrier2 is a triangular wave signal that oscillates at a period shorter than the period T centered on a voltage of 0. Details of the control by the control device 2 will be sequentially described in the description of the configuration of the power supply device 1.

[0021] The DC / DC converter 11 is configured to have four switches S1A, S2A, S1B, and S2B that form a full-bridge circuit. These switches S1A, S2A, S1B, and S2B are each one-way switches composed of a semiconductor element such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), and a diode connected in parallel with this semiconductor element. This also applies to each switch in the auxiliary converters 12A and 12B described later.

[0022] Switches S1A and S2A are connected in series in this order between the positive terminal and the negative terminal (ground terminal) of the DC power supply 3, and form the first leg of the full-bridge circuit. Similarly, switches S1B and S2B are also connected in series in this order between the positive terminal and the negative terminal of the DC power supply 3, and form the second leg of the full-bridge circuit. Switches S1A and S1B are the upper arms (upper switches) of each leg, and switches S2A and S2B are the lower arms (lower switches) of each leg. Hereinafter, the first leg composed of switches S1A and S2A is referred to as the "first phase" of the DC / DC converter 11, and the second leg composed of switches S1B and S2B is referred to as the "second phase" of the DC / DC converter 11. The connection point of switches S1A and S2A constitutes the output terminal of the first phase, and the connection point of switches S1B and S2B constitutes the output terminal of the second phase.

[0023] Figure 2 is a diagram showing a control method of the DC / DC converter 11 by the control device 2. The carrier signals carrier_a and carrier_b shown in the figure are signals generated by the control device 2 based on the above-described carrier signal carrier1. The carrier signal carrier1 is a triangular wave signal that oscillates with a period T, and the carrier signal carrier_a is the carrier signal carrier1 itself. The carrier signal carrier_b is a signal obtained by shifting the phase of the carrier signal carrier1 by 180°.

[0024] The control device 2 controls the on / off states of switches S1A and S2A by comparing the carrier signal carrier_a with the command value Da. Specifically, the control device 2 turns on switch S1A and turns off switch S2A during a period of time dT (0 < d < 1) when the carrier signal carrier_a is smaller than the command value Da, and turns off switch S1A and turns on switch S1A during a period of time (1 - d)T when the carrier signal carrier_a is larger than the command value Da. Also, the control device 2 controls the on / off states of switches S1B and S2B by comparing the carrier signal carrier_b with the command value Db. Specifically, the control device 2 turns on switch S1B and turns off switch S2B during a period of time dT when the carrier signal carrier_b is smaller than the command value Db, and turns off switch S1B and turns on switch S1B during a period of time (1 - d)T when the carrier signal carrier_b is larger than the command value Db.

[0025] With the above control, the output voltages Vma of the first phase and Vmb of the second phase of the DC / DC converter 11 become the voltages represented by the following formulas (1) to (4). However, Vma dc , Vmb dc are the DC components of the output voltages Vma and Vmb respectively, and Vma ac , Vmb ac are the AC components of the output voltages Vma and Vmb respectively. Hereinafter, the periods when the voltages Vma ac , Vmb ac are (1 - d)V dc are respectively referred to as the "high periods" of the output voltages Vma and Vmb, and the periods when the voltages Vma ac , Vmb ac are -dV dc are sometimes respectively referred to as the "low periods" of the output voltages Vma and Vmb.

[0026]

Equation

[0027] Return to FIG. 1. Switch 13 is a single-pole double-throw switch having a common terminal and two selection terminals. The common terminal of switch 13 constitutes the illustrated node n1 (output node). One selection terminal of switch 13 is connected to one terminal of load 4. Therefore, when one selection terminal of switch 13 is selected, node n1 will be connected to one terminal of load 4. The other terminal of load 4 is connected to the negative terminal of DC power supply 3. The other selection terminal of switch 13 constitutes an open end. Therefore, when the other selection terminal of switch 13 is selected, node n1 will be disconnected from load 4.

[0028] An auxiliary converter 12A and a reactor LA are inserted in series between the output terminal of the first phase of DC / DC converter 11 (the connection point of switches S1A and S2A) and node n1. Also, an auxiliary converter 12B and a reactor LB are inserted in series between the output terminal of the second phase of DC / DC converter 11 (the connection point of switches S1B and S2B) and node n1.

[0029] The auxiliary converter 12A (the first auxiliary converter) is composed of four switches S11A1, S12A1, S21A1, S22A1 that form a full-bridge circuit and a capacitor C1A. Switch S11A1 constitutes the upper switch (the first upper switch) of the input-side leg of the full-bridge circuit, and switch S12A1 constitutes the lower-arm side switch (the first lower switch) of the input-side leg of the full-bridge circuit. The connection point of switches S11A1 and S12A1 constitutes the input end of the full-bridge circuit and is connected to the output terminal of the first phase of DC / DC converter 11. Also, switch S21A1 constitutes the upper arm (the second upper switch) of the output-side leg of the full-bridge circuit, and switch S22A1 constitutes the lower arm (the second lower switch) of the output-side leg of the full-bridge circuit. The connection point of switches S21A1 and S22A1 constitutes the output end of the full-bridge circuit and is connected to node n1 via reactor LA. Capacitor C1A is connected in parallel with these between the input-side leg and the output-side leg of the full-bridge circuit.

[0030] The auxiliary converter 12A is configured to operate under the control of the control device 2. The control device 2 controls the on / off of the switches S11A1, S12A1, S21A1, and S22A1 based on the carrier signal carrier2 and the command value D_a supplied from the outside, thereby controlling the operation of the auxiliary converter 12A. The details of this control will be described later with reference to FIGS. 5 to 10.

[0031] The auxiliary converter 12B (second auxiliary converter) includes four switches S11B1, S12B1, S21B1, and S22B1 that form a full-bridge circuit, and a capacitor C1B. The switch S11B1 forms the upper switch (first upper switch) of the input-side leg of the full-bridge circuit, and the switch S12B1 forms the lower switch (first lower switch) of the input-side leg of the full-bridge circuit. The connection point of the switches S11B1 and S12B1 forms the input terminal of the full-bridge circuit and is connected to the output terminal of the second phase of the DC / DC converter 11. Also, the switch S21B1 forms the upper switch (second upper switch) of the output-side leg of the full-bridge circuit, and the switch S22B1 forms the lower switch (second lower switch) of the output-side leg of the full-bridge circuit. The connection point of the switches S21B1 and S22B1 forms the output terminal of the full-bridge circuit and is connected to the node n1 via the reactor LB. The capacitor C1B is connected in parallel between the input-side leg and the output-side leg of the full-bridge circuit.

[0032] The auxiliary converter 12B is also configured to operate under the control of the control device 2. The control device 2 controls the on / off of the switches S11B1, S12B1, S21B1, and S22B1 based on the carrier signal carrier2 and the command value D_b supplied from the outside, thereby controlling the operation of the auxiliary converter 12B. The details of this control will also be described later with reference to FIGS. 5 to 10.

[0033] Before starting the test of the load 4 using the power supply device 1, it is necessary to perform the above-described initial charging on the capacitors C1A and C1B in the auxiliary converters 12A and 12B. According to the present embodiment, this initial charging can be realized without flowing a current through the load 4. Hereinafter, this point will be specifically described.

[0034] FIGS. 3 and 4 are diagrams showing the on / off states of the respective switches during the initial charging of the capacitors C1A and C1B. FIG. 3 shows the states of the respective switches during the initial charging of the capacitor C1A, and FIG. 4 shows the states of the respective switches during the initial charging of the capacitor C1B.

[0035] First, referring to FIG. 3, in this case, the control device 2 controls the switches S1A, S2B, S11A1, S22A1, S21B1, and S11B1 to be on, and controls the switches S2A, S1B, S12A1, S21A1, S22B1, and S12B1 to be off. Also, the other selection terminal (the terminal constituting the open end) of the switch 13 is selected. Thereby, as shown by the broken line in FIG. 3, a current path connecting the DC power supply 3 and the capacitor C1A is formed, and the capacitor C1A is charged. At this time, since the node n1 is disconnected from the load 4, the current for the initial charging does not flow into the load 4.

[0036] Next, referring to FIG. 4, in this case, the control device 2 controls the switches S1A, S2B, S11A1, S21A1, S21B1, and S12B1 to be on, and controls the switches S2A, S1B, S12A1, S22A1, S22B1, and S11B1 to be off. Also, the other selection terminal (the terminal constituting the open end) of the switch 13 is selected. Thereby, as shown by the broken line in FIG. 4, a current path connecting the DC power supply 3 and the capacitor C1B is formed, and the capacitor C1B is charged. Also at this time, since the node n1 is disconnected from the load 4, the current for the initial charging does not flow into the load 4.

[0037] As described above, according to the power supply device 1 according to the present embodiment, since a current path can be formed from the output terminal of the first phase of the DC / DC converter 11 through the auxiliary converters 12A, node n1, and auxiliary converter 12B to the output terminal of the second phase, the capacitors C1A and C1B can be charged without flowing current through the load 4. Therefore, it becomes possible to provide a power supply device to which an auxiliary converter is applied.

[0038] Of course, the current path to be formed for initial charging of the capacitors C1A and C1B is not limited to that shown in FIGS. 3 and 4. For example, taking the case of initially charging the capacitor C1A as an example, the capacitors C1A can also be initially charged by controlling the switches S1B, S2A, S11B1, S21B1, S21A1, and S12A1 to be on and the switches S2B, S1A, S12B1, S22B1, S22A1, and S11A1 to be off. Also, a path for charging the capacitors C1A and C1B simultaneously may be used.

[0039] Next, in order to obtain the effect of reducing output ripple in the power supply device 1 according to the present embodiment, the control of the power supply device 1 performed by the control device 2 according to the present embodiment will be described in detail.

[0040] FIGS. 5 to 7 are diagrams showing the control methods of the auxiliary converters 12A and 12B by the control device 2 according to the background art of the present invention. FIGS. 8 to 10 are diagrams showing the control methods of the auxiliary converters 12A and 12B by the control device 2 according to the present embodiment. Hereinafter, first, after explaining the problems of the background art with reference to FIGS. 5 to 7, the control contents of the auxiliary converters 12A and 12B by the control device 2 according to the present embodiment will be described in detail with reference to FIGS. 8 to 10.

[0041] FIG. 5 shows voltages, signals, etc. related to the control of the auxiliary converter 12A according to the background art of the present invention. The command values D_Va_p and D_Va_n shown in the figure are command values generated by the control device 2 based on the command value D_a supplied from the outside to control the DC / DC converter 11. The control device 2 compares the carrier signal carrier_a with the command value D_a in the same manner as when controlling the DC / DC converter 11, so that the AC component Vma of the output voltage Vma of the first phase ac generates command values D_Va_p and D_Va_n that change in synchronization with

[0042] Also, the carrier signal carrier_p shown in FIG. 5 is a signal generated by the control device 2 based on the carrier signal carrier2 supplied from the outside. The carrier signal carrier_p may be the carrier signal carrier2 itself.

[0043] The specific value of the command value D_Va_p is determined in relation to the amplitude of the carrier signal carrier_p. In one example, the value of the command value D_Va_p during the high period of the output voltage Vma is set to a value slightly smaller than the maximum value of the carrier signal carrier_p (for example, about 85.3% of the maximum value of the carrier signal carrier_p), and the value of the command value D_Va_p during the low period of the output voltage Vma is set to a value slightly smaller than 0 (for example, about 21.3% of the minimum value of the carrier signal carrier_p). The specific value of the command value D_Va_n is set to a value obtained by inverting the sign of the command value D_Va_p.

[0044] Based on the command values D_Va_p, D_Va_n, and the carrier signal carrier_p generated as described above, the control device 2 controls the switches S11A1, S12A1, S21A1, and S22A1 in the auxiliary converter 12A. Specifically, when the command value D_Va_p exceeds the carrier signal carrier_p, the control device 2 controls the switch S11A1 to be on and the switch S12A1 to be off. When the command value D_Va_p is less than or equal to the carrier signal carrier_p, the control device 2 controls the switch S11A1 to be off and the switch S12A1 to be on. Also, when the command value D_Va_n exceeds the carrier signal carrier_p, the control device 2 controls the switch S21A1 to be on and the switch S22A1 to be off. When the command value D_Va_n is less than or equal to the carrier signal carrier_p, the control device 2 controls the switch S21A1 to be off and the switch S22A1 to be on.

[0045] As shown in FIG. 5, the voltage Va, as also shown in FIG. 1, is the potential difference between the input terminal and the output terminal of the auxiliary converter 12A. As a result of the above control, the voltage Va oscillates between -750V and 0V during the low period of the output voltage Vma (the period when the command value D_Va_p is relatively small), and oscillates between 0V and 750V during the high period of the output voltage Vma (the period when the command value D_Va_p is relatively large).

[0046] Next, referring to FIG. 6, the figure shows the voltages, signals, etc. related to the control of the auxiliary converter 12B. The command values D_Vb_p and D_Vb_n shown in the figure are command values generated by the control device 2 based on the command value D_b supplied from the outside to control the DC / DC converter 11. The control device 2 compares the carrier signal carrier_b with the command value D_b in the same way as when controlling the DC / DC converter 11, so that the command values D_Vb_p and D_Vb_n change in synchronization with the AC component Vmb of the output voltage Vma of the first phase. ac are generated.

[0047] Also, the carrier signal carrier_n shown in FIG. 6 is a signal generated by the control device 2 based on the carrier signal carrier2 supplied from the outside. The control device 2 generates the carrier signal carrier_n by delaying the phase of the carrier signal carrier2 by 90°. Therefore, the carrier signal carrier_n is a signal with a phase lag of 90° with respect to the carrier signal carrier_p.

[0048] The specific value of the command value D_Vb_p is determined in the same manner as the command value D_Va_p. As a result, the value of the command value D_Vb_p during the high period of the output voltage Vmb is equal to the value of the command value D_Va_p during the high period of the output voltage Vma, and the value of the command value D_Vb_p during the low period of the output voltage Vmb is equal to the value of the command value D_Va_p during the low period of the output voltage Vma. Also, the specific value of the command value D_Vb_n is set to a value obtained by inverting the sign of the command value D_Vb_p.

[0049] The control device 2 controls the switches S11B1, S12B1, S21B1, and S22B1 in the auxiliary converter 12B based on the command values D_Vb_p, D_Vb_n, and the carrier signal carrier_n generated as described above. Specifically, when the command value D_Vb_p exceeds the carrier signal carrier_n, the control device 2 controls the switch S11B1 to be on and the switch S12B1 to be off, and when the command value D_Vb_p is less than or equal to the carrier signal carrier_n, the control device 2 controls the switch S11B1 to be off and the switch S12B1 to be on. Also, when the command value D_Vb_n exceeds the carrier signal carrier_n, the control device 2 controls the switch S21B1 to be on and the switch S22B1 to be off, and when the command value D_Vb_n is less than or equal to the carrier signal carrier_n, the control device 2 controls the switch S21B1 to be off and the switch S22B1 to be on.

[0050] As shown in Fig. 6, the voltage Vb is the potential difference between the input terminal and the output terminal of the auxiliary converter 12B, as also shown in Fig. 1. As a result of the above control, the voltage Vb oscillates between -750V and 0V during the low period of the output voltage Vmb (the period when the command value D_Vb_p is relatively small), and oscillates between 0V and 750V during the high period of the output voltage Vma (the period when the command value D_Vb_p is relatively large).

[0051] Next, referring to Fig. 7, the figure shows the carrier signals carrier_p and carrier_n, the voltages Va and Vb, which are also shown in Fig. 5 or Fig. 6, and the load current iL flowing into the load 4 as a result of the above control. The illustrated period VDP is a period (the first period) in which the command value D_Va_p and the command value D_Vb_p are different from each other (therefore, the command value D_Va_n and the command value D_Vb_n are also different from each other), and the period VSP is a period (the second period) in which the command value D_Va_p and the command value D_Vb_p are the same as each other (therefore, the command value D_Va_n and the command value D_Vb_n are also the same as each other).

[0052] As can be understood from Fig. 7, in the period VDP, the ripple (output ripple) superimposed on the load current iL is larger than that in the period VSP. This is because the phases of the voltages Va and Vb are different in the period VSP, while the phases of the voltages Va and Vb are the same in the period VDP.

[0053] In this example, the phases of the voltages Va and Vb are the same in the period VDP. However, if the phase difference between the carrier signals carrier_p and carrier_n is always set to 0° (that is, in a state where there is no phase difference between the carrier signals carrier_p and carrier_n), the phases of the voltages Va and Vb will be different in the period VDP, while the phases of the voltages Va and Vb will be the same in the period VSP. Therefore, even if the phase difference between the carrier signals carrier_p and carrier_n is set to 0°, the problem of the output ripple becoming large is not solved.

[0054] Therefore, the control device 2 according to the present embodiment is configured to generate the carrier signals carrier_p and carrier_n such that the phase difference between the carrier signals carrier_p and carrier_n is different between the period VSP and the period VDP. More specifically, the control device 2 according to the present embodiment generates the carrier signals carrier_p and carrier_n such that the phase difference between the carrier signals carrier_p and carrier_n is 90° in the period VSP and 0° or 180° in the period VSP. By doing so, the phases of the voltages Va and Vb can be made different in both the periods VDP and VSP. Therefore, even when the DC / DC converter 10 is provided with the first phase and the second phase and the auxiliary converters are installed respectively as in the power supply device 1 according to the present embodiment, it is possible to obtain the effect of reducing the output ripple. Hereinafter, this point will be described in detail with reference to FIGS. 8 to 10.

[0055] FIG. 8 shows voltages, signals, etc. related to the control of the auxiliary converter 12A, similar to FIG. 5. Further, FIG. 9 shows voltages, signals, etc. related to the control of the auxiliary converter 12B, similar to FIG. 6. As understood from these figures, when generating the carrier signals carrier_p and carrier_n based on the carrier signal carrier, the control device 2 according to the present embodiment generates the carrier signals carrier_p and carrier_n while changing the phase according to the values of the command values D_Va_p and D_Vb_p instead of a fixed phase.

[0056] Specifically, first, regarding the carrier signal carrier_p shown in FIG. 8, the control device 2 generates the carrier signal carrier_p by delaying the phase of the carrier signal carrier2 by 90° during the period when the command value D_Va_p is relatively small (the low period of the output voltage Vma), and generates the carrier signal carrier2 itself as the carrier signal carrier_p during the period when the command value D_Va_p is relatively large (the high period of the output voltage Vma). Next, regarding the carrier signal carrier_n shown in FIG. 9, the control device 2 generates the carrier signal carrier2 itself as the carrier signal carrier_n during the period when the command value D_Vb_p is relatively small (the low period of the output voltage Vmb), and generates the carrier signal carrier_n by delaying the phase of the carrier signal carrier2 by 90° during the period when the command value D_Vb_p is relatively large (the high period of the output voltage Vmb).

[0057] As a result of the control device 2 generating the carrier signals carrier_p and carrier_n as described above, as shown in FIGS. 8 and 9, in this embodiment, both the voltages Va and Vb oscillate at a constant phase, which is different from the examples in FIGS. 5 and 6.

[0058] FIG. 10 shows the carrier signals carrier_p and carrier_n, the voltages Va and Vb, which were also shown in FIGS. 8 and 9, and the load current iL flowing into the load 4 as a result of the control performed by the control device 2 according to the present embodiment. As can be understood by comparison with FIG. 7, in the present embodiment, in the period VDP, the phases of the carrier signals carrier_p and carrier_n coincide, and in the period VSP, the phases of the carrier signals carrier_p and carrier_n are different by 90°. As a result, the phases of the voltages Va and Vb do not coincide in either of the periods VDP and VSP. As a result, in either of the periods VDP and VSP, the magnitude of the output ripple remains approximately the same as the output ripple in the period VSP of FIG. 7. Therefore, according to the control device 2 and the control method of the power supply device 1 according to the present embodiment, it can be said that in the power supply device 1 according to the present embodiment, it is possible to obtain an effect of reducing the output ripple. As can be easily understood from FIG. 10, even if the phases of the carrier signals carrier_p and carrier_n are different by 180° in the period VDP, the same effect can be obtained.

[0059] As described above, according to the control device 2 and the control method of the power supply device 1 according to the present embodiment, since the phases of the voltages Va and Vb can be made different in either of the periods VDP and VSP, even when the DC / DC converter 10 is provided with a first phase and a second phase and an auxiliary converter is installed in each, it is possible to obtain an effect of reducing the output ripple.

[0060] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the gist thereof.

[0061] FIG. 11 is a diagram showing the configuration of a power supply device 1 and its control device 2 according to a modification of the present embodiment. As shown in the figure, the power supply device 1 according to this modification is different from the power supply device 1 according to the present embodiment in that it has three auxiliary converters 12A and 12B each. The three auxiliary converters 12A are connected in series between the output terminal of the first phase of the DC / DC converter 11 and the reactor LA. Hereinafter, the three auxiliary converters 12A are referred to as auxiliary converters 12A-1, 12A-2, and 12A-3 in order from the side closer to the DC / DC converter 11. Similarly, the three auxiliary converters 12B are connected in series between the output terminal of the second phase of the DC / DC converter 11 and the reactor LB. Hereinafter, the three auxiliary converters 12B are referred to as auxiliary converters 12B-1, 12B-2, and 12B-3 in order from the side closer to the DC / DC converter 11.

[0062] When initially charging each of the auxiliary converters 12A and 12B in the power supply device 1 shown in FIG. 11, by appropriately controlling each switch in the DC / DC converter 11 and each of the auxiliary converters 12A and 12B, a current path similar to that shown in FIGS. 3 and 4 is formed, and the capacitors in each of the auxiliary converters 12A and 12B can be charged one by one. Therefore, according to this modification, it can be said that it is possible to provide a power supply device in which a plurality of auxiliary converters are applied to each phase.

[0063] Also, the two angles shown in the auxiliary converter 12A-1 in FIG. 11 indicate the phase of the carrier signal carrier_p generated by the control device 2 to control the auxiliary converter 12A-1. The angle on the left side of the double-headed arrow indicates the phase of the carrier signal carrier_p during the high period of the voltage Vma (in this case, 0°), and the angle on the right side of the double-headed arrow indicates the phase of the carrier signal carrier_p during the low period of the voltage Vma (in this case, 90°). The same applies to the two angles shown in the other auxiliary converters 12A and 12B.

[0064] As understood from the angles shown in Fig. 11, when using three auxiliary converters 12A and 12B each, for the first-stage auxiliary converters 12A-1 and 12B-1, the phases of the carrier signals carrier_p and carrier_n are set to 0° or 90°. For the second-stage auxiliary converters 12A-2 and 12B-2, the phases of the carrier signals carrier_p and carrier_n are set to 30° or 120°. For the third-stage auxiliary converters 12A-3 and 12B-3, the phases of the carrier signals carrier_p and carrier_n may be set to 60° or 150°. Generally speaking, when using N auxiliary converters 12A and 12B each, for the first-stage auxiliary converters 12A and 12B, the phases of the carrier signals carrier_p and carrier_n are set to 0° or 90°. For the Nth-stage auxiliary converters 12A and 12B, the phases of the carrier signals carrier_p and carrier_n are set to 180° / N or 180° / N + 90°. For the nth-stage (n is an integer from 2 to N - 1) auxiliary converters 12A and 12B, the phases of the carrier signals carrier_p and carrier_n may be set to (180° / N)×(n - 1 / N - 1) or (180° / N)×(n - 1 / N - 1)+90°. By doing so, in the power supply device 1 according to this modified example, it is also possible to obtain the effect of reducing the output ripple as in the present embodiment.

Explanation of Signs

[0065] 1 Power supply device 2 Control device 3 DC power supply 4 Load (battery under test) 11 DC / DC converter 12A, 12B Auxiliary converter 13 Switch C1A, C1B Capacitor LA, LB Reactor S1A, S2A, S1B, S2B Switch S11A1, S12A1, S21A1, S22A1 Switch S11B1, S12B1, S21B1, S22B1 Switch VDP First period Second period of VSP

Claims

1. A DC / DC converter having a first phase and a second phase which are the first leg and the second leg of a full-bridge circuit respectively, A first auxiliary converter and a first reactor serially inserted between the output terminal of the first phase and the output node, A second auxiliary converter and a second reactor serially inserted between the output terminal of the second phase and the output node, A switch inserted between the output node and the load, A power supply device including the above.

2. Each of the first auxiliary converter and the second auxiliary converter A full-bridge circuit having an input-side leg composed of a first upper switch and a first lower switch, and an output-side leg composed of a second upper switch and a second lower switch, A capacitor connected in parallel with the input-side leg and the output-side leg, The power supply device according to claim 1.

3. A plurality of the first auxiliary converters serially connected between the output terminal of the first phase and the output node, A plurality of the second auxiliary converters serially connected between the output terminal of the second phase and the output node, The power supply device according to claim 1 or 2 including the above.

4. The load is a storage battery, The power supply device according to claim 1 or 2.

5. A control device for a power supply device including a DC / DC converter having a first phase and a second phase which are the first leg and the second leg of a full-bridge circuit respectively, A first auxiliary converter and a first reactor serially inserted between the output terminal of the first phase and the output node, A second auxiliary converter and a second reactor serially inserted between the output terminal of the second phase and the output node, A switch inserted between the output node and the load, Wherein the operation of the DC / DC converter is controlled such that each of the first output voltage output from the output terminal of the first phase and the second output voltage output from the output terminal of the second phase changes according to a predetermined duty ratio, The operation of the first auxiliary converter is controlled based on a first carrier signal and a first command value that changes in synchronization with the AC component of the first output voltage, The operation of the second auxiliary converter is controlled based on a second carrier signal and a second command value that changes in synchronization with the AC component of the second output voltage. ​ ​ Based on a predetermined carrier signal, the first carrier signal and the second carrier signal are generated such that the phase difference between the first carrier signal and the second carrier signal is different during a first period in which the first command value and the second command value are different from each other, and during a second period in which the first command value and the second command value are the same as each other. A control device for a power supply device.

6. During the first period, the first carrier signal and the second carrier signal are generated such that the phase difference between the first carrier signal and the second carrier signal is 0° or 180°. During the second period, the first carrier signal and the second carrier signal are generated such that the phase difference between the first carrier signal and the second carrier signal is 90°. The control device according to claim 5.

7. Each of the first auxiliary converter and the second auxiliary converter has a full-bridge circuit having an input-side leg composed of a first upper switch and a first lower switch, and an output-side leg composed of a second upper switch and a second lower switch; and a capacitor connected in parallel with the input-side leg and the output-side leg. By controlling the on / off states of the first upper switch, the first lower switch, the second upper switch, and the second lower switch of the first auxiliary converter based on the first carrier signal and the first command value, the operation of the first auxiliary converter is controlled. By controlling the on / off states of the first upper switch, the first lower switch, the second upper switch, and the second lower switch of the second auxiliary converter based on the second carrier signal and the second command value, the operation of the second auxiliary converter is controlled. The control device according to claim 5 or 6.

8. The predetermined carrier signal is a triangular wave signal. The control device according to claim 5 or 6.

9. A DC / DC converter having a first phase and a second phase which are the first leg and the second leg of a full-bridge circuit respectively; a first auxiliary converter and a first reactor inserted in series between the output terminal of the first phase and the output node; a second auxiliary converter and a second reactor inserted in series between the output terminal of the second phase and the output node; a switch inserted between the output node and the load; A control method for a power supply device including: Control the operation of the DC / DC converter such that each of the first output voltage output from the output terminal of the first phase and the second output voltage output from the output terminal of the second phase changes according to a predetermined duty ratio. Control the operation of the first auxiliary converter based on a first command value that changes in synchronization with the first carrier signal and the AC component of the first output voltage. Control the operation of the second auxiliary converter based on a second command value that changes in synchronization with the second carrier signal and the AC component of the second output voltage. Generate the first carrier signal and the second carrier signal based on a predetermined carrier signal such that the phase difference between the first carrier signal and the second carrier signal is different during a first period in which the first command value and the second command value are different from each other and during a second period in which the first command value and the second command value are the same as each other. A method for controlling a power supply device.

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