Power conversion device and vehicle

Abstract

To provide a power conversion device capable of performing a power conversion with high efficiency in a wider input / output voltage ratio.SOLUTION: A power conversion device for performing a power conversion for bidirectionally transmitting power between a first device and a second device includes: a transformer having a core, a plurality of primary windings wound around the core, and a secondary winding wound around the core; a first circuit for transmitting power between each of the plurality of primary windings and the first device; and a second circuit for transmitting power between the secondary winding and the second device. The plurality of primary windings are respectively connected to the first circuit via individual filters so that frequency bands of power for operating the respective primary windings are different between the plurality of primary windings, and the first circuit and the second circuit are configured to be capable of changing a frequency of power for operating the transformer according to a primary winding used in power conversion in the transformer among the plurality of primary windings.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power conversion device and a vehicle. [Background technology]

[0002] In recent years, lithium-ion batteries have come to be used as chargeable and dischargeable power sources (batteries), and a converter (power conversion device) is required for charging and discharging the lithium-ion battery. A lithium-ion battery has a characteristic in which its open-circuit voltage changes significantly depending on its state of charge. Therefore, converters are required to be able to handle a wide range of input / output voltage ratios and bidirectional power transmission, as well as to perform highly efficient power conversion. A known example of a bidirectional converter is the DAB (Dual Active Bridge) converter (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-26961 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional DAB converter described in Patent Document 1, it is possible to change the input / output transformation ratio within a certain range, but it is subject to restrictions imposed by the winding ratio of the transformer.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a power conversion device that can perform highly efficient power conversion over a wider range of input / output voltage ratios. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a power conversion device as one aspect of the present invention is a power conversion device that performs power conversion to transmit power bidirectionally between a first device and a second device, and includes: a transformer unit having a core, a plurality of primary windings wound around the core, and a secondary winding wound around the core; a first circuit that transmits power between each of the plurality of primary windings and the first device; and a second circuit that transmits power between the secondary winding and the second device, wherein the plurality of primary windings are each connected to the first circuit via an individual filter so that the frequency bands of the power that operate each primary winding are different from one another among the plurality of primary windings, and the first circuit and the second circuit are configured to be able to change the frequency of the power that operates the transformer unit depending on which of the plurality of primary windings is used for power conversion in the transformer unit. [Effects of the Invention]

[0007] According to the present invention, for example, it is possible to provide a power conversion device that can perform power conversion with high efficiency over a wider range of input / output voltage ratios. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram showing a configuration example of a power conversion device [Figure 2] FIG. 1 is a diagram showing conditions for an example of operation of a power conversion device. [Figure 3] FIG. 10 is a diagram showing the operation result of the power conversion device when the voltage of the first device is VLOW. [Figure 4] FIG. 10 is a diagram showing the operation result of the power conversion device when the voltage of the first device is VMID. [Figure 5] FIG. 10 is a diagram illustrating the operation result of the power conversion device when the voltage of the first device is VHIGH. [Figure 6] Schematic diagram showing a modified example of the transformer section DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and includes modifications and variations of the configuration within the scope of the present invention. Furthermore, not all of the combinations of features described in the present embodiments are necessarily essential to the present invention. Note that the same reference numerals are used to designate the same components, and their description will be omitted.

[0010] First Embodiment A first embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing a configuration example of a power conversion device 100 of this embodiment. The power conversion device 100 of this embodiment is a bidirectional isolated converter that performs power conversion to transmit (supply) power bidirectionally between a first device D1 and a second device D2. That is, the power conversion device 100 is configured to be able to transmit (supply) power from the first device D1 to the second device D2 and to transmit (supply) power from the second device D2 to the first device D1. The first device D1 may be a rechargeable battery such as a lithium-ion battery. The second device D2 may be a load (e.g., a device such as a motor) that receives power from the battery serving as the first device D1, or a power source (e.g., a charger) that supplies power to the battery serving as the first device D1. In this embodiment, an example will be described in which a battery is used as the first device D1 and a load is used as the second device D2.

[0011] The power conversion device 100 of this embodiment can be mounted on an electric vehicle, a hybrid vehicle, or the like. The vehicle on which the power conversion device 100 is mounted may be a four-wheeled vehicle, or a vehicle other than a four-wheeled vehicle, such as a straddle-type vehicle (motorcycle, tricycle). Furthermore, the power conversion device 100 of this embodiment may be mounted on a moving body other than a vehicle, such as a ship or an aircraft.

[0012] [Example of power conversion device configuration] An example configuration of a power conversion device 100 of this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the power conversion device 100 of this embodiment may include a transformer unit 10, a primary side circuit 20 (first circuit), a secondary side circuit 30 (second circuit), and a control unit 40.

[0013] First, the configuration of transformer unit 10 will be described. Transformer unit 10 is a unit including a transformer, and includes core 11, multiple primary windings (primary coils) 12a to 12c, and secondary windings (secondary coils) 13. Core 11 (iron core) is a member for passing magnetic flux (magnetic field) and can be made of a material with high magnetic permeability and low loss. Examples of materials for core 11 include silicon hard plate, permalloy, and ferrite.

[0014] The primary windings 12a to 12c are wound around the same (common) core 11 and are configured to have different turn ratios relative to the secondary winding 13. In this embodiment, the number of turns n of the primary winding 12a is pL , the number of turns of the primary winding 12b n pM , and the number of turns n of the primary winding 12c pH is n pL <n pM <n pH Although the transformer unit 10 of this embodiment is configured with three primary windings 12a to 12c, the number of primary windings is not limited to three, and may be two or four or more.

[0015] Furthermore, the multiple primary windings 12a to 12c are each connected to the primary circuit 20 via an individual filter so that the frequency bands of the power that operate the primary windings 12a to 12c are different from one another. Specifically, if one of the multiple primary windings 12a to 12c is designated as a first primary winding and the other is designated as a second primary winding, the first primary winding is connected to the primary circuit 20 via a first filter, and the second primary winding is connected to the primary circuit 20 via a second filter. The first filter and the second filter are configured so that they pass different frequency bands of power. The frequency band of power that the first filter passes and the frequency band of power that the second filter pass are preferably set so as not to overlap with each other.

[0016] In this embodiment, the primary winding 12a is connected to the primary circuit 20 via a filter 14a, the primary winding 12b is connected to the primary circuit 20 via a filter 14b, and the primary winding 12c is connected to the primary circuit 20 via a filter 14c. The filters 14a to 14c are each a bandpass filter and are configured to pass different frequency bands of power. The frequency bands of power passed by the filters 14a to 14c are preferably set so as not to overlap with each other.

[0017] 1, each of the filters 14a to 14c is configured by a resonant circuit in which an inductance and a capacitance are connected in series. Specifically, the filter 14a is configured to have a frequency band F fL In order to pass the power of fL and capacitance C fL The filter 14b is configured by a resonant circuit in which a frequency band F fM In order to pass the power of fM and capacitance C fM The filter 14c is configured by a resonant circuit in which a frequency band F fH In order to pass the power of fH and capacitance C fH The filters 14a to 14c are configured by a resonant circuit in which the frequency bands of the powers to be passed do not overlap with each other, and fL <F fM <F fH Each of the filters 14a to 14c is not limited to a resonant circuit in which an inductance and a capacitance are connected in series, and may be configured by another type of resonant circuit or another type of band-pass filter.

[0018] The secondary winding 13 is wound around the core 11 around which the multiple primary windings 12a to 12c are wound, and is used in common for the multiple primary windings 12a to 12c. The turn ratio between the secondary winding 13 and each of the primary windings 12a to 12c is set to a desired input / output voltage ratio (i.e., the voltage E MPP and the voltage E of the second device D2 sdc As an example, the number of turns n of each of the primary windings 12a to 12c is set in accordance with the ratio of pL , n pM , n pH and the number of turns n of the secondary winding 13 s Ratio to (n pL :n pM :n pH :n s ) can be set to 1:1.5:2.5:5. The secondary winding 13 is connected to the inductor L s The secondary winding 13 is connected to the secondary circuit 30 via an inductor L s By connecting the secondary side circuit 30 via this, phase shift control as a DAB converter becomes easy.

[0019] Here, a battery (e.g., a lithium-ion battery) that can be used as the first device D1 has a characteristic in which its open-circuit voltage varies significantly depending on the state of charge. Therefore, the input-output voltage ratio may also vary as the open-circuit voltage of the battery changes. Therefore, a power conversion device (transformer) is desired that can perform high-efficiency power conversion over a wider range of input-output voltage ratios. However, a conventional transformer consisting of one primary winding and one secondary winding can only achieve one type of turns ratio. In this case, high-efficiency power conversion is possible when the input-output voltage ratio matches the specified turns ratio. However, as the input-output voltage ratio deviates from the specified turns ratio, the power conversion efficiency decreases. In other words, a change in the input-output voltage ratio can make it difficult to achieve high-efficiency power conversion. While a configuration in which multiple conventional transformers are provided and the turns ratios are changed across the multiple transformers is also conceivable, this configuration increases the number of components (e.g., cores), which can increase the cost and size of the device.

[0020] On the other hand, in the transformer unit 10 of this embodiment, as described above, multiple primary windings 12a-12c with different turn ratios relative to the secondary winding 13 are provided on one (same) core 11 so as to share one secondary winding 13. Then, through the action of individual filters 14a-14c, power conversion is performed by selectively using one of the multiple primary windings 12a-12c according to the input / output voltage ratio. This enables highly efficient power conversion over a wider range of input / output voltage ratios. Furthermore, the number of components can be reduced, which can be advantageous for reducing the cost and size of the device.

[0021] Next, the configurations of the primary side circuit 20 and the secondary side circuit 30 will be described. In this embodiment, an example will be described in which the power conversion device 100 (primary side circuit 20, secondary side circuit 30) is configured as an isolated bidirectional DC / DC converter of a DAB (Dual Active Bridge) type. However, the power conversion device 100 is not limited to the DAB type, and may be configured as an isolated bidirectional DC / DC converter of another type.

[0022] The primary side circuit 20 is a circuit (first circuit) for transmitting power between each of the multiple primary side windings 12a to 12c and the first device D1. The primary side circuit 20 is provided on the primary side of the transformer unit 10, and is connected to each of the primary side windings 12a to 12c of the transformer unit 10 and the first device D1 (battery). The secondary side circuit 30 is a circuit (second circuit) for transmitting power between the secondary side winding 13 and the second device D2. The secondary side circuit 30 is provided on the secondary side of the transformer unit 10, and is connected to the secondary side winding 13 of the transformer unit 10 and the second device D2. The primary side circuit 20 and the secondary side circuit 30 are configured to be able to change the frequency of the power that operates the transformer unit 10 (i.e., the frequency of the voltage applied to each of the primary side windings 12a to 12c of the transformer unit 10) depending on which of the multiple primary side windings 12a to 12c in the transformer unit 10 is used for power conversion.

[0023] The primary side circuit 20 includes a plurality of switch elements S p1 ~S p4The control unit 40 controls the plurality of switch elements S p1 ~S p4 By controlling the switching element S, the frequency of the power that operates the transformer unit 10 can be changed. p1 ~S p2 are connected in series to form the first leg 21, and the switch element S p3 ~S p4 are connected in series to each other to form the second leg 22. The first leg 21 and the second leg 22 are connected in parallel to each other. The primary side circuit 20 is also provided with a capacitor C1 connected in parallel to the first leg 21 and the second leg 22. This capacitor C1 is connected in series to the switch element S p3 ~S p4 It is for smoothing purposes that correspond to the operation of

[0024] In the primary side circuit 20 configured as described above, the first device D1 is connected in parallel to the first leg 21 and the second leg 22. Furthermore, each of the primary side windings 12a to 12c of the transformer unit 10 is connected to the primary side circuit 20 such that one end is connected to a contact b1 of the first leg 21 and the other end is connected to a contact b2 of the second leg 22. The contact b1 is connected to the switch element S p1 and switch element S p2 The contact b2 is provided on the line between the switch element S p3 and switch element S p4 It is provided on the line between

[0025] The secondary circuit 30 includes a plurality of switch elements S s1 ~S s4 The control unit 40 controls the plurality of switch elements S s1 ~S s4 By controlling the switching element S, the frequency of the power that operates the transformer unit 10 can be changed. s1 ~S s2 are connected in series to form the third leg 31, and the switch element S s3 ~S s4are connected in series to each other to form a fourth leg 32. The third leg 31 and the fourth leg 32 are connected in parallel to each other. The secondary side circuit 30 is also provided with a capacitor C2 connected in parallel to the third leg 31 and the fourth leg 32. This capacitor C2 is connected in series to the switch element S s1 ~S s2 It is for smoothing purposes that correspond to the operation of

[0026] In the secondary circuit 30 configured as described above, the second device D2 is connected in parallel to the third leg 31 and the fourth leg 32. The secondary winding 13 of the transformer unit 10 is connected to the secondary circuit 30 so that one end is connected to the contact b3 of the third leg 31 and the other end is connected to the contact b4 of the fourth leg 32. The contact b3 is connected to the switch element S s1 and switch element S s2 The contact b4 is provided on the line between the switch element S s3 and switch element S s4 It is provided on the line between

[0027] Next, the control unit 40 will be described. The control unit 40 is configured by a computer including a processor represented by a CPU (Central Processing Unit), a storage device such as a semiconductor memory, an interface with an external device, etc. The control unit 40 controls the switching of the multiple switch elements S in the primary side circuit 20. p1 ~S p4 and the on / off of the plurality of switch elements S in the secondary circuit 30. s1 ~S s4 The power conversion in the transformer unit 10 is controlled by controlling the on / off of the power converter 10. That is, the frequency of the power that operates the transformer unit 10 is controlled (changed). Here, in this embodiment, the control unit 40 is provided as a component of the power conversion device 100, but this is not limiting, and for example, an external control device such as an ECU (Electronic Control Unit) provided in a vehicle may function as the control unit 40.

[0028] In this embodiment, the control unit 40 determines (selects) a primary winding to be used in power conversion in the transformer unit 10 from among the multiple primary windings 12a to 12c in the transformer unit 10, depending on the voltage ratio (input / output voltage ratio) to be generated between the first device D1 and the second device D2. For example, since the voltage value to be applied to the second device D2 is predetermined, the control unit 40 detects the voltage value of the first device D1 (battery) and calculates the input / output voltage ratio based on the detected voltage value of the first device D1. The voltage value of the first device D1 can be detected using a voltage sensor in the power conversion device 100 or in a vehicle on which the power conversion device 100 is mounted. Then, the control unit 40 determines, from among the multiple primary windings 12a to 12c, the primary winding having the winding ratio most suitable (closest) to the calculated input / output voltage ratio as the primary winding to be operated. Next, the control unit 40 controls the primary side circuit 20 and the secondary side circuit 30 to generate power at a frequency that operates the determined primary side winding, i.e., power at a frequency that can pass through the filter provided for the determined primary side winding.

[0029] [Example of power conversion device operation] An example of the operation of the power conversion device 100 of this embodiment will be described. Here, an example in which the power conversion device 100 is operated under the conditions (configuration) shown in FIG. 2 will be described. Specifically, when the voltage E MPP V LOW , V MID , V HIGH (V LOW <V MID <V HIGH ) and the voltage E of the second device D2 sdc (5×V LOW ) was set as the turn ratio (n pL :n pM :n pH :n s ) is the input / output voltage ratio between the first device D1 and the second device D2 (i.e., the voltage E MPP and voltage E sdc The ratio is set to 1:1.5:2.5:5.

[0030] The frequency of the power for operating the transformer unit 10 (operating frequency f) is f LOW , f MID , f HIGH (f LOW <f MID <f HIGH ) That is, the filter 14a is set to f LOW is the resonant frequency, and the frequency band to be passed is f LOW Contains f MID and f HIGH Similarly, the filter 14b is configured not to include f MID is the resonant frequency, and the frequency band to be passed is f MID Contains f LOW and f HIGH The filter 14c is configured not to include f HIGH is the resonant frequency, and the frequency band to be passed is f HIGH Contains f LOW and f MID In addition, the duty ratio D of each switch element in the primary side circuit 20 and the secondary side circuit 30 is fixed to 0.5.

[0031] Figure 3 shows the voltage E of the first device D1. MPP V LOW 1 shows the operation result of the power conversion device 100 (transformer unit 10) when the voltage E MPP (That is, the primary voltage V of the transformer 10 p ) is V LOW In this case, the voltage E MPP =V LOW The winding ratio (n s / n pL ) should be used selectively. Therefore, the operating frequency f should be LOW The primary circuit 20 and the secondary circuit 30 are controlled by the control unit 40 so that the current I pL The current I pM ,I pHis suppressed, and the primary winding 12a is selectively used for voltage conversion in the transformer 10. That is, as shown in FIG. 3(a), in the transformer 10, the primary voltage V p =V LOW to secondary voltage V s This allows for efficient voltage conversion to be performed.

[0032] Figure 4 shows the voltage E of the first device D1. MPP V MID 1 shows the operation result of the power conversion device 100 (transformer unit 10) when the voltage E MPP (That is, the primary voltage V of the transformer 10 p ) is V MID In this case, the voltage E MPP =V MID The winding ratio (n s / n pM ) should be used selectively. Therefore, the operating frequency f should be MID The primary side circuit 20 and the secondary side circuit 30 are controlled by the control unit 40 so that the current I pM The current I pL ,I pH is suppressed, and the primary winding 12b is selectively used for voltage conversion in the transformer 10. That is, as shown in FIG. 4(a), in the transformer 10, the primary voltage V p =V MID to secondary voltage V s This allows for efficient voltage conversion to be performed.

[0033] FIG. 5 shows the voltage E of the first device D1. MPP V HIGH 1 shows the operation result of the power conversion device 100 (transformer unit 10) when the voltage E MPP (That is, the primary voltage V of the transformer 10 p ) is V HIGH In this case, the voltage E MPP =V HIGHThe winding ratio (n s / n pH ) should be used selectively. Therefore, the operating frequency f should be HIGH The primary circuit 20 and the secondary circuit 30 are controlled by the control unit 40 so that the current I pH The current I pL ,I pM is suppressed, and the primary winding 12c is selectively used for voltage conversion in the transformer 10. That is, as shown in FIG. 5(a), in the transformer 10, the primary voltage V p =V HIGH to secondary voltage V s This allows for efficient voltage conversion to be performed.

[0034] As described above, in the power conversion device 100 of this embodiment, the transformer unit 10 includes multiple primary windings 12a-12c with different turns ratios relative to the secondary winding 13, each of which is provided on a single core 11 so as to share the same secondary winding 13. Furthermore, the multiple primary windings 12a-12c are individually provided with filters 14a-14c that pass different frequency bands of power. In the transformer unit 10 configured in this manner, by changing the frequency of the power operating the transformer unit 10, the filters 14a-14c can selectively use one of the multiple primary windings 12a-12c according to the input / output voltage ratio to perform power conversion. In other words, highly efficient power conversion is possible over a wider range of input / output voltage ratios. Furthermore, the configuration of the transformer unit 10 of this embodiment reduces the number of components, which can be advantageous for reducing the cost and size of the device.

[0035] Second Embodiment A second embodiment of the present invention will be described. In the first embodiment described above, an example was shown in which the multiple primary windings 12a-12c in the transformer unit 10 were configured as separate windings independent of each other. However, this is not limited thereto, and the multiple primary windings 12a-12c may be configured integrally as a single winding, as shown in FIG. 6. In this case, the midpoint of the single winding is connected to the primary circuit 20 (i.e., contact point b1) via each of the filters 14a-14c. Note that this embodiment basically follows on from the first embodiment, and the configuration other than the transformer unit 10 (e.g., the configuration of the primary circuit 20 and the secondary circuit 30) and the operation of the power conversion device 100 are the same as those described in the first embodiment.

[0036] <Summary of the embodiment> 1. The power conversion device of the above embodiment is A power conversion device (e.g., 100) that performs power conversion for bidirectionally transmitting power between a first device (e.g., D1) and a second device (e.g., D2), a transformer unit (e.g., 10) having a core (e.g., 11), a plurality of primary windings (e.g., 12a to 12c) wound around the core, and a secondary winding (e.g., 13) wound around the core; a first circuit (e.g., 20) that transfers power between each of the plurality of primary windings and the first device; a second circuit (e.g., 30) that transfers power between the secondary winding and the second device; Equipped with the plurality of primary windings are connected to the first circuit via individual filters (e.g., 14a to 14c) so that frequency bands of powers for operating the respective primary windings are different from one another among the plurality of primary windings; The first circuit and the second circuit are configured to be able to change the frequency of the power that operates the transformer unit depending on which of the multiple primary windings is used for power conversion in the transformer unit. This configuration allows power conversion to be performed by selectively using one of the multiple primary windings that matches the input / output voltage ratio, making it possible to achieve highly efficient power conversion over a wider range of input / output voltage ratios. Furthermore, compared to conventional configurations that include multiple transformer units each including one primary winding and one secondary winding, this configuration reduces the number of components, which can be advantageous in terms of reducing device costs and downsizing.

[0037] 2. In the above embodiment, The plurality of primary windings have different winding ratios relative to the secondary winding. According to this configuration, it is possible to selectively use, from among the multiple primary windings, a primary winding having a winding ratio corresponding to a desired input / output voltage ratio, thereby enabling highly efficient power conversion over a wider range of input / output voltage ratios.

[0038] 3. In the above embodiment, the plurality of primary windings include a first primary winding (e.g., one of 12a to 12c) connected to the first circuit via a first filter (e.g., one of 14a to 14c), and a second primary winding (e.g., another one of 12a to 12c) connected to the second circuit via a second filter (e.g., another one of 14a to 14c); The first filter and the second filter pass power in different frequency bands. This configuration enables highly efficient power conversion over a wider range of input / output voltage ratios.

[0039] 4. In the above embodiment, The filter is an inductance (e.g., L fL , L fM , L fH ) and capacitance (e.g., C fL , C fM , C fH ) and a resonant circuit including the According to this configuration, it is possible to realize a configuration in which one primary winding out of a plurality of primary windings is selectively used by using a filter formed of a resonant circuit.

[0040] 5. In the above embodiment, The transformer unit is configured so that one of the multiple primary windings operates according to the frequency of the power generated in the first circuit and the second circuit through the action of the filters provided individually for the multiple primary windings. According to this configuration, by changing the frequency of the power that operates the transformer unit, it is possible to realize a configuration in which one primary winding out of a plurality of primary windings is selectively used.

[0041] 6. In the above embodiment, The secondary winding has an inductance (e.g., L s ) connected to the second circuit. This configuration makes it easy to control the phase shift as a DAB converter.

[0042] 7. In the above embodiment, The power conversion device further includes a control unit (e.g., 40) that controls the first circuit and the second circuit, The control unit controls a switch element (for example, S p1 ~S p4 , S s1 ~S s4 ) is turned on / off to change the frequency of the power that operates the transformer unit. According to this configuration, the frequency of the power that operates the transformer unit can be changed with a simple configuration using a plurality of switch elements.

[0043] 8. In the above embodiment, The power conversion device further includes a control unit (e.g., 40) that controls the first circuit and the second circuit, The control unit determines a primary winding to be used for power conversion in the transformer unit from among the plurality of primary windings in accordance with the voltage ratio to be generated between the first device and the second device, and controls the first circuit and the second circuit to generate power at a frequency that operates the determined primary winding. According to this configuration, a primary winding corresponding to the input / output voltage ratio between the first device and the second device can be appropriately selected from a plurality of primary windings, and voltage conversion can be performed using the selected primary winding.

[0044] 9. In the above embodiment, the first device is a battery; The second device is a load to which power is supplied from the first device, or a power source that supplies power to the first device. This configuration enables power transmission from the battery as the first device to the load as the second device, and power transmission from the power source as the second device to the battery as the first device.

[0045] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0046] 10: transformer section, 11: core, 12a to 12c: primary windings, 13: secondary windings, 14a to 14c: filters, 20: primary circuit (first circuit), S p1 ~S p4 : Switch element of primary side circuit, 30: Secondary side circuit (second circuit), S s1 ~S s4 : switch element of secondary side circuit, 40: control unit, 100: power conversion device

Claims

1. A power conversion device that performs power conversion for bidirectionally transmitting power between a first device and a second device, a transformer unit having a core, a plurality of primary windings wound around the core, and a secondary winding wound around the core; a first circuit that transfers power between each of the plurality of primary windings and the first device; a second circuit that transfers power between the secondary winding and the second device; Equipped with the plurality of primary windings are respectively connected to the first circuit via individual filters such that frequency bands of power operating the respective primary windings are different from one another among the plurality of primary windings; a power conversion device characterized in that the first circuit and the second circuit are configured to be able to change the frequency of the power that operates the transformer unit depending on which of the multiple primary windings is used for power conversion in the transformer unit.

2. 2. The power conversion device according to claim 1, wherein the plurality of primary windings have mutually different turn ratios relative to the secondary winding.

3. the plurality of primary windings include a first primary winding connected to the first circuit via a first filter and a second primary winding connected to the second circuit via a second filter; The power conversion device according to claim 1 , wherein the first filter and the second filter pass power in different frequency bands.

4. 2. The power conversion device according to claim 1, wherein the filter is configured by a resonant circuit including an inductance and a capacitance.

5. 2. The power conversion device according to claim 1, wherein the transformer unit is configured so that one of the plurality of primary windings operates in accordance with the frequency of the power generated in the first circuit and the second circuit due to the action of the filters provided individually for the plurality of primary windings.

6. The power conversion device according to claim 1 , wherein the secondary winding is connected to the second circuit via an inductance.

7. a control unit that controls the first circuit and the second circuit; 2. The power conversion device according to claim 1, wherein the control unit changes the frequency of the power that operates the transformer unit by controlling on / off of switch elements provided in each of the first circuit and the second circuit.

8. a control unit that controls the first circuit and the second circuit; 2. The power conversion device according to claim 1, wherein the control unit determines a primary winding to be used in power conversion in the transformer unit from among the plurality of primary windings in accordance with a voltage ratio to be generated between the first device and the second device, and controls the first circuit and the second circuit to generate power at a frequency that operates the determined primary winding.

9. the first device is a battery, The second device is a load to which power is supplied from the first device, or a power source that supplies power to the first device.

2. The power conversion device according to claim 1.

10. A vehicle comprising the power conversion device according to any one of claims 1 to 9.

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