A control system and method for a boost circuit

Abstract

The application discloses a control system and method of a boost circuit, comprising a first boost branch, a second boost branch, a balancing module and a control module; the balancing module comprises a first balancing unit and a second balancing unit; the first balancing unit is connected between a positive end of a DC bus and a midpoint of the DC bus; the second balancing unit is connected between the midpoint of the DC bus and a negative end of the DC bus; a first control end of the control module is connected with the first balancing unit, and a second control end of the control module is connected with the second balancing unit; the control module is used for acquiring a positive half bus voltage and a negative half bus voltage, and controlling the first balancing unit or the second balancing unit to be switched in or the first balancing unit and the second balancing unit to be switched out according to a voltage deviation between the positive half bus voltage and the negative half bus voltage. The control system provided by the application can realize active balancing of the bus voltage through the balancing module, eliminate the static deviation hidden danger, and greatly improve the reliability of system load operation.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a control system and method for a boost circuit. Background Technology

[0002] In the development of DC-DC converters, the Flying Capacitor Three-Level (FC-TL) Boost topology is highly favored due to its advantages such as low voltage stress and high efficiency. However, this topology has specific technical bottlenecks in bus voltage balance control. Existing solutions are typically used in photovoltaic inverters, relying on the large capacity of the bus and the midpoint potential control strategy in DC-AC conversion topologies to maintain bus balance. However, this method is not suitable for pure DC-DC applications where the bus capacity is small and there is no downstream topology. For the FC-TL Boost circuit, although relative bus balance can be achieved by controlling the flying capacitor voltage during normal operation, the circuit lacks an effective voltage balancing mechanism in standby mode and in the static condition of simply maintaining power after shutdown. This will lead to a significant bias in the bus voltage.

[0003] Crucially, if the system is restarted directly while the bus is biased, the imbalance of capacitor voltage will instantly be converted into an overvoltage surge of half the bus voltage, which can easily cause the voltage stress of the switching devices to exceed the limit, thereby causing circuit failure or device damage, seriously threatening the reliability and stability of the system. Summary of the Invention

[0004] This invention provides a control system and method for a boost circuit. The control module controls the first or second equalization unit to engage or disengage based on the voltage deviation between the positive and negative bus voltages. This balances the bus voltage, eliminates static hazards, and enables rapid energy release from the bus. The equalization is completed in a very short time, significantly improving the reliability of the system under load.

[0005] According to a first aspect of the present invention, a control system for a boost circuit is provided, comprising: a first boost branch, a second boost branch, an equalization module, and a control module; the equalization module includes a first equalization unit and a second equalization unit; The first end of the first boost branch is connected to the positive terminal of the DC input, the second end of the first boost branch is connected to the positive terminal of the DC bus, and the first equalization unit is connected between the positive terminal of the DC bus and the midpoint of the DC bus. The first end of the second boost branch is connected to the negative terminal of the DC input, the second end of the second boost branch is connected to the negative terminal of the DC bus, and the second equalization unit is connected between the midpoint of the DC bus and the negative terminal of the DC bus. The first control terminal of the control module is connected to the first equalization unit, and the second control terminal of the control module is connected to the second equalization unit; The control module is used to acquire the positive half-bus voltage and the negative half-bus voltage, and control the first equalization unit or the second equalization unit to switch in, or control the first equalization unit and the second equalization unit to switch out, based on the voltage deviation between the positive half-bus voltage and the negative half-bus voltage.

[0006] Optionally, the first equalization unit includes a first switching device, a first inductor, and a first resistor; The first switching device, the first inductor, and the first resistor are connected in series between the positive terminal of the DC bus and the midpoint of the DC bus. The second equalization unit includes a second switching device, a second inductor, and a second resistor, which are connected in series between the midpoint of the DC bus and the negative terminal of the DC bus. The first control terminal of the control module is connected to the control terminal of the first switching device, and the second control terminal of the control module is connected to the control terminal of the second switching device.

[0007] Optionally, the first switching device and the second switching device are DC relays.

[0008] Optionally, the control module is a digital signal processor.

[0009] Optionally, it may also include a first voltage sampling circuit and a second voltage sampling circuit; The first voltage sampling circuit is connected between the positive terminal of the DC bus and the midpoint of the DC bus, and is used to collect the positive half bus voltage and send the positive half bus voltage to the control module; The second voltage sampling circuit is connected between the midpoint of the DC bus and the negative terminal of the DC bus, and is used to collect the negative half bus voltage and send the negative half bus voltage to the control module; The output terminal of the first voltage sampling circuit is connected to the first input terminal of the control module, and the output terminal of the second voltage sampling circuit is connected to the second input terminal of the control module.

[0010] According to a second aspect of the present invention, a control method for a boost circuit is provided, executed by the control system of the boost circuit described in any one of the first aspects of the present invention, the control method comprising: Obtain the positive half-bus voltage and the negative half-bus voltage; The voltage deviation is determined based on the positive half-bus voltage and the negative half-bus voltage; The first equalization unit or the second equalization unit can be switched on or off based on the voltage deviation.

[0011] Optionally, controlling the first equalization unit or the second equalization unit to switch on or off based on the voltage deviation includes: When the positive half-bus voltage is higher than the negative half-bus voltage and the voltage deviation is greater than the first deviation threshold, the first equalization unit is controlled to switch in and the second equalization unit is controlled to switch out. When the negative half-bus voltage is higher than the positive half-bus voltage, and the voltage deviation is greater than the first deviation threshold, the second equalization unit is controlled to switch in, and the first equalization unit is controlled to switch out.

[0012] Optionally, the step of controlling the first equalization unit or the second equalization unit to switch on or off based on the voltage deviation further includes: When the voltage deviation is less than the second deviation threshold, the first equalization unit and the second equalization unit are switched off.

[0013] Optionally, before controlling the first equalization unit and the second equalization unit to switch off when the voltage deviation is less than the second deviation threshold, the method further includes: The cut-in time of the first equalization unit or the second equalization unit is controlled to be greater than or equal to the first threshold.

[0014] Optionally, before obtaining the positive half-bus voltage and the negative half-bus voltage, the following steps are also included: Obtain the operating status of the first boost branch and the second boost branch; When the first boost branch and the second boost branch are in standby mode, the positive half bus voltage and the negative half bus voltage are acquired.

[0015] This invention provides a control system and control method for a boost circuit, comprising: a first boost branch, a second boost branch, an equalization module, and a control module; the equalization module includes a first equalization unit and a second equalization unit; a first end of the first boost branch is connected to the positive terminal of the DC input, a second end of the first boost branch is connected to the positive terminal of the DC bus, and the first equalization unit is connected between the positive terminal of the DC bus and the midpoint of the DC bus; a first end of the second boost branch is connected to the negative terminal of the DC input, a second end of the second boost branch is connected to the negative terminal of the DC bus, and the second equalization unit is connected between the midpoint of the DC bus and the negative terminal of the DC bus; a first control terminal of the control module is connected to the first equalization unit, and a second control terminal of the control module is connected to the second equalization unit; the control module is used to acquire the positive half-bus voltage and the negative half-bus voltage, and control the first equalization unit or the second equalization unit to engage or disengage based on the voltage deviation between the positive half-bus voltage and the negative half-bus voltage. The control system of the boost circuit provided by the present invention controls the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation between the positive half bus voltage and the negative half bus voltage through the control module. This can equalize the bus voltage, eliminate static hazards, realize the rapid release of bus energy, complete voltage equalization in a very short time, and greatly improve the reliability of the system under load.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0018] Figure 1 This is a block diagram of a control system for a boost circuit provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of the first equalization unit in the control system of a boost circuit provided in an embodiment of the present invention; Figure 3 This is a structural block diagram of the second equalization unit in the control system of a boost circuit provided in an embodiment of the present invention; Figure 4 This is a flowchart of a control method for a boost circuit provided in an embodiment of the present invention; Figure 5This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention; Figure 6 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention; Figure 7 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention; Figure 8 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Figure 1 This is a control system block diagram of a boost circuit provided in an embodiment of the present invention, with reference to... Figure 1The control system of the boost circuit provided in this embodiment of the invention includes: a first boost branch 1, a second boost branch 2, an equalization module 3, and a control module 4; the equalization module 3 includes a first equalization unit 31 and a second equalization unit 32; the first end of the first boost branch 1 is connected to the positive DC input DC+, and the second end of the first boost branch 1 is connected to the positive DC bus BAT+; the first equalization unit 31 is connected between the positive DC bus BAT+ and the midpoint N of the DC bus; the first end of the second boost branch 2 is connected to the negative DC input DC-, and the second boost branch 2... The second end of the first equalization unit 31 is connected to the negative end BAT- of the DC bus, and the second equalization unit 32 is connected between the midpoint N of the DC bus and the negative end BAT- of the DC bus. The first control end of the control module 4 is connected to the first equalization unit 31, and the second control end of the control module 4 is connected to the second equalization unit 32. The control module 4 is used to acquire the positive half-bus voltage and the negative half-bus voltage, and control the first equalization unit 31 or the second equalization unit 32 to switch in or to switch out according to the voltage deviation between the positive half-bus voltage and the negative half-bus voltage.

[0022] Specifically, the control system provided in the embodiments of the present invention, such as Figure 1 As shown, the control system of the boost circuit includes a first boost branch 1, a second boost branch 2, an equalization module 3, and a control module 4. The equalization module 3 includes a first equalization unit 31 and a second equalization unit 32. The first boost branch 1 is used to boost the input DC voltage and form the output voltage at the positive terminal BAT+ of the DC bus. The first terminal of the first boost branch 1 is connected to the positive DC input DC+, and the second terminal of the first boost branch 1 is connected to the positive terminal BAT+ of the DC bus. The second boost branch 2 is used to boost the input DC voltage and form the output voltage at the negative terminal BAT- of the DC bus. The first terminal of the second boost branch 2 is connected to the negative DC input DC-, and the second terminal of the second boost branch 2 is connected to the negative terminal BAT- of the DC bus. A DC bus can be formed between the positive terminal BAT+ and the negative terminal BAT- of the DC bus through the first boost branch 1 and the second boost branch 2. The positive half-bus is formed between the positive terminal BAT+ and the midpoint N of the DC bus, and the negative half-bus is formed between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus.

[0023] The equalization module 3 is located on both sides of the positive and negative half of the DC bus. The first equalization unit 31 is connected between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus, and is used to equalize the voltage of the positive half of the bus; the second equalization unit 32 is connected between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus, and is used to equalize the voltage of the negative half of the bus.

[0024] In this embodiment, the control module 4 is connected to the first equalization unit 31 and the second equalization unit 32, respectively. The control module 4 can acquire the positive half-bus voltage and the negative half-bus voltage, and determine the current voltage balance state of the DC bus based on the voltage deviation between the positive half-bus voltage and the negative half-bus voltage. The positive half-bus voltage represents the voltage between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus, while the negative half-bus voltage represents the voltage between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus.

[0025] The control module 4 can determine the voltage deviation between the positive half bus voltage and the negative half bus voltage. When the voltage deviation between the positive half bus voltage and the negative half bus voltage meets the preset equalization conditions, the control module 4 selects either the first equalization unit 31 or the second equalization unit 32 to engage based on the magnitude relationship between the positive half bus voltage and the negative half bus voltage.

[0026] For example, when the voltage of the positive half-bus is higher than that of the negative half-bus, and the voltage deviation between the two meets the preset balancing condition, the control module 4 controls the first balancing unit 31 to switch on, so that the first balancing unit 31 and the positive half-bus form a balancing loop to release some energy in the positive half-bus, thereby reducing the voltage of the positive half-bus and making the voltage of the positive half-bus gradually approach the voltage of the negative half-bus. When the first balancing unit 31 is switched on for balancing, the second balancing unit 32 remains switched off, thereby avoiding the first balancing unit 31 and the second balancing unit 32 from releasing energy to the positive and negative half-buses at the same time.

[0027] When the voltage of the negative half-bus is higher than that of the positive half-bus, and the voltage deviation between the two meets the preset balancing condition, the control module 4 controls the second balancing unit 32 to switch on, so that the second balancing unit 32 and the negative half-bus form a balancing loop to release some of the energy in the negative half-bus, thereby reducing the voltage of the negative half-bus and gradually bringing the voltage of the negative half-bus closer to that of the positive half-bus. When the second balancing unit 32 is on for balancing, the first balancing unit 31 remains off.

[0028] When the voltage deviation between the positive and negative bus voltages meets the preset equalization termination condition, the control module 4 controls both the first equalization unit 31 and the second equalization unit 32 to disconnect, causing the equalization module 3 to exit the equalization operation state. In this way, the control module 4 can select the equalization unit corresponding to the high-voltage side for equalization based on the voltage difference between the positive and negative bus voltages, without simultaneously connecting the first equalization unit 31 and the second equalization unit 32, thereby achieving active adjustment of the positive and negative bus voltages of the DC bus.

[0029] This invention provides a control system and method for a boost circuit. The control module controls the first or second equalization unit to engage or disengage based on the voltage deviation between the positive and negative bus voltages. This balances the bus voltage, eliminates static hazards, and enables rapid energy release from the bus. The equalization is completed in a very short time, significantly improving the reliability of the system under load.

[0030] Figure 2 This is a structural block diagram of the first equalization unit in the control system of a boost circuit provided in an embodiment of the present invention; Figure 3 This is a structural block diagram of the second equalization unit in the control system of a boost circuit provided in an embodiment of the present invention; see reference. Figures 1-3 Optionally, in a control system for a boost circuit provided in this embodiment of the invention, the first equalization unit 31 includes a first switching device 311, a first inductor L1, and a first resistor R1; the first switching device 311, the first inductor L1, and the first resistor R1 are connected in series between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus. The second equalization unit 32 includes a second switching device 321, a second inductor L2, and a second resistor R2. The second switching device 321, the second inductor L2, and the second resistor R2 are connected in series between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus. The first control terminal of the control module 4 is connected to the control terminal of the first switching device 311, and the second control terminal of the control module 4 is connected to the control terminal of the second switching device 321.

[0031] Specifically, in the control system of the boost circuit provided in this embodiment of the invention, the first equalization unit 31 includes a first switching device 311, a first inductor L1, and a first resistor R1. The first switching device 311, the first inductor L1, and the first resistor R1 are connected in series between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus. The first switching device 311 is used to control the conduction or disconnection between the first equalization unit 31 and the positive half bus; the first inductor L1 is used to suppress transient current when the first equalization unit 31 is switched on; the first resistor R1 is used to consume electrical energy in the positive half bus when the first equalization unit 31 is switched on, so as to reduce the voltage of the positive half bus.

[0032] The second equalization unit 32 includes a second switching device 321, a second inductor L2, and a second resistor R2. The second switching device 321, the second inductor L2, and the second resistor R2 are connected in series between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus. The second switching device 321 is used to control the connection or disconnection between the second equalization unit 32 and the negative half-bus; the second inductor L2 is used to suppress transient current when the second equalization unit 32 is switched on; and the second resistor R2 is used to consume electrical energy in the negative half-bus when the second equalization unit 32 is switched on, thereby reducing the voltage of the negative half-bus.

[0033] The first control terminal of the control module 4 is connected to the control terminal of the first switching device 311, and the second control terminal of the control module 4 is connected to the control terminal of the second switching device 321. The control module 4 controls the first equalization unit 31 and the second equalization unit 32 to switch in or out by outputting corresponding control signals to the first switching device 311 and the second switching device 321.

[0034] In one embodiment, the first equalization unit 31 and the second equalization unit 32 operate in a mutually exclusive manner. When the voltage of the positive half-bus is higher than that of the negative half-bus and the equalization condition is met, the control module 4 controls the first switching device 311 to turn on, causing the first equalization unit 31 to switch onto the positive half-bus. When the voltage of the negative half-bus is higher than that of the positive half-bus and the equalization condition is met, the control module 4 controls the second switching device 321 to turn on, causing the second equalization unit 32 to switch onto the negative half-bus. When the first equalization unit 31 is switched on, the second equalization unit 32 remains switched off; when the second equalization unit 32 is switched on, the first equalization unit 31 remains switched off, thereby preventing the first equalization unit 31 and the second equalization unit 32 from switching on simultaneously.

[0035] Optional, continue to refer to Figure 2 and Figure 3 In the control system of a boost circuit provided in this embodiment of the invention, the first switching device 311 and the second switching device 321 are DC relays.

[0036] Optional, continue to refer to Figure 1 In the control system of the boost circuit provided in this embodiment of the invention, the control module 4 is a digital signal processor (DSP).

[0037] Optional, continue to refer to Figure 1 The present invention provides a first voltage sampling circuit 5 and a second voltage sampling circuit 6 in a control system for a boost circuit; The first voltage sampling circuit 5 is connected between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus. It is used to collect the positive half bus voltage and send the positive half bus voltage to the control module 4. The second voltage sampling circuit 6 is connected between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus. It is used to collect the negative half bus voltage and send the negative half bus voltage to the control module 4. The output of the first voltage sampling circuit 5 is connected to the first input of the control module 4, and the output of the second voltage sampling circuit 6 is connected to the second input of the control module 4.

[0038] Specifically, the control system for a boost circuit provided in this embodiment of the invention further includes a first voltage sampling circuit 5 and a second voltage sampling circuit 6.

[0039] The first voltage sampling circuit 5 is connected between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus, and is used to collect the voltage of the positive half of the bus. The second voltage sampling circuit 6 is connected between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus, and is used to collect the voltage of the negative half of the bus. The output terminal of the first voltage sampling circuit 5 is connected to the first input terminal of the control module 4, and the output terminal of the second voltage sampling circuit 6 is connected to the second input terminal of the control module 4.

[0040] During the operation of the boost circuit, the first voltage sampling circuit 5 samples the voltage between the positive terminal BAT+ of the DC bus and the midpoint N of the DC bus, and transmits the collected positive half-bus voltage to the control module 4; the second voltage sampling circuit 6 samples the voltage between the midpoint N of the DC bus and the negative terminal BAT- of the DC bus, and transmits the collected negative half-bus voltage to the control module 4. The control module 4 determines the voltage deviation between the received positive and negative half-bus voltages, and controls the first equalization unit 31 or the second equalization unit 32 to engage or disengage based on the voltage deviation, thereby actively equalizing the positive and negative half-buses of the DC bus.

[0041] By setting up a first voltage sampling circuit and a second voltage sampling circuit, the voltage status of the positive half bus and the negative half bus can be obtained respectively, providing a voltage detection basis for the control module to judge the voltage deviation between the positive and negative half buses and control the corresponding equalization unit.

[0042] Based on the same inventive concept, embodiments of the present invention provide a control method for a boost circuit, executed by the control system of the boost circuit in any of the above embodiments. Figure 4 This is a flowchart of a control method for a boost circuit provided in an embodiment of the present invention, for reference. Figure 4 The control methods include: S101. Obtain the positive half-bus voltage and the negative half-bus voltage.

[0043] For details, please refer to the following: Figure 1The positive half-bus voltage is acquired through the first voltage sampling circuit 5, and the negative half-bus voltage is acquired through the second voltage sampling circuit 6. The control module 4 receives the positive half-bus voltage transmitted by the first voltage sampling circuit 5 and the negative half-bus voltage transmitted by the second voltage sampling circuit 6.

[0044] S102. Determine the voltage deviation based on the positive half-bus voltage and the negative half-bus voltage.

[0045] Specifically, control module 4 can calculate the difference between the positive half-bus voltage and the negative half-bus voltage, and determine the voltage deviation based on the absolute value of the difference. The voltage deviation is used to characterize the degree of voltage imbalance between the positive half-bus voltage and the negative half-bus voltage.

[0046] For example, when the positive half-bus voltage is greater than the negative half-bus voltage, the voltage deviation can be determined based on the difference between the positive and negative half-bus voltages; similarly, when the negative half-bus voltage is greater than the positive half-bus voltage, the voltage deviation can be determined based on the difference between the negative and positive half-bus voltages. By determining the voltage deviation between the positive and negative half-bus voltages, the control module can further determine the voltage imbalance state between the positive and negative half-buses and control the corresponding equalization unit to perform equalization based on the determination result.

[0047] S103. Control the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation.

[0048] Specifically, the control module 4 can determine which half of the bus needs to be balanced based on the relationship between the voltage of the positive half of the bus and the voltage of the negative half of the bus. When the voltage of the positive half of the bus is higher than that of the negative half of the bus, and the voltage deviation meets the preset balancing conditions, the control module 4 controls the first balancing unit 31 to switch on and keeps the second balancing unit 32 in the off state to balance the positive half of the bus. When the voltage of the negative half of the bus is higher than that of the positive half of the bus, and the voltage deviation meets the preset balancing conditions, the control module 4 controls the second balancing unit 32 to switch on and keeps the first balancing unit 31 in the off state to balance the negative half of the bus.

[0049] When the voltage deviation meets the preset equalization termination condition, the control module 4 controls both the first equalization unit 31 and the second equalization unit 32 to disconnect, thereby ending the equalization operation on the DC bus.

[0050] Based on the above embodiments, the present invention further refines the control of the first equalization unit or the second equalization unit to switch on or off according to the voltage deviation. Figure 5 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention, for reference. Figure 5The present invention provides a control method for a boost circuit, comprising: S201. Obtain the positive half-bus voltage and the negative half-bus voltage.

[0051] S202. Determine the voltage deviation based on the positive half-bus voltage and the negative half-bus voltage.

[0052] S203. Control the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation.

[0053] S2031. When the voltage of the positive half bus is higher than that of the negative half bus, and the voltage deviation is greater than the first deviation threshold, the first equalization unit is controlled to switch in, and the second equalization unit is controlled to switch out.

[0054] Specifically, when the control module determines that the voltage of the positive half bus is higher than that of the negative half bus, and the voltage deviation is greater than the first deviation threshold (e.g., the first deviation threshold can be 200V), the control module controls the first equalization unit to switch in and controls the second equalization unit to switch out.

[0055] S2032. When the voltage of the negative half bus is higher than that of the positive half bus, and the voltage deviation is greater than the first deviation threshold, control the second equalization unit to switch in and control the first equalization unit to switch out.

[0056] Specifically, when the control module determines that the voltage of the negative half bus is higher than that of the positive half bus, and the voltage deviation is greater than the first deviation threshold (e.g., the first deviation threshold can be 200V), the control module controls the second equalization unit to switch in and controls the first equalization unit to switch out.

[0057] Based on the above embodiments, the present invention further refines the control of the first equalization unit or the second equalization unit to switch on or off according to the voltage deviation. Figure 6 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention, for reference. Figure 6 The present invention provides a control method for a boost circuit, comprising: S301, Obtain the positive half-bus voltage and the negative half-bus voltage.

[0058] S302. Determine the voltage deviation based on the positive half-bus voltage and the negative half-bus voltage.

[0059] S303. Control the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation.

[0060] S304. When the voltage deviation is less than the second deviation threshold, control the first equalization unit and the second equalization unit to switch off.

[0061] Specifically, when the control module detects that the voltage deviation (i.e., the difference between the positive half bus voltage and the negative half bus voltage or the difference between the negative half bus voltage and the positive half bus voltage) is less than the second deviation threshold, for example, the second deviation threshold can be 100V, the control module controls the first equalization unit and the second equalization unit to switch off.

[0062] Based on the above embodiments, the present invention further refines the process of controlling the first and second equalization units to switch off when the voltage deviation is less than the second deviation threshold. Figure 7 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention, for reference. Figure 7 The present invention provides a control method for a boost circuit, comprising: S401, Obtain the positive half-bus voltage and the negative half-bus voltage.

[0063] S402. Determine the voltage deviation based on the positive half-bus voltage and the negative half-bus voltage.

[0064] S403. Control the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation.

[0065] S404. Control the cut-in time of the first equalization unit and / or the second equalization unit to be greater than or equal to the first threshold.

[0066] Specifically, if active equalization of the bus voltage is required, the switching time of the first equalization unit or the second equalization unit should be greater than or equal to the first threshold, which can be 1 second. This setting can avoid frequent starting and stopping of DC relays.

[0067] S405. When the voltage deviation is less than the second deviation threshold, control the first equalization unit and the second equalization unit to switch off.

[0068] Based on the above embodiments, the present invention further refines the process of obtaining the positive half-bus voltage and the negative half-bus voltage. Figure 8 This is a flowchart of another control method for a boost circuit provided in an embodiment of the present invention, for reference. Figure 8 The present invention provides a control method for a boost circuit, comprising: S501, Obtain the operating status of the first boost branch and the second boost branch.

[0069] Specifically, after the system is powered on, the operating status of the first boost branch and the second boost branch is continuously acquired, i.e., whether it is powered on or powered off.

[0070] S502. When the first boost branch and the second boost branch are in standby mode, obtain the positive half bus voltage and the negative half bus voltage.

[0071] Specifically, when the first boost branch and the second boost branch are in standby mode, the positive half bus voltage and the negative half bus voltage need to be continuously acquired; if they are in other states, the operating status of the first boost branch and the second boost branch continues to be detected.

[0072] S503, Obtain the positive half-bus voltage and the negative half-bus voltage.

[0073] S504. Determine the voltage deviation based on the positive half-bus voltage and the negative half-bus voltage.

[0074] S505: Control the first equalization unit or the second equalization unit to switch in or out based on the voltage deviation.

[0075] The control method for a boost circuit provided in this embodiment of the invention can achieve the same technical effect as the control system for a boost circuit in any of the above-mentioned embodiments of the invention, and will not be described in detail here.

[0076] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0077] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control system for a boost circuit, characterized in that, include: The system comprises a first boost branch, a second boost branch, an equalization module, and a control module; the equalization module includes a first equalization unit and a second equalization unit. The first end of the first boost branch is connected to the positive terminal of the DC input, the second end of the first boost branch is connected to the positive terminal of the DC bus, and the first equalization unit is connected between the positive terminal of the DC bus and the midpoint of the DC bus. The first end of the second boost branch is connected to the negative terminal of the DC input, the second end of the second boost branch is connected to the negative terminal of the DC bus, and the second equalization unit is connected between the midpoint of the DC bus and the negative terminal of the DC bus. The first control terminal of the control module is connected to the first equalization unit, and the second control terminal of the control module is connected to the second equalization unit; The control module is used to acquire the positive half-bus voltage and the negative half-bus voltage, and control the first equalization unit or the second equalization unit to switch in, or control the first equalization unit and the second equalization unit to switch out, based on the voltage deviation between the positive half-bus voltage and the negative half-bus voltage.

2. The control system for the boost circuit according to claim 1, characterized in that, The first equalization unit includes a first switching device, a first inductor, and a first resistor; The first switching device, the first inductor, and the first resistor are connected in series between the positive terminal of the DC bus and the midpoint of the DC bus. The second equalization unit includes a second switching device, a second inductor, and a second resistor, which are connected in series between the midpoint of the DC bus and the negative terminal of the DC bus. The first control terminal of the control module is connected to the control terminal of the first switching device, and the second control terminal of the control module is connected to the control terminal of the second switching device.

3. The control system for the boost circuit according to claim 2, characterized in that, The first switching device and the second switching device are DC relays.

4. The control system for the boost circuit according to claim 1, characterized in that, The control module is a digital signal processor.

5. The control system for the boost circuit according to claim 1, characterized in that, It also includes a first voltage sampling circuit and a second voltage sampling circuit; The first voltage sampling circuit is connected between the positive terminal of the DC bus and the midpoint of the DC bus, and is used to collect the positive half bus voltage and send the positive half bus voltage to the control module; The second voltage sampling circuit is connected between the midpoint of the DC bus and the negative terminal of the DC bus, and is used to collect the negative half bus voltage and send the negative half bus voltage to the control module; The output terminal of the first voltage sampling circuit is connected to the first input terminal of the control module, and the output terminal of the second voltage sampling circuit is connected to the second input terminal of the control module.

6. A control method for a boost circuit, characterized in that, The control method, executed by the control system of the boost circuit according to any one of claims 1 to 5, comprises: Obtain the positive half-bus voltage and the negative half-bus voltage; The voltage deviation is determined based on the positive half-bus voltage and the negative half-bus voltage; The first equalization unit or the second equalization unit can be switched on or off based on the voltage deviation.

7. The control method for the boost circuit according to claim 6, characterized in that, The step of controlling the first equalization unit or the second equalization unit to switch on, or controlling the first equalization unit and the second equalization unit to switch off, based on the voltage deviation includes: When the positive half-bus voltage is higher than the negative half-bus voltage and the voltage deviation is greater than the first deviation threshold, the first equalization unit is controlled to switch in and the second equalization unit is controlled to switch out. When the negative half-bus voltage is higher than the positive half-bus voltage, and the voltage deviation is greater than the first deviation threshold, the second equalization unit is controlled to switch in, and the first equalization unit is controlled to switch out.

8. The control method for the boost circuit according to claim 6, characterized in that, The step of controlling the first equalization unit or the second equalization unit to switch on, or controlling the first equalization unit and the second equalization unit to switch off, based on the voltage deviation, further includes: When the voltage deviation is less than the second deviation threshold, the first equalization unit and the second equalization unit are switched off.

9. The control method for the boost circuit according to claim 8, characterized in that, Before controlling the first equalization unit and the second equalization unit to switch off when the voltage deviation is less than the second deviation threshold, the method further includes: The cut-in time of the first equalization unit or the second equalization unit is controlled to be greater than or equal to the first threshold.

10. The control method for the boost circuit according to claim 6, characterized in that, Before obtaining the positive and negative bus voltages, the following steps are also included: Obtain the operating status of the first boost branch and the second boost branch; When the first boost branch and the second boost branch are in standby mode, the positive half bus voltage and the negative half bus voltage are acquired.

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