Auxiliary source power supply control method, resonant conversion system and energy storage system

Abstract

The application relates to an auxiliary power supply control method, a resonant conversion system and an energy storage system. The method comprises the following steps: determining the switching time of the voltage output value of the voltage hysteresis control of the bus voltage from the overvoltage area to the under-voltage area based on the load rate of the heavy load connected to the inverter, the capacitance of the bus capacitor and the bus voltage reference range of the voltage hysteresis control of the bus voltage; the bus voltage is the voltage at the connection position of the inverter and the auxiliary bridge circuit; based on the switching time, the voltage output value is switched from the overvoltage area to the under-voltage area through the hysteresis area, so as to stabilize the power supply voltage of the auxiliary winding. By adopting the application, the power supply voltage of the auxiliary winding can be prevented from falling to the limit value when the inverter carries a heavy load and the bus voltage is in the overvoltage area, and the stability of the power supply voltage provided by the auxiliary winding is improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to an auxiliary 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 resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary source winding and a secondary main winding connected to the secondary bridge circuit. The secondary bridge circuit is also used to connect to an inverter.

[0004] The auxiliary power winding provides the supply voltage to the subsequent auxiliary power circuit. This supply voltage is typically affected by the range of the voltage output value in the voltage hysteresis control process related to the bus voltage and the load connected to the inverter. The bus voltage is the voltage at the connection point between the secondary bridge circuit and the inverter. When the equipment connected to the inverter is under heavy load, its operating power is high, and energy consumption on the bus is rapid. Furthermore, when the aforementioned voltage output value is in the overvoltage region—that is, when the voltage output value exceeds the upper limit of the bus voltage reference range—the primary-side switch of the primary bridge circuit is in the off state. This causes the supply voltage provided by the auxiliary power winding to drop rapidly, resulting in an unstable supply voltage. Summary of the Invention

[0005] Based on this, this application provides an auxiliary power supply control method, a resonant conversion system, and an energy storage system, which can quickly provide power to the auxiliary power winding when the supply voltage of the auxiliary power winding drops rapidly, thereby improving the stability of the supply voltage provided by the auxiliary power winding.

[0006] In a first aspect, this application provides an auxiliary power supply control method applied to a resonant circuit. The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary power supply winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter. The method includes:

[0007] Based on the load rate of the heavy load connected to the inverter, the capacitance value of the bus capacitor, and the reference range of the bus voltage for voltage hysteresis control, the switching time of the voltage output value of the bus voltage for voltage hysteresis control from the overvoltage region to the undervoltage region is determined. The bus voltage is the voltage at the connection between the inverter and the secondary bridge circuit.

[0008] 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.

[0009] Specifically, when the voltage output value is greater than the upper limit of the bus voltage reference range, it is in the overvoltage zone; when the voltage output value is within the bus voltage reference range, it is in the hysteresis zone; and when the voltage output value is less than the lower limit of the bus voltage reference range, it is in the undervoltage zone.

[0010] In some embodiments, based on the load rate of the heavy load connected to the inverter, the capacitance value of the bus capacitor, and the bus voltage reference range of the bus voltage hysteresis control, the switching time of the voltage output value of the bus voltage from the overvoltage region to the undervoltage region is determined, including:

[0011] Based on the preset upper limit and preset lower limit, the voltage squared difference value for the hysteresis region is determined. The preset upper limit and preset lower limit are the upper limit and lower limit of the bus voltage reference range, respectively.

[0012] The operating power for heavy electrical loads is determined by multiplying the load rate and the rated power of the load that the inverter can handle.

[0013] The switching time is determined based on the capacitance value, the squared difference of the voltage, and the operating power.

[0014] In some embodiments, determining the voltage squared difference with respect to the hysteresis region based on a preset upper limit and a preset lower limit includes:

[0015] The difference between the square of the preset upper limit value and the square of the preset lower limit value is determined as the voltage square difference value.

[0016] In some embodiments, the operating power of the heavy-load electrical load is determined based on the product of the load rate and the rated power of the load that the inverter can handle, including:

[0017] The product of the load factor and the rated power of the load that the inverter can withstand is determined as the operating power for heavy electrical loads.

[0018] In some embodiments, the switching time is determined based on capacitance, the squared voltage difference, and operating power, including:

[0019] The target product is determined based on the product of the capacitance and the squared difference of the voltage.

[0020] The target ratio is determined based on the ratio of the target product to the operating power.

[0021] The switching time is determined based on the target ratio.

[0022] In some embodiments, determining the switching time based on a target ratio includes:

[0023] The ratio of the target ratio to 2 is determined as the switching time.

[0024] In some embodiments, 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, including:

[0025] During the switching time, the duty cycle of the drive signal of the primary-side switching transistor of the primary-side bridge circuit is zero, so that the voltage output value switches from the overvoltage region through the hysteresis region to the undervoltage region.

[0026] After the switching time, the duty cycle of the drive signal controlling the primary-side switching transistor is set to the maximum allowable duty cycle to stabilize the power supply voltage of the auxiliary power winding.

[0027] Secondly, this application provides a resonant converter system, comprising:

[0028] The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary power winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter.

[0029] A processor for performing steps in the auxiliary power supply control method as described in any of the first aspects.

[0030] Thirdly, this application provides an energy storage system, characterized in that it includes:

[0031] The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary source winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter.

[0032] 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.

[0033] A processor for performing steps in the auxiliary power supply control method as described in any of the first aspects.

[0034] Fourthly, this application provides a computer storage medium storing a computer program, which, when executed by a processor, implements the steps of the auxiliary power supply control method of any one of the first aspects.

[0035] In the technical solution provided in this application, based on the load rate of the heavy load connected to the inverter, the capacitance value of the bus capacitor, and the reference range of the bus voltage hysteresis control, the switching time of the voltage output value of the bus voltage hysteresis control from the overvoltage region to the undervoltage region is accurately determined. 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 can prevent the bus voltage output value from failing to switch from the overvoltage region to the undervoltage region within the switching time, thus preventing the failure to start the primary-side switching transistor in time. The problem arises because the auxiliary power winding cannot reliably supply power to the auxiliary power circuit. Therefore, by calculating the switching time of the bus voltage output value from the overvoltage region to the undervoltage region, the bus voltage output value can be switched from the overvoltage region to the undervoltage region within this switching time. After the switching time, the duty cycle of the primary-side switch is set to the value corresponding to the undervoltage region in time to prevent the supply voltage of the auxiliary power winding from dropping to the limit value when the inverter is carrying a heavy load and the bus voltage is in the overvoltage region, thereby improving the stability of the supply voltage provided by the auxiliary power winding. Attached Figure Description

[0036] 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.

[0037] Figure 1 A schematic diagram of the circuit structure of a push-pull half-bridge resonant circuit provided for some embodiments;

[0038] Figure 2 A schematic diagram illustrating the change in voltage output value at the bus of a resonant circuit provided in some embodiments under voltage hysteresis control;

[0039] Figure 3 A flowchart illustrating an auxiliary power supply control method provided in some embodiments;

[0040] Figure 4 A flowchart illustrating a method for determining switching time provided in some embodiments;

[0041] Figure 5 A flowchart illustrating a method for stabilizing the supply voltage of an auxiliary power winding by switching the voltage output value from an overvoltage region through a hysteresis region to an undervoltage region based on switching time, as provided in some embodiments.

[0042] Figure 6 A schematic diagram of the circuit structure of a resonant converter system provided for some embodiments;

[0043] Figure 7 A circuit diagram of an energy storage system provided for some embodiments. Detailed Implementation

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In the description of this application, it should be noted that, unless otherwise explicitly 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 for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of 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.

[0050] Figure 1 A 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] The resonant circuit in the embodiments of this application can be Figure 1 The push-pull half-bridge resonant circuit shown can be... Figure 1 The 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.

[0057] The auxiliary power supply circuit can provide drive voltage to related devices. Exemplarily, 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 critical importance. In some embodiments, the drive voltage can be equal to the supply voltage.

[0058] In this embodiment, 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.

[0059] The auxiliary power supply winding provides the power supply voltage to the auxiliary power circuit 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. When the load connected to the inverter is heavily loaded and the voltage output value controlled by the voltage hysteresis loop of the bus voltage is in the overvoltage region, the bus voltage is high, and the battery no longer supplies power to the bus. Because the load of the inverter connected to the bus is heavily loaded and the operating power of the electrical equipment is high, the energy consumption on the bus is relatively fast. Furthermore, when the voltage output value controlled by the voltage hysteresis loop of the bus voltage is in the overvoltage region, that is, when the voltage output value is greater than the upper limit of the bus voltage reference range, the primary-side switch of the primary bridge circuit is in the off state. This causes the power supply voltage provided by the auxiliary power winding to drop rapidly, resulting in an unstable power supply voltage.

[0060] Based on this, the present application provides an auxiliary power supply control method that can quickly provide power to the auxiliary power winding before the supply voltage of the auxiliary power winding drops to the limit value, thereby improving the stability of the supply voltage provided by the auxiliary power winding.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Figure 2This diagram illustrates the voltage output value change at the bus of a resonant circuit provided in some embodiments under voltage hysteresis control. 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 in hysteresis control, V bus_low This is the lower limit of the bus voltage output value in hysteresis control. The hysteresis width of hysteresis control = V bus_high -V bus_low And V bus_high -V bus_ref =V bus_ref -V bus_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.

[0065] 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 the maximum allowable duty cycle), 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 switch continues to generate waves (the duty cycle of the primary-side switch is the maximum allowable duty cycle), and the voltage output value of the bus continues to rise.

[0066] 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.

[0067] 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_highWhen 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.

[0068] At 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 the maximum allowable duty cycle), 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.

[0069] 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 maximum allowable duty cycle. The maximum allowable duty cycle is ideally 50%. However, in practical applications, considering switch operation delay and dead time, the range is typically set to 45%~48%, for example, the maximum allowable duty cycle is 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.

[0070] 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.

[0071] 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 maximum allowable duty cycle.

[0072] like Figure 1As 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.

[0073] 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.

[0074] The core focus of this application's embodiments is the auxiliary power supply control method under the target operating condition, where the current operating condition is the bus voltage output value being in the overvoltage zone and the inverter's electrical load being heavy.

[0075] The auxiliary power supply control method in this application embodiment is executed under the target operating condition where the resonant circuit is currently in operation. The target operating condition is when the bus voltage output value is in the overvoltage region and the inverter's electrical load is heavily loaded. The auxiliary power supply control method will be described below.

[0076] The auxiliary power supply control method in this embodiment is applied to a resonant circuit. The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary power supply winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter.

[0077] The first and second AC terminals of the secondary bridge circuit are connected to the two ends of the secondary main winding, respectively. The positive DC terminal of the secondary bridge circuit is connected to the inverter via the positive bus, and the negative DC terminal is connected to the inverter via the negative bus. The negative bus can be grounded. The port of the secondary bridge circuit connected to the inverter is formed by the positive and negative DC terminals of the secondary bridge circuit. A bus capacitor is connected between the positive and negative DC terminals of the secondary bridge circuit; that is, the positive DC terminal of the secondary bridge circuit is connected to the first terminal of the bus capacitor, and the negative DC terminal is connected to the second terminal of the bus capacitor.

[0078] Figure 3 A flowchart illustrating the auxiliary power supply control method provided in some embodiments, such as... Figure 3 As shown, the method includes the following steps S301 to S302.

[0079] S301. Based on the load rate of the heavy load connected to the inverter, the capacitance value of the bus capacitor, and the reference range of the bus voltage for voltage hysteresis control, determine the switching time of the voltage output value of the bus voltage for voltage hysteresis control from the overvoltage region to the undervoltage region. The bus voltage is the voltage at the connection between the inverter and the secondary bridge circuit.

[0080] Specifically, when the voltage output value is greater than the upper limit of the bus voltage reference range, it is in the overvoltage zone; when the voltage output value is within the bus voltage reference range, it is in the hysteresis zone; and when the voltage output value is less than the lower limit of the bus voltage reference range, it is in the undervoltage zone.

[0081] The term "power load" for an inverter refers to the electrical load connected to the inverter being considered a power load. In some embodiments, a power load connected to the inverter can be determined as a power load based on its actual power. For example, a power load connected to the inverter is determined to be a power load when its actual power is greater than or equal to a preset power threshold. In other embodiments, a power load connected to the inverter can be determined as a power load based on the load rate of the load connected to the inverter. For example, a power load connected to the inverter is determined to be a power load when its load rate is greater than a set threshold. The set threshold is a real number greater than 0 and less than 1.

[0082] Among them, the load factor of the heavy load connected to the inverter is the ratio of the actual power of the heavy load carried by the inverter to the power of the rated load that the inverter can withstand.

[0083] The threshold value can be set to a range of 0.1 to 0.5. For example, the threshold can be set to 0.1, 0.3, or 0.5. In some embodiments, the threshold can be a preset value. In other embodiments, the threshold can be determined based on the maximum allowable duration for which the supply voltage output by the auxiliary winding is less than the preset voltage threshold. For example, if the supply voltage output by the auxiliary winding is less than the preset voltage threshold, since the supply voltage output by the auxiliary winding is the same as the drive voltage output by the auxiliary circuit, the drive voltage output by the auxiliary circuit will be less than the preset voltage threshold. When the auxiliary circuit drives the relay, if the relay's drive voltage is less than the preset threshold for a duration exceeding the maximum allowable duration, the relay may fall off. Therefore, a maximum allowable duration for which the supply voltage output by the auxiliary winding is less than the preset voltage threshold can be set.

[0084] In this application's embodiments, the maximum allowed duration is greater than or equal to the target duration. In some embodiments, the maximum allowed duration is greater than the target duration. For example, the target duration is the difference between the maximum allowed duration and a preset duration margin. In other embodiments, the maximum allowed duration is equal to the target duration.

[0085] 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.

[0086] The bus voltage reference range (which can be simply referred to as the bus voltage reference range) under the voltage hysteresis control of the bus voltage can be: the bus voltage reference range of the resonant circuit under the voltage hysteresis control of the bus voltage.

[0087] The voltage values ​​within the bus voltage reference range are continuous. For example, the bus voltage reference range is the aforementioned hysteresis control lower limit value V. bus_low To the upper limit of hysteresis control V bus_high The voltage range. The lower limit of the bus voltage reference range is V. bus_low The upper limit of the bus voltage reference range is V. bus_high .

[0088] In some embodiments, the upper limit of the bus voltage reference range can be the maximum allowable operating voltage of the bus, and the lower limit can be the minimum allowable operating voltage of the bus. In other embodiments, the upper limit of the bus voltage reference range can be the difference between the maximum allowable operating voltage of the bus and a first offset, and the lower limit can be the sum of the minimum allowable operating voltage of the bus and a second offset. The first offset and the second offset can be the same or different. Exemplarily, both the first offset and the second offset can be negatively correlated with the capacitance value of the bus.

[0089] 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.

[0090] For example, the voltage output value of the bus can be obtained by measuring the voltage of the bus.

[0091] S302. 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.

[0092] In some embodiments, the duty cycle of the switching transistor in the resonant circuit can be adjusted during the switching time to stabilize the power supply voltage of the auxiliary power supply winding.

[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] It is worth noting that when the voltage output value is in the overvoltage region during the voltage hysteresis control process of the bus voltage, the duty cycle of the primary-side switch is 0. Furthermore, due to the heavy load on the inverter at this time, the voltage generated by the auxiliary power winding can easily drop rapidly. If the bus voltage output value does not switch from the overvoltage region to the undervoltage region for an extended period, the supply voltage output by the auxiliary power winding may fall below the preset voltage threshold, leading to a risk of power failure for the components driven by the auxiliary power circuit, thus reducing the stability of the supply voltage provided by the auxiliary power winding. Therefore, calculating the switching time of the voltage output value from the overvoltage region to the undervoltage region is crucial to improving the stability of the supply voltage provided by the auxiliary power winding.

[0095] In this way, the duration for which the supply voltage output by the auxiliary power winding is less than the preset voltage threshold does not exceed the maximum allowable duration, thus reducing the risk of power failure when the auxiliary power circuit drives related devices.

[0096] In the technical solution provided in this application, based on the load rate of the heavy load connected to the inverter, the capacitance value of the bus capacitor, and the reference range of the bus voltage hysteresis control, the switching time of the voltage output value of the bus voltage hysteresis control from the overvoltage region to the undervoltage region is accurately determined. 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 can prevent the bus voltage output value from failing to switch from the overvoltage region to the undervoltage region within the switching time, thus preventing the failure to start the primary-side switching transistor in time. The problem arises because the auxiliary power winding cannot reliably supply power to the auxiliary power circuit. Therefore, by calculating the switching time of the bus voltage output value from the overvoltage region to the undervoltage region, the bus voltage output value can be switched from the overvoltage region to the undervoltage region within this switching time. After the switching time, the duty cycle of the primary-side switch is set to the value corresponding to the undervoltage region in time to prevent the supply voltage of the auxiliary power winding from dropping to the limit value when the inverter is carrying a heavy load and the bus voltage is in the overvoltage region, thereby improving the stability of the supply voltage provided by the auxiliary power winding.

[0097] Figure 4 A flowchart illustrating a method for determining switching time provided in some embodiments, such as... Figure 4 As shown, Figure 4 The method of the embodiment is an exemplary interpretation of S301, which includes steps S3011 to S3013.

[0098] S3011. Based on the preset upper limit and preset lower limit, determine the voltage squared difference value for the hysteresis region.

[0099] The preset upper limit and preset lower limit are the upper limit and lower limit of the bus voltage reference range, respectively.

[0100] For example, S3011 may include: determining the difference between the square of a preset upper limit value and the square of a preset lower limit value as a voltage square difference value.

[0101] For example, the voltage squared difference is expressed as ;in, This is a preset upper limit value, which is the upper limit of the bus voltage reference range. This is the preset lower limit value, which is the lower limit of the bus voltage reference range.

[0102] S3012. Determine the operating power for heavy-load electrical use based on the product of the load rate and the rated power of the load that the inverter can withstand.

[0103] The rated power of the load that the inverter can withstand can be the rated load power of the inverter.

[0104] For example, S3012 may include: determining the operating power of the heavy load by multiplying the load rate and the rated power of the load that the inverter can withstand.

[0105] For example, the operating power of a heavy electrical load is expressed as: ;in, This refers to the rated power of the load that the inverter can withstand. The load rate of the heavy-load electrical load connected to the inverter.

[0106] S3013. Based on capacitance, voltage squared difference, and operating power, determine the switching time.

[0107] For example, S3013 may include: determining a target product based on the product of capacitance and the squared difference of voltage; determining a target ratio based on the ratio of the target product to the operating power; and determining a switching time based on the target ratio.

[0108] For example, the target product can be the product of the capacitance value and the squared difference of the voltage. The target product can be expressed as: Where C is the capacitance value of the bus capacitor; This represents the squared difference in voltage.

[0109] For example, the target ratio can be the ratio of the target product to the operating power. The target ratio can be expressed as... ;in, For the target product, This refers to the operating power under heavy electrical load.

[0110] Among them, determining the switching time based on the target ratio includes: determining the switching time as the ratio of the target ratio to 2.

[0111] For example, switching time Represented as .

[0112] In some embodiments, a set threshold for determining that the electrical load connected to the inverter is a heavy load can be based on Sure; To switch time, This refers to the load rate of the heavily loaded electrical load connected to the inverter. The following is the method for determining the set threshold: Obtain the maximum allowable duration for which the supply voltage output from the auxiliary power winding is less than the preset voltage threshold; substitute the maximum allowable duration into the formula. In Calculated This means setting a threshold.

[0113] The following explanation is for any resonant circuit with an auxiliary source winding and a secondary main winding. The derivation method:

[0114] Bus capacitor current value The capacitance value of the bus capacitor Voltage value of bus capacitor The following relationship exists between them: .

[0115] Since the voltage value of the bus capacitor is the same as the voltage output value of the bus, therefore, ;in This is the bus current value. This is the voltage output value of the bus.

[0116] pass and The formula can be derived as follows: ;in, This represents the actual power of the electrical load connected to the inverter. That is, we obtain... .

[0117] For the formula At the initial moment, both sides To the target time Integrating between them, we obtain the formula. Since the switching time between the overvoltage and undervoltage regions of the voltage output is very short, the actual power of the electrical load connected to the inverter can be considered constant. ,and .Will Defined as the switching time of the voltage output value from the overvoltage region to the undervoltage region. The formula is obtained. .

[0118] Because it is necessary to calculate the switching time of the voltage output value from the overvoltage region to the undervoltage region, and to calculate the voltage output value from... Descending to The switching time will be preset to an upper limit. Substitute into the formula In and the preset lower limit value Substitute into the formula In The formula is obtained. .

[0119] Figure 5 A flowchart illustrating a method for stabilizing the supply voltage of an auxiliary power winding by switching the voltage output value from an overvoltage region through a hysteresis region to an undervoltage region based on switching time, as provided in some embodiments, is shown below. Figure 5 As shown, Figure 5 The method of the embodiment is an exemplary interpretation of S302, which includes steps S3021 to S3022.

[0120] S3021. During the switching time, the duty cycle of the drive signal of the primary-side switching transistor of the primary-side bridge circuit is zero, so that the voltage output value switches from the overvoltage region through the hysteresis region to the undervoltage region.

[0121] In this embodiment, the duty cycle of the drive signal for the secondary switch of the secondary bridge circuit is not limited during the switching time. For example, during the switching time, the duty cycle of the drive signal controlling the secondary switch of the secondary bridge circuit is 0. Another example is that during the switching time, the duty cycle of the drive signal controlling the secondary switch of the secondary bridge circuit is the maximum permissible duty cycle. Yet another example is that during the switching time, the duty cycle of the drive signal controlling the secondary switch of the secondary bridge circuit is a duty cycle greater than 0 and less than the maximum permissible duty cycle.

[0122] S3022. After the switching time, the duty cycle of the drive signal of the primary-side switching transistor is controlled to the maximum allowable duty cycle in order to stabilize the power supply voltage of the auxiliary power winding.

[0123] After the switching time, while controlling the duty cycle of the drive signal of the primary-side switch transistor of the primary-side bridge circuit to the maximum allowable duty cycle, the duty cycle of the drive signal of the secondary-side switch transistor of the secondary-side bridge circuit is also controlled to be 0.

[0124] In the technical solution provided in this application embodiment, when switching from the current operating condition to the target operating condition, where the electrical load connected to the inverter is heavily loaded and the bus voltage output value is in the overvoltage region, during the switching time, the duty cycle of the drive signal of the primary-side switch transistor of the primary-side bridge circuit is controlled 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, the duty cycle of the drive signal of the primary-side switch transistor is controlled to the maximum allowable duty cycle. Thus, when the voltage value of the drive voltage output by the auxiliary power winding is less than the preset voltage threshold for the target duration, the duty cycle of the drive signal of the primary-side switch transistor is controlled to the maximum allowable duty cycle to provide power to the auxiliary power winding, so that the voltage value of the drive voltage output by the auxiliary power winding is greater than the preset voltage threshold. In this way, when the supply voltage of the auxiliary power winding drops rapidly, power can be quickly provided to the auxiliary power winding, improving the stability of the supply voltage provided by the auxiliary power winding.

[0125] Figure 6 A circuit structure diagram of a resonant converter system provided for some embodiments, such as Figure 6As shown, the resonant converter system includes a resonant circuit and a processor. The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary power supply winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor Cs is provided at the port of the secondary bridge circuit connected to the inverter. The processor is used to execute the steps in the auxiliary power supply control method in any embodiment of this application. The resonant converter system also includes an auxiliary power supply circuit, and the auxiliary power supply winding is connected to the auxiliary power supply circuit.

[0126] For example, both the primary-side bridge circuit and the secondary-side bridge circuit are connected to the processor.

[0127] 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.

[0128] Figure 7 A circuit structure diagram of an energy storage system is provided for some embodiments, such as Figure 7 As shown, the energy storage system includes a resonant circuit, an inverter, and a processor. The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary power supply winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor Cs is provided at the port of the secondary bridge circuit connected to the inverter. The inverter input terminal is connected to the end of the secondary bridge circuit where the bus capacitor Cs is provided, and the inverter output terminal is used to connect to a load. The processor is used to execute the steps in the auxiliary power supply control method in any embodiment of this application. The bus capacitor Cs is included in the energy storage system. The energy storage system also includes an auxiliary power supply circuit, and the auxiliary power supply winding is connected to the auxiliary power supply circuit.

[0129] In one embodiment, a computer storage medium is provided, in which a computer program is stored, which, when executed by a processor, implements the steps of the method provided in any of the above embodiments.

[0130] 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.

[0131] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. 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. An auxiliary power supply control method, applied to a resonant circuit, characterized in that, The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary source winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter. The method includes: Based on preset upper and lower limits, the voltage squared difference value for the hysteresis region is determined. The preset upper and lower limits are respectively the upper limit and lower limit of the bus voltage reference range for the voltage hysteresis control of the bus voltage; the bus voltage is the voltage at the connection between the inverter and the secondary bridge circuit. The operating power of the heavy-load electrical load is determined by multiplying the load rate of the heavy-load electrical load connected to the inverter with the rated power of the load that the inverter can withstand. The target product is determined based on the product of the capacitance value of the bus capacitor and the square difference of the voltage. The target ratio is determined based on the ratio of the target product to the operating power. The ratio of the target ratio to 2 is determined as the switching time of the voltage output value of the bus voltage hysteresis control from the overvoltage region to the undervoltage region. 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. Specifically, when the voltage output value is greater than the upper limit of the bus voltage reference range, it is in the overvoltage region; when the voltage output value is within the bus voltage reference range, it is in the hysteresis region; and when the voltage output value is less than the lower limit of the bus voltage reference range, it is in the undervoltage region.

2. The method according to claim 1, characterized in that, The step of determining the voltage squared difference value with respect to the hysteresis region based on preset upper and lower limits includes: The difference between the square of the preset upper limit value and the square of the preset lower limit value is determined as the voltage square difference value.

3. The method according to claim 1, characterized in that, The determination of the operating power of the heavy-load electrical load based on the product of the load rate of the heavy-load electrical load connected to the inverter and the rated power of the load that the inverter can withstand includes: The product of the load rate and the rated power of the load that the inverter can withstand is determined as the operating power of the heavy-load electrical load.

4. The method according to any one of claims 1-3, characterized in that, The step of switching the voltage output value from the overvoltage region through the hysteresis region to the undervoltage region based on the switching time, in order to stabilize the supply voltage of the auxiliary power winding, includes: During the switching time, the duty cycle of the drive signal of the primary-side switch of the primary-side bridge circuit is zero, so that the voltage output value switches from the overvoltage region through the hysteresis region to the undervoltage region. After the switching time, the duty cycle of the drive signal of the primary-side switching transistor is controlled to the maximum allowable duty cycle to stabilize the power supply voltage of the auxiliary power winding.

5. A resonant converter system, characterized in that, include: The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary source winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter. as well as A processor for performing the steps in the auxiliary power supply control method as described in any one of claims 1 to 4.

6. An energy storage system, characterized in that, include: The resonant circuit includes a transformer, a primary bridge circuit, and a secondary bridge circuit. The transformer includes a secondary winding and a primary winding connected to the primary bridge circuit. The secondary winding includes an auxiliary source winding and a secondary main winding connected to the secondary bridge circuit. A bus capacitor is provided at the port of the secondary bridge circuit connected to the inverter. An inverter, wherein the input terminal of the inverter is connected to one end of the secondary bridge circuit where the bus capacitor is located, and the output terminal of the inverter is used to connect to the load; and A processor for performing the steps in the auxiliary power supply control method as described in any one of claims 1 to 4.

7. A computer storage medium, characterized in that, The computer storage medium stores a computer program, which, when executed by a processor, implements the steps of the auxiliary power supply control method according to any one of claims 1 to 4.

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