Control method of power conversion circuit and power conversion device

Abstract

The application provides a control method of a power conversion circuit and a power conversion device. The method obtains an inner phase shift angle of a primary bridge circuit and an outer phase shift angle between the primary bridge circuit and a secondary bridge circuit. When it is confirmed that the edge of a first control signal exceeds the carrier cycle range according to the inner phase shift angle and the outer phase shift angle, the starting point comparison value corresponding to the first control signal and a second control signal is adjusted to limit the edge of the first control signal in the carrier cycle range. Then, the first control signal and the second control signal are updated according to the adjusted starting point comparison value. The waveform of the updated first control signal and the second control signal is normal and complete, so that the normal output of the power conversion circuit can be ensured.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a control method and a power conversion device for a power conversion circuit. Background Technology

[0002] In related technologies, a carrier counter is used to count carrier waves, and a PWM signal is generated based on the comparison result between the carrier count value and the corresponding comparison value. When the carrier count value reaches the comparison value, the PWM signal undergoes a level flip, generating a rising or falling edge accordingly. In scenarios involving multiple phase-shift modulation in power conversion circuits (such as dual active bridge converters), improper PWM modulation can easily lead to partial loss of the primary-side PWM signal waveform, causing changes in the duty cycle, a reduction in the phase shift angle adjustment range, and ultimately, abnormal output from the power conversion circuit. Summary of the Invention

[0003] Therefore, this application provides a control method and a power conversion device for a power conversion circuit, which can prevent the loss of PWM signal and ensure the normal output of the power conversion circuit.

[0004] This application provides a control method for a power conversion circuit, the power conversion circuit including a primary-side bridge circuit, a secondary-side bridge circuit, and a transformer, the primary-side bridge circuit being connected to the primary side of the transformer, and the secondary-side bridge circuit being connected to the secondary side of the transformer; the control method includes: acquiring the inner phase shift angle of the primary-side bridge circuit and the outer phase shift angle between the primary-side bridge circuit and the secondary-side bridge circuit; when it is confirmed based on the inner and outer phase shift angles that the edge of a first control signal exceeds the carrier period range, adjusting the starting point comparison values ​​corresponding to the first control signal and the second control signal to limit the edge of the first control signal within the carrier period range; wherein, the first control signal is used to control the primary-side bridge circuit; the second control signal is used to control the secondary-side bridge circuit; the starting point comparison value corresponding to the first control signal is used to indicate the starting edge of the first control signal within the carrier period range, and the starting point comparison value corresponding to the second control signal is used to indicate the starting edge of the second control signal within the carrier period range; and updating the first control signal and the second control signal based on the adjusted starting point comparison values.

[0005] In the control method of the power conversion circuit of this application, by obtaining the inner phase shift angle of the primary bridge circuit and the outer phase shift angle between the primary bridge circuit and the secondary bridge circuit, and confirming that the edge of the first control signal exceeds the carrier period range based on the inner and outer phase shift angles, the starting point comparison values ​​corresponding to the first and second control signals are adjusted to limit the edge of the first control signal within the carrier period range. Then, the first and second control signals are updated based on the adjusted starting point comparison values, so that the waveform of the updated first control signal is complete and the duty cycle and phase shift angle meet expectations. Therefore, when the updated first and second control signals are used to control the power conversion circuit, the power conversion circuit can output normally.

[0006] In one embodiment, when it is confirmed that the edge of the first control signal exceeds the carrier period range based on the inner and outer phase shift angles, adjusting the starting point comparison values ​​corresponding to the first and second control signals includes: when the edge of the first control signal exceeds the carrier period range, adjusting the starting point comparison values ​​corresponding to the first and second control signals according to a first adjustment rule; the first adjustment rule is used to indicate that the starting point comparison value corresponding to the first control signal is associated with the inner phase shift angle, and the starting point comparison value corresponding to the second control signal is associated with both the inner and outer phase shift angles.

[0007] In one embodiment, the primary-side bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, and the secondary-side bridge circuit includes a third bridge arm and a fourth bridge arm connected in parallel; the starting point comparison value corresponding to the first control signal of the first bridge arm is a first starting point comparison value; the starting point comparison value corresponding to the first control signal of the second bridge arm is a second starting point comparison value; the starting point comparison value corresponding to the second control signals of the third and fourth bridge arms is a third starting point comparison value; accordingly, adjusting the starting point comparison values ​​corresponding to the first and second control signals according to the first adjustment rule includes: when the outward phase angle is greater than 0, setting the first starting point comparison value to a first set value; adjusting the second starting point comparison value according to the first starting point comparison value and the inward phase angle; adjusting the third starting point comparison value according to the second starting point comparison value, the inward phase angle, and the outward phase angle; and / or, when the outward phase angle is less than or equal to 0, setting the second starting point comparison value to a second set value; adjusting the first starting point comparison value according to the second starting point comparison value and the inward phase angle; adjusting the third starting point comparison value according to the first starting point comparison value, the inward phase angle, and the outward phase angle.

[0008] In one embodiment, the method further includes: when the edge of the first control signal does not exceed the carrier period range, determining the starting point comparison value corresponding to the first control signal and the second control signal according to the second adjustment rule; wherein the second adjustment rule is used to indicate that the starting point comparison value corresponding to the first control signal is associated with the inner phase shift angle and the outer phase shift angle, and the starting point comparison value corresponding to the second control signal is a third set value.

[0009] In one embodiment, the primary-side bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, and the secondary-side bridge circuit includes a third bridge arm and a fourth bridge arm connected in parallel; the starting point comparison value corresponding to the first control signal of the first bridge arm is a first starting point comparison value; the starting point comparison value corresponding to the first control signal of the second bridge arm is a second starting point comparison value; the starting point comparison value corresponding to the second control signals of the third and fourth bridge arms is a third starting point comparison value; correspondingly, determining the starting point comparison value corresponding to the first control signal and the second control signal according to the second adjustment rule includes: when the outward phase angle is greater than 0, determining the first starting point comparison value based on the inward phase angle and the outward phase angle; determining the second starting point comparison value based on the first preset value, the inward phase angle, and the outward phase angle; setting the third starting point comparison value to a third set value; when the outward phase angle is less than or equal to 0, determining the first starting point comparison value based on the inward phase angle; determining the second starting point comparison value based on the second preset value, the inward phase angle, and the outward phase angle; setting the third starting point comparison value to a third set value.

[0010] In one embodiment, the method further includes: calculating a phase angle variable based on an inner phase angle and an outer phase angle; and determining whether the edge of the first control signal is within the carrier period range based on the phase angle variable and the outer phase angle.

[0011] In one embodiment, calculating the phase angle variable based on the inner phase angle and the outer phase angle includes: when the outer phase angle is greater than 0, obtaining a first product of the inner phase angle and a first coefficient; calculating the difference between the first product and the outer phase angle to obtain the phase angle variable; when the outer phase angle is less than or equal to 0, obtaining a second product of the inner phase angle and a second coefficient, and obtaining the sum of the second product and the outer phase angle; and calculating the difference between a third preset value and the sum to obtain the phase angle variable.

[0012] In one embodiment, determining whether the edge of the first control signal exceeds the carrier period range based on the phase angle variable and the outward phase angle includes: determining that the edge of the first control signal exceeds the carrier period range when the outward phase angle is greater than 0 and the phase angle variable is less than 0, or when the outward phase angle is less than 0 and the phase angle variable is greater than 1.

[0013] In one embodiment, the method further includes: determining that the edge of the first control signal is outside the carrier period range when the outer phase angle is greater than half of the inner phase angle; and / or determining that the edge of the first control signal is within the carrier period range when the outer phase angle is less than or equal to half of the inner phase angle.

[0014] The second aspect of this application provides a power conversion device, including a power conversion circuit and a controller. The power conversion circuit includes a primary-side bridge circuit, a secondary-side bridge circuit, and a transformer. The primary-side bridge circuit is connected to the primary side of the transformer, and the secondary-side bridge circuit is connected to the secondary side of the transformer. The controller is used to execute the control method of the power conversion circuit described in the first aspect or any embodiment of the first aspect.

[0015] A third aspect of this application provides an energy storage device, including an energy storage battery and the power conversion device described in the second aspect.

[0016] The fourth aspect of this application provides an electronic device, including a processor and a memory, wherein the memory is used to store programs, instructions or code, and the processor is used to execute the programs, instructions or code in the memory to perform the control method of the power conversion circuit described in the first aspect or any embodiment of the first aspect.

[0017] A fifth aspect of this application provides a control device, including an acquisition module, an adjustment module, and an update module. The acquisition module is used to acquire the inner phase shift angle of the primary-side bridge circuit and the outer phase shift angle between the primary-side bridge circuit and the secondary-side bridge circuit. The adjustment module is used to adjust the starting point comparison value corresponding to the first control signal and the second control signal when it is confirmed based on the inner and outer phase shift angles that the edge of the first control signal exceeds the carrier period range, so as to limit the edge of the first control signal within the carrier period range. The starting point comparison value is used to indicate the starting edge of the first control signal within the carrier period range. The first control signal is used to control the primary-side bridge circuit. The second control signal is used to control the secondary-side bridge circuit. The update module is used to update the first control signal and the second control signal based on the adjusted starting point comparison value.

[0018] The sixth aspect of this 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 embodiment of the first aspect.

[0019] Furthermore, the technical effects brought about by any of the embodiments in the second to sixth aspects can be found in the technical effects brought about by the different embodiments in the first aspect, and will not be repeated here. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a power conversion circuit provided in an embodiment of this application.

[0021] Figure 2 This is another schematic diagram of a power conversion circuit provided in an embodiment of this application.

[0022] Figure 3 This is a circuit diagram of a power conversion circuit provided in one embodiment of this application.

[0023] Figure 4 This is a circuit diagram of a power conversion circuit provided in another embodiment of this application.

[0024] Figure 5It is a waveform diagram of the carrier signal and PWM1 to PWM8 of the power conversion circuit.

[0025] Figure 6 This is another waveform diagram of the carrier signal and PWM1 to PWM8 of the power conversion circuit.

[0026] Figure 7 This is a flowchart of a control method for a power conversion circuit provided in an embodiment of this application.

[0027] Figure 8 This is a waveform diagram of the carrier signal and PWM1 to PWM8 of the power conversion circuit when the method of the embodiment of this application is adopted.

[0028] Figure 9 yes Figure 7 A detailed flowchart of step S12 in the process.

[0029] Figure 10 This is another flowchart of the control method for the power conversion circuit provided in one embodiment of this application.

[0030] Figure 11 This is another flowchart of the control method for the power conversion circuit provided in one embodiment of this application.

[0031] Figure 12 This is yet another flowchart of the control method for the power conversion circuit provided in one embodiment of this application.

[0032] Figure 13 yes Figure 12 A detailed flowchart of step S51 in the process.

[0033] Figure 14 Under wide range of output conditions, Figure 4 The power conversion circuit shown is a simulation waveform diagram when the method of the embodiment of this application is not used.

[0034] Figure 15 Under wide range of output conditions, Figure 4 The power conversion circuit shown is a simulation waveform diagram when the method of the embodiment of this application is used.

[0035] Figure 16 This is a schematic diagram of a power conversion device provided by one embodiment of the method of this application.

[0036] Figure 17 This is a schematic diagram of an energy storage device provided by one embodiment of the method of this application.

[0037] Figure 18 This is a schematic diagram of an electronic device provided in one embodiment of this application.

[0038] Figure 19 This is a schematic diagram of a control device provided in one embodiment of this application. Detailed Implementation

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

[0040] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include 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, and some steps can also be deleted.

[0041] Some embodiments will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] Figure 1 This is a schematic diagram of a power conversion circuit provided in an embodiment of this application. The power conversion circuit 10 includes a primary-side bridge circuit 11, a secondary-side bridge circuit 12, and a transformer 13. The first end of the primary-side bridge circuit 11 is connected to the primary side of the transformer 13, and the first end of the secondary-side bridge circuit 12 is connected to the secondary side of the transformer 13.

[0043] In a scenario, such as Figure 1 As shown, the second terminal of the primary-side bridge circuit 11 can be used as an input terminal to connect to the power supply 20. The second terminal of the secondary-side bridge circuit 12 serves as an output terminal to connect to the load 30. Based on this design, the power conversion circuit 10 can be used to convert the energy from the power supply 20 connected to the primary-side bridge circuit 11 to the load 30 connected to the secondary-side bridge circuit 12. Specifically, the energy from the power supply 20 is first converted by the primary-side bridge circuit 11 and then transmitted to the transformer 13. The magnetic field of the transformer 13 couples the energy to the secondary-side bridge circuit 12, where it is then converted again and transmitted to the load 30. In this case, the energy flow direction is from the primary-side bridge circuit 11 to the secondary-side bridge circuit 12.

[0044] In another scenario, such as Figure 2 As shown, the second terminal of the primary-side bridge circuit 11 can also serve as an output terminal, used to connect the load 30. The second terminal of the secondary-side bridge circuit 12 serves as an input terminal, used to connect the power supply 20. Based on this design, the power conversion circuit 10 can be used to convert the energy from the power supply 20 connected to the secondary-side bridge circuit 12 to the load 30 connected to the primary-side bridge circuit 11. In this case, the energy flow direction is from the secondary-side bridge circuit 12 to the primary-side bridge circuit 11. That is to say, the power conversion circuit 10 can operate bidirectionally, realizing bidirectional energy transfer.

[0045] The primary-side bridge circuit 11 can adopt a full-bridge topology, and the secondary-side bridge circuit 12 can also adopt a full-bridge topology or a half-bridge topology; no limitation is made here.

[0046] For ease of understanding, the following will be used as an example. Figure 3 and Figure 4 Two examples further illustrate the power conversion circuit 10.

[0047] exist Figure 3 In the example, both the primary-side bridge circuit 11 and the secondary-side bridge circuit 12 adopt a full-bridge topology. Specifically, the primary-side bridge circuit 11 includes a first bridge arm 111 and a second bridge arm 112 connected in parallel, wherein the first bridge arm 111 includes switches Q1 and Q2 connected in series, and the second bridge arm 112 includes switches Q3 and Q4 connected in series. The midpoint a of the first bridge arm 111 and the midpoint b of the second bridge arm 112 constitute the first end of the primary-side bridge circuit 11. The two ends of the first bridge arm 111 and the second bridge arm 112 constitute the second end of the primary-side bridge circuit 11.

[0048] The secondary-side bridge circuit 12 includes a third bridge arm 121 and a fourth bridge arm 122 connected in parallel. The third bridge arm 121 includes switches Q5 and Q6 connected in series, and the fourth bridge arm 122 includes switches Q7 and Q8 connected in series. The midpoint c of the third bridge arm 121 and the midpoint d of the fourth bridge arm 122 form the first terminal of the secondary-side bridge circuit 12. The two ends of the third bridge arm 121 and the fourth bridge arm 122 form the second terminal of the secondary-side bridge circuit 12.

[0049] The turns ratio of the primary winding to the secondary winding of transformer 13 can be n:1. In this example, transformer 13 is a step-down transformer, and n is a positive number greater than 1. Transformer 13 ( Figure 3 In the case of Tr), the original edge leakage inductance Lk1 is represented as Tr. For ease of understanding, Figure 3 The circuit diagram shows a primary leakage inductance Lk1, which is connected between the primary side of transformer 13 and the midpoint a of the bridge arm. In other embodiments, the primary leakage inductance Lk1 may also be independent of the transformer Tr.

[0050] Power supply 20 is a DC power supply, such as a photovoltaic power generation device. In some embodiments, power supply 20 can also be a circuit capable of outputting DC power, such as a DC-DC converter circuit, a rectifier circuit, or an inverter circuit that also has a rectification function. The DC-DC converter circuit includes, but is not limited to, a boost circuit, a buck circuit, and a buck-boost circuit. Load 30 is a DC load, such as an energy storage battery, a DC motor, or various DC loads in a household.

[0051] Based on this design Figure 3 The power conversion circuit 10 shown constitutes a dual active bridge (DAB) DC-DC converter circuit, which can perform bidirectional DC-DC conversion. In this circuit, the switching transistors Q1 and Q2 in the first bridge arm 111 switch states alternately. The second bridge arm 112, the third bridge arm 121, and the fourth bridge arm 122 operate similarly. The voltage V1 at the second terminal of the primary-side bridge circuit 11 and the voltage V2 at the second terminal of the secondary-side bridge circuit 12 are both DC voltages. The midpoint voltage Vp of the bridge arm of the primary-side bridge circuit 11 and the midpoint voltage Vs of the bridge arm of the secondary-side bridge circuit 12 are both AC voltages.

[0052] exist Figure 4 In the example, the primary-side bridge circuit 11 adopts a full-bridge topology, while the secondary-side bridge circuits 12 all adopt a half-bridge topology. Specifically, as shown... Figure 4 As shown, the primary-side bridge circuit 11 includes a first bridge arm 111 and a second bridge arm 112 connected in parallel. The first bridge arm 111 includes switches Q1 and Q2 connected in series, and the second bridge arm 112 includes switches Q3 and Q4 connected in series. The midpoint e of the first bridge arm 111 and the midpoint f of the second bridge arm 112 constitute the first terminal of the primary-side bridge circuit 11. The two ends of the first bridge arm 111 and the second bridge arm 112 constitute the second terminal of the primary-side bridge circuit 11.

[0053] The secondary-side bridge circuit 12 includes a third bridge arm 121 and a fourth bridge arm 122 connected in parallel. The third bridge arm 121 includes an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm includes switching transistors Q5 and Q6 connected in reverse series, and the lower bridge arm includes switching transistors Q7 and Q8 connected in reverse series. The fourth bridge arm 122 includes a second capacitor unit and a third capacitor unit connected in series. The first capacitor unit may include a capacitor C1 and a resistor R1 connected in series, and the second capacitor unit may include a capacitor C2 and a resistor R2 connected in series. Alternatively, in other embodiments, the first and second capacitor units may be directly capacitors, or other circuits containing capacitors. The midpoint g of the third bridge arm 121 and the midpoint h of the fourth bridge arm 122 constitute the first terminal of the secondary-side bridge circuit 12. The two ends of the third bridge arm 121 and the fourth bridge arm 122 constitute the second terminal of the secondary-side bridge circuit 12.

[0054] The turns ratio of the primary winding to the secondary winding of transformer 13 can be 1:n. In this example, transformer 13 is a step-up transformer, and n is a positive number greater than 1. Transformer 13 ( Figure 4 In the case of Lk2, which is represented as Tr, for ease of understanding, Figure 4The circuit diagram shows a secondary leakage inductance Lk2, which is connected between the secondary side of transformer 13 and the midpoint g of the bridge arm. In other embodiments, the secondary leakage inductance Lk2 may also be independent of the transformer Tr.

[0055] With the second terminal of the primary-side bridge circuit 11 serving as the input and the second terminal of the secondary-side bridge circuit 12 serving as the output, power supply 20 uses a DC power source, such as an energy storage battery or a DC-DC converter circuit. Load 30 uses an AC load, such as various household loads. Alternatively, with the second terminal of the secondary-side bridge circuit 12 serving as the input and the second terminal of the primary-side bridge circuit 11 serving as the output, power supply 20 uses an AC power source, such as the power grid, a generator, or a charging station. Load 30 uses a DC load; its specific type can be found in [reference needed]. Figure 3 Example description.

[0056] Based on this design Figure 4 The power conversion circuit 10 shown constitutes a DAB DC-AC conversion circuit, capable of performing both DC-AC and AC-DC conversion functions. The on / off states of the first bridge arm 111 and the second bridge arm 112 can be referenced... Figure 3 The relevant description is as follows. The upper and lower arms of the third bridge arm 121 alternately switch between on and off states, with the two switches in the upper arm and the two switches in the lower arm switching states alternately. The voltage V1 at the second terminal of the primary-side bridge circuit 11 is a DC voltage, and the voltage V2 at the second terminal of the secondary-side bridge circuit 12 is an AC voltage. The midpoint voltage Vp of the bridge arm of the primary-side bridge circuit 11 and the midpoint voltage Vs of the bridge arm of the secondary-side bridge circuit 12 are both AC voltages.

[0057] It is understood that, in one embodiment, the secondary bridge circuit 12 of the DAB DC-AC converter circuit can adopt a full-bridge topology, wherein the structure of the fourth bridge arm 122 is similar to... Figure 4 The third bridge arm 121 is the same as that in the full-bridge topology, and the working principle of the secondary bridge circuit 12 is the same. Figure 4 The secondary bridge circuit 12 using the half-bridge topology is the same, so it will not be described here.

[0058] In the embodiments of this application, the switching transistors in the power conversion circuit can be of appropriate types of semiconductor switches, such as transistors, MOSFETs, or IGBTs, depending on the actual situation. This application does not impose specific limitations on this. The switching state of the switching transistors is controlled by control signals. For example, a high-level control signal can be used to control the switching transistor to turn on, and a low-level control signal can be used to control the switching transistor to turn off.

[0059] The control signal can be a pulse width modulation (PWM) signal. For ease of distinction, the control signal of the primary-side bridge circuit 11 can be called the first control signal, or the primary-side PWM signal. The control signal of the secondary-side bridge circuit 12 can be called the second control signal, or the secondary-side PWM signal. Specifically, the control signal for switch Q1 can be defined as PWM1, the control signal for switch Q2 as PWM2, the control signal for switch Q3 as PWM3, the control signal for switch Q4 as PWM4, the control signal for switch Q5 as PWM5, the control signal for switch Q6 as PWM6, the control signal for switch Q7 as PWM7, and the control signal for switch Q8 as PWM8.

[0060] In the primary-side bridge circuit 11, there is a certain phase angle difference between the control signals of the switching transistors of the first bridge arm 111 and the second bridge arm 112. For example, there is a certain phase difference between PWM1 and PWM3. This phase angle difference can be called the inward phase shift angle θ of the primary-side bridge circuit 11. θ can be in the range of 0 to 1 (in radians).

[0061] Furthermore, there is a certain phase angle difference between the midpoint voltage Vp of the primary bridge circuit 11 and the midpoint voltage Vs of the secondary bridge circuit 13. This phase angle difference can be called the outward phase angle φ between the primary bridge circuit 11 and the secondary bridge circuit 13. φ can be in the range of -0.5 to 0.5 radians, for example. Specifically, when the energy flow direction is from the primary bridge circuit 11 to the secondary bridge circuit 12, the outward phase angle φ is positive, and Vp leads Vs with the outward phase angle φ. When the energy flow direction is from the secondary bridge circuit 12 to the primary bridge circuit 11, the outward phase angle φ is negative, and Vp lags Vs with the outward phase angle φ.

[0062] Please continue reading. Figure 1 and Figure 2 The primary-side bridge circuit 11 and the secondary-side bridge circuit 12 are respectively connected to the controller 40. The controller 40 can be a microcontroller unit (MCU), a digital signal processor (DSP), or other control circuits.

[0063] The controller 40 can use multiple phase-shift control methods (such as extended phase-shift control method, triple phase-shift control method, etc.) to control the power conversion circuit 10. That is, the controller 40 can output corresponding control signals to the switching transistors of the power conversion circuit 10 to control the switching state of the switching transistors, and regulate the energy conversion of the power conversion circuit 10 by adjusting the inner phase-shift angle θ and the outer phase-shift angle φ.

[0064] Specifically, the controller 40 can periodically count the carrier wave using a carrier counter, and use a comparator to compare the carrier counter with a preset corresponding comparison value, and generate a PWM signal according to the comparison result between the carrier count value and the corresponding comparison value. When the carrier count value reaches the comparison value, the level of the PWM signal flips, correspondingly generating a rising edge or a falling edge.

[0065] Among them, as Figure 5 shown, the carrier counter is used to count from the starting value Val0 to the ending value Val1, and when reaching Val1, it is reset to Val0, and repeats this process to generate a periodic counting sequence, which is the carrier wave. The carrier wave is a triangular wave or a sawtooth wave, and the period is Tc. Among them, the starting value Val0 and the ending value Val1 can be set accordingly according to actual needs. When Val1>Val0, the carrier counter adopts an increasing counting method (for example, see Figure 5 ). When Val1<Val0, the carrier counter adopts a decreasing counting method.

[0066] The magnitude of the comparison value can be set accordingly according to actual needs, and no specific limitation is made here. The comparison value can be stored in a register, for example. The carrier counter, the comparator, and the register can be integrated in the controller 40 or set outside the controller 40. Within a carrier period Tc, at least one comparison value can be set to trigger at least one level jump of the PWM signal within a carrier period Tc, generating a PWM signal with alternating high and low levels. Among them, when the level jump is from high level to low level, a falling edge is generated; when the level jump is from low level to high level, a rising edge is generated.

[0067] The comparison value that triggers the initial level flip of the PWM signal within a carrier period range Tc can be called the starting comparison value. When at least two comparison values are set within a carrier period, the comparison value that triggers the last level flip of the PWM signal within a carrier period range Tc can be called the ending comparison value.

[0068] It should be understood that each control signal of the switch tube with frequent on-off switching has a corresponding starting comparison value. For example, Figure 3 in the example, the starting comparison values of PWM1 and PWM2 are the same, the starting comparison values of PWM3 and PWM4 are the same; the starting comparison values of PWM5 to PWM8 are the same. Another example is Figure 4In the example, PWM1 and PWM2 have the same starting comparison value, and PWM3 and PWM4 have the same starting comparison value; when Q5 and Q7 frequently switch on and off, PWM5 and PWM7 have the same starting comparison value; when Q6 and Q8 frequently switch on and off, PWM6 and PWM8 have the same starting comparison value.

[0069] The edge corresponding to the starting comparison value can be called the starting edge. The starting edge can be a rising edge or a falling edge, depending on the situation, and this application does not impose any restrictions on it. The edge corresponding to the ending comparison value can be called the ending edge.

[0070] Figure 5 It shows Figure 3 The power conversion circuit uses PWM1 to PWM8. Taking PWM5 as an example, assume the starting comparison value CMP1 is 250, the ending comparison value CMP2 is 750, Val0 is 0, and Val1 is 1000. During the process of the carrier count value incrementing from 0 to 1000, such as... Figure 5 As shown by the first dashed line, when the carrier count value increments from Val0 to the start comparison value CMP1, PWM5 transitions from low to high, generating a rising edge. This rising edge is the start edge. Figure 5 As shown by the second dashed line, when the carrier count value continues to increment from CMP1 to the final comparison value CMP2, PWM5 jumps from high level to low level, generating a rising edge.

[0071] Moreover, such as Figure 5 As shown by the dotted lines, the edges of PWM5 all fall within the carrier period range, the centerline of PWM5 is aligned with the midpoint of the carrier count value (500), and the period Ts of PWM5 is the same as the carrier period Tc. This can be understood as... Figure 3 In the circuit, PWM5 and PWM6 are complementary, and PWM5 and PWM8 are the same, while PWM6 and PWM7 are the same. Figure 4 In the circuit, PWM5 and PWM7 are complementary, while PWM6 and PWM8 are identical, or PWM6 and PWM8 are complementary, while PWM5 and PWM7 are identical. Therefore, PWM6 to PWM8 will also fall within the carrier period range, and the central axis is aligned with the midpoint of the carrier count value, 500. In other words, the edges of the secondary PWM signals all fall within the carrier period range, and the waveforms of the secondary PWM signals within the carrier period range are symmetrical about the central axis.

[0072] Thus, when facing the scenario of multiple phase-shift modulation of power conversion circuit, the spatial symmetry of the left and right phase shifts (i.e., lead phase shift and lag phase shift) of the secondary PWM signal is achieved. During the phase shift of the primary PWM signal relative to the secondary PWM signal, the maximum phase shift adjustment range can be provided for the phase shift of the primary PWM signal, so that the primary PWM signal forms the required inner phase shift angle θ, and the required outer phase shift angle φ is formed between the bridge arm midpoint voltage Vp generated by the primary bridge circuit 11 and the bridge arm midpoint voltage Vs generated by the secondary bridge circuit 12.

[0073] Ideally, the edges of the primary-side PWM signal should all fall within the carrier period. However, in some operating conditions, such as those requiring a wide output range with large phase shift angles (inner phase shift angle θ and / or outer phase shift angle φ), improper PWM modulation may cause the edges generated by the primary-side PWM signal within one period Ts to exceed the carrier period range. This results in partial loss of the primary-side PWM signal waveform, leading to changes in the duty cycle, a reduction in the phase shift adjustment range, and ultimately, abnormal output from the power conversion circuit 10. (See, for example...) Figure 6 The start edges of PWM1 and PWM2 and their adjacent high and low level portions (corresponding to Figure 6 The dotted wireframe in the circuit exceeds the carrier cycle range, causing PWM1 and PWM2 to lose their starting edges and adjacent high and low level portions. This results in a change in the ratio of high and low levels within one cycle. The left and right phase shift spaces of PWM1 and PWM2 are asymmetrical, and the phase shift angle adjustment range is limited by the smaller phase shift space. Therefore, the power conversion circuit 10 cannot achieve the required duty cycle and phase shift angle adjustment range, cannot output normally, and the generated voltage and current waveforms are distorted.

[0074] In response, the controller 40 can be used to execute the control method of the power conversion circuit provided in the embodiments of this application to solve the problem of partial loss of PWM signal and ensure that the power conversion circuit 10 can output normally.

[0075] Next, the control method for the power conversion circuit according to an embodiment of this application will be described. It is understood that in other embodiments, it may also be implemented by a control device / electronic device / processor, etc., specifically designed for the power conversion circuit 10 described above.

[0076] Figure 7 A flowchart of a control method for a power conversion circuit provided in an embodiment of this application is shown.

[0077] like Figure 7 As shown, the control method for the power conversion circuit includes:

[0078] Step S11: Obtain the inner phase shift angle of the primary bridge circuit and the outer phase shift angle between the primary bridge circuit and the secondary bridge circuit.

[0079] It can be understood that step S11 obtains the expected inner phase shift angle θ and outer phase shift angle φ of the power conversion circuit. The inner phase shift angle θ is the phase difference between the control signals of the first and second arms of the primary-side bridge circuit. The outer phase shift angle φ is the phase difference between the midpoint voltage Vp of the arm generated by the primary-side bridge circuit and the midpoint voltage Vs of the arm generated by the secondary-side bridge circuit.

[0080] In step S11, the controller can calculate the inner phase shift angle θ and the outer phase shift angle φ using a pre-defined phase shift angle algorithm. Alternatively, the inner phase shift angle θ and the outer phase shift angle φ can be set by the user on a host computer or electronic terminal device (e.g., a mobile phone, computer), and the controller obtains them by communicating with the host computer or terminal device. Furthermore, the inner phase shift angle θ and the outer phase shift angle φ can be pre-stored in memory, and the controller reads them from the memory. It should be understood that the controller's methods for obtaining the inner phase shift angle θ and the outer phase shift angle φ are not limited to these, and will not be listed here.

[0081] Step S12: When it is confirmed that the edge of the first control signal exceeds the carrier period range based on the inner and outer phase shift angles, adjust the starting point comparison values ​​corresponding to the first and second control signals to limit the edge of the first control signal within the carrier period range. The first control signal is used to control the primary-side bridge circuit. The second control signal is used to control the secondary-side bridge circuit. The starting point comparison value corresponding to the first control signal indicates the starting edge of the first control signal within the carrier period range. The starting point comparison value corresponding to the second control signal indicates the starting edge of the second control signal within the carrier period range.

[0082] As mentioned earlier, when the inner phase shift angle θ and / or the outer phase shift angle φ are large, the edge of the first control signal in the primary-side bridge circuit may exceed the carrier period range. Therefore, based on the inner phase shift angle θ and the outer phase shift angle φ, it can be determined whether the edge of the first control signal exceeds the carrier period range.

[0083] Understandably, adjusting the starting comparison value of the first control signal and the starting comparison value of the second control signal when the edge of the first control signal exceeds the range of the carrier period is equivalent to phase shifting the first control signal and the second control signal, that is, shifting the first control signal and the second control signal so that the edges of the first control signal and the second control signal move to the range between the starting value Val0 and the ending value Val1 of the carrier signal.

[0084] Step S13: Update the first control signal and the second control signal according to the adjusted starting point comparison value.

[0085] In other words, the controller can generate new first and second control signals based on the comparison result between the carrier count value and the adjusted starting point comparison value. Specifically, when the carrier count value of the first control signal reaches the corresponding adjusted starting point comparison value, the first control signal undergoes a level flip, generating a new starting edge for the first control signal, which falls within the carrier period range. When the carrier count value of the second control signal reaches the corresponding adjusted starting point comparison value, the first control signal undergoes a level flip, generating a new starting edge for the second control signal, which also falls within the carrier period range. Ultimately, the edges generated by the updated first and second control signals within the carrier period both fall within the carrier period range, the waveforms are complete without loss, and the expected inner phase shift angle θ, outer phase shift angle φ, and duty cycle are achieved. Based on this, the power conversion circuit, under the control of the updated first and second control signals, can perform normal energy conversion and generate normal, expected voltage and current waveforms.

[0086] In summary, the control method of this application obtains the inner phase shift angle of the primary-side bridge circuit and the outer phase shift angle between the primary-side and secondary-side bridge circuits. When it is confirmed that the edge of the first control signal exceeds the carrier period range based on the inner and outer phase shift angles, the starting point comparison values ​​corresponding to the first and second control signals are adjusted. Then, the first and second control signals are updated based on the adjusted starting point comparison values. This ensures that the edge of the updated first control signal is limited to the carrier period range, preventing a series of problems caused by waveform loss due to the edge of the first control signal exceeding the carrier period range. Therefore, the control method of this application can effectively control the phase shift of the power conversion circuit, ensuring that the edges of the control signals of the power conversion circuit are all within the carrier period range, the control signal waveform is complete, and the duty cycle, inner phase shift angle θ, and outer phase shift angle φ meet the expected requirements. This ensures normal output of the power conversion circuit, that the generated voltage and current waveforms are normal and undistorted, and that the devices and circuits can operate safely.

[0087] In some embodiments, the process of adjusting the starting point comparison values ​​corresponding to the first and second control signals when the edge of the first control signal exceeds the carrier period range based on the inner and outer phase shift angles in step S12 may include:

[0088] When the edge of the first control signal exceeds the carrier period range, the starting point comparison value corresponding to the first control signal and the second control signal is adjusted according to the first adjustment rule.

[0089] The first adjustment rule can be used to adjust the starting comparison value of the control signal to within the carrier period range. The first adjustment rule indicates that the starting comparison value corresponding to the first control signal is associated with the inner phase shift angle, and the starting comparison value corresponding to the second control signal is associated with both the inner and outer phase shift angles. The first adjustment rule can be pre-stored in the controller's memory in the form of software algorithms, expressions, mathematical models, etc.

[0090] Therefore, the controller can adjust the starting comparison value corresponding to the first control signal according to the first adjustment rule, based on the inner phase shift angle, and adjust the starting comparison value corresponding to the second control signal according to the inner and outer phase shift angles. Subsequently, when updating the first and second control signals based on the adjusted starting comparison values, the edge generated by the first control signal can accurately fall within the carrier period range, and can achieve the required inner and outer phase shift angles.

[0091] To better understand, the process of adjusting the starting comparison value according to the first adjustment rule is illustrated below.

[0092] In this example, the power conversion circuit is as follows: Figure 3 As shown, the waveforms of PWM1 to PWM8 that have not been updated can be referenced. Figure 6 , where Val0 = 0.

[0093] The first adjustment rule can be expressed as (1) to (2) below.

[0094]

[0095] In the formula, C 12 It is the starting comparison value corresponding to the first control signal (i.e., PWM1, PWM2) of the first bridge arm; C 34 It is the starting comparison value corresponding to the first control signal of the second bridge arm (i.e., PWM3, PWM4); C 5678 These are the starting comparison values ​​corresponding to the second control signals (i.e., PWM5, PWM6, PWM7, PWM8) of the third and fourth bridge arms. L1 is the first set value, L2 is the second set value, d1 is the first constant value, and d2 is the second constant value. The values ​​of L1, L2, d1, and d2 can all be set according to the actual situation.

[0096] For ease of description, this example uses L1 = 0, L2 = 0.5, d1 = 0.5, and d2 = 0.25. Furthermore, the starting comparison value C corresponding to the first control signal of the first bridge arm can be used as an example. 12 Defined as the first starting point comparison value; the starting point comparison value C corresponding to the first control signal of the second bridge arm. 34 Defined as the second starting point comparison value; the starting point comparison value C corresponding to the second control signal of the third and fourth bridge arms. 5678Defined as the third starting point comparison value.

[0097] Therefore, as Figure 9 As shown, the process of adjusting the starting point comparison values ​​corresponding to the first control signal and the second control signal according to the first adjustment rule may include:

[0098] Step S21: Confirm whether the outward phase angle is greater than 0.

[0099] In other words, the controller determines whether φ > 0 or φ ≤ 0. If φ > 0, proceed to step S22. If φ ≤ 0, proceed to step S23.

[0100] Step S22: When the outward phase angle is greater than 0, set the first starting point comparison value to the first set value; adjust the second starting point comparison value according to the first starting point comparison value and the inward phase angle; adjust the third starting point comparison value according to the second starting point comparison value, the inward phase angle and the outward phase angle.

[0101] In other words, if φ>0, the controller can determine the adjusted first starting point comparison value C according to the above formula (1). 12 =0, the adjusted second starting point comparison value C 34 =C 12 +0.5-θ, the adjusted third starting point comparison value C 5678 =C 34 +0.5θ+φ-0.25.

[0102] It is understandable that, due to the adjusted first starting point comparison value C 12 Since it equals 0, which is also equal to Val0, the starting edges of the updated PWM1 and PWM2 can be aligned with Val0. In other words, Figure 6 The amount by which PWM1 and PWM2 exceed the carrier period range determines the amount by which PWM1 and PWM2 will be shifted to the right. The shifted PWM1 and PWM2 will then look like this: Figure 8 As shown, its edges are all within the carrier period range.

[0103] Due to the adjusted second starting point comparison value C 34 Comparison with the adjusted first starting point value C 12 Related to the inner phase shift angle θ, PWM3 and PWM4 can combine the translation of PWM1 and PWM2 with the required inner phase shift angle θ for translation, so that the edges of the updated PWM3 and PWM4 are within the carrier period, and an inner phase shift angle θ can be formed between the updated PWM1 and PWM3. Among them, the adjusted C... 34 =0.5-θ, therefore, as Figure 8 As shown, the phase difference between the falling edge of the updated PWM1 and the falling edge of PWM3 is exactly equal to the inward phase shift angle θ.

[0104] Due to the adjusted third starting point comparison value C 5678 Comparison with the adjusted second starting point value C 34 The inner phase shift angle θ and the outer phase shift angle φ are related. Therefore, PWM5 to PWM8 can combine the translation of PWM1 to PWM4 and the required inner phase shift angle θ and outer phase shift angle φ to perform translation, so that the edges of the updated PWM5 to PWM8 are all within the carrier period. At the same time, the updated PWM1 to PWM8 can form an outer phase shift angle φ between the midpoint voltages Vp and Vs of the bridge arm of the power conversion circuit.

[0105] Step S23: When the outward phase angle is less than or equal to 0, set the second starting point comparison value to the second set value; adjust the first starting point comparison value according to the second starting point comparison value and the inward phase angle; adjust the third starting point comparison value according to the first starting point comparison value, the inward phase angle and the outward phase angle.

[0106] In other words, if φ≤0, the controller can determine the adjusted second starting point comparison value C according to the above equation (2). 34 =0.5, the adjusted first starting point comparison value C 12 =C 34 -0.5+θ, the adjusted third starting point comparison value C 5678 =C 12 +φ+0.25-0.5θ.

[0107] Understandable, due to the adjusted C 34 =0.5, correspondingly, the adjusted C 12 =θ, and θ is usually in the range of 0 to 1. Therefore, the starting edges of the updated PWM1 to PWM4 will all fall within the carrier period range. Since the duty cycle of PWM1 to PWM4 is usually no more than 0.5 in multi-phase shift scenarios, the edges of the updated PWM1 to PWM4 will all be within the carrier period range. Furthermore, because the adjusted C... 12 -C 34 =θ, which means that PWM1 and PWM2 can combine the translation of PWM3 and PWM4 and the required inner phase angle θ to perform translation, so that the updated PWM1 and PWM3 can form an inner phase angle θ.

[0108] Due to the adjusted third starting point comparison value C 5678 Comparison with the adjusted first starting point value C 12The inner phase shift angle θ and the outer phase shift angle φ are related. Therefore, PWM5 to PWM8 can combine the translation of PWM1 to PWM4 and the required inner phase shift angle θ and outer phase shift angle φ to perform translation, so that the edges of the updated PWM5 to PWM8 are all within the carrier period. At the same time, the updated PWM1 to PWM8 can form an outer phase shift angle φ between the midpoint voltages Vp and Vs of the bridge arm of the power conversion circuit.

[0109] In summary, through the above steps S21 to S23, when the edge of the first control signal exceeds the range of the carrier period, the starting comparison value corresponding to the first and second control signals can be adjusted according to the appropriate formula based on the outward phase shift angle. This adjustment method is efficient, accurate, and logically clear, which is conducive to improving control efficiency and control accuracy.

[0110] It should be understood that the expression of the first adjustment rule can be set according to the actual situation and is not limited to the above example. As long as the first adjustment rule can be used to keep the edge of the second control signal within the carrier period range while adjusting the edge of the first control signal within the carrier period range, it is acceptable.

[0111] In some embodiments, the control method can be achieved through... Figure 10 The steps shown are used to confirm whether the edge of the first control signal exceeds the carrier period range.

[0112] Specifically, such as Figure 10 As shown, the control methods include:

[0113] Step S31: Calculate the phase angle variable based on the inner and outer phase angles.

[0114] Among them, the phase angle variable α is an intermediate variable. There is a certain mapping relationship between the phase angle variable α and the inner phase angle θ and the outer phase angle φ. Therefore, in step S31, the controller can calculate the phase angle variable α based on the inner phase angle θ, the outer phase angle φ and the mapping relationship.

[0115] Step S32: Determine whether the edge of the first control signal is within the carrier period range based on the phase angle variable and the outward phase shift angle.

[0116] In step S32, the controller can determine whether the phase angle variable and the magnitude of the outward shift phase angle meet the set edge exceedance condition. If the edge exceedance condition is met, it is determined that the edge of the first control signal exceeds the carrier period range. If the edge exceedance condition is not met, it is determined that the edge of the first control signal is within the carrier period range.

[0117] It should be understood that steps S31 and S32 can be performed after step S11 and before step S12, or they can be performed in step S12.

[0118] The mapping relationship and edge overflow condition can be set according to the actual situation, and this application does not impose specific limitations on them. For better understanding, the mapping relationship and edge overflow condition are illustrated below.

[0119] In one embodiment, the mapping relationship between the phase angle variable α and the inner phase angle θ and the outer phase angle φ is, for example, shown in the following equation (3).

[0120]

[0121] Where K1 is the first coefficient, K2 is the second coefficient, and D3 is a preset value (for clarity, this preset value can also be referred to as the third preset value, distinguishing it from the first and second preset values ​​mentioned below). It should be understood that K1, K2, and D3 can be set according to actual circumstances, and no specific limitations are made here. For ease of description, this example uses the first coefficient K1 = K2 = 0.5 and the third preset value D3 = 1 as an example.

[0122] Therefore, the process of calculating the phase angle variable based on the inner and outer phase shift angles in step S31 can include:

[0123] When the outward phase angle is greater than 0, obtain the first product K1·θ of the inward phase angle and the first coefficient; calculate the difference between the first product and the outward phase angle to obtain the phase angle variable. That is, the phase angle variable α=K1·θ-φ=0.5θ-φ.

[0124] When the outward phase angle is less than or equal to 0, obtain the second product of the inward phase angle and the second coefficient, and obtain the sum of the second product and the outward phase angle; calculate the difference between the third preset value and the sum to obtain the phase angle variable. That is, the phase angle variable α = D3 - K2·θ - φ = 1 - 0.5θ - φ.

[0125] In one embodiment, the edge-out condition includes, for example:

[0126] Condition 1: If (φ>0) and (α<0), then the edge of the first control signal will exceed the range of the carrier period.

[0127] Condition 2: If (φ≤0) and (α>1), then the edge of the first control signal will exceed the range of the carrier period.

[0128] Therefore, the process in step S32 of determining whether the edge of the first control signal exceeds the carrier period range based on the phase angle variable and the outward phase shift angle can include:

[0129] When the outward phase angle is greater than 0 and the phase angle variable is less than 0, or when the outward phase angle is less than or equal to 0 and the phase angle variable is greater than 1, it is determined that the edge of the first control signal exceeds the carrier period range.

[0130] When the outward phase angle is greater than 0 and the phase angle variable is greater than or equal to 0, or when the outward phase angle is less than or equal to 0 and the phase angle variable is less than or equal to 1, the edge of the first control signal is determined to be within the carrier period range.

[0131] In other words, if the phase angle variable and the outward phase angle satisfy either condition 1 or condition 2, it can be determined that the edge of the first control signal exceeds the range of the carrier period.

[0132] Conversely, if the phase angle variable and the outward shift phase angle do not meet condition 1 or condition 2, it can be determined that the edge of the first control signal does not exceed the carrier period range.

[0133] Therefore, in summary, through the above steps S31 and S32, it is possible to quickly predict whether the edge of the first control signal exceeds the carrier period range based on the magnitude of the phase angle variable α and the outward shift phase angle φ. Thus, if it is predicted that the edge of the first control signal will exceed the carrier period range, timely intervention measures can be taken (i.e., executing the above steps S12 and S13) to prevent the edge of the first control signal from exceeding the carrier period range and ensure the normal and safe operation of the power conversion circuit.

[0134] In other embodiments, the control method can be... Figure 11 The steps shown are used to confirm whether the edge of the first control signal exceeds the carrier period range.

[0135] Specifically, such as Figure 11 As shown, the method also includes:

[0136] Step S41: Confirm whether the outer phase angle is greater than half of the inner phase angle.

[0137] In other words, the controller determines whether φ > 0.5θ or φ ≤ 0.5θ.

[0138] If φ > 0.5θ, proceed to step S42. If φ ≤ 0.5θ, proceed to step S43.

[0139] Step S42: When the outer phase angle is greater than half of the inner phase angle, determine that the edge of the first control signal exceeds the carrier period range.

[0140] It is understandable that the outward phase shift angle is usually no more than half of the inward phase shift angle. If the outward phase shift angle exceeds half of the inward phase shift angle, it means that the outward phase shift angle is too large, which will cause the edge of the first control signal to exceed the range of the carrier period.

[0141] Step S43: When the outer phase angle is less than or equal to half of the inner phase angle, determine that the edge of the first control signal is within the carrier period range.

[0142] If the outer phase shift does not exceed half of the inner phase shift angle, it indicates that the outer phase shift angle is appropriate and will not be too large to cause the edge of the first control signal to exceed the carrier period range.

[0143] Therefore, through the above steps S41 to S43, it is also possible to quickly predict whether the edge of the first control signal exceeds the carrier period range based on the magnitude of the phase angle variable α and the outward shift phase angle φ. Thus, if it is predicted that the edge of the first control signal will exceed the carrier period range, timely intervention measures can be taken (i.e., execute the above steps S12 and S13) to prevent the edge of the first control signal from exceeding the carrier period range and ensure the normal and safe operation of the power conversion circuit.

[0144] In some embodiments, if the edge of the first control signal does not exceed the carrier period range, the controller may also perform the following: Figure 12 The method steps of the embodiments of this application shown determine the starting comparison values ​​of each required control signal to ensure that the edge of the first control signal always remains within the carrier period range. That is, under normal circumstances, the starting comparison values ​​of each control signal required for control are determined in the following manner.

[0145] Specifically, such as Figure 12 As shown, the method also includes:

[0146] Step S51: When the edge of the first control signal does not exceed the carrier period range, determine the starting point comparison value corresponding to the first control signal and the second control signal according to the second adjustment rule.

[0147] The second adjustment rule can be used to limit the starting comparison value of the control signal within the carrier period range and to improve the waveform symmetry of the control signal. Specifically, the second adjustment rule indicates that the starting comparison value corresponding to the first control signal is associated with the inner and outer phase shift angles, and the starting comparison value corresponding to the second control signal is a third set value. The second adjustment rule can be pre-stored in the controller's memory in the form of software algorithms, expressions, mathematical models, etc.

[0148] Therefore, the controller can determine the starting comparison value corresponding to the first control signal based on the inner phase shift angle and the outer phase shift angle according to the second adjustment rule, and determine the starting comparison value corresponding to the second control signal as the third set value.

[0149] Step S52: Update the first control signal and the second control signal according to the determined starting point comparison value.

[0150] It is understood that step S52 can refer to the relevant description of step S13 above, so it will not be repeated here.

[0151] Ultimately, the updated first and second control signals can maintain the edges generated within the carrier period within the carrier period. At the same time, the waveforms of the first and second control signals are symmetrical, that is, the first and second control signals have symmetrical left and right phase shift spaces. This provides a larger phase shift adjustment range and reduces the risk of the edges of the first and second control signals exceeding the carrier period range when facing large phase shift angle requirements, ensuring that the edge of the first control signal always remains within the carrier period range.

[0152] In summary, through the above steps S51 and S52, the starting comparison value corresponding to the first control signal and the second control signal can be determined based on the second adjustment rule when the edge of the first control signal does not exceed the carrier period range. This keeps the starting comparison value corresponding to the first control signal and the second control signal within the carrier period range. At the same time, the first control signal and the second control signal are symmetrical, which is beneficial to forming a larger inner phase shift angle and outer phase shift angle, and reducing the probability of edge overshoot.

[0153] To better understand, the process of determining the starting comparison value according to the second adjustment rule is illustrated below.

[0154] In this example, the second adjustment rule can be expressed as, for example, equations (4) to (5).

[0155]

[0156] In the formula, L3 is the third preset value, D1 is the first preset value, and D2 is the second preset value. The values ​​of L3, D1, and D2 can be set according to the actual situation. For ease of description, this example uses L3 = 0.25 and D1 = D2 = 0.5 as an example.

[0157] Therefore, as Figure 13 As shown, the process of determining the starting point comparison value corresponding to the first control signal and the second control signal according to the second adjustment rule may include:

[0158] Step S61: Confirm whether the outward phase angle is greater than 0.

[0159] In other words, the controller determines whether φ > 0 or φ ≤ 0. If φ > 0, proceed to step S62. If φ ≤ 0, proceed to step S63.

[0160] Step S62: When the outward phase angle is greater than 0, determine the first starting point comparison value based on the inward phase angle and the outward phase angle; determine the second starting point comparison value based on the first preset value, the inward phase angle and the outward phase angle; set the third starting point comparison value to the third preset value.

[0161] In other words, if φ>0, the controller can adjust the first starting point comparison value, the second starting point comparison value, and the third starting point comparison value to the magnitude required for phase shift control according to the above formula (4), that is, determine the adjusted first starting point comparison value C. 12 =0.5θ-φ, the adjusted second starting point comparison value C 34 =0.5-0.5θ-φ, the adjusted third starting point comparison value C 5678 =0.25.

[0162] As can be understood from the foregoing, if the edge of the first control signal does not exceed the carrier period range, it means φ < 0.5θ. Therefore, the adjusted first starting point comparison value C 12 >0 ensures that the edges of the updated PWM1 and PWM2 fall within the carrier period range.

[0163] Combining φ<0.5θ and θ<1, we can see that the adjusted second starting point comparison value C 34 >0 ensures that the edges of the updated PWM3 and PWM4 also fall within the carrier period range.

[0164] Due to the adjusted third starting point comparison value C 5678 =0.25, therefore, the updated PWM5~PWM8 can be roughly as follows Figure 5 As shown, its edges are within the carrier period range, and its waveform is symmetrical about the central axis.

[0165] Step S63: When the outward phase angle is less than or equal to 0, determine the first starting point comparison value based on the inward phase angle; determine the second starting point comparison value based on the second preset value, the inward phase angle, and the outward phase angle; set the third starting point comparison value to the third preset value.

[0166] In other words, if φ≤0, the controller can adjust the first starting point comparison value, the second starting point comparison value, and the third starting point comparison value to the magnitude required for phase shift control according to the above formula (5), that is, determine the adjusted first starting point comparison value C. 12 =θ-0.5, the adjusted second starting point comparison value C 34 =0.5-0.5θ-φ, the adjusted third starting point comparison value C 5678 =L3.

[0167] It is understandable that, considering φ≤0 and θ<1, the adjusted second starting point comparison value C... 34 >0 ensures that the edges of the updated PWM3 and PWM4 also fall within the carrier period range.

[0168] Due to the adjusted third starting point comparison value C 5678=0.25, therefore, the edges of the updated PWM5 to PWM8 are within the carrier period range, and their waveforms are symmetrical about the central axis.

[0169] Moreover, due to the first starting point comparison value C 12 Related to the inward phase shift angle θ, PWM1 and PWM2 can perform a translation based on the required inward phase shift angle θ, and the adjusted second starting point comparison value C 34 Related to the inner phase shift angle θ and the outer phase shift angle φ, PWM3 and PWM4 can be translated by combining the required inner phase shift angle θ and outer phase shift angle φ, so that the edges of the updated PWM1 to PWM4 are all within the carrier period range, and an inner phase shift angle θ can be formed between PWM1 and PWM3. At the same time, the updated PWM1 to PWM8 can form an outer phase shift angle φ between the midpoint voltages Vp and Vs of the bridge arm of the power conversion circuit.

[0170] In summary, by using steps S61 to S63, the starting point comparison value of the first and second control signals required for phase shift control can be determined by selecting an appropriate formula based on the outer phase shift angle when the edge of the first control signal does not exceed the carrier period range. This adjustment method is efficient, accurate, and logically clear, which is conducive to improving control efficiency and accuracy.

[0171] Furthermore, to verify the control effect of the control method of the embodiments of this application on the power conversion circuit 10, a simulation experiment was also conducted. In the simulation experiment, the power conversion circuit adopted... Figure 4 The circuit shown operates under a wide range of output conditions.

[0172] Figure 14 The simulation waveform of the power conversion circuit is shown without employing the control method of the embodiments of this application. Figure 15 The simulation waveform of the power conversion circuit is shown when the control method of the embodiment of this application is adopted. Figure 14 and Figure 15 In the diagram, the two waveforms in the first coordinate are plotted based on the sampled value of the AC current I2 output by the power conversion circuit, and the waveform plotted based on the preset reference value of the AC current I2, respectively. The waveforms in the second to fourth coordinates are all displayed on the oscilloscope. The waveform in the second coordinate corresponds to the AC voltage V2 output by the power conversion circuit, the waveform in the third coordinate corresponds to the AC current I2, and the waveforms in the fourth coordinate correspond to the voltages Vp and Vs at the midpoint of the bridge arms. The horizontal axis represents time.

[0173] from Figure 14It can be seen that, without the control method of the embodiments of this application, the waveform of the bridge arm midpoint voltage Vp generated by the power conversion circuit is asymmetrical, with some waveform loss, and the sinusoidal sine of the AC current output by the power conversion circuit is poor, with large oscillations near the zero crossing point. This is actually because the edge of the first control signal of the power conversion circuit exceeds the carrier period range, causing the first control signal to lose part of its waveform, resulting in changes in the duty cycle and phase shift angle, which prevents the generation of normal bridge arm midpoint voltage and AC current, and distorts the waveforms of both the bridge arm midpoint voltage and AC current.

[0174] from Figure 15 It can be seen that, when the control method of the embodiment of this application is adopted, the waveform of the bridge arm midpoint voltage Vp generated by the power conversion circuit is complete and symmetrical, the sinusoidal nature of the AC current output by the power conversion circuit is good, and the oscillation near the zero crossing point is very small.

[0175] As can be seen, the method of this application restricts the edge of the first control signal of the power conversion circuit within the carrier period range, avoiding the loss of part of the waveform of the first control signal, so that the duty cycle and phase shift angle can be maintained at normal values. Therefore, the power conversion circuit can operate normally and generate normal bridge arm midpoint voltage and AC current with good sinusoidal characteristics.

[0176] It should be noted that, for the sake of simplicity, the aforementioned method embodiments are described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps may be performed in other orders or simultaneously.

[0177] Please see Figure 16 This is a schematic diagram of a power conversion device provided in an embodiment of this application.

[0178] like Figure 16 As shown, the power conversion device 100 may include a power conversion circuit 10 and a controller 40. The power conversion circuit 10 may be... Figures 1 to 4 The power conversion circuit 10 shown is connected to the controller 40. The controller 40 can be used to execute the control method of the power conversion circuit to control the power conversion circuit 10, so that the power conversion circuit 10 has a complete PWM signal waveform under wide range of output conditions, ensuring the normal output of the power conversion circuit 10 and the safety of the device.

[0179] The power conversion circuit 10 and the controller 40 can be integrated or separate units; this embodiment does not limit this. The power conversion circuit 10 and controller 40 can also be found in... Figures 1 to 4 The relevant descriptions and control methods for the power conversion circuit can be found in the previous method embodiments, and will not be repeated here.

[0180] Please see Figure 17 This is a schematic diagram of an energy storage device provided in an embodiment of this application.

[0181] like Figure 17 As shown, the energy storage device 200 may include an energy storage battery 50 and the aforementioned power conversion device 100. The energy storage battery 50 and the power conversion device 100 may be integrally arranged or at least partially integrated together; this application embodiment does not limit this.

[0182] In one embodiment, for example, reference may be made to Figures 1 to 3 The power conversion circuit 10 in the power conversion device 100 is a bidirectional DC-DC conversion circuit. The energy storage battery 50 can be electrically connected to the secondary bridge circuit 12 of the power conversion circuit 10. The energy storage battery 50 can serve as a load of the power conversion circuit 10 and be charged by the power conversion circuit 10. The energy storage battery 50 can also serve as a power source for the power conversion circuit 10 and be discharged through the power conversion circuit 10.

[0183] In another embodiment, for example, it may be combined with reference to Figure 1 , Figure 2 and Figure 4 The power conversion circuit 10 in the power conversion device 100 is a bidirectional DC-AC conversion circuit. The energy storage battery 50 can be electrically connected to the primary-side bridge circuit 11 of the power conversion circuit 10. The energy storage battery 50 can serve as a load for the power conversion circuit 10, which can perform AC-DC conversion and charge the energy storage battery 50. The energy storage battery 50 can also serve as a power source for the power conversion circuit 10, which can draw power from the energy storage battery 50 and perform DC-AC conversion.

[0184] Please see Figure 18 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0185] like Figure 18 As shown, the electronic device 300 may include a processor 301 and a memory 302.

[0186] Processor 301 can be a central processing unit (CPU), or 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. A general-purpose processor can be a microprocessor or any conventional processor.

[0187] Memory 302 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. Memory 302 may exist independently and be connected to processor 301 via a bus. Memory 302 may also be integrated with processor 301.

[0188] The memory 302 stores programs, instructions, or code for executing the control method of the aforementioned power conversion circuit. The processor 301 executes the programs, instructions, or code stored in the memory 302. The programs, instructions, or code stored in the memory 302 can execute some or all of the steps in the aforementioned method embodiments.

[0189] Please see Figure 19 The diagram illustrates a control device provided in an embodiment of this application. This control device can be applied to the power conversion circuit 10 to implement the control method described above for the power conversion circuit.

[0190] Specifically, such as Figure 19 As shown, the control device 400 includes: an acquisition module 401, an adjustment module 402, and an update module 403.

[0191] The acquisition module 401 is used to acquire the inner phase shift angle of the primary bridge circuit and the outer phase shift angle between the primary bridge circuit and the secondary bridge circuit.

[0192] The adjustment module 402 is used to adjust the starting point comparison value corresponding to the first control signal and the second control signal when it is confirmed based on the inner and outer phase shift angles that the edge of the first control signal exceeds the carrier period range, so as to limit the edge of the first control signal within the carrier period range. The starting point comparison value is used to indicate the starting edge of the first control signal within the carrier period range; the first control signal is used to control the primary-side bridge circuit; and the second control signal is used to control the secondary-side bridge circuit.

[0193] The update module 403 is used to update the first control signal and the second control signal based on the adjusted starting point comparison value.

[0194] It is understood that the division of the various modules in the control device 400 described above is only for illustrative purposes. In other embodiments, the control device 400 may be divided into different modules as needed to complete all or part of the functions of the control device 400.

[0195] The specific implementation of each module in the embodiments of this application can also refer to the corresponding descriptions of the foregoing method embodiments, so they will not be described in detail here.

[0196] In the various embodiments of this application, all functional modules can be integrated into one processing module / unit, or each module can be a separate module, or two or more modules can be integrated into one module; the integrated module can be implemented in hardware or in the form of hardware plus software functional modules.

[0197] If the integrated modules described above in this application are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, RAM, magnetic disks, or optical disks.

[0198] This application also provides a computer-readable storage medium for storing computer programs or code, which, when loaded and executed by a processor, implement all or part of the steps in the aforementioned method embodiments. 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). Specific embodiments of the computer-readable storage medium can be found in [reference needed]. Figure 16 The description of memory 302 in the memory is not repeated here.

[0199] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A control method for a power conversion circuit, characterized in that, The power conversion circuit includes a primary-side bridge circuit, a secondary-side bridge circuit, and a transformer. The primary-side bridge circuit is connected to the primary side of the transformer, and the secondary-side bridge circuit is connected to the secondary side of the transformer. The control method includes: Obtain the inner phase shift angle of the primary-side bridge circuit, and the outer phase shift angle between the primary-side bridge circuit and the secondary-side bridge circuit; When it is confirmed that the edge of the first control signal exceeds the carrier period range based on the inner phase shift angle and the outer phase shift angle, the starting point comparison value corresponding to the first control signal and the second control signal is adjusted to limit the edge of the first control signal within the carrier period range; wherein, the first control signal is used to control the primary-side bridge circuit; the second control signal is used to control the secondary-side bridge circuit; the starting point comparison value corresponding to the first control signal is used to indicate the generation of the starting edge of the first control signal within the carrier period range, and the starting point comparison value corresponding to the second control signal is used to indicate the generation of the starting edge of the second control signal within the carrier period range; The first control signal and the second control signal are updated based on the adjusted starting point comparison value.

2. The control method as described in claim 1, characterized in that, When it is confirmed that the edge of the first control signal exceeds the carrier period range based on the inner phase shift angle and the outer phase shift angle, adjusting the starting point comparison values ​​corresponding to the first control signal and the second control signal includes: When the edge of the first control signal exceeds the carrier period range, the starting point comparison values ​​corresponding to the first control signal and the second control signal are adjusted according to the first adjustment rule; The first adjustment rule is used to indicate that the starting point comparison value corresponding to the first control signal is associated with the inner phase shift angle, and the starting point comparison value corresponding to the second control signal is associated with both the inner phase shift angle and the outer phase shift angle.

3. The control method as described in claim 2, characterized in that, The primary-side bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, and the secondary-side bridge circuit includes a third bridge arm and a fourth bridge arm connected in parallel; the starting point comparison value corresponding to the first control signal of the first bridge arm is a first starting point comparison value; the starting point comparison value corresponding to the first control signal of the second bridge arm is a second starting point comparison value; and the starting point comparison value corresponding to the second control signal of the third bridge arm and the fourth bridge arm is a third starting point comparison value. The step of adjusting the starting comparison values ​​corresponding to the first control signal and the second control signal according to the first adjustment rule includes: When the outward phase angle is greater than 0, the first starting point comparison value is set to the first set value; Adjust the second starting point comparison value according to the first starting point comparison value and the inner phase shift angle; adjust the third starting point comparison value according to the second starting point comparison value, the inner phase shift angle and the outer phase shift angle; and / or When the outward phase angle is less than or equal to 0, the second starting point comparison value is set to the second set value; the first starting point comparison value is adjusted according to the second starting point comparison value and the inward phase angle; the third starting point comparison value is adjusted according to the first starting point comparison value, the inward phase angle and the outward phase angle.

4. The control method as described in claim 1, characterized in that, The method further includes: When the edge of the first control signal does not exceed the carrier period range, the starting point comparison value corresponding to the first control signal and the second control signal is determined according to the second adjustment rule; The second adjustment rule is used to indicate that the starting point comparison value corresponding to the first control signal is associated with the inner phase shift angle and the outer phase shift angle, and the starting point comparison value corresponding to the second control signal is a third set value.

5. The control method as described in claim 4, characterized in that, The primary-side bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, and the secondary-side bridge circuit includes a third bridge arm and a fourth bridge arm connected in parallel; the starting point comparison value corresponding to the first control signal of the first bridge arm is a first starting point comparison value; the starting point comparison value corresponding to the first control signal of the second bridge arm is a second starting point comparison value; and the starting point comparison value corresponding to the second control signal of the third bridge arm and the fourth bridge arm is a third starting point comparison value. The step of determining the starting point comparison value corresponding to the first control signal and the second control signal according to the second adjustment rule includes: When the outer phase angle is greater than 0, the first starting point comparison value is determined based on the inner phase angle and the outer phase angle; The second starting point comparison value is determined based on the first preset value, the inner phase angle, and the outer phase angle; the third starting point comparison value is set as the third preset value. When the outward phase angle is less than or equal to 0, the first starting point comparison value is determined based on the inward phase angle; the second starting point comparison value is determined based on the second preset value, the inward phase angle, and the outward phase angle; and the third starting point comparison value is set as the third preset value.

6. The control method according to any one of claims 1 to 5, characterized in that, The method further includes: Calculate the phase angle variable based on the inner phase angle and the outer phase angle; Based on the phase angle variable and the outward phase angle, determine whether the edge of the first control signal is within the carrier period range.

7. The control method as described in claim 6, characterized in that, Calculating the phase angle variable based on the inner phase angle and the outer phase angle includes: When the outward phase angle is greater than 0, obtain the first product of the inward phase angle and the first coefficient; calculate the difference between the first product and the outward phase angle to obtain the phase angle variable; When the outward phase angle is less than or equal to 0, the second product of the inward phase angle and the second coefficient is obtained, and the sum of the second product and the outward phase angle is obtained; the difference between the third preset value and the sum is calculated to obtain the phase angle variable.

8. The control method as described in claim 6 or 7, characterized in that, The step of determining whether the edge of the first control signal exceeds the carrier period range based on the phase angle variable and the outward phase shift angle includes: When the outward phase angle is greater than 0 and the phase angle variable is less than 0, or when the outward phase angle is less than or equal to 0 and the phase angle variable is greater than 1, it is determined that the edge of the first control signal exceeds the carrier period range.

9. The control method according to any one of claims 1 to 5, characterized in that, The method further includes: When the outer phase shift angle is greater than half of the inner phase shift angle, it is determined that the edge of the first control signal exceeds the carrier period range; and / or When the outer phase shift angle is less than or equal to half of the inner phase shift angle, it is determined that the edge of the first control signal is within the carrier period range.

10. A power conversion device, characterized in that, The device includes a power conversion circuit and a controller. The power conversion circuit includes a primary-side bridge circuit, a secondary-side bridge circuit, and a transformer. The primary-side bridge circuit is connected to the primary side of the transformer, and the secondary-side bridge circuit is connected to the secondary side of the transformer. The controller is used to execute the control method of the power conversion circuit as described in any one of claims 1 to 9.

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