Power converter and power conversion method

Abstract

The invention provides a power converter. The power converter comprises a first bus capacitor, a second bus capacitor, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a first inductor, a second inductor, a first load capacitor, a second load capacitor, a first relay and a second relay. The first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first relay and the second relay are configured to switch the switch states, so that the first inductor and the second inductor store or release energy, and then electric energy is transmitted among the first bus capacitor, the second bus capacitor, the first load capacitor and the second load capacitor.

Description

Technical Field

[0001] The present invention relates to a power converter and a power conversion method, and more particularly to a power converter and a power conversion method capable of achieving energy balance and hybrid power supply. Background Art

[0002] In an existing DC / DC converter with dual bus capacitors, the two bus capacitors are connected between the positive input terminal and the negative input terminal, so the input side includes the positive bus capacitor voltage and the negative bus capacitor voltage. When the DC / DC converter steps down the voltage and supplies power to the output terminal, the positive and negative bus capacitor voltages may be unbalanced due to the different duty cycles of the switches in the converter.

[0003] In order to balance the voltages of the positive and negative bus capacitors, existing practices often adjust the bus capacitor voltages by adding a set of balancing circuits. However, the added balancing circuits will make the overall circuit larger and result in a decrease in power density.

[0004] Therefore, how to invent a power converter and a power conversion method that can improve the above-mentioned prior art is an urgent need. Summary of the invention

[0005] The purpose of this case is to provide a power converter and a power conversion method, which can achieve capacitor voltage balance based on the inherent inductance element of the converter, so compared with the existing practice of adding a balance circuit, it can effectively reduce the overall circuit volume and improve the power density. In addition. The power converter and power conversion method of this case can achieve energy balance and mixed power supply by transmitting electric energy between each capacitor and inductor, and meet various load requirements.

[0006] To achieve the above-mentioned purpose, the present case provides a power converter, comprising a first upper bridge voltage conversion module, a first lower bridge voltage conversion module, a second upper bridge voltage conversion module and a second lower bridge voltage conversion module. The first upper bridge voltage conversion module comprises a first bus capacitor, a first switch, a second switch, a first inductor and a first load capacitor, wherein the first switch, the second switch and the first inductor are electrically connected between the first bus capacitor and the first load capacitor. The first lower bridge voltage conversion module comprises a second bus capacitor, a third switch, a fourth switch, a second inductor and a second load capacitor, wherein the third switch, the fourth switch and the second inductor are electrically connected between the second bus capacitor and the second load capacitor. The second upper bridge voltage conversion module comprises a fifth switch and a first relay, wherein the first end of the fifth switch is connected to the first end of the first bus capacitor, and the first relay can selectively switch the first inductor to connect to the second end of the fifth switch or the first end of the first load capacitor, and the second end of the first load capacitor is connected to the second end of the first bus capacitor. The second lower bridge voltage conversion module includes a sixth switch and a second relay, wherein the first end of the second load capacitor is connected to the first end of the second bus capacitor, the second relay can selectively switch the second inductor to connect to the first end of the sixth switch or the second end of the second load capacitor, and the second end of the sixth switch is connected to the second end of the second bus capacitor. The first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first relay and the second relay are configured to switch the switch state so that the first inductor and the second inductor store or release energy, thereby transmitting electric energy between the first bus capacitor, the second bus capacitor, the first load capacitor and the second load capacitor.

[0007] To achieve the above-mentioned purpose, the present case further provides a power conversion method, which is applicable to the power converter of the present case and includes the steps of: sensing the voltages on the first bus capacitor, the second bus capacitor, the first load capacitor and the second load capacitor to determine whether to perform one of the first operation mode, the second operation mode, the third operation mode, the fourth operation mode and the fifth operation mode; and according to one of the first operation mode to the fifth operation mode, controlling the switching states of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first relay and the second relay to enable the first inductor and the second inductor to store energy or release energy, thereby allowing electrical energy to be transmitted between the first bus capacitor, the second bus capacitor, the first load capacitor and the second load capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of the circuit structure of a power converter according to the first embodiment of the present invention;

[0009] Figure 2 is a schematic diagram of the power converter of the present invention in a first operation mode;

[0010] Figure 3is a schematic diagram of the power converter of the present invention in the second operation mode;

[0011] Figure 4 is a schematic diagram of the power converter of the present invention in a third operation mode;

[0012] Figure 5A and Figure 5B is a schematic diagram of the power converter of the present invention in a fourth operation mode;

[0013] Fig. 6A and Figure 6B is a schematic diagram of the power converter of the present invention in a fifth operation mode;

[0014] Figure 7 is a schematic diagram of a circuit structure of a power converter according to a second embodiment of the present invention;

[0015] Figure 8 FIG. 4 is a flow chart of a power conversion method according to an embodiment of the present invention.

[0016] Description of Figure Numbers:

[0017] 1: Power Converter

[0018] 11: First upper bridge voltage conversion module

[0019] 12: First lower bridge voltage conversion module

[0020] 13: Second upper bridge voltage conversion module

[0021] 14: Second lower bridge voltage conversion module

[0022] C1: First bus capacitor

[0023] S1: First switch

[0024] S2: Second switch

[0025] L1: First inductor

[0026] C3: First load capacitor

[0027] C2: Second bus capacitor

[0028] S3: The third switch

[0029] S4: The fourth switch

[0030] L2: Second inductor

[0031] C4: Second load capacitor

[0032] S5: Fifth switch

[0033] RY1: First relay

[0034] P1: First moving contact

[0035] P2: First static contact

[0036] P3: Second static contact

[0037] S6: Sixth switch

[0038] RY2: Second relay

[0039] P4: Second moving contact

[0040] P5: The third static contact

[0041] P6: Fourth static contact

[0042] V1: first voltage

[0043] V2: Second voltage

[0044] V3: The third voltage

[0045] 2: Power supply

[0046] C: Capacitance

[0047] Bus+: positive input

[0048] N: Neutral end

[0049] Bus-: negative input terminal

[0050] PS1: The first energy storage path

[0051] PR1: First energy release path

[0052] PS2: Second energy storage path

[0053] PR2: Second energy release path

[0054] PS3: The third energy storage path

[0055] PR3: The third energy release path

[0056] PS4: The Fourth Energy Storage Path

[0057] PS5: The fifth energy storage path

[0058] PR4: The fourth energy release path

[0059] PR5: The fifth energy release path

[0060] PS6: Sixth Energy Storage Path

[0061] PS7: Seventh Energy Storage Path

[0062] PR6: Sixth Energy Release Path

[0063] PR7: Seventh Energy Release Path

[0064] 3: Power Factor Correction Converter

[0065] ST1, ST2: Steps DETAILED DESCRIPTION

[0066] Some typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention.

[0067] Figure 1 FIG. 1 is a schematic diagram of the circuit structure of a power converter according to the first embodiment of the present invention. Figure 1 As shown, the power converter 1 includes a first upper bridge voltage conversion module 11 , a first lower bridge voltage conversion module 12 , a second upper bridge voltage conversion module 13 and a second lower bridge voltage conversion module 14 .

[0068] The first upper bridge voltage conversion module 11 includes a first bus capacitor C1, a first switch S1, a second switch S2, a first inductor L1 and a first load capacitor C3, wherein the first switch S1, the second switch S2 and the first inductor L1 are electrically connected between the first bus capacitor C1 and the first load capacitor C3. The first lower bridge voltage conversion module 12 includes a second bus capacitor C2, a third switch S3, a fourth switch S4, a second inductor L2 and a second load capacitor C4, wherein the third switch S3, the fourth switch S4 and the second inductor L2 are electrically connected between the second bus capacitor C2 and the second load capacitor C4.

[0069] The second upper bridge voltage conversion module 13 includes a fifth switch S5 and a first relay RY1, wherein the first end of the fifth switch S5 is connected to the first end of the first bus capacitor C1, and the first relay RY1 can selectively switch the first inductor L1 to connect to the second end of the fifth switch S5 or the first end of the first load capacitor C3, and the second end of the first load capacitor C3 is connected to the second end of the first bus capacitor C1. In this embodiment, the first relay RY1 includes a first moving contact P1, a first static contact P2, and a second static contact P3, wherein the first moving contact P1, the first static contact P2, and the second static contact P3 are respectively connected to the first inductor L1, the second end of the fifth switch S5, and the first end of the first load capacitor C3. When the first relay RY1 switches the first moving contact P1 to connect to the first static contact P2, the first inductor L1 is connected to the second end of the fifth switch S5; and when the first relay RY1 switches the first moving contact P1 to connect to the second static contact P3, the first inductor L1 is connected to the first end of the first load capacitor C3.

[0070] The second lower bridge voltage conversion module 14 includes a sixth switch S6 and a second relay RY2, wherein the first end of the second load capacitor C4 is connected to the first end of the second bus capacitor C2, the second relay RY2 can selectively switch the second inductor L2 to connect to the first end of the sixth switch S6 or the second end of the second load capacitor C4, and the second end of the sixth switch S6 is connected to the second end of the second bus capacitor C2. In this embodiment, the second relay RY2 includes a second moving contact P4, a third static contact P5 and a fourth static contact P6, wherein the second moving contact P4, the third static contact P5 and the fourth static contact P6 are respectively connected to the second inductor L2, the first end of the sixth switch S6 and the second end of the second load capacitor C4. When the second relay RY2 switches the second moving contact P4 to connect to the third static contact P5, the second inductor L2 is connected to the first end of the sixth switch S6; and when the second relay RY2 switches the second moving contact P4 to connect to the fourth static contact P6, the second inductor L2 is connected to the second end of the second load capacitor C4. In addition, the second end of the fifth switch S5 and the first end of the sixth switch S6 are connected to each other. Figure 1 The first to sixth switches S1-S6 are exemplified by IGBTs (insulated gate bipolar transistors), but possible implementations of the switches are not limited thereto. For example, the first to sixth switches S1-S6 may also be MOSFETs (metal-oxide-semiconductor field effect transistors).

[0071] The first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the fifth switch S5, the sixth switch S6, the first relay RY1 and the second relay RY2 are configured to switch the switch state so that the first inductor L1 and the second inductor L2 store energy or release energy, thereby transmitting electric energy between the first bus capacitor C1, the second bus capacitor C2, the first load capacitor C3 and the second load capacitor C4. In this way, capacitor voltage balance can be achieved based on the inherent inductance element of the converter, so compared with the existing practice of adding a balancing circuit, the overall circuit volume can be effectively reduced and the power density can be improved. In addition. The power converter and power conversion method of the present case can achieve energy balance and mixed power supply by transmitting electric energy between each capacitor and inductor, and meet various load requirements.

[0072] In addition, the first bus capacitor C1 is configured to establish a first voltage V1, the second bus capacitor C2 is configured to establish a second voltage V2, and the first load capacitor C3 and the second load capacitor C4 are configured to establish a third voltage V3. Figure 1In the embodiment shown, the first voltage V1 and the second voltage V2 are used as input voltages, and the third voltage V3 is used as output voltage. In this case, the power converter 1 may further include a power source 2 and a load (eg Figure 1 The capacitor C in the figure), wherein the power supply 2 is connected to the positive input terminal Bus+, the neutral terminal N and the negative input terminal Bus- of the power converter 1. The positive input terminal Bus+ is connected to the first end of the first bus capacitor C1, the negative input terminal Bus- is connected to the second end of the second bus capacitor C2, and the load (capacitor C) is connected to the first end of the first load capacitor C3 and the second end of the second load capacitor C4. The neutral terminal N is connected to the second end of the first bus capacitor C1, the first end of the second bus capacitor C2, the second end of the first load capacitor C3, the first end of the second load capacitor C4, the second end of the second switch S2 and the first end of the third switch S3. Of course, in fact, the power converter 1 of the present case is a bidirectional power converter. Specifically, in other embodiments, the third voltage V3 can also be used as the input side voltage, and the first voltage V1 and the second voltage V2 are used as the output side voltages accordingly. In this case, the setting positions of the power supply 2 and the load are interchanged, and the operation method thereof can be based on Figure 1 The embodiments shown are deduced, so this case will not be described in detail.

[0073] In some embodiments, such as Figure 1 As shown, the first end and the second end of the first switch S1 are respectively connected to the first end of the first bus capacitor C1 and the first end of the second switch S2, and the second end of the second switch S2 is connected to the second end of the first bus capacitor C1. The first end of the first inductor L1 is connected to the second end of the first switch S1 and the first end of the second switch S2, and the second end of the first inductor L1 is connected to the first relay RY1.

[0074] In some embodiments, such as Figure 1 As shown, the first end and the second end of the third switch S3 are respectively connected to the first end of the second bus capacitor C2 and the first end of the fourth switch S4, and the second end of the fourth switch S4 is connected to the second end of the second bus capacitor C2. The first end of the second inductor L2 is connected to the second end of the third switch S3 and the first end of the fourth switch S4, and the second end of the second inductor L2 is connected to the second relay RY2.

[0075] In one embodiment, the power converter 1 is controlled by a controller (not shown), such as a digital signal processor, a programmable logic controller, a microcontroller, etc. The controller is configured to detect the voltage change rate of a plurality of capacitors, and judge whether the power converter 1 executes one of the first to fifth operation modes, thereby achieving energy balance and hybrid power supply. In another embodiment, the controller receives a user instruction to control the power converter 1 to execute a specific operation mode to achieve energy scheduling.

[0076] See also Figure 2, which is a schematic diagram of the power converter in the first operation mode of the present invention. Figure 2 As shown, in the first operation mode, the first relay RY1 switches the first inductor L1 to connect to the first end of the first load capacitor C3, and the second relay RY2 switches the second inductor L2 to connect to the second end of the second load capacitor C4. First, the first switch S1 and the fourth switch S4 are turned on, so that the energy stored in the first bus capacitor C1 and the second bus capacitor C2 stores energy in the first inductor L1 and the second inductor L2 (the first energy storage path PS1 shown in the figure). Then, the first switch S1 and the fourth switch S4 are turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the first load capacitor C3 and the second load capacitor C4 (the first energy release path PR1 shown in the figure). In the first operation mode, the power converter 1 can make the first bus capacitor C1 and the second bus capacitor C2 transfer energy to the first load capacitor C3 and the second load capacitor C4, thereby realizing the DC-DC conversion (step-down) function.

[0077] See also Figure 3 , which is a schematic diagram of the power converter in the second operation mode of the present invention. Figure 3 As shown, in the second operation mode, the first relay RY1 switches the first inductor L1 to connect to the second end of the fifth switch S5, and the second relay RY2 switches the second inductor L2 to connect to the first end of the sixth switch S6. First, the second switch S2, the third switch S3 and the fifth switch S5 are turned on, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1 and the second inductor L2 (the second energy storage path PS2 shown in the figure). Then, the second switch S2 and the third switch S3 are turned on, and the fifth switch S5 is turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the second bus capacitor C2 (the second energy release path PR2 shown in the figure). In the second operation mode, the power converter 1 can transfer energy from the first bus capacitor C1 to the second bus capacitor C2, thereby adjusting the energy stored in the first bus capacitor C1 and the second bus capacitor C2 to achieve a balance of the bus capacitor voltage.

[0078] See also Figure 4 , which is a schematic diagram of the power converter in the third operation mode of the present invention. Figure 4As shown, in the third operation mode, the first relay RY1 switches the first inductor L1 to connect to the second end of the fifth switch S5, and the second relay RY2 switches the second inductor L2 to connect to the first end of the sixth switch S6. First, the second switch S2, the third switch S3 and the sixth switch S6 are turned on, so that the energy stored in the second bus capacitor C2 stores energy in the first inductor L1 and the second inductor L2 (the third energy storage path PS3 shown in the figure). Then, the second switch S2 and the third switch S3 are turned on, and the sixth switch S6 is turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the first bus capacitor C1 (the third energy release path PR3 shown in the figure). The power converter 1 can transfer energy from the second bus capacitor C2 to the first bus capacitor C1 in the third operation mode, thereby adjusting the energy stored in the first bus capacitor C1 and the second bus capacitor C2 to achieve a balance of the bus capacitor voltage.

[0079] See also Figure 5A and Figure 5B , which is a schematic diagram of the power converter in the fourth operation mode of the present invention. Figure 5A and Figure 5B As shown, in the fourth operation mode, the first relay RY1 switches the first inductor L1 to connect to the first end of the first load capacitor C3, and the second relay RY2 switches the second inductor L2 to connect to the first end of the sixth switch S6. Figure 5A As shown, the first switch S1, the third switch S3 and the sixth switch S6 are turned on, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1 (as shown in the fourth energy storage path PS4), and the energy stored in the second bus capacitor C2 stores energy in the second inductor L2 (as shown in the fifth energy storage path PS5). Then, as Figure 5B As shown, the third switch S3 is turned on, and the first switch S1 and the sixth switch S6 are turned off, so that the energy stored in the first inductor L1 is released to the first load capacitor C3 (the fourth energy release path PR4 shown in the figure), and the energy stored in the second inductor L2 is released to the first bus capacitor C1 (the fifth energy release path PR5 shown in the figure). In the fourth operation mode, the power converter 1 can make the first bus capacitor C1 transfer energy to the first load capacitor C3, and make the second bus capacitor C2 transfer energy to the first bus capacitor C1, thereby realizing hybrid power supply.

[0080] See also Fig. 6A and Figure 6B , which is a schematic diagram of the power converter of the present invention in the fifth operation mode. Fig. 6A and Figure 6B As shown, in the fifth operation mode, the first relay RY1 switches the first inductor L1 to connect to the second end of the fifth switch S5, and the second relay RY2 switches the second inductor L2 to connect to the second end of the second load capacitor C4. Fig. 6AAs shown, the second switch S2, the fourth switch S4 and the fifth switch S5 are turned on, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1 (the sixth energy storage path PS6 shown in the figure), and the energy stored in the second bus capacitor C2 stores energy in the second inductor L2 (the seventh energy storage path PS7 shown in the figure). Then, as Figure 6B As shown, the second switch S2 is turned on, and the fourth switch S4 and the fifth switch S5 are turned off, so that the energy stored in the first inductor L1 is released to the second bus capacitor C2 (the sixth energy release path PR6 shown in the figure), and the energy stored in the second inductor L2 is released to the second load capacitor C4 (the seventh energy release path PR7 shown in the figure). In the fifth operation mode, the power converter 1 can make the first bus capacitor C1 transfer energy to the second bus capacitor C2, and make the second bus capacitor C2 transfer energy to the second load capacitor C4, thereby realizing hybrid power supply.

[0081] See also Figure 7 , which is a schematic diagram of the circuit structure of a power converter according to the second embodiment of the present case. Figure 7 The second embodiment shown is Figure 1 The difference between the illustrated embodiments is that the power converter further includes a power factor correction converter (PFC) 3. In the second embodiment, Figure 7 As shown, the first upper bridge voltage conversion module 11, the first lower bridge voltage conversion module 12, the second upper bridge voltage conversion module 13 and the second lower bridge voltage conversion module 14 form a buck converter, and the power supply 2 is an AC power supply, and the power factor correction converter 3 is connected between the power supply 2 and the buck converter.

[0082] See also Figure 8 , which is a flow chart of a power conversion method according to an embodiment of the present invention. The power conversion method is applicable to the power converter of any of the above embodiments of the present invention. Figure 8 As shown, the power conversion method includes steps ST1 and ST2. First, in step ST1, the voltages on the first bus capacitor C1, the second bus capacitor C2, the first load capacitor C3 and the second load capacitor C4 are sensed to determine whether to perform one of the first operation mode, the second operation mode, the third operation mode, the fourth operation mode and the fifth operation mode. Then, in step ST2, according to one of the first operation mode to the fifth operation mode, the switch states of the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the fifth switch S5, the sixth switch S6, the first relay RY1 and the second relay RY2 are controlled to store or release energy in the first inductor L1 and the second inductor L2, thereby transmitting electric energy between the first bus capacitor C1, the second bus capacitor C2, the first load capacitor C3 and the second load capacitor C4.

[0083] In the first operation mode, the power conversion method includes the following steps: first, the first relay RY1 is controlled to switch the first inductor L1 to connect to the first end of the first load capacitor C3, and the second relay RY2 is controlled to switch the second inductor L2 to connect to the second end of the second load capacitor C4. Then, the first switch S1 and the fourth switch S4 are turned on, so that the energy stored in the first bus capacitor C1 and the second bus capacitor C2 stores energy in the first inductor L1 and the second inductor L2. Finally, the first switch S1 and the fourth switch S4 are turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the first load capacitor C3 and the second load capacitor C4.

[0084] In the second operation mode, the power conversion method includes the following steps: first, the first relay RY1 is controlled to switch the first inductor L1 to connect to the second end of the fifth switch S5, and the second relay RY2 is controlled to switch the second inductor L2 to connect to the first end of the sixth switch S6. Next, the second switch S2, the third switch S3 and the fifth switch S5 are turned on, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1 and the second inductor L2. Finally, the second switch S2 and the third switch S3 are turned on, and the fifth switch S5 is turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the second bus capacitor C2.

[0085] In the third operation mode, the power conversion method includes the following steps: first, the first relay RY1 is controlled to switch the first inductor L1 to connect to the second end of the fifth switch S5, and the second relay RY2 is controlled to switch the second inductor L2 to connect to the first end of the sixth switch S6. Then, the second switch S2, the third switch S3 and the sixth switch S6 are turned on, so that the energy stored in the second bus capacitor C2 stores energy in the first inductor L1 and the second inductor L2. Finally, the second switch S2 and the third switch S3 are turned on, and the sixth switch S6 is turned off, so that the energy stored in the first inductor L1 and the second inductor L2 is released to the first bus capacitor C1.

[0086] In the fourth operation mode, the power conversion method includes the following steps: first, the first relay RY1 is controlled to switch the first inductor L1 to connect to the first end of the first load capacitor C3, and the second relay RY2 is controlled to switch the second inductor L2 to connect to the first end of the sixth switch S6. Next, the first switch S1, the third switch S3 and the sixth switch S6 are turned on, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1, and the energy stored in the second bus capacitor C2 stores energy in the second inductor L2. Finally, the third switch S3 is turned on, and the first switch S1 and the sixth switch S6 are turned off, so that the energy stored in the first inductor L1 is released to the first load capacitor C3, and the energy stored in the second inductor L2 is released to the first bus capacitor C1.

[0087] In the fifth operation mode, the power conversion method includes the following steps: first, control the first relay RY1 to switch the first inductor L1 to connect to the second end of the fifth switch S5, and control the second relay RY2 to switch the second inductor L2 to connect to the second end of the second load capacitor C4. Next, turn on the second switch S2, the fourth switch S4 and the fifth switch S5, so that the energy stored in the first bus capacitor C1 stores energy in the first inductor L1, and the energy stored in the second bus capacitor C2 stores energy in the second inductor L2. Finally, turn on the second switch S2, and turn off the fourth switch S4 and the fifth switch S5, so that the energy stored in the first inductor L1 is released to the second bus capacitor C2, and the energy stored in the second inductor L2 is released to the second load capacitor C4.

[0088] In summary, this case provides a power converter and a power conversion method, which can achieve capacitor voltage balance based on the inherent inductance element of the converter, so compared with the existing practice of adding a balance circuit, it can effectively reduce the overall circuit volume and improve the power density. In addition. The power converter and power conversion method of this case can achieve energy balance and mixed power supply by transmitting electric energy between each capacitor and inductor, and meet various load requirements.

[0089] It should be noted that the above are only preferred embodiments for illustrating the present invention, and the present invention is not limited to the embodiments described. The scope of the present invention is determined by the attached patent claims. Moreover, the present invention may be modified in various ways by those skilled in the art, but all of them are within the scope of the protection intended by the attached patent claims.

Claims

1. A power converter, comprising: A first upper bridge voltage conversion module, comprising a first bus capacitor, a first switch, a second switch, a first inductor and a first load capacitor, wherein the first switch, the second switch and the first inductor are electrically connected between the first bus capacitor and the first load capacitor; A first lower bridge voltage conversion module, comprising a second bus capacitor, a third switch, a fourth switch, a second inductor and a second load capacitor, wherein the third switch, the fourth switch and the second inductor are electrically connected between the second bus capacitor and the second load capacitor; A second upper bridge voltage conversion module comprises a fifth switch and a first relay, wherein a first end of the fifth switch is connected to a first end of the first bus capacitor, the first relay can selectively switch the first inductor to connect to a second end of the fifth switch or a first end of the first load capacitor, and a second end of the first load capacitor is connected to a second end of the first bus capacitor; and The second lower bridge voltage conversion module comprises a sixth switch and a second relay, wherein the first end of the second load capacitor is connected to the first end of the second bus capacitor, the second relay can selectively switch the second inductor to connect to the first end of the sixth switch or the second end of the second load capacitor, and the second end of the sixth switch is connected to the second end of the second bus capacitor. The first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first relay and the second relay are configured to switch the switch state so that the first inductor and the second inductor store energy or release energy, thereby transmitting electrical energy between the first bus capacitor, the second bus capacitor, the first load capacitor and the second load capacitor.

2. The power converter according to claim 1, wherein the first relay comprises a first moving contact, a first stationary contact and a second stationary contact, which are respectively connected to the first inductor, the second end of the fifth switch and the first end of the first load capacitor, and when the first relay switches the first moving contact to connect to the first stationary contact, the first inductor is connected to the second end of the fifth switch; when the first relay switches the first moving contact to connect to the second stationary contact, the first inductor is connected to the first end of the first load capacitor.

3. The power converter according to claim 1, wherein the second relay comprises a second moving contact, a third stationary contact and a fourth stationary contact, which are respectively connected to the second inductor, the first end of the sixth switch and the second end of the second load capacitor, and when the second relay switches the second moving contact to connect to the third stationary contact, the second inductor is connected to the first end of the sixth switch; when the second relay switches the second moving contact to connect to the fourth stationary contact, the second inductor is connected to the second end of the second load capacitor. 4 . The power converter as claimed in claim 1 , wherein the second end of the fifth switch and the first end of the sixth switch are connected to each other.

5. The power converter according to claim 1, wherein the first end and the second end of the first switch are respectively connected to the first end of the first bus capacitor and the first end of the second switch, the second end of the second switch is connected to the second end of the first bus capacitor, the first end of the first inductor is connected to the second end of the first switch and the first end of the second switch, and the second end of the first inductor is connected to the first relay.

6. The power converter according to claim 1, wherein the first end and the second end of the third switch are respectively connected to the first end of the second bus capacitor and the first end of the fourth switch, the second end of the fourth switch is connected to the second end of the second bus capacitor, the first end of the second inductor is connected to the second end of the third switch and the first end of the fourth switch, and the second end of the second inductor is connected to the second relay.

7. The power converter of claim 1, wherein the first bus capacitor is configured to establish a first voltage, the second bus capacitor is configured to establish a second voltage, and the first load capacitor and the second load capacitor are configured to establish a third voltage.

8. The power converter according to claim 1 further comprises a neutral terminal, a power supply and a load, wherein the power supply is connected to the first end and the second end of the first bus capacitor and the first end and the second end of the second bus capacitor, the load is connected to the first end of the first load capacitor and the second end of the second load capacitor, and the neutral terminal is connected to the second end of the first bus capacitor, the first end of the second bus capacitor, the second end of the first load capacitor, the first end of the second load capacitor, the second end of the second switch and the first end of the third switch.

9. The power converter according to claim 1 further comprises a power supply and a power factor correction converter, wherein the first upper bridge voltage conversion module, the first lower bridge voltage conversion module, the second upper bridge voltage conversion module and the second lower bridge voltage conversion module form a buck converter, and the power factor correction converter is connected between the power supply and the buck converter.

10. A power conversion method, used in the power converter as claimed in claim 1, comprising the steps of: sensing voltages on the first bus capacitor, the second bus capacitor, the first load capacitor, and the second load capacitor to determine whether to perform one of a first operation mode, a second operation mode, a third operation mode, a fourth operation mode, and a fifth operation mode; and According to one of the first operating mode to the fifth operating mode, the switching states of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first relay, and the second relay are controlled to enable the first inductor and the second inductor to store energy or release energy, thereby enabling electric energy to be transmitted between the first bus capacitor, the second bus capacitor, the first load capacitor, and the second load capacitor.

11. The power conversion method according to claim 10, comprising the steps of: Controlling the first relay to switch the first inductor to connect to the first end of the first load capacitor, and controlling the second relay to switch the second inductor to connect to the second end of the second load capacitor; Turning on the first switch and the fourth switch allows the energy stored in the first bus capacitor and the second bus capacitor to store energy in the first inductor and the second inductor; and The first switch and the fourth switch are turned off, so that the energy stored in the first inductor and the second inductor is released to the first load capacitor and the second load capacitor.

12. The power conversion method according to claim 10, comprising the steps of: controlling the first relay to switch the first inductor to connect to the second end of the fifth switch, and controlling the second relay to switch the second inductor to connect to the first end of the sixth switch; Turning on the second switch, the third switch, and the fifth switch so that the energy stored in the first bus capacitor stores energy in the first inductor and the second inductor; and The second switch and the third switch are turned on, and the fifth switch is turned off, so that the energy stored in the first inductor and the second inductor is released to the second bus capacitor.

13. The power conversion method according to claim 10, comprising the steps of: controlling the first relay to switch the first inductor to connect to the second end of the fifth switch, and controlling the second relay to switch the second inductor to connect to the first end of the sixth switch; Turning on the second switch, the third switch and the sixth switch so that the energy stored in the second bus capacitor stores energy in the first inductor and the second inductor; and The second switch and the third switch are turned on, and the sixth switch is turned off, so that the energy stored in the first inductor and the second inductor is released to the first bus capacitor.

14. The power conversion method according to claim 10, comprising the steps of: Control the first relay to switch the first inductor to connect to the first end of the first load capacitor, and control the second relay to switch the second inductor to connect to the first end of the sixth switch; Turning on the first switch, the third switch, and the sixth switch so that the energy stored in the first bus capacitor stores energy in the first inductor, and the energy stored in the second bus capacitor stores energy in the second inductor; and The third switch is turned on, and the first switch and the sixth switch are turned off, so that the energy stored in the first inductor is released to the first load capacitor, and the energy stored in the second inductor is released to the first bus capacitor.

15. The power conversion method according to claim 10, comprising the steps of: Control the first relay to switch the first inductor to connect to the second end of the fifth switch, and control the second relay to switch the second inductor to connect to the second end of the second load capacitor; Turning on the second switch, the fourth switch and the fifth switch so that the energy stored in the first bus capacitor stores energy in the first inductor, and the energy stored in the second bus capacitor stores energy in the second inductor; and The second switch is turned on, and the fourth switch and the fifth switch are turned off, so that the energy stored in the first inductor is released to the second bus capacitor, and the energy stored in the second inductor is released to the second load capacitor.

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