Power conversion device

Abstract

To provide a power conversion device that is capable of performing control so that an output voltage is maintained constant over a wide range from a low output voltage to a high output voltage.SOLUTION: A power conversion device in an embodiment comprises a plurality of non-insulated DC-DC converter circuits including a bilateral element. Inputs of the plurality of non-insulated DC-DC converter are connected in parallel, and outputs of the plurality of non-insulated DC-DC converter circuits are connected in serial. Another power conversion device in the embodiment comprises a plurality of non-insulated DC-DC converter circuits including a bilateral element. The inputs of the plurality of non-insulated DC-DC converter circuits are connected in serial, and the outputs of the plurality of non-insulated DC-DC converter circuits are connected in parallel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present embodiment relates to a power conversion device. [Background technology]

[0002] 2. Description of the Related Art There is known a power conversion device that steps up or steps down a DC input voltage and outputs a constant DC voltage, for example, a power conversion device that uses an LLC resonant converter circuit.

[0003] In the case of a power conversion device using an LLC resonant converter circuit, it is difficult for the LLC resonant converter circuit alone to control the output voltage so that it remains constant over a wide range from low to high output voltages. Therefore, it is common to provide a constant voltage circuit in the previous stage of the LLC resonant converter circuit, and first perform constant voltage control using the first stage constant voltage circuit, and then step up and down the voltage using the second stage LLC resonant converter circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-108771 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present embodiment is to provide a power conversion device that can control the output voltage so as to be kept constant over a wide range from a low output voltage to a high output voltage. [Means for solving the problem]

[0006] In order to solve the above problems, the power conversion device according to this embodiment includes a plurality of non-isolated DC-DC converter circuits including bidirectional elements, and the inputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel and the outputs of the plurality of non-isolated DC-DC converter circuits are connected in series.

[0007] Moreover, another power conversion device according to the present embodiment includes a plurality of non-isolated DC-DC converter circuits including bidirectional elements, and the inputs of the plurality of non-isolated DC-DC converter circuits are connected in series and the outputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of a power conversion device according to a first embodiment. [Diagram 2] 1 is a diagram showing a detailed configuration of a non-isolated DC-DC converter circuit according to a first embodiment. [Diagram 3] 4 is a diagram showing an example of time waveforms of a first PWM control signal and a second PWM control signal according to the first embodiment. [Figure 4] 3 is a diagram showing the on / off operation timing of each of the N non-isolated DC-DC converter circuits according to the first embodiment. FIG. [Diagram 5] FIG. 11 is a diagram showing a configuration of a power conversion device according to a second embodiment. [Figure 6] FIG. 11 is a diagram showing the on / off operation timing of each of the N non-isolated DC-DC converter circuits according to the second embodiment. [Figure 7] FIG. 11 is a diagram showing a configuration of a power conversion device according to a third embodiment. [Figure 8] FIG. 11 is a diagram showing a detailed configuration of a non-insulated DC-DC converter circuit according to a third embodiment. [Figure 9] FIG. 13 is a diagram showing a configuration of a power conversion device according to a fourth embodiment. [Figure 10] FIG. 13 is a diagram showing a detailed configuration of a non-insulated DC-DC converter circuit according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present embodiment will be described with reference to the drawings. In the drawings, the same or corresponding elements are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0010] (Embodiment 1) 1 is a diagram showing a configuration of a power conversion device 100 according to a first embodiment. The power conversion device 100 is a device that boosts a DC input voltage and outputs it as a constant DC voltage, and includes input terminals INa and INb and output terminals OUTa and OUTb. A DC input voltage Vin is applied to the input terminals INa and INb, and a DC output voltage Vo (>Vin) is output from the output terminals OUTa and OUTb.

[0011] The power conversion device 100 includes N non-insulated DC-DC converter circuits 101(1) to 101(N) and a timing control circuit 102 that controls the operation timing of these N DC-DC converter circuits 101(1) to 101(N). The inputs of the DC-DC converter circuits 101(1) to 101(N) are connected in parallel, with one connected to an input terminal INa and the other connected to an input terminal INb. The input voltages V1 of the DC-DC converter circuits 101(1) to 101(N) are all equal, i.e., V1=Vin.

[0012] The outputs of the DC-DC converter circuits 101(1) to 101(N) are connected in series, with one output of the top DC-DC converter circuit 101(1) being connected to the output terminal OUTa and the other output of the bottom DC-DC converter circuit 101(N) being connected to the output terminal OUTb. The output voltages V2 of the DC-DC converter circuits 101(1) to 101(N) are all equal, and therefore V2×N=Vo.

[0013] 2 is a diagram showing a detailed configuration of the non-insulated DC-DC converter circuit 101 according to the present embodiment 1. Since the DC-DC converter circuits 101(1) to 101(N) all have the same configuration, they are collectively referred to as the DC-DC converter circuits 101.

[0014] The DC-DC converter circuit 101 includes a first input terminal 11a and a second input terminal 11b, a first output terminal 12a and a second output terminal 12b, a first bidirectional element 13 provided between the first input terminal 11a and the first output terminal 12a, and a second bidirectional element 14 provided between the second input terminal 11b and the second output terminal 12b.

[0015] The first bidirectional element 13 includes semiconductor switching elements M1 and M2. For example, N-channel type metal oxide semiconductor field effect transistors (MOSFETs) can be used as the semiconductor switching elements M1 and M2. In this case, the source terminals and gate terminals of the semiconductor switching elements M1 and M2 are connected to each other. The drain terminal of the semiconductor switching element M1 is connected to one terminal 13a of the first bidirectional element 13, and the drain terminal of the semiconductor switching element M2 is connected to the other terminal 13b of the first bidirectional element 13.

[0016] When the control signal G1 supplied to the first bidirectional element 13 is on, the first bidirectional element 13 is bidirectionally conductive. That is, a current can flow to the right in the figure via the drain-source channel of the semiconductor switching element M1 and the parasitic diode of the semiconductor switching element M2, and a current can also flow to the left in the figure via the drain-source channel of the semiconductor switching element M2 and the parasitic diode of the semiconductor switching element M1.

[0017] When the control signal G1 supplied to the first bidirectional element 13 is off, no current flows in either direction through the first bidirectional element 13. That is, the potential of one terminal 13a of the first bidirectional element 13 and the potential of the other terminal 13b are electrically separated.

[0018] The second bidirectional element 14 includes semiconductor switching elements M3 and M4. For example, N-channel MOSFETs can be used as the semiconductor switching elements M3 and M4. In this case, the source terminals and gate terminals of the semiconductor switching elements M3 and M4 are connected to each other. The drain terminal of the semiconductor switching element M3 is connected to one terminal 14a of the second bidirectional element 14, and the drain terminal of the semiconductor switching element M4 is connected to the other terminal 14b of the second bidirectional element 14.

[0019] When the control signal G2 supplied to the second bidirectional element 14 is on, the second bidirectional element 14 is bidirectionally conductive. That is, a current can flow to the right in the figure via the drain-source channel of the semiconductor switching element M3 and the parasitic diode of the semiconductor switching element M4, and a current can also flow to the left in the figure via the drain-source channel of the semiconductor switching element M4 and the parasitic diode of the semiconductor switching element M3.

[0020] When the control signal G2 supplied to the second bidirectional element 14 is off, no current flows in either direction through the second bidirectional element 14. That is, the potential of one terminal 14a of the second bidirectional element 14 and the potential of the other terminal 14b are electrically separated.

[0021] The DC-DC converter circuit 101 also includes a first inductor L1, a first unidirectional element D1, and a second unidirectional element D2. One end of the first inductor L1 is connected to a first node N1 between the first bidirectional element 13 and the first output terminal 12a, and the other end of the first inductor L1 is connected to a second node N2 between the second bidirectional element 14 and the second output terminal 12b.

[0022] The first unidirectional element D1 may be, for example, a semiconductor diode. In this case, the anode of the first unidirectional element D1 is connected to the first output terminal 12a, and the cathode of the first unidirectional element D1 is connected to the first node N1.

[0023] The second unidirectional element D2 may be, for example, a semiconductor diode. In this case, the anode of the second unidirectional element D2 is connected to the second node N2, and the cathode of the second unidirectional element D2 is connected to the second output terminal 12b.

[0024] The DC-DC converter circuit 101 also includes a first capacitor C1 and a second capacitor C2. The first capacitor C1 is connected between the first input terminal 11a and the second input terminal 11b. The second capacitor C2 is connected between the first output terminal 12a and the second output terminal 12b.

[0025] Furthermore, the DC-DC converter circuit 101 includes a first voltage sensor 15 , a second voltage sensor 16 , a first current sensor 17 , a first drive circuit 18 , a second drive circuit 19 , and a control circuit 20 .

[0026] The first voltage sensor 15 detects an input voltage V1 (first voltage) of the DC-DC converter circuit 101. The second voltage sensor 16 detects an output voltage V2 (second voltage) of the DC-DC converter circuit 101. The first current sensor 17 detects a first current I1 flowing through the first inductor L1.

[0027] The first drive circuit 18 supplies a first PWM control signal G1 to the first bidirectional element 13. The second drive circuit 19 supplies a second PWM control signal G2 to the second bidirectional element 14. The control circuit 20 controls the operations of the first drive circuit 18 and the second drive circuit 19 based on the timing control signal TS input from the timing control circuit 102, the input voltage V1 and the output voltage V2, and the first current I1.

[0028] FIG. 3 is a diagram showing an example of the time waveforms of a first PWM control signal G1 and a second PWM control signal G2. The first PWM control signal G1 and the second PWM control signal G2 are controlled so as to have the same waveform that changes at the same timing. That is, when the first PWM control signal G1 turns on, the second PWM control signal G2 also turns on, and when the first PWM control signal G1 turns off, the second PWM control signal G2 also turns off. However, the voltage level of the first PWM control signal G1 is different from the voltage level of the second PWM control signal, and the GNDs of both are separated.

[0029] When both the first PWM control signal G1 and the second PWM control signal G2 turn on, both the first bidirectional element 13 and the second bidirectional element 14 become conductive. At this time, current flows through the path of the first input terminal 11a, the first bidirectional element 13, the first inductor L1, the second bidirectional element 14, and the second input terminal 11b, and due to this current, magnetic energy is stored in the first inductor L1.

[0030] When both the first PWM control signal G1 and the second PWM control signal G2 turn off, both the first bidirectional element 13 and the second bidirectional element 14 become non-conductive. At this time, due to the magnetic energy stored in the first inductor L1, current flows through the path of the first inductor L1, the second unidirectional element D2, the second output terminal 12b, the first output terminal 12a, and the first unidirectional element D1.

[0031] The control circuit 20 can control the output voltage V2 of the DC-DC converter circuit 101 to be kept constant by appropriately adjusting the duty ratio D (0 < D < 1) of the first PWM control signal G1 and the second PWM control signal G2.

[0032] For example, when the input voltage V1 is smaller than the output voltage V2, the DC-DC converter circuit 101 functions as a step-up converter circuit. Also, when the input voltage V1 is larger than the output voltage V2, the DC-DC converter circuit 101 functions as a step-down converter circuit.

[0033] 4 is a diagram showing the on / off operation timing of each of the N non-insulated DC-DC converter circuits 101(1) to 101(N) according to the present embodiment 1. The timing control circuit 102 controls the operation of the N DC-DC converter circuits 101(1) to 101(N) by repeating N time slots TS_1 to TS_N. In the figure, fsw is the switching frequency.

[0034] In the first time slot TS_1, only the first bidirectional element 13 and the second bidirectional element 14 of the first DC-DC converter circuit 101(1) are off, and the first bidirectional elements 13 and second bidirectional elements 14 of all of the other N-1 DC-DC converter circuits are on.

[0035] In the second time slot TS_2, only the first bidirectional element 13 and the second bidirectional element 14 of the second DC-DC converter circuit 101(2) are off, and the first bidirectional elements 13 and the second bidirectional elements 14 of the other N-1 DC-DC converter circuits are all on.

[0036] Similarly, in the Nth time slot TS_N, only the first bidirectional element 13 and the second bidirectional element 14 of the Nth DC-DC converter circuit 101(N) are off, and the first bidirectional elements 13 and second bidirectional elements 14 of the other N-1 DC-DC converter circuits are all on.

[0037] In the first embodiment, the transformation ratios V2 / V1 of the DC-DC converter circuits 101(1) to 101(N) are all equal, that is, D / (1-D). Therefore, the relationship between the input voltage Vin and the output voltage Vo of the power conversion device 100 formed by connecting the N DC-DC converter circuits 101(1) to 101(N) is expressed as follows:

[0038]

number

[0039] As described above, the power conversion device 100 according to the first embodiment includes a plurality of non-isolated DC-DC converter circuits 101 including bidirectional elements, with the inputs of the DC-DC converter circuits 101 connected in parallel and the outputs of the DC-DC converter circuits 101 connected in series.

[0040] As mentioned above, for example, in the case of a power conversion device using a conventional LLC resonant converter circuit, it was difficult for the LLC resonant converter circuit alone to control the output voltage to be constant over a wide range from low output voltage to high output voltage. Therefore, it was common to provide a constant voltage circuit in the previous stage of the LLC resonant converter circuit, and first perform constant voltage control using the first stage constant voltage circuit, and then step up and down the voltage using the second stage LLC resonant converter circuit.

[0041] In contrast, in the power conversion device 100 according to the first embodiment, by connecting a plurality of non-isolated DC-DC converter circuits 101 each having both a constant voltage control function and a step-up / step-down function, it is possible to control the output voltage V2 to be kept constant over a wide range from a low output voltage to a high output voltage with a circuit configuration simpler than that of the prior art. In addition, since an arbitrary output voltage V2 can be obtained by adjusting the number of DC-DC converter circuits 101, it has excellent scalability.

[0042] Moreover, in the power conversion device 100 according to the first embodiment, a high transformation ratio is realized not by a single DC-DC converter circuit, but by connecting a plurality of DC-DC converter circuits 101. Therefore, the transformation ratio of each DC-DC converter circuit 101 may be low. As a result, by appropriately adjusting the number N of the DC-DC converter circuits 101, it is possible to set the duty ratio D of each DC-DC converter circuit 101 to about 0.5, and it is possible to provide a margin for the on / off time of the PWM control of each DC-DC converter circuit 101. As a result, it is easy to increase the switching frequency fsw and the first inductor L1 can be relatively small.

[0043] Moreover, the on / off operation of the non-isolated DC-DC converter circuit 101 according to the first embodiment can be controlled by PWM control similar to that of a general step-up / step-down chopper circuit. Also, for example, components such as a transformer and a snubber that are required in a conventional non-isolated flyback circuit are not required. This makes the design and control extremely easy.

[0044] Moreover, the non-isolated DC-DC converter circuit 101 according to the first embodiment includes a first bidirectional element 13 and a second bidirectional element 14. The first bidirectional element 13 is composed of two semiconductor switching elements M1 and M2. The second bidirectional element 14 is composed of two semiconductor switching elements M3 and M4. When the DC-DC converter circuit 101 is in the off state, the input potential and the output potential are electrically separated by the parasitic capacitance between the drain and source of the semiconductor switching elements.

[0045] In contrast, in a conventional LLC resonant converter circuit, the input potential and the output potential in the on-state and the off-state are electrically separated by a high-frequency transformer. The high-frequency transformer is a component that occupies a large area on the circuit and can also increase the man-hours required for circuit design. In the non-insulated DC-DC converter circuit 101 according to the first embodiment, since it is not necessary to use a high-frequency transformer, miniaturization of the circuit area and reduction of the man-hours required for design can be expected.

[0046] (Embodiment 2) FIG. 5 is a diagram showing the configuration of a power conversion device 200 according to the second embodiment. The power conversion device 200 is a device that steps down a DC input voltage and outputs it as a constant DC voltage. A DC input voltage Vin is applied to the input terminals INa and INb, and a DC output voltage Vo (<Vin) is output from the output terminals OUTa and OUTb.

[0047] The power conversion device 200 includes N non-insulated DC-DC converter circuits 101(1) to 101(N) having the same configuration as that of the first embodiment described above. The power conversion device 200 also includes a timing control circuit 202 that controls the operation timings of these N DC-DC converter circuits 101(1) to 101(N).

[0048] The inputs of the DC-DC converter circuits 101(1) to 101(N) are connected in series. One input of the uppermost DC-DC converter circuit 101(1) is connected to the input terminal INa, and the other input of the lowermost DC-DC converter circuit 101(N) is connected to the input terminal INb. The input voltages V1 of the DC-DC converter circuits 101(1) to 101(N) are all equal, and thus V1 = Vin / N.

[0049] The outputs of the DC-DC converter circuits 101(1) to 101(N) are connected in parallel, one connected to the output terminal OUTa and the other connected to the output terminal OUTb. The output voltages V2 of the DC-DC converter circuits 101(1) to 101(N) are all equal, i.e., V2=Vo.

[0050] 6 is a diagram showing the on / off operation timing of each of the N non-insulated DC-DC converter circuits 101(1) to 101(N) according to the present embodiment 2. The timing control circuit 202 controls the operation of the N DC-DC converter circuits 101(1) to 101(N) by repeating N time slots TS_1 to TS_N.

[0051] In the first time slot TS_1, only the first bidirectional element 13 and the second bidirectional element 14 of the first DC-DC converter circuit 101(1) are on, and the first bidirectional elements 13 and second bidirectional elements 14 of the other N-1 DC-DC converter circuits are all off.

[0052] In the second time slot TS_2, only the first bidirectional element 13 and the second bidirectional element 14 of the second DC-DC converter circuit 101(2) are on, and the first bidirectional elements 13 and the second bidirectional elements 14 of the other N-1 DC-DC converter circuits are all off.

[0053] Similarly, in the Nth time slot TS_N, only the first bidirectional element 13 and the second bidirectional element 14 of the Nth DC-DC converter circuit 101(N) are on, and the first bidirectional elements 13 and second bidirectional elements 14 of the other N-1 DC-DC converter circuits are all off.

[0054] In the second embodiment, the transformation ratios V2 / V1 of the DC-DC converter circuits 101(1) to 101(N) are all equal, that is, D / (1-D). In this case, the relationship between the input voltage Vin and the output voltage Vo of the power conversion device 200 formed by connecting the N DC-DC converter circuits 101(1) to 101(N) is expressed as follows:

[0055]

number

[0056] As described above, the power conversion device 200 according to the second embodiment includes a plurality of non-insulated DC-DC converter circuits 101 including bidirectional elements, with the inputs of the DC-DC converter circuits 101 connected in series and the outputs of the DC-DC converter circuits 101 connected in parallel. This allows the power conversion device 200 according to the second embodiment to obtain the same effects as those of the first embodiment.

[0057] (Embodiment 3) FIG. 7 is a diagram showing a configuration of a power conversion device 300 according to the third embodiment. The power conversion device 300 is obtained by replacing the N non-insulated DC-DC converter circuits 101-101(N) in the power conversion device 100 according to the first embodiment with N non-insulated DC-DC converter circuits 301(1)-301(N). The power conversion device 300 boosts a DC input voltage and outputs it as a constant DC voltage. The on / off operation timing of each of the DC-DC converter circuits 301(1)-301(N) is the same as that of the first embodiment.

[0058] 8 is a diagram showing a detailed configuration of a non-insulated DC-DC converter circuit 301 according to the present embodiment 3. Since the DC-DC converter circuits 301(1) to 301(N) all have the same configuration, they are collectively referred to as DC-DC converter circuits 301.

[0059] The DC-DC converter circuit 301 includes a first bidirectional element 13 provided between a first input terminal 11a and a first output terminal 12a, and a second bidirectional element 14 provided between a second input terminal 11b and a second output terminal 12b.

[0060] The DC-DC converter circuit 301 also includes a second inductor L2, a second current sensor 321, and a semiconductor switching element M5. The second inductor L2 is connected between the first input terminal 11a and the first bidirectional element 13. The second current sensor 321 detects a second current I2 flowing through the second inductor L2.

[0061] The semiconductor switching element M5 may be, for example, an N-channel MOSFET. In this case, the drain terminal of the semiconductor switching element M5 is connected to a third node N3 between the second inductor L2 and the first bidirectional element 13, and the source terminal of the semiconductor switching element M5 is connected to a fourth node N4 between the second input terminal 11b and the second bidirectional element 14.

[0062] The control circuit 220 controls the operations of the first drive circuit 18 and the second drive circuit 19 based on the timing control signal TS input from the timing control circuit 102, the input voltage V1 and the output voltage V2, and the second current I2.

[0063] In the third embodiment, the transformation ratios V2 / V1 of the DC-DC converter circuits 301(1) to 301(N) are all equal, 1 / (1-D). Therefore, V2>V1 is always satisfied. The relationship between the input voltage Vin and the output voltage Vo of the power conversion device 300 is expressed as follows:

[0064]

number

[0065] (Embodiment 4) FIG. 9 is a diagram showing a configuration of a power conversion device 400 according to the fourth embodiment. The power conversion device 400 is obtained by replacing the N non-insulated DC-DC converter circuits 101-101(N) in the power conversion device 200 according to the second embodiment with N non-insulated DC-DC converter circuits 401(1)-401(N). The power conversion device 400 steps down a DC input voltage and outputs it as a constant DC voltage. The on / off operation timing of each of the DC-DC converter circuits 401(1)-401(N) is the same as that of the second embodiment.

[0066] 10 is a diagram showing a detailed configuration of a non-insulated DC-DC converter circuit 401 according to the present embodiment 4. Since the DC-DC converter circuits 401(1) to 401(N) all have the same configuration, they are collectively referred to as DC-DC converter circuits 401.

[0067] The DC-DC converter circuit 401 includes a first bidirectional element 13 provided between a first input terminal 11a and a first output terminal 12a, and a second bidirectional element 14 provided between a second input terminal 11b and a second output terminal 12b.

[0068] The DC-DC converter circuit 401 also includes a third inductor L3, a third current sensor 422, and a third unidirectional element D3. The third inductor L3 is connected between the first bidirectional element 13 and the first output terminal 12a. The third current sensor 422 detects a third current I3 flowing through the third inductor L3.

[0069] The third unidirectional element D3 may be, for example, a semiconductor diode. In this case, the cathode of the third unidirectional element D3 is connected to a fifth node N5 between the first bidirectional element 13 and the third inductor L3, and the anode of the third unidirectional element D3 is connected to a sixth node N6 between the second bidirectional element 14 and the second output terminal 12b.

[0070] The control circuit 420 controls the operations of the first drive circuit 18 and the second drive circuit 19 based on the timing control signal TS input from the timing control circuit 202, the input voltage V1 and the output voltage V2, and the third current I3.

[0071] In the fourth embodiment, the voltage conversion ratios V2 / V1 of the DC-DC converter circuits 401(1) to 401(N) are all equal to D. Therefore, V2<V1 always holds. The relationship between the input voltage Vin and the output voltage Vo of the power conversion device 400 is expressed as follows.

[0072] [Number]

[0073] (Modification example) In the above-described first to fourth embodiments, N-channel MOSFETs have been used as the semiconductor switching elements M1 to M5. Instead of this, P-channel MOSFETs may be used as the semiconductor switching elements M1 to M5.

[0074] In the above-described first to fourth embodiments, semiconductor diodes have been used as the unidirectional elements D1 to D3. Instead of this, synchronous rectification may be performed by using semiconductor switching elements such as MOSFETs as the unidirectional elements D1 to D3. Alternatively, a configuration in which two semiconductor switching elements similar to the bidirectional elements 13 or 14 are connected may be used as the unidirectional elements D1 to D3. By these means, heat generation of the unidirectional elements D1 to D3 can be suppressed.

[0075] In addition, the semiconductor switching element is not limited to a MOSFET. For example, an IGBT (Insulated Gate Bipolar Transistor) or a BJT (Bipolar Junction Transistor) may be used as the semiconductor switching element. In addition, various materials such as Si (Silicon), SiC (Silicon Carbide), or GaN (Gallium Nitride) may be used as the semiconductor constituting the semiconductor switching element and the semiconductor diode.

[0076] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the embodiments, and these embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, combinations, etc. can be made without departing from the gist of the embodiments. These embodiments and modifications thereof are included in the scope of the claims and their equivalents, as well as the scope and gist of the embodiments.

[0077] This embodiment can also be configured as follows. [Item 1] (Real 1, Real 3) A plurality of non-isolated DC-DC converter circuits including bidirectional elements are provided, a power conversion device, wherein inputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel, and outputs of the plurality of non-isolated DC-DC converter circuits are connected in series. [Item 2] (Real 1, Real 3) Each of the plurality of non-isolated DC-DC converter circuits a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first bidirectional element provided between the first input terminal and the first output terminal; a second bidirectional element provided between the second input terminal and the second output terminal; 2. The power conversion device of item 1, comprising: [Item 3] (Real 1, Real 3) each of the first bidirectional element and the second bidirectional element includes a first semiconductor switching element and a second semiconductor switching element; The power conversion device according to item 2, wherein first terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other, and control terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other. [Item 4] (Real 1) Each of the plurality of non-isolated DC-DC converter circuits 4. The power conversion device according to item 2 or 3, further including a first inductor having one end connected to a first node between the first bidirectional element and the first output terminal and having the other end connected to a second node between the second bidirectional element and the second output terminal. [Item 5] (Real 1) Each of the plurality of non-isolated DC-DC converter circuits a first unidirectional element having one end connected to the first output terminal and the other end connected to the first node; a second unidirectional element having one end connected to the second node and the other end connected to the second output terminal; 5. The power conversion device of item 4, further comprising: [Item 6] (Real 1) Each of the plurality of non-isolated DC-DC converter circuits a first drive circuit that provides a first PWM control signal to the first bidirectional element; a second drive circuit that provides a second PWM control signal to the second bidirectional element; a control circuit that controls the operation of the first drive circuit and the second drive circuit; 6. The power conversion device according to any one of items 2 to 5, further comprising: [Item 7] (Real 1) Each of the plurality of non-isolated DC-DC converter circuits a first voltage sensor that detects a first voltage between the first input terminal and the second input terminal; a second voltage sensor that detects a second voltage between the first output terminal and the second output terminal; a first current sensor that detects a first current flowing through the first inductor; Further comprising: 7. The power conversion device of claim 6, wherein the control circuit controls operation of the first drive circuit and the second drive circuit based on the first voltage and the second voltage, and the first current. [Item 8] (Real 1) The number of the non-isolated DC-DC converter circuits is N, and the system further includes a timing control circuit that controls operation timings of the N DC-DC converter circuits by repeating N time slots, In the first time slot, only the first DC-DC converter circuit is off, and the other N-1 DC-DC converter circuits are all on; In the second time slot, only the second DC-DC converter circuit is off, and the other N-1 DC-DC converter circuits are all on; The power conversion device according to item 7, further controlled in the same manner. [Item 9] (Real 3) Each of the plurality of non-isolated DC-DC converter circuits a second inductor connected between the first input terminal and the first bidirectional element; a third switching element, one end of which is connected to a third node between the second inductor and the first bidirectional element and the other end of which is connected to a fourth node between the second input terminal and the second bidirectional element; 4. The power conversion device according to item 2 or 3, further comprising: [Item 10] (Real 2, Real 4) A plurality of non-isolated DC-DC converter circuits including bidirectional elements are provided, a power conversion device in which inputs of the plurality of non-isolated DC-DC converter circuits are connected in series, and outputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel. [Item 11] (Real 2, Real 4) Each of the plurality of non-isolated DC-DC converter circuits a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first bidirectional element provided between the first input terminal and the first output terminal; a second bidirectional element provided between the second input terminal and the second output terminal; Item 11. The power conversion device of item 10, comprising: [Item 12] Actual 2, Actual 4) each of the first bidirectional element and the second bidirectional element includes a first semiconductor switching element and a second semiconductor switching element; Item 12. The power conversion device according to item 11, wherein first terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other, and control terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other. [Item 13] (Real 2) Each of the plurality of non-isolated DC-DC converter circuits 13. The power conversion device according to item 11 or 12, further including a first inductor having one end connected to a first node between the first bidirectional element and the first output terminal and having the other end connected to a second node between the second bidirectional element and the second output terminal. [Item 14] (Real 2) Each of the plurality of non-isolated DC-DC converter circuits a first unidirectional element having one end connected to the first output terminal and the other end connected to the first node; a second unidirectional element having one end connected to the second node and the other end connected to the second output terminal; Item 14. The power conversion device of item 13, further comprising: [Item 15] (Real 2) Each of the plurality of non-isolated DC-DC converter circuits a first drive circuit that provides a first PWM control signal to the first bidirectional element; a second drive circuit that provides a second PWM control signal to the second bidirectional element; a control circuit that controls the operation of the first drive circuit and the second drive circuit; 15. The power conversion device according to any one of items 11 to 14, further comprising: [Item 16] (Real 2) Each of the plurality of non-isolated DC-DC converter circuits a first voltage sensor that detects a first voltage between the first input terminal and the second input terminal; a second voltage sensor that detects a second voltage between the first output terminal and the second output terminal; a first current sensor that detects a first current flowing through the first inductor; Further comprising: 16. The power conversion device according to claim 15, wherein the control circuit controls operations of the first drive circuit and the second drive circuit based on the first voltage, the second voltage, and the first current. [Item 17] (Real 2) The number of the non-isolated DC-DC converter circuits is N, and the system further includes a timing control circuit that controls operation timings of the N DC-DC converter circuits by repeating N time slots, In the first time slot, only the first DC-DC converter circuit is on, and the other N-1 DC-DC converter circuits are all off; In the second time slot, only the second DC-DC converter circuit is on, and the other N-1 DC-DC converter circuits are all off; Item 17. The power conversion device according to item 16, further controlled in the same manner. [Item 18] (4) Each of the plurality of non-isolated DC-DC converter circuits a third inductor connected between the first bidirectional element and the first output terminal; a third unidirectional element, one end of which is connected to a fifth node between the first bidirectional element and the third inductor, and the other end of which is connected to a sixth node between the second bidirectional element and the second output terminal; 13. The power conversion device according to item 11 or 12, further comprising: [Explanation of symbols]

[0078] 11a First input terminal 11b Second input terminal 12a First output terminal 12b Second output terminal 13 First bidirectional element 13a One terminal 13b Other terminal 14 Second bidirectional element 14a One terminal 14b Other terminal 15 First Voltage Sensor 16 Second Voltage Sensor 17 First current sensor 18 First driving circuit 19 Second driver circuit 20 Control circuit 100 Power conversion device 101 DC-DC converter circuit 102 Timing control circuit 200 Power conversion device 202 Timing control circuit 300 Power Converter 301 DC-DC converter circuit 320 Control circuit 321 Second Current Sensor 400 Power Converter 401 DC-DC converter circuit 420 Control circuit 422 3rd Current Sensor C1 First capacitor C2 Second capacitor D Duty ratio D1 First unidirectional element D2 Second unidirectional element D3 Third unidirectional element fsw Switching frequency G1 First PWM control signal G2 Second PWM control signal L1 First inductor L2 Second inductor L3 Third inductor M1 Semiconductor switching element (first semiconductor switching element) M2 semiconductor switching element (second semiconductor switching element) M3 Semiconductor switching element (first semiconductor switching element) M4 Semiconductor switching element (second semiconductor switching element) M5 Semiconductor switching element (third semiconductor switching element) N1 First node N2 Second node N3 Third node N4 Fourth Node N5 5th node N6 6th node I1 First current I2 Second current I3 Third current INa input terminal INb Input terminal OUTa output terminal OUTb Output terminal TS Timing control signal V1 First voltage V2 Second voltage

Claims

1. A plurality of non-isolated DC-DC converter circuits including bidirectional elements are provided, a power conversion device in which the inputs of the plurality of non-insulated DC-DC converter circuits are connected in parallel, and the outputs of the plurality of non-insulated DC-DC converter circuits are connected in series.

2. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first bidirectional element provided between the first input terminal and the first output terminal; a second bidirectional element provided between the second input terminal and the second output terminal; The power converter of claim 1 .

3. each of the first bidirectional element and the second bidirectional element includes a first semiconductor switching element and a second semiconductor switching element; 3. The power conversion device according to claim 2, wherein first terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other, and control terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other.

4. Each of the plurality of non-isolated DC-DC converter circuits comprises:

3. The power conversion device according to claim 2, further comprising a first inductor having one end connected to a first node between the first bidirectional element and the first output terminal and having the other end connected to a second node between the second bidirectional element and the second output terminal.

5. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first unidirectional element having one end connected to the first output terminal and the other end connected to the first node; a second unidirectional element having one end connected to the second node and the other end connected to the second output terminal; The power converter of claim 4 further comprising:

6. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first drive circuit that supplies a first PWM control signal to the first bidirectional element; a second drive circuit that supplies a second PWM control signal to the second bidirectional element; a control circuit that controls the operation of the first drive circuit and the second drive circuit; The power converter of claim 4 further comprising:

7. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first voltage sensor that detects a first voltage between the first input terminal and the second input terminal; a second voltage sensor that detects a second voltage between the first output terminal and the second output terminal; a first current sensor that detects a first current flowing through the first inductor; Further comprising: The power conversion device according to claim 6 , wherein the control circuit controls operations of the first drive circuit and the second drive circuit based on the first voltage, the second voltage, and the first current.

8. The number of the plurality of non-isolated DC-DC converter circuits is N, and the system further includes a timing control circuit that controls operation timings of the N DC-DC converter circuits by repeating N time slots; In the first time slot, only the first DC-DC converter circuit is off, and the other N-1 DC-DC converter circuits are all on; In a second time slot, only the second DC-DC converter circuit is off, and the other N-1 DC-DC converter circuits are all on; The power conversion device according to claim 7 , wherein the following are similarly controlled.

9. Each of the plurality of non-isolated DC-DC converter circuits comprises: a second inductor connected between the first input terminal and the first bidirectional element; a third switching element, one end of which is connected to a third node between the second inductor and the first bidirectional element and the other end of which is connected to a fourth node between the second input terminal and the second bidirectional element; The power converter of claim 2 further comprising:

10. A plurality of non-isolated DC-DC converter circuits including bidirectional elements are provided, a power conversion device in which the inputs of the plurality of non-insulated DC-DC converter circuits are connected in series, and the outputs of the plurality of non-insulated DC-DC converter circuits are connected in parallel.

11. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first input terminal and a second input terminal; a first output terminal and a second output terminal; a first bidirectional element provided between the first input terminal and the first output terminal; a second bidirectional element provided between the second input terminal and the second output terminal; The power converter of claim 10 .

12. each of the first bidirectional element and the second bidirectional element includes a first semiconductor switching element and a second semiconductor switching element; The power conversion device according to claim 11, wherein first terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other, and control terminals of the first semiconductor switching element and the second semiconductor switching element are connected to each other.

13. Each of the plurality of non-isolated DC-DC converter circuits comprises:

12. The power conversion device according to claim 11, further comprising a first inductor having one end connected to a first node between the first bidirectional element and the first output terminal and having the other end connected to a second node between the second bidirectional element and the second output terminal.

14. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first unidirectional element having one end connected to the first output terminal and the other end connected to the first node; a second unidirectional element having one end connected to the second node and the other end connected to the second output terminal; The power converter of claim 13 further comprising:

15. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first drive circuit that supplies a first PWM control signal to the first bidirectional element; a second drive circuit that supplies a second PWM control signal to the second bidirectional element; a control circuit that controls the operation of the first drive circuit and the second drive circuit; The power converter of claim 13 further comprising:

16. Each of the plurality of non-isolated DC-DC converter circuits comprises: a first voltage sensor that detects a first voltage between the first input terminal and the second input terminal; a second voltage sensor that detects a second voltage between the first output terminal and the second output terminal; a first current sensor that detects a first current flowing through the first inductor; Further comprising: The power conversion device according to claim 15 , wherein the control circuit controls operations of the first drive circuit and the second drive circuit based on the first voltage, the second voltage, and the first current.

17. The number of the plurality of non-isolated DC-DC converter circuits is N, and the system further includes a timing control circuit that controls operation timings of the N DC-DC converter circuits by repeating N time slots; In the first time slot, only the first DC-DC converter circuit is on, and the other N-1 DC-DC converter circuits are all off; In a second time slot, only the second DC-DC converter circuit is on, and the other N-1 DC-DC converter circuits are all off; The power conversion device according to claim 16, further controlled in the same manner.

18. Each of the plurality of non-isolated DC-DC converter circuits comprises: a third inductor connected between the first bidirectional element and the first output terminal; a third unidirectional element, one end of which is connected to a fifth node between the first bidirectional element and the third inductor, and the other end of which is connected to a sixth node between the second bidirectional element and the second output terminal; The power converter of claim 11 further comprising:

Images