Power supply control method, resonant conversion system and energy storage system

Abstract

The application relates to a power supply control method, a resonant conversion system and an energy storage system. The method comprises the following steps: when the current time is in the working condition of an under-voltage area and light load, the working condition of an under-voltage area and heavy load or the working condition of an over-voltage area and light load, the duty cycle of a switch tube of a resonant circuit is regulated to stabilize the power supply voltage of an auxiliary source winding; when the current time is in the working condition of an over-voltage area and heavy load, the width of a hysteresis area and the load rate of an inverter are used to determine the switching time of the voltage output value from the over-voltage area to the under-voltage area, so as to stabilize the power supply voltage of the auxiliary source winding; when the current time is in other working conditions with the voltage interval being the hysteresis area, the same power supply voltage stabilizing strategy as a target interval is executed, and the target interval is the voltage interval corresponding to the previous entering of the other working conditions. The application can stabilize the output voltage of the auxiliary source winding, so as to ensure the normal operation of the power load supplied by the auxiliary source circuit.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a power supply control method, a resonant converter system, and an energy storage system. Background Technology

[0002] Resonant circuits (LLCs) are widely used in power electronic systems due to their high efficiency, high power density, and ease of implementing zero voltage switching (ZVS) and zero current switching (ZCS).

[0003] The transformer in a resonant circuit includes a primary winding and a secondary winding. The secondary winding consists of an auxiliary power supply winding and a secondary main winding. The secondary main winding connects to the secondary bridge circuit of the inverter. The auxiliary power supply winding provides the power supply voltage to the subsequent auxiliary power supply circuit. The stability of the output voltage of the auxiliary power supply winding directly affects the stability of the electrical load powered by the auxiliary power supply circuit. However, in practical applications, the output voltage of the auxiliary power supply winding is often affected by the output voltage state controlled by the voltage hysteresis of the bus voltage and the load conditions of the inverter. Therefore, stabilizing the output voltage of the auxiliary power supply winding to ensure the normal operation of the electrical load powered by the auxiliary power supply circuit is crucial. Summary of the Invention

[0004] Based on this, this application provides a power supply control method, a resonant conversion system, and an energy storage system, which can stabilize the output voltage of the auxiliary power source winding to ensure the normal operation of the electrical load powered by the auxiliary power source circuit.

[0005] In a first aspect, this application provides a power supply control method applied to a resonant circuit. The resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary power supply winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. The method includes:

[0006] The voltage range of the voltage output value of the voltage hysteresis control of the bus voltage at the current moment and the load state of the inverter are obtained. The bus voltage is the voltage at the connection between the secondary bridge circuit and the inverter. The voltage range includes the undervoltage region, hysteresis region or overvoltage region. The load state includes light load or heavy load. Any voltage range and any load state form a working condition of the resonant circuit.

[0007] When the current operating condition is the first, second, or third operating condition, the duty cycle of the switching transistor in the resonant circuit is adjusted to stabilize the supply voltage of the auxiliary power winding.

[0008] When the current operating condition is the fourth condition, the switching time of the voltage output value from the overvoltage region to the undervoltage region is determined based on the width of the hysteresis region and the load rate of the inverter, so as to stabilize the power supply voltage of the auxiliary power winding.

[0009] When the current operating condition is in another operating condition where the voltage range is in the hysteresis region, the same power supply voltage stabilization strategy as the target range is executed. The target range is the voltage range corresponding to the previous operating condition.

[0010] The first operating condition is the undervoltage and light load condition, the second operating condition is the undervoltage and heavy load condition, the third operating condition is the overvoltage and light load condition, and the fourth operating condition is the overvoltage and heavy load condition. The hysteresis region is the voltage output value within the set bus voltage reference range, the undervoltage region is the range where the voltage output value is less than the minimum value of the bus voltage reference range, and the overvoltage region is the range where the voltage output value is greater than the maximum value of the bus voltage reference range.

[0011] In some embodiments, when the current operating condition is either the first or the second operating condition, stabilizing the supply voltage of the auxiliary power supply winding based on the duty cycle of the switching transistor in the resonant circuit includes:

[0012] The primary duty cycle is adjusted to a preset upper limit to stabilize the supply voltage of the auxiliary power winding;

[0013] Wherein, the primary-side duty cycle is the duty cycle of the switching transistor in the primary-side bridge circuit.

[0014] In some embodiments, when the current operating condition is the third condition, stabilizing the supply voltage of the auxiliary power supply winding based on adjusting the duty cycle of the switching transistor in the resonant circuit includes:

[0015] The target secondary duty cycle is determined based on the parameters of the secondary winding and the bus current value.

[0016] The supply voltage of the auxiliary power winding is stabilized by adjusting the duty cycle of the secondary side to the target duty cycle.

[0017] The secondary duty cycle is the duty cycle of the switching transistor in the secondary bridge circuit.

[0018] In some embodiments, other operating conditions include a fifth operating condition, which is an operating condition in the hysteresis region and under light load. When the current time is in the fifth operating condition where the voltage range is in the hysteresis region, the same supply voltage stabilization strategy as the target range is executed, including:

[0019] If the target range before entering the fifth operating condition is the undervoltage zone at the current moment, then the operating condition before entering the fifth operating condition is the first operating condition, and the same power supply voltage stabilization strategy as the first operating condition is executed: based on the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power winding.

[0020] If the target range before entering the fifth operating condition is an overvoltage zone at the current moment, then the operating condition before entering the fifth operating condition is the third operating condition, and the same power supply voltage stabilization strategy as the third operating condition is implemented: based on adjusting the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power winding.

[0021] In some embodiments, other operating conditions include a sixth operating condition, which is an operating condition in the hysteresis region and under heavy load. When the current time is in the sixth operating condition where the voltage range is in the hysteresis region, the same supply voltage stabilization strategy as the target range is executed, including:

[0022] If the target range before entering the sixth operating condition is the undervoltage region at the current moment, then the operating condition before entering the sixth operating condition is the second operating condition, and the same power supply voltage stabilization strategy as the second operating condition is implemented: based on the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power supply winding.

[0023] If the target range before entering the sixth operating condition is the overvoltage zone at the current moment, then the corresponding operating condition before entering the sixth operating condition is the fourth operating condition. The same power supply voltage stabilization strategy as the fourth operating condition is executed: based on the width of the hysteresis zone and the inverter load rate, the switching time of the voltage output value from the overvoltage zone to the undervoltage zone is determined to stabilize the power supply voltage of the auxiliary power winding.

[0024] In some embodiments, the parameters of the secondary winding include the permeability of the secondary primary winding, the first number of turns of the secondary primary winding, the radius of the secondary primary winding and the rate of change of current of the secondary primary winding, the second number of turns of the auxiliary source winding, the winding area of ​​the auxiliary source winding and the magnetic circuit constant of the auxiliary source winding, and the cosine of the angle between the direction of the magnetic field generated by the secondary primary winding and the normal direction of the auxiliary source winding; based on the parameters of the secondary winding and the bus current value, the target secondary duty cycle is determined, including:

[0025] The first product is determined based on the product of magnetic permeability, first number of turns, rate of change of current, second number of turns, winding area, and the cosine of the included angle.

[0026] The first ratio is determined based on the ratio of the first product to twice the radius;

[0027] The second product is determined based on the product of the magnetic circuit constant and the bus current value;

[0028] The target secondary side duty cycle is determined based on the ratio of the first ratio to the second product.

[0029] In some embodiments, the switching time for the voltage output value to switch from the overvoltage region to the undervoltage region is determined based on the width of the hysteresis region and the inverter load rate, in order to stabilize the supply voltage of the auxiliary power winding, including:

[0030] The third product is determined based on the product of the width of the hysteresis region and the capacitance of the bus capacitor in the resonant circuit.

[0031] The fourth product is determined based on the product of the inverter's load factor and the bus's rated current.

[0032] Based on the ratio of the third product to the fourth product, the switching time for stabilizing the supply voltage of the auxiliary power winding is determined.

[0033] In some embodiments, the method further includes:

[0034] If the inverter's load rate is greater than a set threshold at the current moment, the load carried by the inverter at the current moment is determined to be overloaded.

[0035] If the inverter's load rate is less than or equal to a set threshold at the current moment, the load carried by the inverter at the current moment is determined to be light load.

[0036] Secondly, this application provides a resonant converter system, comprising:

[0037] A resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary source winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding.

[0038] A processor for performing steps in the power supply control method as described in any of the first aspects.

[0039] Thirdly, this application provides an energy storage system, comprising:

[0040] The resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary source winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding.

[0041] The inverter has its input terminal connected to the end of the secondary bridge circuit equipped with a bus capacitor, and its output terminal connected to the load.

[0042] A processor for performing steps in the power supply control method as described in any of the first aspects.

[0043] In the technical solution provided in this application embodiment, the power supply control method covers various operating conditions, including the voltage range of the bus voltage output value being in the undervoltage region, hysteresis region, or overvoltage region, and the current inverter load state being in the light load or heavy load state. By accurately dividing the resonant circuit into multiple operating conditions, differentiated power supply voltage stabilization strategies can be matched. For example, for the first, second, or third operating conditions, the duty cycle of the resonant circuit switching transistor is adjusted to achieve power supply voltage stabilization. For the fourth operating condition, the voltage output value range switching time is determined based on the width of the hysteresis region and the inverter load rate to achieve power supply voltage stabilization. With the electrical voltage stable, the power supply control for other operating conditions corresponding to the hysteresis region is based on the power supply voltage stabilization strategy of the previous operating condition. This achieves precise control of the power supply voltage output of the auxiliary power source winding under multiple operating conditions, significantly reducing the interference of bus voltage fluctuations and load changes on the auxiliary power supply, improving the steady-state accuracy and anti-interference performance of the power supply, and effectively solving the technical problem of insufficient stability of the power supply voltage output of the auxiliary power source winding under wide-range fluctuations and load state changes. Thus, when the resonant circuit operates under multiple operating conditions, it can stabilize the output voltage of the auxiliary power source winding to ensure the normal operation of the electrical load powered by the auxiliary power source circuit. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A schematic diagram of the circuit structure of a push-pull half-bridge resonant circuit provided for some embodiments;

[0046] Figure 2 A schematic diagram illustrating the change in voltage output value during voltage hysteresis control of a resonant circuit with respect to the voltage at the bus, provided for some embodiments;

[0047] Figure 3 A flowchart illustrating a power supply control method provided in some embodiments;

[0048] Figure 4 A schematic diagram of the circuit structure of a resonant converter system provided for some embodiments;

[0049] Figure 5 A circuit diagram of an energy storage system provided for some embodiments. Detailed Implementation

[0050] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0052] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. In the description of the embodiments of this application, "each" means each of the multiple options, unless otherwise explicitly defined.

[0053] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0054] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0055] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] Figure 1A schematic diagram of the circuit structure of a push-pull half-bridge resonant circuit provided in some embodiments, such as... Figure 1 As shown, the push-pull half-bridge resonant circuit includes a primary bridge circuit, a secondary bridge circuit, and a transformer T1.

[0057] The transformer T1 includes a primary winding on the primary side and a secondary winding on the secondary side. The primary winding includes a first winding L1 and a second winding L2. The secondary winding includes an auxiliary power supply winding L3 and a secondary main winding L4. The auxiliary power supply winding L3 provides power supply voltage to the auxiliary power supply circuit of the subsequent stage.

[0058] The primary-side bridge circuit is connected to the primary winding, and the secondary-side bridge circuit is connected to the secondary main winding. The primary-side bridge circuit includes a first switch Q1 connected to the first winding L1 and a second switch Q2 connected to the second winding L2; the secondary-side bridge circuit includes a third switch Q3 and a fourth switch Q4, which form a half-bridge circuit.

[0059] In the push-pull operation mode, the first switch Q1 and the second switch Q2 on the primary side are alternately turned on under the control of complementary PWM drive signal. By providing alternating current to the first winding L1 and the second winding L2 of transformer T1 respectively, alternating magnetic flux is generated in the transformer core, thereby realizing the transfer of electrical energy to the secondary winding of transformer T1.

[0060] In the primary side of the push-pull half-bridge resonant circuit, the first conducting terminal of the first switch Q1 is connected to the negative terminal of the battery BAT through the first capacitor C1, and the second conducting terminal of the first switch Q1 is connected to the positive terminal of the battery BAT through the first winding L1. The first conducting terminal of the second switch Q2 is connected to the negative terminal of the battery BAT through the first capacitor C1, and the second conducting terminal of the second switch Q2 is connected to the positive terminal of the battery BAT through the second winding L2.

[0061] On the secondary side of the push-pull half-bridge resonant circuit, both ends of the auxiliary power supply winding L3 are connected to the auxiliary power supply circuit to output power supply voltage. The secondary main winding L4 is connected to the input terminal of the half-bridge circuit formed by the third switch Q3 and the fourth switch Q4. The output terminal of the half-bridge circuit is connected to the input terminal of the inverter, and the output terminal of the inverter is connected to the electrical load. The connection point between the inverter and the half-bridge circuit is the bus, i.e., the connection point between the inverter and the secondary bridge circuit is the bus. The bus voltage BUS_+ is as follows. Figure 1 As shown. A bus capacitor Cs is connected in parallel to the output of the half-bridge circuit.

[0062] The resonant circuit in the embodiments of this application can be Figure 1 The push-pull half-bridge resonant circuit shown can be... Figure 1The push-pull half-bridge resonant circuit shown can be a modified circuit or other types of resonant circuits. This application does not limit this. Any resonant circuit whose secondary winding includes a secondary main winding and an auxiliary source winding, and which can implement the method in this application, should be within the protection scope of this application.

[0063] The auxiliary power supply circuit can provide drive voltage to related devices. For example, the related devices can be, but are not limited to, relays. When the supply voltage output from the auxiliary power supply winding to the auxiliary power supply circuit is low, the drive voltage provided by the auxiliary power supply circuit to the related devices will also be low, easily leading to drive failure of the related devices. Therefore, improving the reliability of the supply voltage provided by the auxiliary power supply winding to the auxiliary power supply circuit is of crucial importance.

[0064] The supply voltage provided by the auxiliary power supply winding to the auxiliary power supply circuit is obtained by inducing alternating magnetic flux in the transformer core through electromagnetic induction. This alternating magnetic flux is generated by the alternating current of the primary winding or the alternating current of the secondary main winding. The supply voltage provided by the auxiliary power supply winding to the auxiliary power supply circuit is easily affected by the operating conditions of the resonant circuit, resulting in low reliability of the supply voltage provided to the auxiliary power supply circuit.

[0065] In the embodiments of this application, the switching transistors in the primary-side bridge circuit are called primary-side switching transistors, which include a first switching transistor Q1 and a second switching transistor Q2. The switching transistors in the secondary-side bridge circuit are called secondary-side switching transistors, which include a third switching transistor Q3 and a fourth switching transistor Q4.

[0066] Based on this, this application provides a power supply control method that can stabilize the output voltage of the auxiliary power supply winding to ensure the normal operation of the electrical load powered by the auxiliary power supply circuit.

[0067] The method described in this application embodiment can be applied to a processor. Exemplarily, the processor can be disposed in a resonant converter system, which may further include a resonant circuit. Exemplarily, the processor is used to connect a switching transistor in the resonant circuit and stabilize the supply voltage of the auxiliary power supply winding by adjusting the duty cycle of the switching transistor in the resonant circuit.

[0068] The processor in this application embodiment may include any one or more of the following integrated components: general-purpose processor, application-specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field-programmable gate array (FPGA), central processing unit (CPU), graphics processing unit (GPU), embedded neural-network processing unit (NPU), controller, microcontroller, microprocessor, programmable logic device, discrete gate or transistor logic device, discrete hardware component, quantum computing-based data processing logic unit, artificial intelligence (AI) processor, etc. Exemplarily, the general-purpose processor may be a microprocessor or any conventional processor.

[0069] Before describing the method in the embodiments of this application, the voltage hysteresis control strategy of the bus voltage in the resonant circuit will be explained. Hysteresis control involves comparing the controlled variable with a hysteresis control upper limit and a hysteresis control lower limit. When the controlled variable exceeds the hysteresis control upper limit, it switches to a first operating state; when the controlled variable falls below the hysteresis control lower limit, it switches to a second operating state, thus maintaining the controlled variable within the hysteresis region as much as possible in a closed-loop control method.

[0070] Figure 2 This diagram illustrates the change in voltage output value during a voltage hysteresis control process with respect to the bus voltage in some embodiments of the resonant circuit. The hysteresis control can be a PI loop control process, used to regulate the bus voltage BUS_+ at the aforementioned bus BUS. In the hysteresis control, V bus_ref The target value for the bus voltage, V bus_high It is the upper limit of the bus voltage output value during the hysteresis control process, V bus_low This is the lower limit of the voltage output value during hysteresis control. The hysteresis width of hysteresis control = V bus_high -V bus_low And V bus_high -V bus_ref =V bus_ref -Vbus_low The current bus voltage output value is less than V. bus_low At that time, the bus voltage output value is in the undervoltage region; at that time, the bus voltage output value is greater than or equal to V. bus_low And less than or equal to V bus_high At that time, the bus voltage output value is in the hysteresis region; at that time, the bus voltage output value is greater than V. bus_high At that time, the voltage output value of the bus is in the overvoltage zone.

[0071] During the time interval 0 to t1, the bus voltage output value is in the undervoltage region. The primary-side switching transistor is controlled to generate a waveform (the duty cycle of the primary-side switching transistor is set to a preset upper limit), and the bus voltage output value gradually increases. When the bus voltage output value reaches V... bus_low When the voltage output value of the bus enters the hysteresis region, it continues the control state of the undervoltage region, that is, the primary-side switching transistor continues to generate waves (the duty cycle of the primary-side switching transistor is the preset upper limit value), and the voltage output value of the bus continues to rise.

[0072] In this embodiment, the switching transistor waveform refers to the switching transistor performing high-frequency, periodic on and off actions according to a set duty cycle and frequency.

[0073] At time t2, the bus voltage output value exceeds V. bus_high Upon entering the overvoltage region, the primary-side switching transistor stops transmitting voltage (the duty cycle of the primary-side switching transistor is 0). As the power of the bus is consumed, the bus voltage output value begins to decrease. Figure 2 In the illustrated embodiment, after time t2, the bus voltage output value continues to rise slightly because the bus voltage output value is detected to have reached V. bus_high There is a certain reaction time required before the stop signal transmission command is issued. When the bus voltage output value drops back to V... bus_high When the bus enters the hysteresis region, it continues the control state of the overvoltage region, that is, the primary-side switching transistor stops generating waves (the duty cycle of the primary-side switching transistor is 0), and the voltage output value of the bus continues to decrease.

[0074] After time t3, the bus voltage output value is lower than V. bus_low Upon entering the undervoltage region, the primary-side switching transistor begins to generate a waveform (the duty cycle of the primary-side switching transistor is at a preset upper limit value), providing power to the bus, and the bus voltage output value begins to rise. Figure 2 In the illustrated embodiment, after time t3, the bus voltage output value continues to drop slightly because the bus voltage output value is detected to have reached V. bus_low There is a certain reaction time before the waveform transmission command is issued. The bus voltage output value begins to rise after the primary-side switching transistor transmits the waveform, enters the hysteresis region, and repeats the cycle.

[0075] In hysteresis control, when the bus voltage output is in the undervoltage region, the duty cycle of the primary-side switch is controlled to the preset upper limit. The preset upper limit is ideally 50%. However, in practical applications, considering switch operation delay and dead time, the range is typically set to 45%~48%, for example, preset upper limits of 45%, 46%, 47%, or 48%. Dead time refers to the brief period within a switching cycle during which the control strategy forces two complementary switches to be simultaneously off. For example, ... Figure 1 As shown, after the first switch Q1 is turned off, the second switch Q2 is turned on after a certain delay; after the second switch Q2 is turned off, the first switch Q1 is also turned on after a certain delay. This delay time is called the dead zone.

[0076] During hysteresis control, when the bus voltage output value is in the overvoltage region, the duty cycle of the primary-side switch is adjusted to 0, the primary-side switch stops emitting waves, and waits for the bus voltage output value to drop.

[0077] During hysteresis control, if the bus voltage output value enters the hysteresis region from the overvoltage region, the duty cycle of the primary-side switch in the hysteresis region is the same as the duty cycle corresponding to the overvoltage region, i.e., the duty cycle of the primary-side switch is 0. If the bus voltage output value enters the hysteresis region from the undervoltage region, the duty cycle of the primary-side switch in the hysteresis region is the same as the duty cycle corresponding to the undervoltage region, i.e., the duty cycle of the primary-side switch is the preset upper limit value.

[0078] like Figure 1 As shown, after the primary-side switching transistors (including the first switching transistor Q1 and the second switching transistor Q2) are turned off, the transformer T1 no longer transmits electrical energy, and the electrical energy of the auxiliary power supply winding L3 cannot be replenished, causing the voltage to drop rapidly. At this time, the secondary-side switching transistors, including the third switching transistor Q3 and the fourth switching transistor Q4, can be turned on, allowing current to flow through the secondary-side main winding L4. The secondary-side main winding L4 generates a magnetic field, which passes through the auxiliary power supply winding L3. According to Faraday's law of electromagnetic induction, when the magnetic flux through the closed coil changes, an induced electromotive force is generated in the coil. Therefore, turning on the secondary-side switching transistors can provide a certain amount of electrical energy to the auxiliary power supply winding, maintaining the supply voltage of the auxiliary power supply winding. At the same time, turning on the secondary-side switching transistors will consume the bus power, causing the bus voltage output value to drop to the undervoltage region more rapidly.

[0079] The auxiliary power supply circuit is powered by the auxiliary winding. The supply voltage provided by the auxiliary winding is determined based on the turns ratio of the first winding L1 and the second winding L2, the voltage of the battery BAT, and the duty cycles of the primary and secondary switching transistors. The turns ratio of the first winding L1 and the second winding L2 is fixed, and the voltage of the battery BAT can also be considered constant. Therefore, the supply voltage provided by the auxiliary winding is controlled by the duty cycles of the primary and secondary switching transistors. In the resonant circuit, the primary and secondary switching transistors control the bus voltage, thereby providing a stable bus voltage for the inverter. They have the highest priority. Therefore, the control in this embodiment stabilizes the supply voltage of the auxiliary winding while satisfying the bus voltage control requirements.

[0080] The bus voltage output value is affected by the inverter's operating state. The following section differentiates between different operating conditions and provides corresponding control strategies. The bus connects to the inverter, and the inverter's load state can be divided into: light load (inverter load rate ≤ set threshold) and heavy load (inverter load rate > set threshold). The inverter load rate is the ratio of the inverter's current load to its rated load. The bus voltage output value can be in the overvoltage region, hysteresis region, or undervoltage region.

[0081] The power supply control method in this embodiment is applied to a resonant circuit, which includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary power supply winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding.

[0082] Figure 3 A flowchart illustrating a power supply control method provided in some embodiments, such as Figure 3 As shown, the method includes steps S301 to S304.

[0083] S301. Obtain the voltage range of the voltage output value of the current bus voltage hysteresis control and the load state of the inverter; the bus voltage is the voltage at the connection between the secondary bridge circuit and the inverter, the voltage range includes the undervoltage region, hysteresis region or overvoltage region, and the load state includes light load or heavy load. Any voltage range and any load state form a working condition of the resonant circuit.

[0084] The voltage output value of the bus voltage under voltage hysteresis control (which can be simply referred to as the bus voltage output value, or simply the voltage output value) can be: the bus voltage output value of the resonant circuit under the voltage hysteresis control of the bus voltage.

[0085] The hysteresis region is a defined bus voltage reference range, the undervoltage region is the range where the voltage is less than the minimum value of the bus voltage reference range, and the overvoltage region is the range where the voltage is greater than the maximum value of the bus voltage reference range. For example, the bus voltage reference range is V... bus_low To V bus_high The voltage range. The minimum value of the bus voltage reference range is V. bus_low The maximum value V of the bus voltage reference range bus_high .

[0086] For example, the voltage output value of the bus can be obtained by measuring the voltage of the bus.

[0087] The load factor of the inverter connected to the resonant circuit at the current moment is the ratio of the actual power of the load carried by the inverter to the rated power of the load that the inverter can withstand. In some embodiments, if the load factor of the inverter at the current moment is greater than a set threshold, it is determined that the current moment is under heavy load. In some embodiments, if the load factor of the inverter at the current moment is less than or equal to the set threshold, it is determined that the current moment is under light load. The set threshold is a real number greater than 0 and less than 1. The value range of the set threshold can be 0.1 to 0.5. For example, the set threshold is 0.1, 0.3, or 0.5.

[0088] In some embodiments, the threshold value can be a preset value. In other embodiments, the threshold value can be determined based on the maximum allowable duration for which the supply voltage output by the auxiliary power winding is less than the preset voltage threshold. For example, if the supply voltage output by the auxiliary power winding is less than the preset voltage threshold, the driving voltage output by the auxiliary power circuit will also be less than the preset voltage threshold. When the auxiliary power circuit drives the relay, if the relay's driving voltage is less than the preset threshold for a duration exceeding the maximum allowable duration, the relay may disengage. Therefore, a maximum allowable duration for which the supply voltage output by the auxiliary power winding is less than the preset voltage threshold can be set.

[0089] For example, the maximum allowable duration can be the maximum tolerable duration for which the drive voltage required for the relay to remain on is less than a preset voltage threshold.

[0090] S302. When the current operating condition is the first, second, or third operating condition, the duty cycle of the switching transistor in the resonant circuit is adjusted to stabilize the power supply voltage of the auxiliary power winding.

[0091] The first operating condition is under the condition of undervoltage and light load, the second operating condition is under the condition of undervoltage and heavy load, and the third operating condition is under the condition of overvoltage and light load.

[0092] In some embodiments, adjusting the duty cycle of the switching transistor in the resonant circuit may include: adjusting the duty cycle of the primary-side switching transistor in the resonant circuit. In some embodiments, adjusting the duty cycle of the switching transistor in the resonant circuit may include: adjusting the duty cycle of the secondary-side switching transistor in the resonant circuit. In some embodiments, adjusting the duty cycle of the switching transistor in the resonant circuit may include: adjusting the duty cycle of both the primary-side and secondary-side switching transistors in the resonant circuit.

[0093] In this embodiment of the application, a stable supply voltage of the auxiliary power supply winding can mean that the supply voltage of the auxiliary power supply winding can support the auxiliary power circuit to drive the operation of related devices, or it can mean that the voltage value of the supply voltage of the auxiliary power supply winding is less than a preset voltage threshold for a duration not exceeding the maximum allowable duration.

[0094] S303. When the current operating condition is in the fourth condition, based on the width of the hysteresis region and the load rate of the inverter, determine the switching time of the voltage output value from the overvoltage region to the undervoltage region in order to stabilize the power supply voltage of the auxiliary power winding.

[0095] The fourth operating condition is the condition of being in the overpressure zone and under heavy load.

[0096] It is worth noting that at the current moment, in the fourth operating condition, the voltage output value of the bus voltage under voltage hysteresis control is in the overvoltage region, and the load rate of the inverter's load is heavy. To stabilize the auxiliary power supply voltage, from the current moment onwards, the control process of the switching transistors that maintains the bus voltage in the overvoltage region of voltage hysteresis control during the switching time is as follows: According to the aforementioned voltage hysteresis control process, the duty cycle of the primary-side switching transistors is maintained at 0 during the switching time, meaning that all primary-side switching transistors are kept in the off state during the switching time. Since the inverter is connected to the resonant circuit at this time... If the load is heavy, the bus voltage will automatically drop to a stable value during the switching time. After the switching time, the control process of the switching transistor to maintain the bus voltage in the undervoltage region of voltage hysteresis control is carried out. That is, after the switching time, the duty cycle of the primary-side switching transistor is controlled to the preset upper limit value. In other words, after the switching time, the primary-side switching transistor is turned on and the duty cycle of the drive signal of the primary-side switching transistor is the preset upper limit value. Since the supply voltage of the auxiliary power winding is affected by the bus voltage, the supply voltage of the auxiliary power winding can be maintained accordingly after the bus voltage drops to a stable value.

[0097] It is worth noting that during the control of the stable auxiliary power supply voltage in the fourth operating condition, the rate of decrease of the bus voltage is related to the load factor of the load carried by the inverter, the parameters of the auxiliary power supply winding, and the parameters of the secondary main winding.

[0098] S304. When the current operating condition is in another operating condition where the voltage range is in the hysteresis region, the same power supply voltage stabilization strategy as the target range shall be executed. The target range is the voltage range corresponding to the previous operating condition.

[0099] The target range is the voltage range corresponding to the previous operating condition under other operating conditions.

[0100] It is worth noting that other operating conditions may include the fifth or sixth operating condition. The fifth operating condition may be a condition in the hysteresis zone and under light load, while the sixth operating condition may be a condition in the hysteresis zone and under heavy load.

[0101] In some embodiments, the power supply voltage stabilization strategy for the fifth operating condition is the same as the power supply voltage stabilization strategy for the operating condition preceding the fifth operating condition. In other embodiments, the power supply voltage stabilization strategy for the sixth operating condition is the same as the power supply voltage stabilization strategy for the operating condition preceding the sixth operating condition.

[0102] In the technical solution provided in this application embodiment, the power supply control method covers various operating conditions, including the voltage range of the bus voltage output value being in the undervoltage region, hysteresis region, or overvoltage region, and the current inverter load state being in the light load or heavy load state. By accurately dividing the resonant circuit into multiple operating conditions, differentiated power supply voltage stabilization strategies can be matched. For example, for the first, second, or third operating conditions, the duty cycle of the resonant circuit switching transistor is adjusted to achieve power supply voltage stabilization. For the fourth operating condition, the power supply voltage stabilization is achieved by determining the voltage output value range switching time based on the width of the hysteresis region and the inverter load rate. Other operating conditions corresponding to the hysteresis region are based on... The power supply voltage stabilization strategy of the previous operating condition is used for power supply control, which realizes precise control of the power supply voltage output of the auxiliary power source winding under multiple operating conditions. It significantly reduces the interference of bus voltage fluctuation and load change on the auxiliary power supply, improves the steady-state accuracy and anti-disturbance performance of the power supply, simplifies the control logic in the hysteresis region, reduces the control oscillation caused by voltage output fluctuation near the critical value, and effectively solves the technical problem of insufficient stability of the power supply voltage output of the auxiliary power source winding under wide fluctuation and load state change scenarios. Thus, when the resonant circuit operates under multiple operating conditions, it can stabilize the output voltage of the auxiliary power source winding to ensure the normal operation of the electrical load powered by the auxiliary power source circuit.

[0103] The following describes the control process of the auxiliary power supply voltage for the aforementioned six operating conditions.

[0104] Regarding the first, second, and third working conditions:

[0105] As before, in the first operating condition (undervoltage and light load), the second operating condition (undervoltage and heavy load), and the third operating condition (overvoltage and light load), the duty cycle of the switching transistor in the resonant circuit is adjusted to stabilize the supply voltage of the auxiliary power winding.

[0106] In some embodiments, when the current operating condition is a first condition (undervoltage and light-load condition) or a second condition (undervoltage and heavy-load condition), the supply voltage of the auxiliary power supply winding is stabilized based on the duty cycle of the switching transistor of the regulating resonant circuit, including:

[0107] The primary duty cycle is adjusted to a preset upper limit to stabilize the supply voltage of the auxiliary power winding;

[0108] Wherein, the primary-side duty cycle is the duty cycle of the switching transistor in the primary-side bridge circuit.

[0109] For example, the preset upper limit value can be the preset upper limit value of the primary-side switching transistor. For example, the range of the preset upper limit value can be 45% to 50%. For example, the preset upper limit value can be 45%, 46%, 47%, 48%, 49%, or 50%.

[0110] In this embodiment, since the voltage output value of the bus voltage hysteresis control is in the undervoltage region in the first operating condition (undervoltage region and light load condition) and the second operating condition (undervoltage region and heavy load condition), the duty cycle of the drive signal of the primary-side switch is at a preset upper limit value in the undervoltage region. Thus, when the duty cycle of the primary-side switch is set to the preset upper limit value, it can be ensured that the auxiliary power winding obtains sufficient energy, thereby enabling the auxiliary power winding to provide sufficient power supply voltage to the subsequent auxiliary power circuit.

[0111] For example, stabilizing the supply voltage of the auxiliary power winding by adjusting the primary-side duty cycle to a preset upper limit value can include: adjusting the primary-side duty cycle to the preset upper limit value and adjusting the secondary-side duty cycle to 0 to stabilize the supply voltage of the auxiliary power winding. It should be noted that although the secondary-side duty cycle is 0, the electrical energy output from the secondary-side primary winding will be transferred to the bus through the body diode in the secondary-side switching transistor. Here, the secondary-side duty cycle refers to the duty cycle of the switching transistor in the secondary-side bridge circuit.

[0112] In other embodiments, when the current operating condition is the third condition (overvoltage region and light load condition), the supply voltage of the auxiliary power supply winding is stabilized based on the duty cycle of the switching transistor of the resonant circuit, including:

[0113] Step A1: Determine the target secondary duty cycle based on the parameters of the secondary winding and the bus current value.

[0114] Step A2: Based on adjusting the secondary duty cycle to the target secondary duty cycle, stabilize the power supply voltage of the auxiliary power winding; wherein, the secondary duty cycle is the duty cycle of the switching transistor of the secondary bridge circuit.

[0115] It is worth noting that in the third operating condition, the voltage output value of the bus voltage hysteresis control is in the overvoltage region. According to the aforementioned hysteresis control process, when the bus voltage is in the overvoltage region, the duty cycle of the primary-side switch is maintained at 0, that is, the primary-side switch is closed. At this time, the resonant circuit no longer charges the bus and no longer supplies energy to the auxiliary power winding. Therefore, in the third operating condition, it is necessary to compensate for the coil energy of the auxiliary power winding.

[0116] Understandably, when current flows through the coil of the secondary main winding, a magnetic field is generated. When the magnetic field passes through the auxiliary power winding, an induced current is generated on the auxiliary power winding. When the secondary switching transistor is driven, it consumes energy on the bus, causing the bus voltage to drop rapidly. At the same time, it transfers some energy to the auxiliary power winding, reducing the rate at which the supply voltage of the auxiliary power winding drops.

[0117] In this embodiment, the parameters of the secondary winding include the permeability of the secondary primary winding. The number of the first turns of the secondary main winding The radius of the secondary main winding and the rate of change of current in the secondary main winding The second number of turns of the auxiliary power winding The winding area of ​​the auxiliary power source winding and the magnetic circuit constant of the auxiliary source winding The cosine θ of the angle between the direction of the magnetic field generated by the secondary main winding and the normal direction of the auxiliary source winding. The rate of change of current in the secondary main winding is also considered. It refers to the rate of change of the current in the secondary main winding during the response time of the secondary switch being turned on or the response time of the secondary switch being turned off.

[0118] In this embodiment of the application, regarding step A1: determining the target secondary duty cycle based on the parameters of the secondary winding and the bus current value, the steps include A11 to A14.

[0119] Step A11: Determine the first product based on the product of permeability, first number of turns, rate of change of current, second number of turns, winding area, and cosine of the included angle.

[0120] Wherein, the first product is the permeability. First number of turns Current change rate Second number of turns Winding area and the cosine of the included angle The product of . The first product is expressed as . .

[0121] Step A12: Determine the first ratio based on the ratio of the first product to twice the radius.

[0122] The first ratio is the first product. With twice the radius The ratio. The first ratio is expressed as .

[0123] Step A13: Determine the second product based on the product of the magnetic circuit constant and the bus current value.

[0124] The second product is the magnetic circuit constant. With bus current value The product of . The second product is expressed as .

[0125] Step A14: Determine the target secondary side duty cycle based on the ratio of the first ratio to the second product.

[0126] In some embodiments, step A14 may include: setting the first ratio With the second product The ratio is determined as the initial secondary side duty cycle. : ,so, Greater than 0; based on the initial secondary edge duty cycle Determine the target secondary duty cycle .

[0127] Target secondary duty cycle It also needs to meet the requirement of being less than or equal to the preset upper limit value of the secondary-side switch; therefore, the initial secondary-side duty cycle If the initial secondary duty cycle is less than or equal to the preset upper limit value of the secondary switch, the duty cycle will be... Determined as the target secondary duty cycle ; initial secondary side duty cycle If the value exceeds the preset upper limit of the secondary-side switch, the preset upper limit of the secondary-side switch is determined as the target secondary-side duty cycle. .

[0128] For example, the preset upper limit value of the secondary-side switch tube may be the same as or different from the preset upper limit value of the primary-side switch tube, and this application embodiment does not limit this.

[0129] The following explanation is for any resonant circuit with an auxiliary source winding and a secondary main winding. The derivation method:

[0130] The formula for calculating the magnetic flux density generated by the secondary winding when the secondary switch is turned on is as follows: ;in, The magnetic flux density generated by the secondary winding (unit: T). The permeability of the secondary winding with a magnetic core is k × 4π × 10⁻⁶. −7H / m, where k is related to the core material; This represents the current in the secondary winding of the primary winding (unit: A). The number of turns of the secondary main winding. Radius of the secondary main winding (unit: m).

[0131] The formula for calculating the induced electromotive force generated by the auxiliary power source winding is: ;in, The induced electromotive force generated by the auxiliary power winding is measured in volts (V). For the number of turns of the auxiliary power source winding, The area of ​​the auxiliary power winding is expressed in square meters (m²). 2 ), It is the angle between the direction of the magnetic field generated by the secondary main winding and the normal to the auxiliary source winding. t represents the magnetic flux density generated by the secondary winding (unit: T), and t represents time.

[0132] Therefore, the induced electromotive force generated by the auxiliary source winding can be derived. Current of the secondary main winding The relationship between them: ;in, This represents the rate of change of current in the secondary winding, which is the same as the rate of change of current in the secondary switching transistor. This information can be obtained from the datasheet of the secondary-side switching transistor.

[0133] When the secondary-side switching transistor is turned on, it provides electrical energy to the auxiliary power winding. The amount of electrical energy increases within a certain range as the duty cycle of the secondary-side switching transistor increases. By changing the duty cycle of the secondary-side switching transistor, the power supply can be controlled. This allows control of the induced electromotive force generated by the auxiliary power winding. Size, bus current value Duty cycle and induced electromotive force of the secondary switch They show a positive correlation. Among them, ;in, The magnetic circuit constant of the auxiliary power source winding is related to the number of turns, winding radius, and core material. The duty cycle of the secondary switch transistor. Given the bus current value, the duty cycle of the secondary switching transistor can be obtained when it is necessary to maintain a stable supply voltage to the auxiliary power winding. With bus current value The relationship between them is Therefore, to maintain a stable supply voltage to the auxiliary winding, the bus current value... The smaller the value, the higher the duty cycle of the secondary switching transistor needs to be. The larger the value, the lower the bus current value. The larger the value, the higher the duty cycle required for the secondary-side switching transistor. The smaller.

[0134] Due to the induced electromotive force generated by the auxiliary power winding Current of the secondary main winding The relationship between them is and bus current value Duty cycle and induced electromotive force of the secondary switch Positive correlation So, if the auxiliary power supply circuit requires a voltage of... ,So , Therefore, the formula can be obtained. ,because It needs to be greater than or equal to 0, so that we can get .

[0135] Regarding the fourth working condition:

[0136] In some embodiments, when the current time is in the fourth operating condition (in the overvoltage region and heavy load condition), the switching time of the bus voltage output value from the overvoltage region to the undervoltage region is determined based on the width of the hysteresis region and the load rate of the inverter. Based on the switching time, the voltage output value is switched from the overvoltage region through the hysteresis region to the undervoltage region to stabilize the supply voltage of the auxiliary power winding. This prevents the bus voltage output from failing to switch from the overvoltage zone to the undervoltage zone within the switching time, which would prevent timely power supply to the auxiliary winding by controlling the primary-side switching transistor. Consequently, the auxiliary winding would be unable to reliably supply power to the auxiliary circuit. Therefore, by calculating the switching time of the bus voltage output from the overvoltage zone to the undervoltage zone, the bus voltage output can be switched from the overvoltage zone to the undervoltage zone within this switching time. After the switching time, the duty cycle of the primary-side switching transistor is promptly set to the value corresponding to the undervoltage zone. This prevents the auxiliary winding's supply voltage from dropping to its limit when the inverter is under heavy load and the bus voltage is in the overvoltage zone, thereby improving the stability of the supply voltage provided by the auxiliary winding.

[0137] In some embodiments, the switching time for the bus voltage output value to switch from the overvoltage region to the undervoltage region is determined based on the width of the hysteresis region and the load rate of the inverter, including the following steps B1 to B3.

[0138] Step B1: Determine the third product based on the product of the width of the hysteresis region and the capacitance of the bus capacitor in the resonant circuit.

[0139] Where the third product is the width of the hysteresis region. The capacitance value of the bus capacitor The product of . The third product is expressed as .

[0140] Step B2: Determine the fourth product based on the product of the inverter's load rate and the bus's rated current.

[0141] Where the fourth product is the inverter's load factor. and the rated current of the busbar The product of . The fourth product is expressed as .

[0142] Step B3: Based on the ratio of the third product to the fourth product, determine the switching time for stabilizing the supply voltage of the auxiliary power winding.

[0143] Among them, switching time The third product With the fourth product The ratio. Switching time. .

[0144] In some embodiments, the set threshold for determining whether a system is under light or heavy load can be based on... Confirmed. For example, the following is how to determine the threshold: Obtain the maximum allowable duration for which the supply voltage value output by the auxiliary winding is less than the preset voltage threshold; substitute the maximum allowable duration into the formula. In Calculated To set a threshold.

[0145] The following explanation The derivation method:

[0146] The bus voltage output value changes from the overvoltage region to the undervoltage region by at least reducing the width of the hysteresis region. ,remember When the primary-side switch of the resonant circuit is off, the electrical energy of the auxiliary power winding is provided by the bus capacitor. When the charge of the bus capacitor is consumed, the voltage of the bus capacitor drops. The relationship between the voltage, capacitance, and charge of the bus capacitor is as follows: ;in, The voltage (V) of the bus capacitor is expressed in volts. This represents the charge on the busbar capacitor, measured in coulombs (C). Here, represents the capacitance of the bus capacitor, measured in farads (F). Since the capacitance of the bus capacitor is fixed, if a voltage drop of ΔU is required on the bus, the amount of charge in the bus capacitor needs to be reduced by ΔU. .

[0147] Under normal circumstances, the time for the control loop to switch from the overvoltage region to the undervoltage region is not too long, therefore the switching time... The current can be considered constant when the load rate is... At that time, the bus current value is The amount of charge that needs to be reduced in the bus capacitor is related to the bus current value, that is... ;in, The rated current of the busbar is expressed in amperes (A). This is for switching time.

[0148] According to the formula , and We can obtain the following expression: Therefore, we can obtain .

[0149] Given that the inverter is currently under heavy load, the bus voltage output value needs to be... It moves from the overvoltage zone to the undervoltage zone.

[0150] For example, based on the switching time, the voltage output value is switched from the overvoltage region through the hysteresis region to the undervoltage region to stabilize the power supply voltage of the auxiliary power winding, including: during the switching time, controlling the duty cycle of the drive signal of the primary-side switch of the primary-side bridge circuit to be zero so that the voltage output value switches from the overvoltage region through the hysteresis region to the undervoltage region; after the switching time, controlling the duty cycle of the drive signal of the primary-side switch to a preset upper limit value to stabilize the power supply voltage of the auxiliary power winding.

[0151] Regarding the fifth and sixth operating conditions:

[0152] As before, the power supply voltage stabilization strategy for the fifth operating condition (the operating condition in the hysteresis region and light load) is the same as the power supply voltage stabilization strategy for the operating condition corresponding to the target range before entering the fifth operating condition.

[0153] In some embodiments, if the target interval before entering the fifth operating condition is an undervoltage region at the current moment, then the operating condition corresponding to the fifth operating condition is the first operating condition, and the same power supply voltage stabilization strategy as the first operating condition is executed: based on adjusting the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power supply winding.

[0154] Specifically, if the operating condition before entering the fifth operating condition is the first operating condition, the same power supply voltage stabilization strategy as the first operating condition is executed: based on adjusting the primary side duty cycle to a preset upper limit value, the power supply voltage of the auxiliary power supply winding is stabilized, and the primary side duty cycle is the duty cycle of the switching transistor of the primary side bridge circuit.

[0155] In some embodiments, if the target range before entering the fifth operating condition is an overvoltage zone at the current moment, then the operating condition before entering the fifth operating condition is the third operating condition, and the same power supply voltage stabilization strategy as the third operating condition is executed: based on the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power supply winding.

[0156] Specifically, if the operating condition before entering the fifth operating condition is the third operating condition, the same power supply voltage stabilization strategy as the third operating condition is executed, that is, the power supply voltage stabilization strategy is executed according to the aforementioned steps A1 to A2, which will not be repeated here.

[0157] As before, the power supply voltage stabilization strategy for the sixth operating condition (the operating condition in the hysteresis region and under heavy load) is the same as the power supply voltage stabilization strategy for the operating condition corresponding to the target range before entering the sixth operating condition.

[0158] In some embodiments, if the target interval before entering the sixth operating condition is an undervoltage region at the current moment, then the operating condition corresponding to the sixth operating condition is the second operating condition, and the same power supply voltage stabilization strategy as the second operating condition is executed: based on adjusting the duty cycle of the switching transistor of the resonant circuit, to stabilize the power supply voltage of the auxiliary power supply winding.

[0159] Specifically, if the operating condition before entering the sixth operating condition is the second operating condition, the same power supply voltage stabilization strategy as the second operating condition is executed: based on adjusting the primary side duty cycle to the preset upper limit value, the power supply voltage of the auxiliary power supply winding is stabilized, and the primary side duty cycle is the duty cycle of the switching transistor of the primary side bridge circuit.

[0160] In some embodiments, if the target range before entering the sixth operating condition is an overvoltage zone at the current moment, then the operating condition before entering the sixth operating condition is the fourth operating condition, and the same power supply voltage stabilization strategy as the fourth operating condition is executed: based on the width of the hysteresis zone and the inverter load rate, the switching time of the voltage output value from the overvoltage zone to the undervoltage zone is determined to stabilize the power supply voltage of the auxiliary power winding.

[0161] Specifically, if the operating condition before entering the sixth operating condition is the fourth operating condition, the same power supply voltage stabilization strategy as the fourth operating condition is executed, that is, the power supply voltage stabilization strategy is executed according to the aforementioned steps B1 to B3, which will not be repeated here.

[0162] Figure 4 A circuit structure diagram of a resonant converter system provided for some embodiments, such as Figure 4 As shown, the resonant converter system includes a resonant circuit and a processor. The resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary power supply winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. The processor is used to execute the steps in the power supply control method of any embodiment of this application. The auxiliary power supply winding is used to connect to the auxiliary power supply circuit.

[0163] For example, both the primary-side bridge circuit and the secondary-side bridge circuit are connected to the processor.

[0164] For example, the primary-side bridge circuit includes a primary-side switch, and the secondary-side bridge circuit includes a secondary-side switch. The control terminals of the switches in both the primary-side and secondary-side bridge circuits can be connected to a processor, so that the processor can regulate the duty cycle of the switches.

[0165] For example, the first end of the secondary main winding is connected to the positive terminal of the bus, and the second end of the secondary main winding is connected to the ground terminal of the bus.

[0166] Figure 5 A circuit structure diagram of an energy storage system is provided for some embodiments, such as Figure 5 As shown, the energy storage system includes a resonant circuit, an inverter, and a processor. The resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary power supply winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. The inverter input is connected to the end of the secondary bridge circuit that has a bus capacitor, and the inverter output is used to connect to a load. The processor is used to execute the steps in the power supply control method of any embodiment of this application. The auxiliary power supply winding is used to connect to the auxiliary power supply circuit.

[0167] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0168] The above embodiments merely illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application's patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A power supply control method applied to a resonant circuit, characterized in that, The resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary source winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. The method includes: The voltage range of the voltage output value of the voltage hysteresis control of the bus voltage at the current moment and the load state of the inverter are obtained; the bus voltage is the voltage at the connection between the secondary bridge circuit and the inverter; the voltage range includes the undervoltage region, hysteresis region or overvoltage region; the load state includes light load or heavy load; any voltage range and any load state form an operating condition of the resonant circuit. When the current operating condition is the first, second, or third operating condition, the power supply voltage of the auxiliary source winding is stabilized by adjusting the duty cycle of the switching transistor of the resonant circuit. When the current operating condition is the fourth condition, the switching time for the voltage output value to switch from the overvoltage region to the undervoltage region is determined based on the width of the hysteresis region and the load rate of the inverter, so as to stabilize the power supply voltage of the auxiliary power winding. When the voltage range is in other operating conditions that are currently in the hysteresis region, the same power supply voltage stabilization strategy as the target range is executed. The target range is the voltage range that corresponds to the other operating conditions. Wherein, the first operating condition is the operating condition of being in the undervoltage zone and the light load condition, the second operating condition is the operating condition of being in the undervoltage zone and the heavy load condition, the third operating condition is the operating condition of being in the overvoltage zone and the light load condition, and the fourth operating condition is the operating condition of being in the overvoltage zone and the heavy load condition; the hysteresis zone is the period in which the voltage output value is within a set bus voltage reference range, the undervoltage zone is the period in which the voltage output value is less than the minimum value of the bus voltage reference range, and the overvoltage zone is the period in which the voltage output value is greater than the maximum value of the bus voltage reference range.

2. The method according to claim 1, characterized in that, When the current operating condition is either the first or the second operating condition, the supply voltage of the auxiliary source winding is stabilized by adjusting the duty cycle of the switching transistor in the resonant circuit, including: The supply voltage of the auxiliary power winding is stabilized by adjusting the primary duty cycle to a preset upper limit value. Wherein, the primary-side duty cycle is the duty cycle of the switching transistor in the primary-side bridge circuit.

3. The method according to claim 1, characterized in that, When the current operating condition is described in the third condition, the supply voltage of the auxiliary power supply winding is stabilized by adjusting the duty cycle of the switching transistor in the resonant circuit, including: The target secondary duty cycle is determined based on the parameters of the secondary winding and the bus current value. The power supply voltage of the auxiliary source winding is stabilized by adjusting the secondary duty cycle to the target secondary duty cycle. Wherein, the duty cycle of the secondary side is the duty cycle of the switching transistor in the secondary side bridge circuit.

4. The method according to claim 1, characterized in that, The other operating conditions include a fifth operating condition, which is the operating condition within the hysteresis region and the light load condition. When the current time is within the fifth operating condition where the voltage range is the hysteresis region, the same power supply voltage stabilization strategy as the target range is executed, including: If the target interval is undervoltage before entering the fifth operating condition at the current moment, then the operating condition corresponding to the fifth operating condition is the first operating condition, and the same power supply voltage stabilization strategy as the first operating condition is executed: based on adjusting the duty cycle of the switching transistor of the resonant circuit, the power supply voltage of the auxiliary source winding is stabilized. If the target range before entering the fifth operating condition is an overvoltage zone at the current moment, then the operating condition before entering the fifth operating condition is the third operating condition, and the same power supply voltage stabilization strategy as the third operating condition is executed: based on adjusting the duty cycle of the switching transistor of the resonant circuit, the power supply voltage of the auxiliary source winding is stabilized.

5. The method according to claim 1, characterized in that, The other operating conditions include a sixth operating condition, which is the operating condition within the hysteresis region and the heavy load condition. When the current time is within the sixth operating condition where the voltage range is the hysteresis region, the same power supply voltage stabilization strategy as the target range is executed, including: If the target interval before entering the sixth operating condition is an undervoltage region at the current moment, then the operating condition before entering the sixth operating condition is the second operating condition, and the same power supply voltage stabilization strategy as the second operating condition is executed: based on adjusting the duty cycle of the switching transistor of the resonant circuit, the power supply voltage of the auxiliary source winding is stabilized. If the target range before entering the sixth operating condition is an overvoltage zone at the current moment, then the operating condition before entering the sixth operating condition is the fourth operating condition. The same power supply voltage stabilization strategy as the fourth operating condition is executed: based on the width of the hysteresis zone and the load rate of the inverter, the switching time of the voltage output value from the overvoltage zone to the undervoltage zone is determined to stabilize the power supply voltage of the auxiliary power winding.

6. The method according to claim 3, characterized in that, The parameters of the secondary winding include the permeability of the secondary main winding, the first number of turns of the secondary main winding, the radius of the secondary main winding and the rate of change of current of the secondary main winding, the second number of turns of the auxiliary source winding, the winding area of ​​the auxiliary source winding and the magnetic circuit constant of the auxiliary source winding, and the cosine value of the angle between the direction of the magnetic field generated by the secondary main winding and the normal direction of the auxiliary source winding; Determining the target secondary duty cycle based on the parameters of the secondary winding and the bus current value includes: The first product is determined based on the product of the permeability, the first number of turns, the rate of change of current, the second number of turns, the winding area, and the cosine of the included angle. The first ratio is determined based on the ratio of the first product to twice the radius. The second product is determined based on the product of the magnetic circuit constant and the bus current value; The target secondary edge duty cycle is determined based on the ratio of the first ratio to the second product.

7. The method according to any one of claims 1-6, characterized in that, The step of determining the switching time for the voltage output value to switch from the overvoltage region to the undervoltage region based on the width of the hysteresis region and the load rate of the inverter, in order to stabilize the supply voltage of the auxiliary power winding, includes: The third product is determined based on the product of the width of the hysteresis region and the capacitance of the bus capacitor in the resonant circuit; The fourth product is determined based on the product of the inverter's load rate and the bus's rated current; The switching time for stabilizing the power supply voltage of the auxiliary power source winding is determined based on the ratio of the third product to the fourth product.

8. The method according to any one of claims 1 to 6, characterized in that, The method further includes: If the load rate of the inverter is greater than a set threshold at the current moment, the load carried by the inverter at the current moment is determined to be a heavy load. When the load rate of the inverter at the current moment is less than or equal to the set threshold, the load carried by the inverter at the current moment is determined to be light load.

9. A resonant converter system, characterized in that, include: A resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary source winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. as well as A processor for performing the steps in the power supply control method as described in any one of claims 1 to 8.

10. An energy storage system, characterized in that, include: A resonant circuit includes a transformer, a secondary bridge circuit, and a primary bridge circuit. The transformer includes a primary winding and a secondary winding. The secondary winding includes an auxiliary source winding and a secondary main winding. The secondary bridge circuit and the primary bridge circuit are respectively connected to the secondary main winding and the primary winding. An inverter, wherein the input terminal of the inverter is connected to one end of the secondary bridge circuit that is provided with a bus capacitor, and the output terminal of the inverter is used to connect to a load; as well as A processor for performing the steps in the power supply control method as described in any one of claims 1 to 8.

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