Automatic bus equalization power supply and power supply system

Abstract

This invention provides an automatic bus voltage equalization power supply and power supply system. The power supply includes: 2N voltage-dividing capacitors and 2N voltage-regulating modules; N voltage-dividing capacitors are connected in series between the positive DC bus and the neutral line, and the other N voltage-dividing capacitors are connected in series between the neutral line and the negative DC bus; for any given voltage-regulating module, its positive input terminal and negative input terminal are respectively connected to the two ends of the corresponding voltage-dividing capacitor, its positive output terminal is connected to the positive output terminal of the power supply, and its negative output terminal is connected to the negative output terminal of the power supply; the positive and negative output terminals of the power supply are used to supply power to the load. This application uses voltage-dividing capacitors to divide the voltage between the positive and negative buses, and multiple modules are connected in parallel to draw power from the bus; because multiple modules are connected in parallel, the load automatically draws power from the module with the higher voltage. After drawing power, the voltage drops, automatically balancing the positive and negative bus voltages. The circuit structure is simple and does not require an additional balancing bridge.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to an automatic bus voltage equalization power supply and power supply system. Background Technology

[0002] In a DC power supply system, the battery is converted into positive and negative DC power by a DC-DC converter to power the inverter. However, when the positive and negative bus voltages are unbalanced, it will cause the inverter output waveform to be distorted, resulting in an increase in the low-order harmonic content of the output; at the same time, the midpoint potential deviation will also increase the voltage stress on the devices, causing overvoltage damage to the devices.

[0003] In existing technologies, a balancing bridge circuit is usually set between the positive and negative DC buses. The balance of the positive and negative buses is achieved by controlling the state of the switching transistors in the balancing bridge, which increases the complexity of the circuit. Summary of the Invention

[0004] This invention provides an automatic bus voltage equalization power supply and power supply system to solve the problem of high circuit complexity in the prior art, which uses a balance bridge to balance the positive and negative bus voltages.

[0005] In a first aspect, embodiments of the present invention provide an automatic bus voltage equalization power supply, comprising: 2N voltage dividing capacitors and 2N voltage regulating modules; wherein, the parameters of each voltage dividing capacitor are the same, the parameters of each voltage regulating module are the same, and each voltage dividing capacitor corresponds one-to-one with each voltage regulating module;

[0006] N voltage-dividing capacitors are connected in series between the positive DC bus and the neutral line, and the other N voltage-dividing capacitors are connected in series between the neutral line and the negative DC bus.

[0007] For any given voltage regulator module, its positive input terminal and negative input terminal are respectively connected to the two ends of the corresponding voltage divider capacitor, its positive output terminal is connected to the positive output terminal of the power supply, and its negative output terminal is connected to the negative output terminal of the power supply.

[0008] The positive and negative output terminals of the power supply are used to supply power to the load.

[0009] The negative input terminals of the voltage regulator modules are connected in parallel. When the positive bus voltage is greater than the negative bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the positive DC bus, thereby reducing the positive bus voltage.

[0010] When the negative bus voltage is greater than the positive bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the negative DC bus, thereby reducing the negative bus voltage.

[0011] Optionally, the voltage regulator module is a flyback regulator.

[0012] Optionally, the flyback regulator is a single-tube flyback regulator.

[0013] Optionally, the power supply also includes: a DC-DC converter; the positive input terminal and the negative input terminal of the DC-DC converter are connected to the positive and negative terminals of the battery, respectively;

[0014] The DC-DC converter includes: a flying capacitor, a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a first inductor, a switching unit, and a controller; wherein the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor all have body diodes;

[0015] The first terminal of the first switch is connected to the first terminal of the first inductor and the first terminal of the third switch, respectively. The second terminal of the first switch is connected to the first terminal of the second switch, the second terminal of the flying capacitor, and the first terminal of the switching unit, respectively. The second terminal of the second switch is connected to the negative input terminal and the negative DC bus of the DC converter, respectively. The second terminal of the third switch is connected to the first terminal of the flying capacitor and the first terminal of the fourth switch, respectively.

[0016] The second terminal of the fourth switching transistor is connected to the positive DC bus; the second terminal of the first inductor is connected to the positive input terminal of the DC-DC converter; the second terminal of the switching unit is connected to the neutral line.

[0017] The controller is connected to the control terminals of the first switch, the second switch, the third switch, the fourth switch, and the switch unit, respectively.

[0018] The controller is used to acquire the positive bus voltage and the negative bus voltage, and control the operation of each switch and switching unit of the DC converter according to the positive bus voltage and the negative bus voltage, so that the positive bus voltage and the negative bus voltage are balanced.

[0019] Optionally, the power supply also includes: a positive DC bus capacitor and a negative DC bus capacitor; the positive DC bus capacitor is connected between the positive DC bus and the neutral line, and the negative DC bus capacitor is connected between the neutral line and the negative DC bus; the operation of each switch and switching unit of the DC converter is controlled according to the positive bus voltage and the negative bus voltage to balance the positive bus voltage and the negative bus voltage, including:

[0020] The operation of each switch and switching unit of the DC converter is controlled by the positive bus voltage and the negative bus voltage to charge and discharge the positive DC bus capacitor and the negative DC bus capacitor, so that the positive bus voltage and the negative bus voltage are balanced.

[0021] Optionally, the operation of each switch and switching unit of the DC-DC converter is controlled according to the positive and negative bus voltages to charge and discharge the positive and negative DC bus capacitors, thereby balancing the positive and negative bus voltages. This includes:

[0022] When the positive bus voltage is greater than the negative bus voltage, the first terminal of the control switch unit is turned on unidirectionally to the second terminal, and the operation of each switch of the DC converter is controlled to charge the negative DC bus capacitor.

[0023] When the positive bus voltage is less than the negative bus voltage, the second terminal of the control switch unit is turned on unidirectionally to the first terminal, and the operation of each switch of the DC converter is controlled, and the negative DC bus capacitor is discharged.

[0024] Optionally, the first terminal of the control switching unit is unidirectionally turned on to the second terminal, and the operation of each switch of the DC-DC converter is controlled to charge the negative DC bus capacitor, including:

[0025] The first terminal of the control switch unit is unidirectionally connected to the second terminal, and the second and third switching transistors are both disconnected.

[0026] When the battery discharges, the fourth switch is turned off and the first switch is turned on.

[0027] When the battery is charging, the fourth switch is turned on and the first switch is turned off.

[0028] Optionally, the second terminal of the control switching unit is unidirectionally turned on to the first terminal, and the operation of each switch of the DC-DC converter is controlled, and the negative DC bus capacitor is discharged, including:

[0029] The second terminal of the control switch unit is unidirectionally connected to the first terminal, and the first and fourth switching transistors are both disconnected.

[0030] When the battery discharges, the third switch is turned off and the second switch is turned on.

[0031] When the battery is charging, the third switch is turned on and the second switch is turned off.

[0032] Optionally, the switching unit includes a fifth switching transistor and a sixth switching transistor; wherein both the fifth switching transistor and the sixth switching transistor have a body diode;

[0033] The fifth and sixth switching transistors are connected in series between the first and second terminals of the switching unit;

[0034] In this configuration, the cathode of the body diode of the fifth switching transistor is connected to the cathode of the body diode of the sixth switching transistor; or the anode of the body diode of the fifth switching transistor is connected to the anode of the body diode of the sixth switching transistor.

[0035] Secondly, embodiments of the present invention provide a power supply system, including the automatic bus equalization power supply provided in any embodiment of the first aspect of the present invention.

[0036] This invention provides an automatic bus voltage equalization power supply and power supply system. The automatic bus voltage equalization power supply includes: 2N voltage-dividing capacitors and 2N voltage-regulating modules; wherein, the parameters of each voltage-dividing capacitor are identical, the parameters of each voltage-regulating module are identical, and each voltage-dividing capacitor corresponds one-to-one with each voltage-regulating module; N voltage-dividing capacitors are connected in series between the positive DC bus and the neutral line, and the other N voltage-dividing capacitors are connected in series between the neutral line and the negative DC bus; for any given voltage-regulating module, its positive input terminal and its negative input terminal are respectively connected to the two ends of the corresponding voltage-dividing capacitor. The positive output terminal of the voltage regulator module is connected to the positive output terminal of the power supply, and the negative output terminal of the voltage regulator module is connected to the negative output terminal of the power supply. The positive and negative output terminals of the power supply are used to supply power to the load. The negative input terminals of the voltage regulator modules are connected in parallel. When the positive bus voltage is greater than the negative bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the positive DC bus, causing the positive bus voltage to decrease. When the negative bus voltage is greater than the positive bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the negative DC bus, causing the negative bus voltage to decrease. In this embodiment of the invention, the positive and negative bus voltages are divided by a voltage dividing capacitor to match the input of the voltage regulator module. The outputs of multiple voltage regulator modules are connected in parallel, and the parameters of each voltage regulator module are the same. The voltage regulator module with the higher input voltage supplies power to the load. When the positive bus voltage is high, the voltage regulator module corresponding to the positive DC bus supplies power, and then the voltage gradually decreases; conversely, when the negative bus voltage is high, the voltage regulator module corresponding to the negative DC bus supplies power, and then the voltage gradually decreases. Therefore, as the load consumes electricity, the positive bus voltage and the negative bus voltage are automatically balanced. The circuit structure is simple, requiring no additional balancing bridge or complex control logic. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the circuit structure of an automatic bus voltage equalization power supply provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the circuit structure of a DC-DC converter provided in an embodiment of the present invention;

[0040] Figure 3 yes Figure 2 The first equivalent circuit diagram of the DC-DC converter is shown.

[0041] Figure 4 yes Figure 2The second equivalent circuit diagram of the DC-DC converter is shown.

[0042] Figure 5 yes Figure 2 The diagram shows the third equivalent circuit of the DC-DC converter.

[0043] Figure 6 yes Figure 2 The fourth equivalent circuit diagram of the DC-DC converter shown is shown.

[0044] Figure 7 yes Figure 2 The fifth equivalent circuit diagram of the DC-DC converter shown is shown.

[0045] Figure 8 This is a schematic diagram of the circuit structure of another DC-DC converter provided in an embodiment of the present invention. Detailed Implementation

[0046] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0047] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0048] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0049] Figure 1 This is a schematic diagram of an automatic busbar voltage equalization power supply provided in an embodiment of the present invention. (Refer to...) Figure 1 The automatic voltage equalization power supply for the bus includes 2N voltage divider capacitors Ck and 2N voltage regulator modules 11; wherein, the parameters of each voltage divider capacitor Ck are the same, the parameters of each voltage regulator module 11 are the same, and each voltage divider capacitor Ck corresponds one-to-one with each voltage regulator module 11.

[0050] N voltage-dividing capacitors Ck are connected in series between the positive DC bus BUS+ and the neutral line, and the other N voltage-dividing capacitors Ck are connected in series between the neutral line and the negative DC bus BUS-.

[0051] For any given voltage regulator module 11, the positive input terminal and the negative input terminal of the voltage regulator module 11 are respectively connected to the two ends of the corresponding voltage divider capacitor Ck, the positive output terminal of the voltage regulator module 11 is connected to the positive output terminal of the power supply, and the negative output terminal of the voltage regulator module 11 is connected to the negative output terminal of the power supply.

[0052] The positive and negative output terminals of the power supply are used to supply power to the load.

[0053] Among them, the negative input terminal of the voltage regulator module 11 is connected in parallel; when the positive bus voltage is greater than the negative bus voltage, the load draws power from the output terminal of the voltage regulator module 11 corresponding to the positive DC bus BUS+, thereby reducing the positive bus voltage.

[0054] When the negative bus voltage is greater than the positive bus voltage, the load draws power from the output terminal of the voltage regulator module 11 corresponding to the negative DC bus BUS-, thereby reducing the negative bus voltage.

[0055] The voltage difference between the positive and negative DC buses may not match the load's required voltage. For example, the load may be an auxiliary power supply board, typically low-voltage equipment with a low supply voltage. Therefore, in this embodiment, a voltage regulator module 11 is used to regulate the voltage and meet the load's power requirements. Meanwhile, since the positive and negative bus voltages are usually high, and the gain of the voltage regulator module 11 is limited, N voltage-dividing capacitors Ck are used in this embodiment to divide the voltage, ensuring that the voltage meets the input voltage requirements of the voltage regulator module 11. The outputs of multiple voltage regulator modules 11 are connected in parallel. Since the parameters of each voltage regulator module 11 are the same, the voltage regulator module 11 with the highest input voltage prioritizes supplying power to the load.

[0056] For example, when the positive bus voltage is high, the input voltage to the voltage regulator module 11 after voltage division by the voltage divider capacitor Ck is also high, and the output voltage is correspondingly high. Therefore, the voltage regulator module 11 corresponding to the positive DC bus BUS+ prioritizes power supply to the load, while the voltage regulator module 11 corresponding to the negative DC bus BUS- does not supply power, and the positive bus voltage gradually decreases. Similarly, when the negative bus voltage is high, the input voltage to the voltage regulator module 11 after voltage division by the voltage divider capacitor Ck is also high, and the output voltage is correspondingly high. Therefore, the voltage regulator module 11 corresponding to the negative DC bus BUS- prioritizes power supply to the load, while the voltage regulator module 11 corresponding to the positive DC bus BUS+ has a low output voltage and does not supply power, and the negative bus voltage gradually decreases. Thus, as the load consumes power, the positive bus voltage and the negative bus voltage automatically tend to balance, without the need for an additional balancing bridge circuit or load control logic. The circuit structure is simple and the cost is low.

[0057] It should be noted that the voltage regulator modules 11 in this embodiment of the invention are voltage regulator modules 11 whose outputs can be connected in parallel, and their outputs do not affect each other. Wherein, N is a positive integer.

[0058] In one possible implementation, the voltage regulator module 11 can be a flyback regulator.

[0059] Flyback voltage regulators are isolated voltage regulators, with isolated input and output sources. They use transformers and their outputs can be directly connected in parallel without affecting each other.

[0060] In one possible implementation, the flyback regulator can be a single-tube flyback regulator.

[0061] The single-tube flyback regulator has a simple circuit structure, few components, low cost, and is suitable for specific applications.

[0062] In one possible implementation, the power supply may further include: a DC-DC converter; the positive input terminal and the negative input terminal of the DC-DC converter are respectively connected to the positive and negative terminals of the battery;

[0063] The DC-DC converter may include: a flying capacitor C1, a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a first inductor L1, a switching unit 12, and a controller; wherein the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 all have body diodes;

[0064] The first terminal of the first switch Q1 is connected to the first terminal of the first inductor L1 and the first terminal of the third switch Q3, respectively. The second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2, the second terminal of the flying capacitor C1 and the first terminal of the switching unit 12, respectively. The second terminal of the second switch Q2 is connected to the negative input terminal of the DC-DC converter and the negative DC bus BUS-, respectively. The second terminal of the third switch Q3 is connected to the first terminal of the flying capacitor C1 and the first terminal of the fourth switch Q4, respectively.

[0065] The second terminal of the fourth switch Q4 is connected to the positive DC bus BUS+; the second terminal of the first inductor L1 is connected to the positive input terminal of the DC converter; the second terminal of the switching unit 12 is connected to the neutral line.

[0066] The controller is connected to the control terminals of the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, and the control terminal of the switch unit 12, respectively.

[0067] The controller is used to acquire the positive bus voltage and the negative bus voltage, and control the operation of each switch and switching unit 12 of the DC converter according to the positive bus voltage and the negative bus voltage, so that the positive bus voltage and the negative bus voltage are balanced.

[0068] In this embodiment of the invention, a DC-DC converter is also connected to the positive and negative DC buses. The battery supplies power to the positive and negative DC buses through the DC-DC converter, or the positive and negative DC buses charge the battery through the DC-DC converter. In this embodiment of the invention, a charging and discharging path can be formed by controlling the operation of each switch transistor and switch unit 12 in the DC-DC converter, thereby balancing the positive bus voltage and the negative bus voltage.

[0069] refer to Figure 2 A first capacitor C2 is connected in parallel across the two ends of the battery. This is a conventional technique in the field and will not be described in detail here.

[0070] In one possible implementation, the power supply may further include: a positive DC bus capacitor C+ and a negative DC bus capacitor C-; the positive DC bus capacitor C+ is connected between the positive DC bus BUS+ and the neutral line, and the negative DC bus capacitor C- is connected between the neutral line and the negative DC bus BUS-; the operation of each switch and switching unit 12 of the DC converter is controlled according to the positive bus voltage and the negative bus voltage to balance the positive bus voltage and the negative bus voltage, including:

[0071] The operation of each switch and switch unit 12 of the DC converter is controlled according to the positive bus voltage and the negative bus voltage, so as to charge and discharge the positive DC bus capacitor C+ and the negative DC bus capacitor C-, thereby balancing the positive bus voltage and the negative bus voltage.

[0072] Specifically, positive DC bus capacitor C+ and negative DC bus capacitor C- are connected between the positive DC bus BUS+ and the negative DC bus BUS-. The positive bus voltage is equal to the voltage across positive DC bus capacitor C+, and the negative bus voltage is equal to the voltage across negative DC bus capacitor C-. Therefore, by controlling the operation of each switch transistor and switch unit 12 in the DC converter, a corresponding charging and discharging path is formed for charging and discharging positive DC bus capacitor C+ and negative DC bus capacitor C-, thereby adjusting the positive bus voltage and negative bus voltage and achieving a balance between the positive and negative bus voltages.

[0073] For example, when the positive bus voltage is too high, the corresponding path can be opened to discharge the positive DC bus capacitor C+, or the corresponding path can be opened to charge the negative DC bus capacitor C-, or both the positive DC bus capacitor C+ and the negative bus capacitor can be charged at the same time, but the charging current of the positive DC bus capacitor C+ is less than the charging current of the negative bus capacitor, etc., which will not be elaborated further.

[0074] Similarly, when the negative bus voltage is too high, the corresponding paths are opened to charge and discharge the positive DC bus capacitor C+ and the negative DC bus capacitor C-, so as to balance the positive and negative bus voltages.

[0075] It should be noted that when N=1, there is only one voltage divider capacitor Ck between the positive DC bus BUS+ and the negative DC bus BUS-. In this case, only one of the voltage divider capacitor and the positive DC bus capacitor C+ needs to be set. Similarly, only one of the voltage divider capacitor and the negative DC bus capacitor C- needs to be set.

[0076] In one possible implementation, the operation of each switch and switching unit 12 of the DC-DC converter is controlled according to the positive bus voltage and the negative bus voltage to charge and discharge the positive DC bus capacitor C+ and the negative DC bus capacitor C-, thereby balancing the positive bus voltage and the negative bus voltage, including:

[0077] S101: When the positive bus voltage is greater than the negative bus voltage, the first terminal of the control switch unit 12 is turned on unidirectionally to the second terminal, and the operation of each switch of the DC converter is controlled to charge the negative DC bus capacitor C-.

[0078] S102: When the positive bus voltage is less than the negative bus voltage, the second terminal of the control switch unit 12 is turned on unidirectionally to the first terminal, and the operation of each switch of the DC converter is controlled, and the negative DC bus capacitor C- is discharged.

[0079] Corresponding to Figure 2 The DC-DC converter shown in the diagram, when the positive bus voltage is greater than the negative bus voltage, controls the first terminal of the control switch unit 12 to conduct unidirectionally to the second terminal, opening the charging path of the negative DC bus capacitor C-. The negative DC bus capacitor C- is charged through the switch unit 12, increasing the negative bus voltage to balance the positive and negative bus voltages. When the positive bus voltage is less than the negative bus voltage, controls the second terminal of the control switch unit 12 to conduct unidirectionally to the first terminal, opening the discharge path of the negative DC bus capacitor C-. The negative DC bus capacitor C- is discharged through the switch unit 12, reducing the negative bus voltage to balance the positive and negative bus voltages.

[0080] In one possible implementation, S101 may include:

[0081] S1011: Control the first end of the control switch unit 12 to conduct unidirectionally to the second end, and control the second switch Q2 and the third switch Q3 to be disconnected;

[0082] S1012: When the battery is discharging, the fourth switch Q4 is turned off and the first switch Q1 is turned on.

[0083] S1013: When the battery is charging, control the fourth switch Q4 to turn on and control the first switch Q1 to turn off.

[0084] When the battery discharges, the normal control logic of the DC-DC converter is to disconnect the third switch Q3 and the fourth switch Q4, and to control the operation of the first switch Q1 and the second switch Q2 to achieve voltage changes. To ensure the normal operation of the DC-DC converter, it normally supplies power to the positive and negative DC buses (BUS+ and BUS-), and tries to maintain the original control mode unchanged during the voltage balance control process.

[0085] Therefore, in this embodiment of the invention, during battery discharge, the third switch Q3 and the fourth switch Q4 are still controlled to be disconnected, the second switch Q2 is controlled to be disconnected, and the first switch Q1 is controlled to be turned on, forming... Figure 3 As shown in the current path, the battery charges the negative DC bus capacitor C- through the first switch Q1 and the switch unit 12, and at the same time charges the positive DC bus capacitor C+ through the flying capacitor C1. However, due to the presence of the flying capacitor C1, the charging current of the negative DC bus capacitor C- is greater than the charging current of the positive DC bus BUS+, which increases the voltage of the negative DC bus capacitor C- and achieves voltage balance.

[0086] Compared to the normal discharge of the battery, it is equivalent to only changing the PWM duty cycle of the first switch Q1 and the second switch Q2, so it does not affect the normal operation of the system and achieves voltage balance while ensuring the normal power supply of the positive and negative DC buses.

[0087] When the battery is charging, the normal control logic of the DC-DC converter is to disconnect the first switch Q1 and the second switch Q2, and to control the third switch Q3 and the fourth switch Q4 to achieve voltage changes. Similarly, to maintain the original control mode as much as possible during voltage balance control, when the battery is charging, the first switch Q1 and the second switch Q2 are still disconnected, the third switch Q3 is disconnected, and the fourth switch Q4 is turned on, forming... Figure 4 The current path shown allows the positive DC bus capacitor C+ to discharge and, through the flying capacitor C1 and the fourth switch Q4, to charge the negative DC bus BUS-, achieving voltage balance. Simultaneously, the positive DC bus BUS+ also charges the battery through the flying capacitor C1 and the body diode of the first switch Q1, ensuring normal system operation.

[0088] Based on the above, this embodiment of the invention adds a switching unit 12 to the DC converter without affecting the normal operation of the system. Voltage balance is achieved through the operation of the switching unit 12 and each switching transistor. The control logic is simple and the balancing effect is good.

[0089] In one possible implementation, S102 may include:

[0090] S1021: Control the second end of the control switch unit 12 to conduct unidirectionally to the first end, and control the first switch Q1 and the fourth switch Q4 to be disconnected;

[0091] S1022: When the battery is discharging, the third switch Q3 is turned off and the second switch Q2 is turned on.

[0092] S1023: When the battery is charging, control the third switch Q3 to turn on and control the second switch Q2 to turn off.

[0093] Similarly, it is the discharge balance voltage of the negative DC bus capacitor C-, but it does not affect the normal operation of the system.

[0094] When the battery discharges, the third switch Q3 and the fourth switch Q4 are turned off, the second switch Q2 is turned on, and the first switch Q1 is turned off, forming... Figure 5 As shown in the current path, the battery charges the flying capacitor C1 through the body diode of the third switch Q3, and the negative DC bus capacitor C- discharges through the second switch Q2 to achieve voltage balance.

[0095] When the battery is charging, the first switch Q1 and the second switch Q2 are turned off, the third switch Q3 is turned on, and the fourth switch Q4 is turned off, forming... Figure 6 The current path is shown. The negative DC bus capacitor C- discharges, charging the battery through the flying capacitor C1 and the third switch Q3 to achieve voltage balance.

[0096] Similarly, voltage balance is achieved without affecting the normal operation of the system.

[0097] It should be noted that the embodiments of the present invention include, but are not limited to, the control methods for battery charging or discharging described above. Other current paths can also be formed to achieve voltage balance by charging and discharging the positive DC bus capacitor C+ and the negative DC bus capacitor C-.

[0098] For example, when the positive bus voltage is greater than the negative bus voltage, a current path can be controlled to discharge the positive DC bus capacitor C+ to reduce the positive bus voltage, charge the negative DC bus capacitor C- to increase the negative bus voltage, and simultaneously charge both the positive DC bus capacitor C+ and the negative DC bus capacitor C- (the charge amount of the positive DC bus capacitor C+ is less than the charge amount of the negative DC bus capacitor C-), and simultaneously discharge both the positive DC bus capacitor C+ and the negative DC bus capacitor C- (the discharge amount of the positive DC bus capacitor C+ is greater than the discharge amount of the negative DC bus capacitor C-), thereby achieving a balance between the positive and negative bus voltages. The control when the positive bus voltage is less than the negative bus voltage is similar.

[0099] Specifically, for example, when the battery is charging and the positive bus voltage is greater than the negative bus voltage, the control switch unit 12, the first switch Q1, the second switch Q2 and the third switch Q3 are disconnected, and the fourth switch Q4 is turned on.

[0100] The fourth switch Q4 is turned on, while all others are turned off, forming... Figure 7 The current path shown indicates that the positive DC bus capacitor C+ charges the battery through the fourth switch Q4, the flying capacitor C1, the body diode of the first switch Q1, and the first inductor L1. While ensuring normal battery charging, the discharge voltage of the positive DC bus capacitor C+ decreases, achieving voltage balance. Other voltage balance control methods will not be elaborated here.

[0101] For example, when the battery is prohibited from charging or discharging, other pathways can be formed to achieve voltage balance.

[0102] Furthermore, the voltage regulator module 11 can be connected to the load, and the load's power consumption can achieve voltage balance.

[0103] The priority of various control methods can be set according to the actual application requirements.

[0104] In one possible implementation, refer to Figure 8 The switching unit 12 includes a fifth switching transistor Q5 and a sixth switching transistor Q6; wherein both the fifth switching transistor Q5 and the sixth switching transistor Q6 have a body diode.

[0105] The fifth switch Q5 and the sixth switch Q6 are connected in series between the first end of the switching unit 12 and the second end of the switching unit 12;

[0106] In this configuration, the cathode of the body diode of the fifth switch Q5 is connected to the cathode of the body diode of the sixth switch Q6; or the anode of the body diode of the fifth switch Q5 is connected to the anode of the body diode of the sixth switch Q6.

[0107] In this embodiment of the invention, a switching unit can be formed by a fifth switching transistor Q5 and a sixth switching transistor Q6. The body diodes of the fifth switching transistor Q5 and the sixth switching transistor Q6 are positioned opposite each other. When the fifth switching transistor Q5 is turned on, the sixth switching transistor Q6 is turned off, achieving unidirectional conduction of the switching unit 12 through the body diode of the sixth switching transistor Q6. Similarly, when the sixth switching transistor Q6 is turned on, the fifth switching transistor Q5 is turned off, achieving directional conduction of the switching unit 12 through the body diode of the fifth switching transistor Q5.

[0108] Furthermore, the switching unit 12 may also include a bidirectional thyristor.

[0109] In this embodiment of the invention, a bidirectional thyristor can also be used to achieve unidirectional controllable conduction of the switching unit 12 in both directions.

[0110] Corresponding to the above embodiments, this invention also provides a power supply system, including the automatic bus equalization power supply provided in any of the above embodiments, and has the advantages of the above automatic bus equalization power supply, which will not be described in detail here.

[0111] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A busbar automatic voltage equalization power supply, characterized in that, include: 2N voltage divider capacitors and 2N voltage regulator modules; wherein, the parameters of each voltage divider capacitor are the same, the parameters of each voltage regulator module are the same, and each voltage divider capacitor corresponds one-to-one with each voltage regulator module; N voltage-dividing capacitors are connected in series between the positive DC bus and the neutral line, and the other N voltage-dividing capacitors are connected in series between the neutral line and the negative DC bus; where N is a positive integer; For any given voltage regulator module, its positive input terminal and negative input terminal are respectively connected to the two ends of the corresponding voltage divider capacitor, its positive output terminal is connected to the positive output terminal of the power supply, and its negative output terminal is connected to the negative output terminal of the power supply. The positive output terminal and the negative output terminal of the power supply are used to supply power to the load. The negative input terminal of the voltage regulator module is connected in parallel; when the positive bus voltage is greater than the negative bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the positive DC bus, thereby reducing the positive bus voltage. When the negative bus voltage is greater than the positive bus voltage, the load draws power from the output terminal of the voltage regulator module corresponding to the negative DC bus, thereby reducing the negative bus voltage.

2. The automatic bus equalization power supply as described in claim 1, characterized in that, The voltage regulator module is a flyback voltage regulator.

3. The automatic bus equalization power supply as described in claim 2, characterized in that, The flyback regulator is a single-tube flyback regulator.

4. The automatic bus equalization power supply as described in any one of claims 1 to 3, characterized in that, The power supply further includes: a DC-DC converter; the positive input terminal and the negative input terminal of the DC-DC converter are respectively connected to the positive and negative terminals of the battery; The DC-DC converter includes: a flying capacitor, a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a first inductor, a switching unit, and a controller; wherein the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor all have a body diode; The first terminal of the first switching transistor is connected to the first terminal of the first inductor and the first terminal of the third switching transistor, respectively. The second terminal of the first switching transistor is connected to the first terminal of the second switching transistor, the second terminal of the flying capacitor, and the first terminal of the switching unit, respectively. The second terminal of the second switching transistor is connected to the negative input terminal of the DC-DC converter and the negative DC bus, respectively. The second terminal of the third switching transistor is connected to the first terminal of the flying capacitor and the first terminal of the fourth switching transistor, respectively. The second terminal of the fourth switch is connected to the positive DC bus; the second terminal of the first inductor is connected to the positive input terminal of the DC converter; the second terminal of the switching unit is connected to the neutral line. The controller is connected to the control terminals of the first switch, the second switch, the third switch, the fourth switch, and the switch unit, respectively. The controller is used to acquire the positive bus voltage and the negative bus voltage, and control the operation of each switch and the switching unit of the DC converter according to the positive bus voltage and the negative bus voltage, so that the positive bus voltage and the negative bus voltage are balanced.

5. The automatic bus equalization power supply as described in claim 4, characterized in that, The power supply further includes: a positive DC bus capacitor and a negative DC bus capacitor; the positive DC bus capacitor is connected between the positive DC bus and the neutral line, and the negative DC bus capacitor is connected between the neutral line and the negative DC bus; the step of controlling the operation of each switch and the switching unit of the DC converter according to the positive bus voltage and the negative bus voltage, so that the positive bus voltage and the negative bus voltage are balanced, includes: The operation of each switch and the switching unit of the DC-DC converter is controlled according to the positive bus voltage and the negative bus voltage to charge and discharge the positive DC bus capacitor and the negative DC bus capacitor, so that the positive bus voltage and the negative bus voltage are balanced.

6. The automatic bus equalization power supply as described in claim 5, characterized in that, The step of controlling the operation of each switch and the switching unit of the DC-DC converter according to the positive bus voltage and the negative bus voltage, and charging and discharging the positive DC bus capacitor and the negative DC bus capacitor to balance the positive bus voltage and the negative bus voltage, includes: When the positive bus voltage is greater than the negative bus voltage, the first terminal of the switching unit is controlled to conduct unidirectionally to the second terminal, and the switching transistors of the DC converter are controlled to operate to charge the negative DC bus capacitor. When the positive bus voltage is less than the negative bus voltage, the second terminal of the switching unit is controlled to conduct unidirectionally to the first terminal, and the switching transistors of the DC converter are controlled to operate, and the negative DC bus capacitor is discharged.

7. The automatic bus equalization power supply as described in claim 6, characterized in that, The control of the first terminal of the switching unit to conduct unidirectionally to the second terminal, and the control of the operation of each switching transistor of the DC-DC converter to charge the negative DC bus capacitor, includes: The first terminal of the switching unit is controlled to conduct unidirectionally to the second terminal, and both the second and third switching transistors are controlled to be disconnected. When the battery discharges, the fourth switch is turned off and the first switch is turned on. When the battery is charging, the fourth switch is turned on and the first switch is turned off.

8. The automatic bus equalization power supply as described in claim 6, characterized in that, The control of the second terminal of the switching unit to conduct unidirectionally to the first terminal, and the control of the operation of each switching transistor of the DC converter, and the discharge of the negative DC bus capacitor, include: The second terminal of the switching unit is controlled to conduct unidirectionally to the first terminal, and both the first switching transistor and the fourth switching transistor are controlled to be disconnected. When the battery discharges, the third switch is turned off and the second switch is turned on. When the battery is charging, the third switch is turned on and the second switch is turned off.

9. The automatic bus equalization power supply as described in claim 4, characterized in that, The switching unit includes a fifth switching transistor and a sixth switching transistor; wherein both the fifth switching transistor and the sixth switching transistor have a body diode; The fifth and sixth switching transistors are connected in series between the first end of the switching unit and the second end of the switching unit. Wherein, the cathode of the body diode of the fifth switching transistor is connected to the cathode of the body diode of the sixth switching transistor; or the anode of the body diode of the fifth switching transistor is connected to the anode of the body diode of the sixth switching transistor.

10. A power supply system, characterized in that, Includes the automatic bus equalization power supply as described in any one of claims 1 to 9.

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