Control method of power conversion circuit, power conversion device and energy storage equipment

Abstract

The invention provides a control method of a power conversion circuit, a power conversion device and energy storage equipment. The control method comprises the steps of firstly obtaining working condition parameters of the power conversion circuit, obtaining a predicted value of a first out-shift ratio according to the working condition parameters, then obtaining an adjusting value of the first out-shift ratio according to the working condition parameters of the power conversion circuit and target parameters, and obtaining a target value of the first out-shift ratio according to the predicted value and the adjusting value of the first out-shift ratio. And finally, generating a control signal according to the target value of the first out-shift ratio to control the power conversion circuit to perform energy conversion. Through the method, the regulation and control efficiency of the power conversion circuit can be effectively improved, so that the work of the power conversion circuit can quickly follow the change of working conditions, and the dynamic response performance of the power conversion circuit is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and particularly relates to a control method for a power conversion circuit, a power conversion device, and an energy storage device. Background Art

[0002] In practice, the operating conditions faced by the power conversion circuit are complex and variable. Whenever the operating conditions change, the power conversion circuit needs to adjust its operation accordingly. Therefore, it is necessary to improve the dynamic response performance of the power conversion circuit. Summary of the Invention

[0003] In view of this, the present application provides a control method for a power conversion circuit, a power conversion device, and an energy storage device, which can improve the dynamic response performance of the power conversion circuit.

[0004] In the first aspect of the present application, a control method for a power conversion circuit is provided. The power conversion circuit includes a high-voltage side bridge circuit, a low-voltage side bridge circuit, and a transformer. The high-voltage side bridge circuit is connected to the primary side of the transformer, and the low-voltage side bridge circuit is connected to the secondary side of the transformer. The control method includes: obtaining the operating condition parameters of the power conversion circuit; obtaining a predicted value of a first external shift ratio according to the operating condition parameters; the first external shift ratio is the duty cycle corresponding to the time difference between the fundamental wave of the midpoint voltage of the bridge arm of the high-voltage side bridge circuit and the fundamental wave of the midpoint voltage of the bridge arm of the low-voltage side bridge circuit; obtaining an adjustment value of the first external shift ratio according to the operating condition parameters and target parameters of the power conversion circuit; obtaining a target value of the first external shift ratio according to the predicted value and adjustment value of the first external shift ratio; generating a control signal according to the target value of the first external shift ratio; the control signal is used to control the power conversion circuit to perform energy conversion.

[0005] In the control method of the power conversion circuit of the present application, the operating condition parameters of the power conversion circuit are used to predict the magnitude of the first external shift ratio to obtain the predicted value of the first external shift ratio, and the operating condition parameters and target parameters of the power conversion circuit are used to obtain the adjustment value of the first external shift ratio. Furthermore, the target value of the first external shift ratio can be quickly determined according to the predicted value and adjustment value of the first external shift ratio, and the energy conversion process of the power conversion circuit can be controlled according to the target value of the first external shift ratio. Therefore, through the control method of the present application, the regulation efficiency of the power conversion circuit can be effectively improved, so that the operation of the power conversion circuit can quickly follow the change of the operating conditions, and the dynamic response performance of the power conversion circuit is effectively improved.

[0006] In one embodiment, the process of obtaining the predicted value of the first external shift ratio according to the operating condition parameters includes: determining the working mode in which the power conversion circuit is currently located according to the operating condition parameters; obtaining the corresponding prediction relationship according to the working mode; different working modes correspond to different prediction relationships of the first external shift ratio; obtaining the predicted value of the first external shift ratio according to the operating condition parameters and the prediction relationship.

[0007] In one embodiment, the operating mode includes a light load mode and a heavy load mode. The process of determining the current operating mode of the power conversion circuit according to the operating condition parameters includes: calculating the actual output power and the critical output power of the power conversion circuit according to the operating condition parameters; when the actual output power is higher than the critical output power, determining the operating mode as the heavy load mode; when the actual output power is lower than the critical output power, determining the operating mode as the light load mode.

[0008] In one embodiment, the operating condition parameters include the actual high-side DC voltage, the actual low-side DC voltage, the actual high-side DC current, the primary leakage inductance of the transformer, and the turns ratio. Furthermore, the process of calculating the actual output power and the critical output power of the power conversion circuit according to the operating condition parameters includes: calculating the gain according to the actual high-side DC voltage, the actual low-side DC voltage, and the turns ratio; calculating the critical output power according to the gain; when the gain is less than 1, calculating the actual output power according to the actual high-side DC voltage, the actual high-side DC current, the primary leakage inductance, and the preset operating cycle of the power conversion circuit; or when the gain is greater than 1, calculating the actual output power according to the actual high-side DC voltage, the actual high-side DC current, the actual low-side DC voltage, the primary leakage inductance, the turns ratio, and the preset operating cycle of the power conversion circuit.

[0009] In one embodiment, the operating condition parameters include the actual output power, the high-side DC voltage, the low-side DC voltage, and the turns ratio of the transformer. Furthermore, the process of obtaining the predicted value of the first external shift ratio according to the operating condition parameters and the prediction relationship includes: calculating the predicted value of the first external shift ratio according to the actual output power, the actual high-side DC voltage, the actual low-side DC voltage, the turns ratio, and the prediction relationship.

[0010] In one embodiment, generating a control signal according to the target value of the first external shift ratio includes: calculating a first duty cycle and a second duty cycle according to the target value of the first external shift ratio; the first duty cycle is the duty cycle of the voltage waveform at the midpoint of the bridge arm of the high-side bridge circuit; the second duty cycle is the duty cycle of the voltage waveform at the midpoint of the bridge arm of the low-side bridge circuit; calculating a second external shift ratio according to the target value of the first external shift ratio, the first duty cycle, and the second duty cycle; the second external shift ratio is the duty cycle corresponding to the time difference between the voltage waveform at the midpoint of the bridge arm of the high-side bridge circuit and the voltage waveform at the midpoint of the bridge arm of the low-side bridge circuit; generating a control signal according to the second external shift ratio, the first duty cycle, and the second duty cycle.

[0011] In one embodiment, calculating a first duty cycle and a second duty cycle based on a target value of a first external shift ratio includes: calculating a critical value of the first external shift ratio according to operating condition parameters; determining a target mapping relationship according to the magnitude relationship between the target value of the first external shift ratio and the critical value of the first external shift ratio; the target mapping relationship being a mapping relationship between the first external shift ratio and the first duty cycle and the second duty cycle; and determining the first duty cycle and the second duty cycle according to the target value of the first external shift ratio and the target mapping relationship.

[0012] In one embodiment, the operating condition parameters include the actual DC voltage on the high voltage side, and the target parameters include the target DC voltage on the high voltage side. Furthermore, the process of obtaining an adjustment value of the first external shift ratio according to the operating condition parameters and the target parameters of the power conversion circuit includes: calculating the voltage difference between the target DC voltage on the high voltage side and the actual DC voltage on the high voltage side; and performing deviation adjustment on the voltage difference to obtain the adjustment value of the first external shift ratio.

[0013] The second aspect of the present application provides a power conversion device, which includes a power conversion circuit and a controller. The controller is configured to execute the control method of the power conversion circuit described in the first aspect or any one of the embodiments of the first aspect.

[0014] The third aspect of the present application provides an energy storage device, which includes an energy storage battery, a power conversion circuit and a controller. The energy storage battery is connected to the low-voltage side bridge circuit of the power conversion circuit, and the controller is configured to execute the control method of the power conversion circuit described in the first aspect or any one of the embodiments of the first aspect.

[0015] The fourth aspect of the present application provides an electronic device, which includes a processor and a memory. The memory is used to store programs, instructions or codes, and the processor is used to execute the programs, instructions or codes in the memory to complete the control method of the power conversion circuit described in the first aspect or any one of the embodiments of the first aspect.

[0016] The fifth aspect of the present application provides a control device for a power conversion circuit, which includes an acquisition module, a prediction module, a first calculation module, a second calculation module and a generation module. The acquisition module is used to acquire the operating condition parameters of the power conversion circuit. The prediction module is used to obtain a predicted value of the first external shift ratio according to the operating condition parameters; the first external shift ratio is the duty cycle corresponding to the time difference between the fundamental wave of the midpoint voltage of the bridge arm of the high-voltage side bridge circuit and the fundamental wave of the midpoint voltage of the bridge arm of the low-voltage side bridge circuit. The first calculation module is used to obtain an adjustment value of the first external shift ratio according to the operating condition parameters and the target parameters of the power conversion circuit. The second calculation module is used to obtain a target value of the first external shift ratio according to the predicted value and the adjustment value of the first external shift ratio. The generation module is used to generate a control signal according to the target value of the first external shift ratio; the control signal is used to control the power conversion circuit to perform energy conversion.

[0017] The sixth aspect of the present application provides a computer-readable storage medium storing a computer program, which is loaded by a processor to execute the control method of the power conversion circuit described in the first aspect or any one of the embodiments of the first aspect.

[0018] In addition, for the technical effects brought by any possible implementation manner among the second aspect to the sixth aspect, reference can be made to the technical effects brought by different implementation manners in the first aspect, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a schematic diagram of an application scenario of the control method of the power conversion circuit provided by one embodiment of the present application.

[0020] Figure 2 FIG. is another schematic diagram of an application scenario of the control method of the power conversion circuit provided by one embodiment of the present application.

[0021] Figure 3 is Figure 1 or Figure 2 a circuit diagram of the power conversion circuit in

[0022] Figure 4 is Figure 3 a signal waveform diagram of the power conversion circuit shown in

[0023] Figure 5 is Figure 3 a signal waveform diagram of the power conversion circuit shown in the light load mode.

[0024] Figure 6 is Figure 3 a signal waveform diagram of the power conversion circuit shown in the heavy load mode.

[0025] Figure 7 FIG. is a flowchart of the control method of the power conversion circuit provided by one embodiment of the present application.

[0026] Figure 8 is Figure 7 a refined flowchart of step 12 in

[0027] Figure 9 is Figure 8 a refined flowchart of step 21 in

[0028] Figure 10 is Figure 9 a refined flowchart of step 31 in

[0029] Figure 11 is Figure 7 a refined flowchart of step 13 in

[0030] Figure 12 is Figure 7 a refined flowchart of step 15 in

[0031] Figure 13 is Figure 13 a refined flowchart of step 61 in

[0032] Figure 14 a simulation waveform diagram of the power conversion circuit when the method of the embodiment of the present application is not used.

[0033] Figure 15 a simulation waveform diagram of the power conversion circuit when the method of the embodiment of the present application is used.

[0034] Figure 16 a control loop diagram of the control method of the power conversion circuit of the embodiment of the present application.

[0035] Figure 17 a schematic diagram of a power conversion device provided by one embodiment of the present application.

[0036] Figure 18 a schematic diagram of an energy storage device provided by one embodiment of the present application.

[0037] Figure 19 a schematic diagram of an electronic device provided by one embodiment of the present application.

[0038] Figure 20 a schematic diagram of a control device of a power conversion circuit provided by one embodiment of the present application. Detailed implementation manners

[0039] It should be noted that the terms "first" and "second" in the specification, claims and drawings of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0040] In addition, it should be noted that for the method disclosed in the method or flowchart shown in the embodiment of the present application, which includes one or more steps for implementing the method, without departing from the scope of the claims, the execution order of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0041] Some embodiments will be described below with reference to the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0042] In practice, the operating conditions faced by the power conversion circuit are complex and changeable. Whenever the operating conditions change, the power conversion circuit needs to adjust its operation accordingly. Therefore, it is necessary to improve the dynamic response performance of the power conversion circuit.

[0043] In response to this, an embodiment of the present application provides a control method for a power conversion circuit, which can improve the dynamic response performance of the power conversion circuit.

[0044] The technical solution of the present application will be further described in detail below with reference to the accompanying drawings.

[0045] Please refer to Figure 1 , which is an application scenario diagram of the control method for the power conversion circuit according to the embodiment of the present application. Figure 1 The scenario includes a power conversion circuit 10, a power supply 20, and a load 30.

[0046] Specifically, the power conversion circuit 10 includes a high-voltage side bridge circuit 11, a low-voltage side bridge circuit 12, and a transformer 13. The first end of the high-voltage side bridge circuit 11 is connected to the primary side of the transformer 13, and the second end of the high-voltage side bridge circuit 11 is used as an input end and can be used to connect to the power supply 20. The secondary side of the transformer 13 is connected to the first end of the low-voltage side bridge circuit 12, and the second end of the low-voltage side bridge circuit 12 is used as an output end and can be used to connect to the load 30.

[0047] Among them, the high-voltage side bridge circuit 11 can adopt a full-bridge topology or a half-bridge topology, and the low-voltage side bridge circuit 12 can also adopt a full-bridge topology or a half-bridge topology, which is not limited here.

[0048] The turns ratio of the primary coil to the secondary coil of the transformer 13 can be n:1, that is, the turns ratio of the transformer 13 can be n. In the embodiment of the present application, the transformer 13 is a step-down transformer, so n is a positive number greater than 1. Therefore, the primary side of the transformer 13 is the high-voltage side, and the secondary side of the transformer 13 is the low-voltage side.

[0049] The power supply 20 is a DC power supply, such as a photovoltaic power generation device, a DC-DC conversion circuit, a rectifier circuit, or an inverter circuit with a rectification function. Among them, the DC-DC (that is, Direct Current-Direct Current, DC-DC) conversion circuit includes, but is not limited to, a BOOST boost circuit, a BUCK buck circuit, and a BUCK-BOOST buck-boost circuit. When the power supply 20 is an inverter circuit, the DC side of the inverter circuit can be connected to the power conversion circuit 10 through a bus. The load 30 is a DC load 30, such as an energy storage battery, a DC motor, or various DC loads in a household.

[0050] Based on such a design, the power conversion circuit 10 can be used to convert the energy of the power supply 20 connected to the high-voltage side bridge circuit 11 to the load 30 connected to the low-voltage side bridge circuit 12. Specifically, the high-voltage side bridge circuit 11 can be used to invert the energy of the power supply 20 and then transmit it to the transformer 13. The transformer 13 then transmits the energy to the low-voltage side bridge circuit 12 through a magnetic field. The low-voltage side bridge circuit 12 can be used to rectify the energy and then transmit it to the load 30. At this time, the energy flow direction is from the high-voltage side bridge circuit 11 to the low-voltage side bridge circuit 12.

[0051] In another scenario, the power conversion circuit 10 can also be compatible with realizing the energy flow from the low-voltage side bridge circuit 12 to the high-voltage side bridge circuit 11. For example, please refer to Figure 2 , Figure 2 the scenario and Figure 1 the difference between the scenarios is that: the second end of the high-voltage side bridge circuit 11 is used as the output end and is used to connect the load 30. The second end of the low-voltage side bridge circuit 12 is used as the input end and is used to connect the power supply 20. Among them, the power supply 20 can be, for example, a storage battery or other DC power supply 20 that can provide direct current. The load 30 can be, for example, an inverter circuit or other DC load 30 that can consume direct current.

[0052] Based on such a design, the power conversion circuit 10 can be used to convert the energy of the power supply 20 connected to the low-voltage side bridge circuit 12 to the load 30 connected to the high-voltage side bridge circuit 11. At this time, the energy flow direction is from the low-voltage side bridge circuit 12 to the high-voltage side bridge circuit 11.

[0053] It can be seen that the power conversion circuit 10 can achieve DC-DC conversion and can achieve bidirectional energy flow.

[0054] Among them, the direction of energy flowing from the high-voltage side bridge circuit 11 to the low-voltage side bridge circuit 12 can be defined as the forward direction, and the direction of energy flowing from the low-voltage side bridge circuit 12 to the high-voltage side bridge circuit 11 can be defined as the reverse direction. The forward energy flow or forward operation can be regarded as charging. The reverse energy flow or reverse operation can be regarded as discharging. Of course, in other embodiments, the forward and reverse directions can be reversed, and it can be determined according to the actual situation, all within the scope of the embodiments of the present application.

[0055] In the embodiments of the present application, Figure 1 and Figure 2The scene shown also includes a controller 40, which can be a Microcontroller Unit (MCU) or other control circuit. The controller 40 is connected to the high-voltage side bridge circuit 11 and the low-voltage side bridge circuit 12, and can thus be used to control the high-voltage side bridge circuit 11 to implement a direct current-alternating current (DC-AC) conversion function, and control the low-voltage side bridge circuit 12 to implement an alternating current-direct current (AC-DC) conversion function. In another embodiment, the high-voltage side bridge circuit 11 and the low-voltage side bridge circuit 12 can also be controlled by two controllers 40 respectively.

[0056] In the embodiment of the present application, the controller 40 can adopt a multi-phase shift control method to control the power conversion circuit 10, which involves 4 control degrees of freedom, namely: the duty cycle D1 of the primary side voltage waveform of the transformer 13 (i.e., the midpoint voltage waveform of the bridge arm of the high-voltage side bridge circuit 11), the duty cycle D2 of the secondary side voltage waveform of the transformer 13 (i.e., the midpoint voltage waveform of the bridge arm of the low-voltage side bridge circuit 12), the duty cycle Df corresponding to the time difference between the fundamental wave of the primary side voltage of the transformer 13 and the fundamental wave of the secondary side voltage of the transformer 13, and the duty cycle D3 corresponding to the time difference between the primary side voltage waveform of the transformer 13 and the secondary side voltage waveform of the transformer 13. For ease of description, D1 can be referred to as the first duty cycle, D2 as the second duty cycle, Df as the first external phase shift ratio, and D3 as the second external phase shift ratio. D1, D2, Df, and D3 all affect the operation of the power conversion circuit 10.

[0057] Based on the multi-phase shift control method, the controller 40 can be used to execute the control method of the power conversion circuit provided in the embodiment of the present application to control the energy conversion of the power conversion circuit 10, so that the power conversion circuit 10 can respond quickly and dynamically.

[0058] For better understanding, the following takes Figure 3 the circuit shown as an example to further illustrate the power conversion circuit 10. In Figure 3 the power conversion circuit 10 shown, both the high-voltage side bridge circuit 11 and the low-voltage side bridge circuit 12 adopt a full-bridge topology.

[0059] Specifically, as Figure 3As shown, the high-voltage side bridge circuit 11 includes a first arm 111 and a second arm 112 connected in parallel. The first arm 111 includes an upper switch Q1 and a lower switch Q2 connected in series, and the second arm 112 includes an upper switch Q3 and a lower switch Q4 connected in series. The midpoint a of the first arm 111 and the midpoint b of the second arm 112 form the first end of the high-voltage side bridge circuit 11. Therefore, the arm midpoint voltage V of the high-voltage side bridge circuit 11 ab is also the primary side voltage of the transformer 13. The two ends of the first arm 111 and the second arm 112 form the second end of the high-voltage side bridge circuit 11.

[0060] The low-voltage side bridge circuit 12 includes a third arm 121 and a fourth arm 122 connected in parallel. The third arm 121 includes an upper switch Q5 and a lower switch Q6 connected in series, and the fourth arm 122 includes an upper switch Q7 and a lower switch Q8 connected in series. The midpoint c of the third arm 121 and the midpoint d of the fourth arm 122 form the first end of the low-voltage side bridge circuit 12. Therefore, the arm midpoint voltage V of the low-voltage side bridge circuit 12 cd is also the secondary side voltage of the transformer 13. The two ends of the third arm 121 and the fourth arm 122 form the second end of the low-voltage side bridge circuit 12.

[0061] The transformer 13 ( Figure 3 denoted as Tr in the figure) has a primary leakage inductance L k , for the convenience of understanding, Figure 2 the primary leakage inductance L k is shown in the circuit. The primary leakage inductance L k is connected between the primary side of the transformer 13 and the arm midpoint a. In other embodiments, the primary leakage inductance L k can also be independent of the transformer Tr.

[0062] Based on such a design, Figure 3 the power conversion circuit 10 shown can be called a Dual Active Bridges (DAB) conversion circuit. During forward operation, the second end of the high-voltage side bridge circuit 11 serves as the input terminal, and the second end of the low-voltage side bridge circuit 12 serves as the output terminal. During reverse operation, the second end of the low-voltage side bridge circuit 12 serves as the input terminal, and the second end of the high-voltage side bridge circuit 11 serves as the output terminal. The actual high-voltage side DC voltage on the second end of the high-voltage side bridge circuit 11 can be expressed as V HV , the actual high-voltage side DC current can be expressed as I HV , the actual low-voltage side DC voltage on the second end of the low-voltage side bridge circuit 12 can be expressed as V LV , and the actual low-voltage side DC current can be expressed as I LV .

[0063] In this embodiment, the switching transistors Q1 - Q4 and Q5 - Q8 can be semiconductor switches of corresponding types according to actual situations, such as triodes, MOSFETs, or IGBTs, etc. The present application does not make specific limitations on this. The switching transistors Q1 - Q4 and Q5 - Q8 can all be used to receive control signals from the controller 40, and then conduct or turn off under the control of the control signals.

[0064] Among them, the control signals of the upper and lower switching transistors in the same bridge arm are complementary or opposite, so that the upper and lower switching transistors in the same bridge arm conduct alternately. That is, Q1 and Q2 conduct alternately, Q3 and Q4 conduct alternately, Q5 and Q6 conduct alternately, and Q7 and Q8 conduct alternately. It should be understood that when alternately switching the upper and lower switching transistors, a dead time can be delayed first and then the switching can be performed. The dead time can be used to prevent the bridge arm from being short - circuited.

[0065] There is a certain time difference between the control signals of the two upper switching transistors in different bridge arms of the same bridge circuit, so that these two upper switching transistors conduct or turn off successively with a certain time difference. The same is true for the two lower switching transistors in different bridge arms of the same bridge circuit.

[0066] For example, in the high - voltage - side bridge circuit 11, Q1 and Q3 conduct or turn off successively with a certain time difference. Based on this, as Figure 4 shown, the high - voltage - side bridge circuit 11 generates the bridge - arm mid - point voltage V ab , and the duty cycle of its waveform is the first duty cycle D1, which is equal to the ratio of the time difference between Q1 and Q3 to a preset working cycle T s . Figure 4 The T hs in s refers to half of the preset working cycle, that is, T

[0067] / 2. Figure 4 In the low - voltage - side bridge circuit 12, Q5 and Q7 conduct or turn off successively with a certain time difference. Based on this, as cd shown, the low - voltage - side bridge circuit 12 generates the bridge - arm mid - point voltage V s , and the duty cycle of its waveform is the second duty cycle D2, which is equal to the ratio of the time difference between Q5 and Q7 to a preset working cycle T

[0068] When the power conversion circuit 10 operates in the forward direction (that is, in the charging mode and the energy flows forward), the waveform of the bridge - arm mid - point voltage V ab of the high - voltage - side bridge circuit 11 is ahead of the waveform of the bridge - arm mid - point voltage V cd of the low - voltage - side bridge circuit 12 (as Figure 4 ). When the power conversion circuit 10 operates in the reverse direction (that is, in the discharging mode and the energy flows backward), the bridge - arm mid - point voltage V abThe waveform lags behind the midpoint voltage V of the bridge arm of the low-voltage side bridge circuit 12 cd waveform. Therefore, there is also a certain time difference between the midpoint voltage V ab waveform of the bridge arm of the high-voltage side bridge circuit 11 and the midpoint voltage V cd waveform of the bridge arm of the low-voltage side bridge circuit 12. The duty cycle corresponding to this time difference is the second external shift ratio D3. The positive and negative polarities of the second external shift ratio D3 reflect the operating direction of the power conversion circuit 10 (i.e., the energy flow direction).

[0069] Moreover, according to the Fourier transform principle, a periodic signal can be decomposed into the superposition form of a fundamental wave component and harmonic components, and the fundamental wave component is the main component in the signal. Therefore, as Figure 4 shown, the midpoint voltage V ab of the bridge arm of the high-voltage side bridge circuit 11 has a corresponding fundamental wave V fab of the midpoint voltage of the bridge arm, and the midpoint voltage V cd of the bridge arm of the low-voltage side bridge circuit 12 has a corresponding fundamental wave V fcd of the midpoint voltage of the bridge arm. There is also a corresponding time difference between the fundamental wave V fab of the midpoint voltage of the bridge arm of the high-voltage side bridge circuit 11 and the fundamental wave V fcd of the midpoint voltage of the bridge arm of the low-voltage side bridge circuit 12. The duty cycle corresponding to this time difference is the first external shift ratio Df. The positive and negative polarities of the first external shift ratio Df can also reflect the energy flow direction of the power conversion circuit 10.

[0070] Taking half of the preset working cycle T hs as a reference, the value ranges of D1, D2, D3, and Df are 0≤D1≤1, 0≤D2≤1, -1≤D3≤1, and -1≤Df≤1 respectively.

[0071] In the embodiment of the present application, the power conversion circuit 10 can operate in different working modes, such as a charging mode and a discharging mode, etc. The discharging mode includes a light load mode and a heavy load mode, where the light load mode and the heavy load mode are dual modes to each other, and the charging mode and the discharging mode are dual modes to each other. The power conversion circuit 10 has corresponding outputs and D1, D2, D3, Df under different working modes.

[0072] For example, please refer to Figure 5 and Figure 6 , Figure 5 shows Figure 3 a signal waveform diagram of the normal operation of the power conversion circuit 10 in the light load mode,[[]] Figure 5 shows Figure 3 a signal waveform diagram of the normal operation of the power conversion circuit 10 in the heavy load mode. Combining Figure 5 and Figure 6It can be seen that in the light load mode, the primary leakage inductance current IL of the power conversion circuit 10 is small, so the actual output power is small. In the heavy load mode, the primary leakage inductance current IL of the power conversion circuit 10 is large, so the actual output power is large. The magnitudes of D1, D2, D3, and Df are different in the light load mode and the heavy load mode. For example, Df in the light load mode is significantly smaller than Df in the heavy load mode.

[0073] In the embodiment of the present application, there is a correlation between the output power of the power conversion circuit 10 and the operating condition parameters of the power conversion circuit 10. Moreover, in different operating modes, the correlation can also be different.

[0074] For example, Figure 3 The power conversion circuit 10 shown has the following output power expression:

[0075]

[0076]

[0077] Where d is the voltage ratio between the high and low voltage sides of the transformer 13, which can be called the gain.

[0078] It can be understood that d < 1, V HV > nV LV indicates that the actual output power is small, and d > 1, V HV < nV LV indicates that the actual output power is large. Therefore, when the power conversion circuit 10 is in the light load mode, the output power expression can adopt the When the power conversion circuit 10 is in the heavy load mode, the output power expression can adopt the

[0079] The output power corresponding to the junction of the two different operating modes of the power conversion circuit 10 can be called the critical output power. It should be understood that the critical output power of the power conversion circuit 10 is also correlated with the operating condition parameters of the power conversion circuit 10.

[0080] For example, the expression of the critical output power P crit can be:

[0081]

[0082] Where, when P out > P crit it indicates that the actual output power will be higher than the critical output power, and the power demand of the load 30 is large, so the operating mode corresponds to the heavy load mode. When P out < P critWhen it shows that the actual output power will be lower than the critical output power and the power demand of the load 30 is small, the working mode correspondingly is the light load mode.

[0083] In the embodiment of the present application, the power conversion circuit 10 also has relevant expressions of D1, D2, D3, and Df. Moreover, in different working modes, the expressions can also be different.

[0084] Among them, the first external shift ratio Df is associated with the operating condition parameters of the power conversion circuit 10. For example, Figure 3 The power conversion circuit 10 shown has the following expression of the first external shift ratio Df:

[0085]

[0086] The first external shift ratio corresponding to the power conversion circuit 10 at the junction of two different working modes can be called the critical value Df_crit of the first external shift ratio.

[0087] For example, the power conversion circuit 10 has the following expression of the critical value Df_crit of the first external shift ratio:

[0088]

[0089] The expression of the first duty cycle D1 is associated with the operating condition parameters of the power conversion circuit 10 and the first external shift ratio Df. For example, Figure 3 The power conversion circuit 10 shown has the following expression of the first duty cycle D1:

[0090]

[0091] It can be understood that as Figure 5 and Figure 6 shown, Df in the light load mode is significantly smaller than Df in the heavy load mode. Therefore, when Df < Df_crit, it shows that Df is small, so the working mode correspondingly is the light load mode. When Df > Df_crit, it shows that Df is large, so the working mode correspondingly is the heavy load mode.

[0092] The expression of the second duty cycle D2 is also associated with the operating condition parameters of the power conversion circuit 10 and the first external shift ratio Df. For example, Figure 3 The power conversion circuit 10 shown has the following expression of the second duty cycle D2:

[0093]

[0094] Among them, both formula (6) and formula (7) are expressions that can make the power conversion circuit 10 have the minimum current stress to ensure the soft switching of the switching tube.

[0095] It can be understood by combining Equations (4) to (7):

[0096] When Df < Df_crit, the expression of the first outward shift relative to Df can adopt the one in Equation (4) The expression of the first duty cycle D1 can adopt the one in Equation (6) The expression of the second duty cycle D2 can adopt the one in Equation (7)

[0097] When Df > Df_crit, the expression of the first outward shift relative to Df can adopt the one in Equation (4) The expression of the first duty cycle D1 can adopt the one in Equation (6) The expression of the second duty cycle D2 can be D2 = 1 in Equation (7).

[0098] In addition, D1, D2, D3, and Df are linearly related. For example, there is the following linear relationship:

[0099] Df = D3 + 0.5D2 - 0.5D1 (8)

[0100] It should be understood that the above Equations (1) to (8) are only schematic examples provided by the embodiments of the present application. In other embodiments, corresponding expressions can be established according to different power conversion circuits 10, which can be determined according to actual situations and are all within the protection scope of the present application.

[0101] Next, the control method of the power conversion circuit in the embodiments of the present application will be introduced. It can be understood that in other embodiments, it can also be implemented by a control device / electronic device / processor dedicated to the above power conversion circuit 10.

[0102] Please refer to Figure 7 , the control method of the power conversion circuit includes:

[0103] Step S11: Obtain the operating condition parameters of the power conversion circuit.

[0104] Specifically, the operating condition parameters of the power conversion circuit 10 may include actual operating parameters and component parameters. Among them, the operating parameters may include, for example, the actual high-side DC voltage V HV and the actual high-side DC current I HV of the high-side bridge circuit 11, and the actual low-side DC voltage V LV and the actual low-side DC current I LV of the low-side bridge circuit 12, etc. at least in part. The component parameters may include, for example, the primary leakage inductance L k and the turns ratio n of the transformer Tr, etc. at least in part.

[0105] Among them, the actual DC voltage V on the high-voltage side HV can be obtained by the voltage sampling circuit performing real-time voltage sampling on the second end of the high-voltage side bridge circuit 11. The actual DC voltage V on the low-voltage side LV can be obtained by the voltage sampling circuit performing real-time voltage sampling on the second end of the low-voltage side bridge circuit 12. The actual DC current I on the high-voltage side HV can be obtained by the current sampling circuit performing real-time current sampling on the second end of the high-voltage side bridge circuit 11. The actual DC current I on the low-voltage side LV can be obtained by the current sampling circuit performing real-time current sampling on the second end of the low-voltage side bridge circuit 12. Among them, both the voltage sampling circuit and the current sampling circuit can be independently set or integrated into the controller 40.

[0106] The primary leakage inductance L of the transformer Tr k and the turns ratio n are both the self-parameters of the transformer Tr and are known parameters.

[0107] It should be understood that in the case of the forward operation of the power conversion circuit 10, the actual DC voltage V on the high-voltage side HV is the actual input voltage, and the actual DC current I on the high-voltage side HV is the actual input current. The actual DC voltage V on the low-voltage side LV is the actual output voltage, and the actual DC current I on the low-voltage side LV is the actual output current. In the case of the reverse operation of the power conversion circuit 10, the actual DC voltage V on the low-voltage side LV is the actual input voltage, and the actual DC current I on the low-voltage side LV is the actual input current. The actual DC voltage V on the high-voltage side HV is the actual output voltage, and the actual DC current I on the high-voltage side HV is the actual output current.

[0108] Step S12: Obtain the predicted value of the first external shift ratio according to the operating condition parameters.

[0109] It can be understood that the first external shift ratio Df is a control degree of freedom of the power conversion circuit 10 and will affect the operation of the power conversion circuit 10. Therefore, the first external shift ratio Df is related to the operating condition parameters when the power conversion circuit 10 operates. For example, reference can be made to the aforementioned formula (4). Therefore, the obtained operating condition parameters can be used to predict the first external shift ratio Df to obtain the predicted value Df_predict of the first external shift ratio Df.

[0110] Step S13: Obtain the adjustment value of the first external shift ratio according to the operating condition parameters and target parameters of the power conversion circuit.

[0111] Among them, the target parameters of the power conversion circuit 10 refer to the operating parameters that the power conversion circuit 10 needs to achieve, which can be preset according to actual needs. In step S13, closed-loop control can be performed on the actual operating condition parameters and the preset target parameters to obtain an adjustment value △Df of an appropriate magnitude for the first external shift ratio.

[0112] Step S14: Obtain the target value of the first external shift ratio based on the predicted value and the adjustment value of the first external shift ratio.

[0113] Specifically, the predicted value Df_predict of the first external shift ratio and the adjustment value △Df of the first external shift ratio can be summed, weighted summed, or other mathematical operation processes can be performed to obtain the target value Df_target of the first external shift ratio. The specific mathematical operation process can be set accordingly according to the actual situation and is not limited herein.

[0114] Step S15: Generate a control signal based on the target value of the first external shift ratio; the control signal is used to control the power conversion circuit to perform energy conversion.

[0115] It can be understood that the first external shift ratio Df is associated with the operation of the power conversion circuit 10. For example, the polarity of the first external shift ratio Df reflects the energy flow direction of the power conversion circuit 10. Therefore, the polarity of the target value Df_target of the first external shift ratio will affect the control of the energy flow direction of the power conversion circuit 10 by the control signal. Moreover, the first external shift ratio Df is linearly related to the first duty cycle D1, the second duty cycle D2, and the second external shift ratio D3 of the power conversion circuit 10. The first duty cycle D1, the second duty cycle D2, and the second external shift ratio D3 reflect the conduction duration and conduction time difference of the switching tubes of the high-voltage side bridge circuit 11 and the low-voltage side bridge circuit 12. Therefore, the magnitude of the target value Df_target of the first external shift ratio will affect the on-off control of the switching tubes of the power conversion circuit 10 by the control signal, thereby affecting the energy transmission. Therefore, in step S15, the control signal generated based on the target value Df_target of the first external shift ratio can effectively control the energy conversion of the power conversion circuit 10.

[0116] Generally speaking, in the control method of the power conversion circuit according to the embodiments of the present application, by predicting the magnitude of the first external shift ratio based on the operating condition parameters of the power conversion circuit 10, a predicted value of the first external shift ratio is obtained, and by obtaining the adjustment value of the first external shift ratio based on the operating condition parameters and target parameters of the power conversion circuit 10, the target value of the first external shift ratio can be quickly obtained according to the predicted value and the adjustment value of the first external shift ratio, and the energy conversion process of the power conversion circuit 10 can be controlled according to the target value of the first external shift ratio. Compared with gradually adjusting the first external shift ratio until it is stable through multiple feedback adjustments and correspondingly controlling the power conversion circuit 10 each time, the control method according to the embodiments of the present application can quickly determine the target value of the first external shift ratio, thereby significantly improving the control efficiency of the power conversion circuit 10, enabling the operation of the power conversion circuit 10 to quickly follow the changes in the operating conditions, effectively improving the dynamic response performance of the power conversion circuit 10, and being beneficial to the normal operation of the load 30.

[0117] For example, when the operating mode of the power conversion circuit 10 switches from the charging mode to the discharging mode, the traditional method is to gradually adjust the first external shift ratio to the steady-state value through PI closed-loop control, for example, gradually adjusting from +0.3 to -0.2. However, in the embodiments of the present application, since the first external shift ratio is predicted, the predicted value -0.2 of the first external shift ratio can be directly obtained, which obviously speeds up the adjustment process of the first external shift ratio and improves the dynamic response ability. Moreover, the predicted value -0.2 can also be adjusted to obtain a better target value of the first external shift ratio, further improving the control efficiency and control accuracy of the power conversion circuit 10.

[0118] In some embodiments, in different operating modes, the first external shift ratio and the operating condition parameters will have different correlations. Therefore, in the above step S12, it is necessary to first determine the current operating mode of the power conversion circuit 10, and then obtain the predicted value of the first external shift ratio corresponding to the current operating mode.

[0119] Therefore, please refer to Figure 8 , obtaining the predicted value of the first external shift ratio according to the operating condition parameters may include:

[0120] Step S21: Determine the operating mode in which the power conversion circuit is currently located according to the operating condition parameters.

[0121] It can be understood that when the power conversion circuit 10 is in different operating modes, the operating process of the power conversion circuit 10 is different, so the operating condition parameters will correspondingly vary. For example, when the power conversion circuit 10 is in the charging mode, the high-voltage side bridge circuit 11 of the power conversion circuit 10 accesses the current and power, and the low-voltage side bridge circuit 12 outputs the current and power. When the power conversion circuit 10 is in the discharging mode, the low-voltage side bridge circuit 12 of the power conversion circuit 10 accesses the current and power, and the high-voltage side bridge circuit 11 outputs the current and power. That is, the transmission direction of the current and power in the discharging mode will be different from that in the charging mode. Another example is that the current and power generated by the power conversion circuit 10 in the light load mode will be less than those generated in the heavy load mode. Therefore, according to the operating condition parameters, it can be judged which operating mode the power conversion circuit 10 is currently in.

[0122] Step S22: Obtain the corresponding prediction relationship according to the operating mode.

[0123] Among them, the prediction relationship of the first outer shift ratio Df indicates the relationship between the first outer shift ratio Df and the operating condition parameters in the corresponding operating mode. Therefore, this prediction relationship can be used to predict the magnitude of the first outer shift ratio Df. Different operating modes correspond to different prediction relationships of the first outer shift ratio.

[0124] It can be understood that the prediction relationship can be pre-stored in the internal memory or external memory of the controller 40 in the form of expressions, charts, etc. Furthermore, in step S22, the prediction relationship corresponding to the currently operating mode can be obtained from the memory.

[0125] Step S23: Obtain the predicted value of the first outer shift ratio according to the operating condition parameters and the prediction relationship.

[0126] Specifically, the obtained operating condition parameters can be substituted into the prediction relationship of the first outer shift ratio Df corresponding to the current operating mode, so as to calculate the available and effective predicted value Df_predict of the first outer shift ratio applicable to the current operating mode.

[0127] Generally speaking, through steps S21 to S23, the predicted value Df_predict of the first outer shift ratio corresponding to the current operating mode of the power conversion circuit 10 can be quickly determined. Furthermore, in the subsequent steps, the predicted value Df_predict can be fine-tuned to obtain the target value of the first outer shift ratio Df required for the current operating mode. In this way, the adjustment duration of the first outer shift ratio Df can be effectively shortened, the dynamic response speed of the power conversion circuit 10 can be accelerated, and it is also helpful for the accurate adjustment of the first outer shift ratio Df.

[0128] More specifically, please refer to Figure 9, in one embodiment, the process of determining the current operating mode of the power conversion circuit according to the operating conditions parameters in step S21 may include:

[0129] Step S31: Calculate the actual output power and the critical output power of the power conversion circuit according to the operating conditions parameters.

[0130] As described above, there is a corresponding relationship between the output power of the power conversion circuit 10 and the operating conditions parameters of the power conversion circuit 10, and there is also a corresponding relationship between the critical output power of the power conversion circuit 10 and the operating conditions parameters of the power conversion circuit 10. Therefore, the actual output power Pout and the critical output power Pcrit can be calculated according to the obtained operating conditions parameters.

[0131] Here, the critical output power Pcrit may be the critical output power between the heavy load mode and the light load mode.

[0132] Step S32: Confirm whether the actual output power is higher than the critical output power.

[0133] It can be understood that the critical output power is the boundary of the output powers of two different operating modes. Therefore, the actual output power being higher than the critical output power and the actual output power being lower than the critical output power respectively correspond to two different operating modes.

[0134] Step S33: When the actual output power is higher than the critical output power, determine the operating mode as the heavy load mode.

[0135] When the actual output power is higher than the critical output power, it indicates that the power demand of the load 30 is large and the power conversion circuit 10 is carrying a heavy load. Therefore, it can be determined that the current operating mode of the power conversion circuit 10 is the heavy load mode.

[0136] Step S34: When the actual output power is lower than the critical output power, determine the operating mode as the light load mode.

[0137] When the actual output power is lower than the critical output power, it indicates that the power demand of the load 30 is small and the power conversion circuit 10 is carrying a light load. Therefore, it can be determined that the current operating mode of the power conversion circuit 10 is the light load mode.

[0138] Generally speaking, in the above steps S31 to S34, the magnitude relationship between the actual output power and the critical output power is used to accurately judge the current operating mode of the power conversion circuit 10, so that it is convenient to subsequently obtain a predicted value of an appropriate magnitude that matches the current operating mode for comparison with the first external shift.

[0139] For better understanding, the following uses Figure 3 the power conversion circuit 10 to further illustrate steps S31 to S34 by way of example.

[0140] As described above, Figure 3 The relationship between the output power of the power conversion circuit 10 and the operating condition parameters can be as shown in the aforementioned formulas (1) and (2), and the relationship between the critical output power of the power conversion circuit 10 and the operating condition parameters can be as shown in the aforementioned formula (3).

[0141] Therefore, referring to Figure 10 , the process of calculating the actual output power and the critical output power of the power conversion circuit according to the operating condition parameters in step S31 may include:

[0142] Step S41: Calculate the gain based on the actual high-side DC voltage, the actual low-side DC voltage, and the turns ratio.

[0143] Specifically, as shown in the aforementioned formula (2), the gain d has a negative correlation with the actual high-side DC voltage V HV and a positive correlation with the actual low-side DC voltage V LV , and the gain d has a positive correlation with the turns ratio n. Therefore, the actual high-side DC voltage V HV , the actual low-side DC voltage V LV , and the turns ratio n can be substituted into formula (2) to calculate the gain d.

[0144] Step S42: Calculate the critical output power based on the gain.

[0145] Specifically, as shown in the aforementioned formula (3), the critical output power P crit is related to the gain d. Therefore, the gain d can be substituted into formula (3) to calculate the critical output power P crit .

[0146] Step S43: Confirm whether the gain is less than 1.

[0147] It can be understood that judging whether the gain is less than 1 is to confirm the specific expression of the output power. Specifically, according to formula (2), if the gain is less than 1, the output power expression corresponding to the power conversion circuit 10 is If the gain is greater than 1, the output power expression corresponding to the power conversion circuit 10 is

[0148] Step S44: When the gain is less than 1, calculate the actual output power based on the actual high-side DC voltage, the actual high-side DC current, the primary leakage inductance, and the preset operating cycle of the power conversion circuit.

[0149] Specifically, the actual high-side DC voltage V HV , the actual high-side DC current I HV , and the primary leakage inductance Lk and the preset duty cycle T s Substitute into so as to calculate the actual output power P out .

[0150] Step S45: When the gain is greater than 1, calculate the actual output power according to the actual high-voltage side DC voltage, the actual high-voltage side DC current, the actual low-voltage side DC voltage, the primary leakage inductance, the turns ratio, and the preset duty cycle of the power conversion circuit.

[0151] Specifically, the actual high-voltage side DC voltage V HV , the actual high-voltage side DC current I HV , the actual low-voltage side DC voltage V LV , the primary leakage inductance L k , the turns ratio n, and the preset duty cycle T s Substitute into so as to calculate the actual output power P out .

[0152] It should be understood that if the gain is equal to 1, the actual output power can be calculated by referring to the calculation process when the gain is less than 1, or the actual output power can be calculated by referring to the calculation process when the gain is greater than 1. Specifically, it can be selected according to the actual situation and is not specifically limited here.

[0153] Furthermore, steps S32 to S34 can be executed to determine the working mode of the power conversion circuit.

[0154] Furthermore, step S22 can be executed to obtain the prediction relationship corresponding to the working mode, and step S23 can be executed to obtain the predicted value of the first external shift ratio.

[0155] Specifically, as described above, the relationship between the first external shift ratio Df of the power conversion circuit 10 and the operating condition parameters can be shown as the foregoing formula (4).

[0156] Therefore, if P calculated in step S21 out < P crit , and the working mode is determined to be the light load mode, then the prediction relationship corresponding to the light load mode obtained in step S22 is:[[]]

[0157] If P calculated in step S21 out > P crit , and the working mode is determined to be the heavy load mode, then the prediction relationship corresponding to the heavy load mode obtained in step S22 is:[[]]

[0158] Furthermore, in step S23, the actual output power P out , the actual high-voltage side DC voltage VHV 1. The actual DC voltage V on the low-voltage side LV 2. The turns ratio n and the corresponding prediction relationship, and calculate the predicted value of the first external shift ratio.

[0159] Among them, in the calculation process, the actual DC voltage V on the high-voltage side can be first HV 1. The actual DC voltage V on the low-voltage side LV 2. The turns ratio n are substituted into Equation (2) to calculate the gain d, and then the actual output power P out and the gain d are substituted into the corresponding prediction relationship, so as to calculate the predicted value of the first external shift ratio.

[0160] It can be seen that according to the output power of the power conversion circuit 10 and the expression of the first external shift ratio, different operating modes can be accurately distinguished, and the actual output power, critical output power and predicted value of the first external shift ratio suitable for the current operating mode can be accurately and quickly calculated according to the expression corresponding to the current operating mode. Moreover, the calculation process is very simple, which is beneficial to reducing the control complexity and improving the implementability of the method.

[0161] It can be understood that these expressions can be recorded and pre-stored in the internal memory or external memory of the controller 40 for easy acquisition and use. Different power conversion circuits 10 have corresponding expressions of output power and first external shift ratio. Therefore, for different power conversion circuits 10, the specific calculation methods of actual output power and critical output power, and the specific calculation method of the predicted value of the first external shift ratio can all be adjusted according to the actual circuit, and are all within the protection scope of this application.

[0162] In some embodiments, the target parameter in step S13 may include the target DC voltage on the high-voltage side. Furthermore, please refer to Figure 11 , in step S13, obtaining the adjustment value of the first external shift ratio according to the operating condition parameters and target parameters of the power conversion circuit includes:

[0163] Step S51: Calculate the voltage difference between the target DC voltage on the high-voltage side and the actual DC voltage on the high-voltage side.

[0164] That is, subtract the actual DC voltage V HV_target on the high-voltage side from the target DC voltage V HV on the high-voltage side, and the voltage difference △V can be obtained, △V = V HV_target - V HV .

[0165] Step S52: Perform deviation adjustment on the voltage difference to obtain the adjustment value of the first external shift ratio.

[0166] Among them, the voltage difference △V can be subjected to PI (Proportion Integration) regulation, PID (Proportion Integration Differentiation) regulation, or other regulation processes to obtain the regulation value △Df of the first external shift ratio.

[0167] It can be understood that the above process obtains the regulation value △Df of the first external shift ratio through the voltage loop. Among them, a deviation regulation algorithm is used, which can help improve the control accuracy and control speed, and is beneficial to quickly adjusting the appropriate regulation value △Df of the first external shift ratio.

[0168] It should be understood that in other embodiments, the regulation value △Df of the first external shift ratio can also be obtained by selecting other target parameters and other loops according to the actual situation, such as a current loop, a voltage-current loop, or a power loop, and is not limited to the implementation methods mentioned in this embodiment.

[0169] In some embodiments, considering that the first duty cycle D1, the second duty cycle D2, and the second external shift ratio D3 directly affect the conduction duration and conduction timing of the switching tubes in the power conversion circuit 10, therefore, in step S15, the first duty cycle D1, the second duty cycle D2, and the second external shift ratio D3 can be determined first according to the target value of the first external shift ratio, and then the first duty cycle D1, the second duty cycle D2, and the second external shift ratio D3 are applied to the control of the power conversion circuit 10.

[0170] Specifically, please refer to Figure 12 , the process of generating a control signal according to the target value of the first external shift ratio in step S15 may include:

[0171] Step S61: Calculate the first duty cycle and the second duty cycle according to the target value of the first external shift ratio.

[0172] It can be understood that since both the first duty cycle D1 and the second duty cycle D2 are related to the first external shift ratio Df, therefore, the first duty cycle D1 and the second duty cycle D2 can be calculated according to the target value Df_target of the first external shift ratio.

[0173] Step S62: Calculate the second external shift ratio according to the target value of the first external shift ratio, the first duty cycle, and the second duty cycle.

[0174] It can be understood that since there is a certain linear relationship among the first duty cycle D1, the second duty cycle D2, the first external shift ratio Df, and the second external shift ratio D3, therefore, the second external shift ratio D3 can be calculated according to the target value Df_target of the first external shift ratio, the first duty cycle D1, and the second duty cycle D2.

[0175] Step S63: Generate a control signal based on the second external shift ratio, the first duty cycle, and the second duty cycle.

[0176] It can be understood that since there is a linear relationship among the second external shift ratio D3, the first duty cycle D1, the second duty cycle D2, and the first external shift ratio Df, when the second external shift ratio, the first duty cycle, and the second duty cycle are determined, the first external shift ratio Df is also determined. Therefore, step S63 can also be regarded as generating a control signal based on the second external shift ratio D3, the first duty cycle D1, the second duty cycle D2, and the first external shift ratio Df.

[0177] Among them, the control signal can be a Pulse Width Modulation (PWM) signal, which can be used to control the on / off state of the switching tube in the power conversion circuit 10.

[0178] For better understanding, the following uses Figure 3 of the power conversion circuit 10 to further illustrate steps S61 - S63 by way of example.

[0179] As mentioned above, Figure 3 the relationship between the first duty cycle D1 and the first external shift ratio Df of the power conversion circuit 10 of

[0180] can be as shown in the aforementioned formula (6), the relationship between the second duty cycle D2 and the first external shift ratio Df can be as shown in the aforementioned formula (7), and the relationship among the first duty cycle D1, the second duty cycle D2, the second external shift ratio D3, and the first external shift ratio Df can be as shown in the aforementioned formula (8). Figure 13 Therefore, referring to

[0181] Step S71: Calculate the critical value of the first external shift ratio according to the operating condition parameters.

[0182] Specifically, the actual high - voltage - side DC voltage V HV and the actual low - voltage - side DC voltage V LV and the turns ratio n can be substituted into formula (5) to calculate the critical value Df_crit of the first external shift ratio. Among them, in the calculation process, the actual high - voltage - side DC voltage V HV and the actual low - voltage - side DC voltage V LV and the turns ratio n can be substituted into formula (2) to calculate the gain d, and then the gain d is substituted into formula (5), so as to calculate the critical value Df_crit of the first external shift ratio.

[0183] Step S72: Determine the target mapping relationship according to the magnitude relationship between the target value of the first external shift ratio and the critical value of the first external shift ratio. The target mapping relationship is the mapping relationship between the first external shift ratio and the first duty cycle and the second duty cycle.

[0184] Specifically, according to equations (6) and (7), it can be known that the target mapping relationship may include:

[0185] When the target value of the first external shift ratio is less than the critical value of the first external shift ratio, that is, Df_target < Df_crit, The working mode in this case corresponds to the light load mode.

[0186] When the target value of the first external shift ratio is greater than the critical value of the first external shift ratio, that is, Df_target > Df_crit, D2 = 1. The working mode in this case corresponds to the heavy load mode.

[0187] It should be understood that if Df_target = Df_crit, the target mapping relationship of Df_target < Df_crit can be referred to, or the target mapping relationship of Df_target > Df_crit can be referred to. It can be specifically selected according to the actual situation and is not specifically limited here.

[0188] Step S73: Determine the first duty cycle and the second duty cycle according to the target value of the first external shift ratio and the target mapping relationship.

[0189] It can be understood that since the specific magnitude of Df_target has been calculated in the aforementioned step S14, and the specific magnitude of the critical value Df_crit of the first external shift ratio has been calculated in the aforementioned step S71, the first duty cycle and the second duty cycle can be calculated according to Df_target, the critical value Df_crit of the first external shift ratio, and the target mapping relationship in step S72.

[0190] In this process, if the calculated Df_target < Df_crit, the actual output power Pout and the gain d can be substituted into to calculate the first duty cycle D1, and substituted into to calculate the second duty cycle D2.

[0191] If the calculated Df_target > Df_crit, the actual output power Pout and the gain d can be substituted into to calculate the first duty cycle D1, and the second duty cycle D2 can be obtained according to D2 = 1.

[0192] Furthermore, in step S62, the target value Df_target of the first external shift ratio, the first duty cycle D1, and the second duty cycle D2 can be substituted into Equation (8) to calculate the second external shift ratio D3.

[0193] It can be seen that according to the duty cycle related expressions of the power conversion circuit 10, corresponding expressions can be selected according to the size of the target value of the first external shift ratio to accurately and quickly calculate the appropriate first duty cycle and second duty cycle. Furthermore, the second external shift ratio is calculated based on the first duty cycle, the second duty cycle, and the target value of the first external shift ratio, so that the first duty cycle, the second duty cycle, the second external shift ratio, and the target value of the first external shift ratio can all be adapted to the current working mode of the power conversion circuit 10. Moreover, the calculation process is very simple, which is beneficial to reducing the control complexity and improving the feasibility of the method.

[0194] It can be understood that these expressions can be recorded and pre-stored in the internal memory or external memory of the controller 40 for easy acquisition and use. Different power conversion circuits 10 have corresponding expressions related to the first duty cycle, the second duty cycle, and the second external shift ratio. Therefore, for different power conversion circuits 10, the specific calculation methods of the first duty cycle, the second duty cycle, and the second external shift ratio can all be adjusted according to the actual circuit, and all are within the protection scope of this application.

[0195] In addition, in order to verify the improvement effect of the control method of the embodiment of this application on the dynamic response speed of the power conversion circuit 10, a simulation experiment was also carried out.

[0196] In the simulation experiment, the power conversion circuit 10 is Figure 3 the circuit shown. Among them, the second end of the high-voltage side bridge circuit 11 is connected to an inverter through the bus, and the working state of the inverter changes from charging to discharging. At this time, for the bus, it is equivalent to instantaneously switching from charging the bus capacitor to discharging the bus capacitor. For the power conversion circuit 10, it is equivalent to instantaneously switching from inputting electrical energy to the second end of the high-voltage side bridge circuit 11 to outputting electrical energy from the second end of the high-voltage side bridge circuit 11, that is, the power conversion circuit 10 changes from charging to discharging.

[0197] Please refer to Figure 14 and Figure 15 , Figure 14 are the simulation waveform diagrams of the AC voltage and AC current of the inverter and the bus voltage when the power conversion circuit 10 does not adopt the control method of the embodiment of this application. Figure 15When the control method of the embodiment of the present application is adopted in the power conversion circuit 10, the simulation waveform diagrams of the AC voltage, AC current, and bus voltage of the inverter are shown. The working conditions of these two experiments are kept consistent. It should be understood that the data on the horizontal and vertical coordinates are only for illustration and can be different in different experiments, which does not constitute a limitation to the present application.

[0198] In Figure 14 and Figure 15 , the AC voltage Vac and the bus voltage Vbus are represented by solid lines, and the AC current Iac is represented by dashed lines. In fact, the bus voltage Vbus is actually the actual high-side DC voltage V HV .

[0199] From Figure 14 and Figure 15 , it can be seen that in both of these two experiments, the inverter instantaneously switches from the charging state to the discharging state at 1.0 s, causing the bus voltage to drop. Moreover, compared with Figure 14 , Figure 15 , the drop amplitude of the bus voltage in

[0200] is significantly smaller, and the duration to recover to the steady state is shorter. This is mainly because, when the control method of the embodiment of the present application is adopted in the power conversion circuit 10, the dynamic response speed of the power conversion circuit 10 can be faster, making the dynamic response speed of the bus voltage faster accordingly. Therefore, the voltage dip of the bus voltage is smaller, and the time taken to recover to the steady state is shorter.

[0201] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously.

[0202] In addition, the controller 40 can also implement the control method of the power conversion circuit shown in Figure 16 through the control loop shown in Figures 7 to 13 .

[0203] As shown in Figure 16 , the controller 40 includes an actual output power calculator 401, a critical output power calculator 402, a first selector 403, a first predicted value calculator 404, a second predicted value calculator 405, a subtractor 406, a deviation controller 407, an adder 408, a critical value calculator 409, a second selector 410, a first calculator 411, a second calculator 412, a third calculator 413, and a modulator 414.

[0204] Specifically, the actual high-voltage side DC voltage V HV , the actual low-voltage side DC voltage V LV , the actual high-voltage side DC current I HV , the primary leakage inductance L of the transformer Tr k and the turn ratio n, the preset duty cycle T s These operating condition parameters are all input into the actual output power calculator 401, and the actual output power calculator 401 outputs the actual output power P out to the first selector 403.

[0205] The actual high-voltage side DC voltage V HV , the actual low-voltage side DC voltage V LV and the turn ratio n of these operating condition parameters are all input into the critical output power calculator 402, and the critical output power calculator 402 outputs the critical output power P crit to the first selector 403.

[0206] The first selector 403 compares the actual output power P out and the critical output power P crit , and when P out < P crit , it selects the first predicted value calculator 404 to generate the predicted value Df_predict of the first external shift ratio. When P out > P crit , it selects the second predicted value calculator 405 to generate the predicted value Df_predict of the first external shift ratio. The calculation methods of the second predicted value calculator 405 and the first predicted value calculator 404 are different.

[0207] When the first predicted value calculator 404 is selected, the actual output power P out , the actual high-voltage side DC voltage V HV , the actual low-voltage side DC voltage V LV and the turn ratio n are input into the first predicted value calculator 404, and the first predicted value calculator 404 can thus calculate the predicted value Df_predict of the first external shift ratio according to the actual output power P out , the actual high-voltage side DC voltage V HV , the actual low-voltage side DC voltage V LV and the turn ratio n and transmit it to the adder 408.

[0208] When the second predicted value calculator 405 is selected, the actual output power P out , the actual high-voltage side DC voltage V HV , the actual low-voltage side DC voltage V LVThe turns ratio n and the input are applied to the second predicted value calculator 405, and the second predicted value calculator 405 can thereby calculate the predicted value Df_predict of the first external shift ratio based on the actual output power P out 、the actual high-side DC voltage V HV 、the actual low-side DC voltage V LV and the turns ratio n, and transmit it to the adder 408.

[0209] In addition, the actual high-side DC voltage V HV and the target high-side DC voltage V HV_target are input to the subtractor 406. The subtractor 406 subtracts the target high-side DC voltage V HV_target from the actual high-side DC voltage V HV to obtain the voltage difference △V, and transmits the voltage difference △V to the deviation controller 407. The deviation controller 407 performs deviation processing on the voltage difference △V to obtain the adjustment value △Df of the first external shift ratio and outputs it to the adder 408.

[0210] The adder 408 adds the predicted value Df_predict of the first external shift ratio and the adjustment value △Df of the first external shift ratio to obtain the target value Df_target of the first external shift ratio, and outputs the target value Df_target of the first external shift ratio to the second selector 410.

[0211] The actual high-side DC voltage V HV 、the actual low-side DC voltage V LVk and the turns ratio n, these operating condition parameters are all input to the threshold calculator 409. The threshold calculator 409 outputs the threshold Df_crit of the first external shift ratio to the second selector 410 according to the input operating condition parameters.

[0212] The second selector 410 compares the target value Df_target of the first external shift ratio with the threshold Df_crit of the first external shift ratio. When Df_target < Df_crit, it selects the first calculator 411 to generate the first duty ratio D1 and the second duty ratio D2. When Df_target > Df_crit, it selects the second calculator 412 to generate the first duty ratio D1 and the second duty ratio D2, where the calculation methods of the second calculator 412 and the first calculator 411 are different.

[0213] When the first calculator 411 is selected, the actual output power Pout, the actual high-side DC voltage V HV 、the actual low-side DC voltage V LV and the turns ratio n are input to the first calculator 411. The first calculator 411 can thereby calculate according to the actual output power P out 、the actual high-side DC voltage V HV, the actual DC voltage V on the low-voltage side LV and the turns ratio n output the first duty cycle D1 and the second duty cycle D2 to the third arithmetic unit 413.

[0214] When the second arithmetic unit 412 is selected, the actual output power Pout, the actual DC voltage V on the high-voltage side HV , the actual DC voltage V on the low-voltage side LV and the turns ratio n are input to the second arithmetic unit 412, and the second arithmetic unit 412 can thus output the first duty cycle D1 and the second duty cycle D2 to the third arithmetic unit 413 according to the actual output power P out , the actual DC voltage V on the high-voltage side HV , the actual DC voltage V on the low-voltage side LV and the turns ratio n.

[0215] The target value Df_target of the first external shift ratio is also input to the third arithmetic unit 413. The third arithmetic unit 413 can thus output the second external shift ratio D3 to the modulator 414 according to the target value Df_target of the first external shift ratio, the first duty cycle D1 and the second duty cycle D2.

[0216] The first duty cycle D1 and the second duty cycle D2 are also input to the modulator 414. Finally, the modulator 414 can generate the control signal of the power conversion circuit 10 according to the second external shift ratio D3, the first duty cycle D1 and the second duty cycle D2.

[0217] It should be understood that each link in the above control loop can also refer to the relevant descriptions in the foregoing method embodiments.

[0218] The control loop described above is only a schematic example provided by this application. The specific composition of the control loop can be adjusted accordingly according to the actual situation, and is not limited to the implementation manner mentioned in this application.

[0219] Please refer to Figure 17 , which is a schematic diagram of a power conversion device provided by an embodiment of this application.

[0220] As Figure 17 shown, the power conversion device 100 may include a power conversion circuit 10 and a controller 40. The power conversion circuit 10 may be the power conversion circuit 10 shown in Figures 1 to 3 . The power conversion circuit 10 is connected to the controller 40. The controller 40 can be used to execute the control method of the above power conversion circuit to control the energy conversion of the power conversion circuit 10, so that the power conversion circuit 10 can follow the dynamic changes of the working conditions and has good dynamic response capabilities.

[0221] Among them, the power conversion circuit 10 and the controller 40 can be integrated or separated, and the embodiments of the present application do not limit this. For the relevant descriptions of the power conversion circuit 10 and the controller 40, reference can also be made to Figures 1 to 3 For the relevant descriptions of the power conversion circuit, reference can also be made to the relevant descriptions in the foregoing method embodiments of the control method of the power conversion circuit, which will not be repeated here.

[0222] Please refer to Figure 18 , which is a schematic diagram of an energy storage device provided by an embodiment of the present application. The energy storage device 200 can be applied to any energy storage system, such as a photovoltaic energy storage system, etc., and is not limited here.

[0223] As Figure 18 shown, the energy storage device 200 may include an energy storage battery 50, a power conversion circuit 10, and a controller 40. The power conversion circuit 10 may be the Figures 1 to 3 power conversion circuit 10 shown. The low-voltage side bridge circuit 12 of the power conversion circuit 10 is connected to the energy storage battery 50, and both the high-voltage side bridge circuit 11 and the low-voltage side bridge circuit 12 of the power conversion circuit 10 are connected to the controller 40. The controller 40 can be used to execute the above control method of the power conversion circuit.

[0224] Among them, the energy storage battery 50 can be used as a load of the power conversion circuit 10. Under the control of the controller 40, the power conversion circuit 10 can operate forward to charge the energy storage battery 50. The energy storage battery 50 can also be used as a power source of the power conversion circuit 10. Under the control of the controller 40, the power conversion circuit 10 can operate in reverse to obtain electrical energy from the energy storage battery 50. Whether in the forward operation process, the reverse operation process, or during the forward and reverse switching, the power conversion circuit 10 can quickly respond to the changes in the working conditions. Therefore, the energy storage device 200 can have better dynamic response performance.

[0225] Among them, the energy storage battery 50, the power conversion circuit 10, and the controller 40 can be integrally arranged or at least partially integrated together, and the embodiments of the present application do not limit this. For the relevant descriptions of the power conversion circuit 10 and the controller 40, reference can also be made to Figures 1 to 3 For the relevant descriptions of the power conversion circuit, reference can also be made to the relevant descriptions in the foregoing method embodiments of the control method of the power conversion circuit, which will not be repeated here.

[0226] Please refer to Figure 19 , which shows a schematic structural diagram of an electronic device provided by an embodiment of the present application.

[0227] As Figure 19 shown, the electronic device 300 may include a processor 301 and a memory 302.

[0228] The processor 301 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0229] The memory 302 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or may also be an Electrically Erasable Programmable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory (CD-ROM), or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 302 may exist independently and be connected to the processor 301 through a bus. The memory 302 may also be integrated with the processor 301.

[0230] Among them, the memory 302 is used to store the programs, instructions, or codes for executing the above control method of the power conversion circuit. The processor 301 is used to execute the programs, instructions, or codes stored in the memory 302. The programs, instructions, or codes stored in the memory 302 can execute some or all of the steps in the above embodiments of the control method of the power conversion circuit.

[0231] Please refer to Figure 20 , which shows a schematic diagram of a control device for a power conversion circuit provided by an embodiment of the present application. The control device 400 of this DC converter can be used to implement the above control method of the power conversion circuit.

[0232] Specifically, as Figure 20As shown in the figure, the control device 400 of the power conversion circuit includes: an acquisition module 401, a prediction module 402, a first calculation module 403, a second calculation module 404, and a generation module 405.

[0233] The acquisition module 401 is configured to acquire the operating condition parameters of the power conversion circuit.

[0234] The prediction module 402 is configured to obtain a predicted value of the first external shift ratio according to the operating condition parameters. The first external shift ratio is the duty cycle corresponding to the time difference between the fundamental wave of the midpoint voltage of the bridge arm of the high-voltage side bridge circuit and the fundamental wave of the midpoint voltage of the bridge arm of the low-voltage side bridge circuit.

[0235] The first calculation module 403 is configured to obtain an adjustment value of the first external shift ratio according to the operating condition parameters and the target parameters of the power conversion circuit.

[0236] The second calculation module 404 is configured to obtain a target value of the first external shift ratio according to the predicted value and the adjustment value of the first external shift ratio.

[0237] The generation module 405 is configured to generate a control signal according to the target value of the first external shift ratio. The control signal is used to control the power conversion circuit to perform energy conversion.

[0238] It can be understood that the division of each module in the above control device 400 of the power conversion circuit is only for illustrative purposes. In other embodiments, the control device 400 of the power conversion circuit can be divided into different modules as needed to complete all or part of the functions of the above control device 400.

[0239] For the specific implementation of each module in the embodiments of the present application, reference can also be made to the corresponding descriptions in the foregoing method embodiments, so details are not described herein again.

[0240] In each embodiment of the present application, all the functional modules can be integrated in one processing module / unit, or each module can be separately used as one module, or two or more modules can be integrated in one module; the above integrated modules can be implemented in the form of hardware, or in the form of a combination of hardware and software functional modules.

[0241] If the above integrated module of the present application is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the embodiments of the present application, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: various media that can store program codes, such as removable storage devices, ROM, RAM, magnetic disks, or optical discs.

[0242] The embodiments of the present application also provide a computer-readable storage medium for storing a computer program or code. When the computer program or code is loaded and executed by a processor, all or part of the steps in the embodiments of the above control method of the power conversion circuit are implemented. Among them, the computer-readable storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). For the specific implementation manner of the computer-readable storage medium, reference can be made to the description of the memory 302 in Figure 19 and details are not described herein again.

[0243] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A control method for a power conversion circuit, characterized in that The power conversion circuit includes a high-voltage side bridge circuit, a low-voltage side bridge circuit, and a transformer. The high-voltage side bridge circuit is connected to the primary side of the transformer, and the low-voltage side bridge circuit is connected to the secondary side of the transformer. The control method includes: Obtaining the operating condition parameters of the power conversion circuit; Obtaining a predicted value of a first external shift ratio according to the operating condition parameters; the first external shift ratio is the duty ratio corresponding to the time difference between the fundamental wave of the midpoint voltage of the bridge arm of the high-voltage side bridge circuit and the fundamental wave of the midpoint voltage of the bridge arm of the low-voltage side bridge circuit; Obtaining an adjustment value of the first external shift ratio according to the operating condition parameters and target parameters of the power conversion circuit; Obtaining a target value of the first external shift ratio according to the predicted value and the adjustment value of the first external shift ratio; Generating a control signal according to the target value of the first external shift ratio; the control signal is used to control the power conversion circuit to perform energy conversion.

2. The control method according to claim 1, wherein The obtaining the predicted value of the first external shift ratio according to the operating condition parameters includes: Determining the current operating mode of the power conversion circuit according to the operating condition parameters; Obtaining a corresponding prediction relationship according to the operating mode; different operating modes correspond to different prediction relationships of the first external shift ratio; Obtaining the predicted value of the first external shift ratio according to the operating condition parameters and the prediction relationship.

3. The control method according to claim 2, characterized in that, The operating mode includes a light load mode and a heavy load mode. The determining the current operating mode of the power conversion circuit according to the operating condition parameters includes: Calculating the actual output power and the critical output power of the power conversion circuit according to the operating condition parameters; When the actual output power is higher than the critical output power, determining the operating mode as the heavy load mode; When the actual output power is lower than the critical output power, determining the operating mode as the light load mode.

4. The control method according to claim 3, wherein The operating condition parameters include the actual high-voltage side DC voltage, the actual low-voltage side DC voltage, the actual high-voltage side DC current, the primary side leakage inductance of the transformer, and the turns ratio; The calculating the actual output power and the critical output power of the power conversion circuit according to the operating condition parameters includes: Calculating a gain according to the actual high-voltage side DC voltage, the actual low-voltage side DC voltage, and the turns ratio; Calculating the critical output power according to the gain; When the gain is less than 1, calculating the actual output power according to the actual high-voltage side DC voltage, the actual high-voltage side DC current, the primary side leakage inductance, and the preset operating cycle of the power conversion circuit; or, When the gain is greater than 1, calculating the actual output power according to the actual high-voltage side DC voltage, the actual high-voltage side DC current, the actual low-voltage side DC voltage, the primary side leakage inductance, the turns ratio, and the preset operating cycle of the power conversion circuit.

5. The control method according to claim 2, characterized in that The operating condition parameters include the actual output power, the high-voltage side DC voltage, the low-voltage side DC voltage, and the turns ratio of the transformer; The obtaining the predicted value of the first external shift ratio according to the operating condition parameters and the prediction relationship includes: Based on the actual output power, the actual high-voltage side DC voltage, the actual low-voltage side DC voltage, the turns ratio, and the prediction relationship, a predicted value of the first external shift ratio is calculated.

6. The control method according to claim 1, characterized in that The generating the control signal according to the target value of the first external shift ratio includes: Calculating a first duty cycle and a second duty cycle according to the target value of the first external shift ratio; the first duty cycle is the duty cycle of the midpoint voltage waveform of the arm of the high-voltage side bridge circuit; the second duty cycle is the duty cycle of the midpoint voltage waveform of the arm of the low-voltage side bridge circuit; Calculating a second external shift ratio according to the target value of the first external shift ratio, the first duty cycle, and the second duty cycle; the second external shift ratio is the duty cycle corresponding to the time difference between the midpoint voltage waveform of the arm of the high-voltage side bridge circuit and the midpoint voltage waveform of the arm of the low-voltage side bridge circuit; Generating the control signal according to the second external shift ratio, the first duty cycle, and the second duty cycle.

7. The control method according to claim 6, wherein The calculating the first duty cycle and the second duty cycle according to the target value of the first external shift ratio includes: Calculating a critical value of the first external shift ratio according to the operating condition parameters; Determining a target mapping relationship according to the magnitude relationship between the target value of the first external shift ratio and the critical value of the first external shift ratio; the target mapping relationship is the mapping relationship between the first external shift ratio and the first duty cycle, the second duty cycle; Determining the first duty cycle and the second duty cycle according to the target value of the first external shift ratio and the target mapping relationship.

8. The control method according to claim 1, wherein The operating condition parameters include the actual high-voltage side DC voltage, and the target parameters include the target high-voltage side DC voltage; The obtaining the adjustment value of the first external shift ratio according to the operating condition parameters and the target parameters of the power conversion circuit includes: Calculating the voltage difference between the target high-voltage side DC voltage and the actual high-voltage side DC voltage; Performing deviation adjustment on the voltage difference to obtain the adjustment value of the first external shift ratio.

9. A power conversion device, characterized in that, The power conversion device includes a power conversion circuit and a controller, and the controller is configured to execute the control method of the power conversion circuit according to any one of claims 1 to 8.

10. An energy storage device, characterized in that, The energy storage device includes an energy storage battery, a power conversion circuit, and a controller. The energy storage battery is connected to the low-voltage side bridge circuit of the power conversion circuit, and the controller is configured to execute the control method of the power conversion circuit according to any one of claims 1 to 8.

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