An isolated inverter circuit, an inverter circuit driving method, and an energy storage converter

Abstract

This application provides an isolated inverter circuit, an inverter circuit driving method, and an energy storage converter. The isolated inverter circuit includes a primary-side switching unit, a transformer unit, a secondary-side switching unit, and a controller. The primary-side switching unit is connected to the primary side of the transformer unit, and the secondary-side switching unit is connected to the secondary side of the transformer unit. The primary-side switching unit includes at least two switching circuits, and the transformer unit includes at least two transformer circuits. Each transformer circuit is connected to its primary side via a switching circuit, and the secondary sides of the transformer circuits are connected in series. In practical use, the controller can generate at least one drive control signal based on the load power of the load device connected to the secondary-side switching unit to control at least one switching circuit for power conversion. All switching circuits do not need to be in a constant power conversion state, which can reduce the additional power consumption of some switching circuits on the DC bus, achieving the effect of saving DC power.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to an isolated inverter circuit, an inverter circuit driving method, and an energy storage converter. Background Technology

[0002] An isolated inverter circuit is a circuit that converts DC to AC through power conversion. Its input and output sides are isolated from each other, which can effectively prevent interference from affecting the normal operation of the circuit. Due to its isolation characteristics, isolated inverter circuits are often used in scenarios such as vehicle current equipment and energy storage converters to convert the DC power output from the battery in the equipment into AC power and output it.

[0003] In order to meet the power conversion requirements when supplying power to load devices according to the rated load power, traditional isolated inverter circuits generate power consumption, which consumes the DC power at the input end and affects the battery life of DC power storage devices. Summary of the Invention

[0004] In view of this, embodiments of this application provide an isolated inverter circuit, an inverter circuit driving method, and an energy storage converter to reduce the power consumption of the isolated inverter circuit for DC power.

[0005] In a first aspect, embodiments of this application provide an isolated inverter circuit, the isolated inverter circuit comprising: a primary-side switching unit, a transformer unit, a secondary-side switching unit, and a controller; wherein: The primary-side switching unit is connected to the primary side of the transformer unit, and the secondary-side switching unit is connected to the secondary side of the transformer unit. The primary-side switching unit includes at least two switching circuits, and the transformer unit includes at least two transformer circuits; one end of one of the switching circuits is connected to the DC bus voltage signal, and the other end is connected to the primary side of one of the transformer circuits. The secondary side of each transformer circuit is connected in series and then connected to one end of the secondary side switching unit, and the other end of the secondary side switching unit is connected to the load device. The controller is connected to each of the switching circuits. The controller is used to output at least one drive control signal to the corresponding switching circuit according to the load power of the load device, so that at least one of the switching circuits performs power conversion in response to the drive control signal.

[0006] In a second aspect, embodiments of this application provide an inverter circuit driving method, the method being applied to a controller in an isolated inverter circuit as described in the first aspect, the method comprising: The load power of the load device connected to the isolated inverter circuit is obtained, and the drive control signal of at least one switching circuit in the isolated inverter circuit is determined according to the load power. The corresponding switching circuit in the isolated inverter circuit is controlled to perform power conversion based on the drive control signal.

[0007] Thirdly, embodiments of this application provide an energy storage converter device, which includes the isolated inverter circuit described in the first aspect.

[0008] Fourthly, embodiments of this application provide an electronic device, wherein the electronic device includes: a processor; and a memory storing a program; wherein the program includes instructions that, when executed by the processor, cause the processor to perform the inverter circuit driving method described in the second aspect.

[0009] Fifthly, embodiments of this application provide a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the inverter circuit driving method described in the second aspect.

[0010] The beneficial effects of this application are: This application provides an isolated inverter circuit, an inverter circuit driving method, and an energy storage converter. The isolated inverter circuit includes a primary-side switching unit, a transformer unit, a secondary-side switching unit, and a controller. The primary-side switching unit is connected to the primary side of the transformer unit, and the secondary-side switching unit is connected to the secondary side of the transformer unit. The primary-side switching unit includes at least two switching circuits, and the transformer unit includes at least two transformer circuits. The primary side of each transformer circuit is connected to the primary side through a switching circuit, and the secondary sides of the transformer circuits are connected in series. In actual use, the controller can generate at least one drive control signal based on the load power of the load device connected to the secondary-side switching unit, and at least one switching circuit performs power conversion.

[0011] By using the embodiments of this application, all the switching circuits in the isolated inverter circuit do not need to be in the power conversion state all the time, which can reduce the extra power consumption of some switching circuits on the DC bus terminal and achieve the effect of saving DC terminal power. Attached Figure Description

[0012] Further details, features, and advantages of this application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which: Figure 1 This application provides a schematic diagram of a circuit topology for a conventional isolated inverter circuit. Figure 2 A schematic diagram of a circuit topology for an isolated inverter circuit provided in this application is shown. Figure 3 A schematic diagram of a circuit topology for an isolated inverter circuit provided in this application is shown. Figure 4 This paper presents a schematic diagram of an output waveform of the high-voltage DC bus voltage HV_BUS obtained by the conventional isolated inverter circuit provided in this application. Figure 5 This paper shows a schematic diagram of an output waveform of the high-voltage DC bus voltage HV_BUS obtained by the isolated inverter circuit provided in this application. Figure 6 A schematic flowchart of the inverter circuit driving method provided in this application is shown; Figure 7 A structural block diagram of an exemplary electronic device that can be used to implement embodiments of this application is shown; Explanation of reference numerals in the attached figures: Q1~Q8: Switching transistors in the primary-side switching unit; Q9~Q12: Switching transistors in the first switching circuit; Q13~Q16: Switching transistors in the second switching circuit; T1: Transformer; C1~C5: Capacitors; L1~L3: Inductors; DRV1~DRV12: Drive control signals for the switching transistors; LV_BUS: Low-voltage DC bus voltage; HV_BUS: High-voltage DC bus voltage. Detailed Implementation

[0013] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0014] It should be understood that the steps described in the method embodiments of this application may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0015] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this application are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0016] It should be noted that the terms "a" and "a plurality of" used in this application are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0017] To facilitate understanding of the traditional isolated inverter circuit described in the background section, it can be combined with, for example... Figure 1 Understanding the circuit topology shown, the common internal circuit structure of a traditional isolated inverter circuit includes a primary-side switching unit, a transformer circuit, and a secondary-side switching unit. The primary-side switching unit and the secondary-side switching unit are separated by the transformer circuit. The primary-side switching unit is connected to the DC terminal and is used to convert the low-voltage DC bus voltage LV_BUS output from the DC terminal into low-voltage high-frequency AC power. This low-voltage high-frequency AC power is then output to the input terminal of the transformer circuit, where it is converted into high-voltage high-frequency AC power.

[0018] The secondary-side switching unit includes a primary-side switching circuit and a secondary-side switching circuit. The primary-side switching circuit rectifies the high-voltage, high-frequency AC power into high-voltage DC power (i.e., the high-voltage DC bus voltage HV_BUS). The secondary-side switching circuit then inverts this high-voltage DC power into power frequency AC power, which is then connected to the power grid via its output terminal (specifically, through the live and neutral wires). The primary-side switching unit and the primary-side switching circuit together constitute the isolated DC / DC circuit in the entire isolated inverter circuit, enabling electrical isolation and voltage boosting. This allows for the conversion of low-voltage DC power to high-voltage DC power, i.e., HV_BUS = LV_BUS * N, where N is the turns ratio of transformer T1 in the transformer circuit.

[0019] This isolated inverter circuit enables bidirectional energy conversion. The process described above converts DC power to AC power at the DC end. It can also convert AC power input from the grid into low-voltage DC power, which is then output to the DC end to charge the battery. The entire process of converting AC power to low-voltage DC power is the reverse of the above process. Specifically, the AC power is converted to high-voltage DC power by a secondary-side switching circuit, and then converted to high-voltage high-frequency AC power by a primary-side switching circuit. This high-voltage high-frequency AC power is then transformed by a transformer circuit to obtain low-voltage high-frequency AC power, which is finally inverted into low-voltage DC power by a primary-side switching unit and output to the DC end to charge the battery.

[0020] The output of this secondary-side switching circuit can also be connected to a load device to supply power. In practical applications of isolated inverter circuits, there are often situations requiring full-load operation (i.e., connected to a load device with rated power). To meet this full-load requirement, both the primary-side and secondary-side switching units (including the primary and secondary-side switching circuits) employ... Figure 1 The diagram shows a full-bridge topology switching circuit structure. This structure includes two bridge arms (a first bridge arm and a second bridge arm), each consisting of an upper bridge arm switching unit and a lower bridge arm switching unit connected in series.

[0021] In order to achieve redundant design and meet the requirement of increasing the current carrying capacity of the primary-side switching unit under full load, it is possible to... Figure 1 As shown, each upper arm switch unit of the primary side switch unit consists of two switches connected in parallel, and each lower arm switch unit also consists of two switches connected in parallel.

[0022] The primary-side switching unit includes: input bus capacitor C1, input bus capacitor C2, and switching transistors Q1 to Q8. Specifically, Q1 and Q3 are located on the upper arm of the first bridge arm, connected in parallel to form the upper bridge arm switching unit of the first bridge arm; Q2 and Q4 are located on the lower arm of the first bridge arm, connected in parallel to form the lower bridge arm switching unit of the first bridge arm. Q5 and Q7 are located on the upper arm of the second bridge arm, connected in parallel to form the upper bridge arm switching unit of the second bridge arm; Q6 and Q8 are located on the lower arm of the second bridge arm, connected in parallel to form the lower bridge arm switching unit of the second bridge arm.

[0023] In this configuration, two switches located in the same upper bridge arm (or the same lower bridge arm) are driven to turn on or off using the same drive control signal. For example, switches Q1 and Q3 in the upper bridge arm switch unit of the first bridge arm are driven by the same drive control signal DRV1, and the driving method for other switches follows the same principle.

[0024] Since this isolated DC / DC circuit is actually a resonant inverter circuit (i.e., primary-side switching unit + transformer circuit, or first switching circuit + transformer circuit), when a load device is connected to the output, the current flowing through transformer T1, inductor L1, and capacitor C3 in the resonant circuit of the isolated DC / DC circuit is large enough. At this time, the switching transistors Q1~Q12 in the primary-side switching unit and the first switching circuit have soft-switching conditions (i.e., the voltage drops to 0 before conduction and the current drops to 0 before turn-off), reducing the losses caused by voltage and current overlap. However, if no load device is connected to the output, the current in the entire resonant circuit is close to 0, causing the soft-switching condition to fail. At this time, when the switching transistors are turned on or off, the voltage and current will overlap, resulting in switching losses.

[0025] Furthermore, to meet the power conversion capacity under full load, the magnetic cores of the magnetic components in the entire isolated inverter circuit need to have the largest possible effective volume Ve and effective cross-sectional area Ae. This can easily lead to a situation where, once the output is not connected to a load (i.e., in an unloaded state), the entire primary-side switching unit + transformer circuit + first switching circuit needs to maintain a constant switching frequency and voltage output in order to keep the high-voltage DC bus voltage stable. This results in a larger fluctuation in the magnetic flux density of transformer T1 and inductor L1, and consequently, a larger magnetic loss in the magnetic components.

[0026] It is evident that traditional isolated inverter circuits, due to the special nature of their internal circuit structure, generate significant power consumption under no-load conditions, which impairs the DC-side battery life.

[0027] In view of this, this application provides an isolated inverter circuit, an inverter circuit driving method, and an energy storage converter. The isolated inverter circuit provided by this application reduces switching losses and magnetic losses of magnetic components in the entire isolated inverter circuit under no-load or low-load conditions, thereby reducing the negative impact of the isolated inverter circuit on battery life when no-loaded.

[0028] In one aspect, this application provides an isolated inverter circuit, which can, as Figure 2 As shown, this isolated inverter circuit includes: a primary-side switching unit, a transformer unit, a secondary-side switching unit, and a controller. Wherein: The primary-side switching unit is connected to the primary side of the transformer unit, and the secondary-side switching unit is connected to the secondary side of the transformer unit. The primary-side switching unit includes at least two switching circuits, and the transformer unit includes at least two transformer circuits. One end of a switching circuit is connected to the DC bus voltage signal, and the other end is connected to the primary side of a transformer circuit.

[0029] The secondary sides of each transformer circuit are connected in series and then connected to one end of the secondary-side switching unit. The other end of the secondary-side switching unit is connected to the load device.

[0030] The controller is connected to each switching circuit and the output terminal of the secondary-side switching unit. The controller is used to output at least one drive control signal to the corresponding switching circuit according to the load power of the load device, so that at least one switching circuit performs power conversion in response to the corresponding drive control signal.

[0031] The isolated inverter circuit provided in this application connects the primary side of a transformer circuit to a switching circuit, and the secondary side of the transformer circuit is connected in series. In actual use, the controller can generate at least one drive control signal based on the load power of the load device connected to the secondary switching unit, and control at least one switching circuit to perform power conversion. All switching circuits do not need to be in the power conversion state all the time, which can reduce the extra power consumption of some switching circuits on the DC bus and achieve the effect of saving DC power.

[0032] The isolated inverter circuit provided in this application will be described in detail below with specific examples: In this application, the generation of DC bus voltage includes: energy storage devices (such as batteries) outputting stored electrical energy in DC form, and power generation devices (such as photovoltaic arrays) converting other forms of energy into electrical energy and then outputting it in DC form. Power frequency AC refers to AC signals with a signal frequency equal to the power frequency. The frequency of power frequency AC depends on the power grid frequency of different countries and regions. As one implementation, the inverter circuit is used to output sinusoidal AC with a frequency of 50Hz or 60Hz, corresponding to a power frequency of 50Hz or 60Hz.

[0033] In this application, the primary-side switching unit includes at least two switching circuits, each of which is an inverter switching circuit. Each switching circuit has the capability to convert DC bus voltage into AC voltage. The inverter switching circuit can be of any topology, such as a half-bridge inverter switching circuit or a full-bridge inverter switching circuit. As an example, each switching circuit can be as follows: Figure 3 The figure shows an inverter switching circuit using a full-bridge topology.

[0034] The transformer unit includes several transformer circuits and other components connected to the transformer circuits. As an example, it can be like this: Figure 3 As shown, the transformer unit includes transformer circuit T1 and transformer circuit T2, as well as inductor L1 and capacitor C3 connected to the transformer circuits.

[0035] One end of each switching circuit is connected to the DC bus voltage, and the other end is connected to its corresponding transformer circuit. The specific connection method is as follows: One end of each switching circuit is connected to the primary coil of its corresponding transformer circuit. The primary coils of each transformer circuit are then connected in parallel, but the secondary coils of the transformer circuits are connected in series. The series-connected secondary coils of the transformer circuits are then connected to the input terminal of the secondary-side switching unit. The output terminal of the secondary-side switching unit is connected to the power frequency AC power and / or the load equipment to supply power to the load equipment or to feed the converted electrical energy into the power grid.

[0036] In this system, each switching transistor (or simply switching tube) within the inverter switching circuit opens or closes under the control of a drive control signal sent by the controller to perform power conversion, thereby converting DC power into AC power. Based on this, the controller outputs at least one drive control signal to the corresponding switching circuit according to the load power of the load device, aiming to control the number of switching circuits performing power conversion based on the load power of the load device. In one implementation, the number of switching circuits performing power conversion in response to the drive control signal is positively correlated with the load power of the load device. That is, the higher the load power of the load device, the more switching circuits the controller controls for power conversion.

[0037] In this application, the drive control signal is a signal used by the controller to control the switching circuit to perform power conversion. The term "drive control signal" is a general term and can be understood as a collection of drive signals for the switching transistors in the switching circuit. The drive control signal includes a first drive signal and a second drive signal. Details regarding the first and second drive signals are provided below.

[0038] In some possible embodiments, the controller is configured to output a first drive signal when the load power of the load device is greater than a preset first power threshold, so that all switching circuits respond to the first drive signal to perform power conversion within a preset first phase interval of the power frequency AC.

[0039] The preset first power threshold can be flexibly set according to the power supply provided by the actual product application scenario, and this application does not impose strict limitations on it. In the embodiments of this application, if the load power of the load device is greater than the preset first power threshold, it indicates that the power supply required by the current load device is very large, and the load device is a heavy load. The controller can output a first drive signal to all switching circuits to control all switching circuits to perform power conversion within the preset first phase interval of the power frequency AC power, so as to ensure the power demand of the heavy load device.

[0040] In one implementation, a power detection circuit is provided at the output terminal of the secondary-side switching unit. This power detection circuit can be connected to a controller, which acquires the load power of the load device detected by the power detection circuit. The power detection circuit can determine the load power of the load device based on its supply current. The specific method for acquiring the load power can refer to existing power calculation methods, and this application does not impose strict limitations on this method.

[0041] In one implementation, to ensure the stability of the power frequency AC supply to the load device, the drive control signals of each switching circuit are identical within the first phase interval. For example, assuming the isolated inverter circuit provided in this application is as follows... Figure 3 As shown, the transformer unit includes two transformer circuits (transformer circuit T1 and transformer circuit T2), and the corresponding primary-side switching unit includes two switching circuits (a first switching circuit and a second switching circuit). Each switching circuit has a DC bus capacitor connected in parallel; the first switching circuit has a DC bus capacitor C1 connected in parallel, and the second switching circuit has a DC bus capacitor C2 connected in parallel.

[0042] Both the first and second switching circuits are inverter switching circuits consisting of four switching transistors (Q1, Q2, Q5, and Q6 in the first switching circuit, and Q3, Q4, Q7, and Q8 in the second switching circuit) connected in a full-bridge topology. Within the first phase interval, the controller outputs a first drive signal to both the first and second switching circuits, causing them to perform power conversion within this first phase interval according to the same first drive signal. This converts the DC bus voltage into AC power, which is then output to the primary coil of their respective connected transformer circuits. This synchronized power conversion between the first and second switching circuits ensures the power demand of the load equipment is met.

[0043] For example, such as Figure 3 As shown, the drive signal DRV1 for the switch Q1 in the first switching circuit is the same as the drive signal DRV1S for the switch Q3 in the second switching circuit. Similarly, the drive signal DRV2 for the switch Q2 in the first switching circuit is the same as the drive signal DRV2S for the switch Q4 in the second switching circuit, and so on for other switches. In this application, drive signals DRV1~DRV12 and DRV1S~DRV4S are all drive signals for the switches, specifically PWM signals (Pulse Width Modulation signals). "Same drive signals" means that the corresponding PWM signals are completely identical, including the same frequency, the same duty cycle, and the same timing throughout the entire phase period (0~2π) of the power frequency AC current.

[0044] In some possible embodiments, the controller outputs a preset number of second drive signals when the load power of the load device is less than or equal to the first power threshold, so that a portion of the switching circuits respond to the second drive signals to perform power conversion within a preset second phase interval of the power frequency AC power. The preset number is positively correlated with the load power of the load device. That is, the higher the load power of the load device, the larger the corresponding preset number, and the larger the number of switching circuits driving the power conversion.

[0045] It is understood that in the embodiments of this application, when the load power of the load device is less than or equal to the first power threshold, the power required by the load device is low, and the load device is in an unloaded or lightly loaded state. At this time, the controller outputs a preset number of second drive signals, and one second drive signal controls one switching circuit. The controllable part of the switching circuit (i.e., the preset number of switching circuits) performs power conversion in the second phase interval.

[0046] The first phase interval and the second phase interval are two adjacent phase intervals. The voltage amplitude of the power frequency AC current in the second phase interval is smaller than that in the first phase interval. Because the voltage amplitude of the power frequency AC current in the second phase interval is smaller than that in the first phase interval, the electrical energy converted by the switching circuit in the second phase interval is relatively smaller than that converted by the switching circuit in the first phase interval. This reduces the energy consumption of the switching circuit when the load device is under light load or no load.

[0047] As can be seen, when the phase of the power frequency AC is in the second phase interval, only a portion of the switching circuits have drive signals, while a portion of the switching circuits do not have drive control signals. For the switching circuits without drive control signals, the primary coil of the corresponding transformer circuit has no voltage input, and only a portion of the transformer circuit is in operation. The number of switching transistors required to maintain stability in the entire isolation inverter circuit is reduced, and the corresponding magnetic flux density fluctuation amplitude is reduced, effectively reducing the magnetic loss of magnetic components.

[0048] In this application, the function of the transformer circuit is to change the voltage level of the input signal. Whether it boosts or bucks the voltage depends on the turns ratio of the primary and secondary coils of the transformer circuit, where the turns ratio equals the number of turns in the primary coil : the number of turns in the secondary coil. Specifically, using... Figure 1 For example, if the turns ratio of the primary coil (also referred to as the primary coil) to the secondary coil (also referred to as the secondary coil) in a transformer circuit is 1:N, it means that the signal input to the primary coil is boosted N times and then output through the secondary coil. In this application, the turns ratio of the transformer coils in each transformer circuit can be the same or different.

[0049] In some possible embodiments, if the turns ratios of the transformer coils in each transformer circuit are different, the controller outputs a second drive signal to the target switching circuit when the load power of the load device is less than or equal to the first power threshold. The number of target switching circuits depends on the load power of the load device. Each target switching circuit has the characteristic that the turns ratio of the transformer circuits connected to it is less than a preset turns ratio threshold. This preset turns ratio threshold can be flexibly set according to actual circuit requirements. Transformer circuits with turns ratios less than the preset turns ratio threshold have lower transformation capabilities compared to transformer circuits with turns ratios greater than the preset turns ratio threshold; they can be understood as smaller transformer circuits.

[0050] Since the load power of the load device is less than or equal to the first power threshold, it indicates that the load of the entire isolated inverter circuit is currently unloaded or lightly loaded. In this embodiment, when the load device is unloaded or lightly loaded, the switching circuit connected to the small transformer circuit is selected as the target switching circuit for power conversion. This can better reduce the loss of DC power by the switching circuit and the transformer circuit, thereby achieving the effect of saving DC power.

[0051] In one implementation, if the load power of the load device is 0, it indicates that the isolated inverter circuit is currently in an unloaded state. The controller controls one of the switching circuits to perform power conversion by outputting a second drive signal in the second phase interval.

[0052] In another implementation, if the load power of the load device is greater than 0 and less than or equal to the first power threshold, it indicates that the isolated inverter circuit is currently in a light-load state. The controller can control at least one switching circuit to perform power conversion by outputting a second drive signal within the second phase interval. Specifically, the number of switching circuits to be driven can be determined according to the load power. Alternatively, at least one transformer circuit with a suitable coil turns ratio can be selected to drive the target switching circuit according to the load power.

[0053] In this embodiment, the electrical performance parameters of each switching circuit are the same, while the electrical performance parameters of each transformer circuit may be different; that is, as described above, the turns ratio of the transformer coils in each transformer circuit may be different. In one implementation, the turns ratio N of the transformer coils in each transformer circuit is... i satisfy:

[0054] in, This represents the minimum power required for the i-th transformer circuit to operate in its high-efficiency region. U represents the highest power of the i-th transformer circuit operating in its high-efficiency region, and U is the DC bus voltage. The current is the current of the secondary-side switching unit.

[0055] It is understandable that, since the primary sides of each transformer circuit are connected in parallel and the secondary sides are connected in series, the transformers in each transformer circuit will allocate corresponding energy conversion power according to the turns ratio of the transformer coils. In other words, the turns ratio of the transformer directly determines the power sharing ratio of that transformer. In the embodiments of this application, if a combination of transformers with different turns ratios is selected for energy conversion, the turns ratio of the transformer coils can be set according to the load power of the load equipment that the isolated inverter will actually support in the application process. The turns ratio of the transformer coils can be set according to the following principles: When selecting transformer combinations with different coil turns ratios for energy conversion based on the load power of the load equipment, it is necessary to ensure that each transformer put into use operates in the high-efficiency operating range.

[0056] The high-efficiency operating range (also known as the high-efficiency zone) is 30% to 80% of the transformer's rated power, and its upper and lower limit power values ​​correspond to the above-mentioned... , The coil turns ratio of the transformers in each transformer circuit can be set according to the minimum and maximum power corresponding to the high-efficiency zone, combined with the current required by the final load equipment.

[0057] If the turns ratio of the transformer coils in each transformer circuit is different, when the entire isolated inverter circuit is under no-load or light-load conditions, the target switching circuit corresponding to the transformer circuit with the smaller turns ratio can be selected for power conversion according to the load power of the load equipment. In this way, the energy required for power conversion can be reduced, thereby further saving DC power.

[0058] In this application, each switching circuit is equivalent to the others. For example, it can be as follows: Figure 3 As shown, the first switching circuit includes a first bridge arm (including switching transistors Q1 and Q2) and a second bridge arm (including switching transistors Q5 and Q6). The first and second bridge arms are used to form a full-bridge converter circuit in response to drive signals. The control terminals of each switching transistor Q1, Q2, Q5, and Q6 in the first switching circuit are respectively input with drive signals DRV1, DRV2, DRV3, and DRV4. The controller drives each switching transistor Q1, Q2, Q5, and Q6 in the first switching circuit to turn on or off by sending drive signals DRV1, DRV2, DRV3, and DRV4, respectively, to form a full-bridge converter circuit, which converts the DC bus voltage into AC power and outputs it to the primary coil of the transformer T1 in the first transformer circuit.

[0059] The second switching circuit includes a third bridge arm (comprising switches Q3 and Q4) and a fourth bridge arm (comprising switches Q7 and Q8). The first and third bridge arms are equivalent, as are the second and fourth bridge arms. Correspondingly, the upper bridge arm transistor Q1 in the first bridge arm is equivalent to the upper bridge arm transistor Q3 in the third bridge arm, and so on for other switches. Circuit equivalence means that two equivalent components or circuits use the same component types, models, and circuit parameters, and the resulting bridge switching circuits are also identical.

[0060] As one implementation method, a switching circuit can be defined as a normal switching circuit, which means that the controller drives and controls it to convert electrical energy throughout the entire signal cycle of the power frequency AC signal. For example, using... Figure 3 Taking the isolated inverter circuit shown as an example, the controller can control the first switching circuit to form a full-bridge inverter switching circuit for power conversion throughout the entire phase cycle of the power frequency AC current. The second switching circuit only forms a full-bridge inverter switching circuit in response to the first drive signal when the phase of the power frequency AC current is in the first phase interval, and performs power conversion together with the first switching circuit to ensure the power demand of the load equipment.

[0061] Since the phase of the power frequency AC is within the second phase interval, only the second drive signal can be sent to the first switching circuit, without sending a second drive signal to the second switching circuit. Since the second switching circuit has no drive control signal, the entire second switching circuit does not need to perform power conversion, and the second switching circuit will have no voltage output, which can reduce the consumption of DC power by the second switching circuit.

[0062] When a voltage is applied to the primary coil of a transformer, the magnetic flux inside the transformer core increases over time. The higher the applied voltage and the longer the applied time, the faster the magnetic flux increases. However, after the magnetic flux increases to a certain level, such as reaching a maximum value, further increases will cause the permeability of the core to drop sharply, leading to core saturation. At this point, the excitation current will surge, resulting in increased magnetic losses and potentially damaging the transformer. The volt-second threshold of the transformer corresponds to the maximum value reached by the magnetic flux, and this threshold depends on the transformer model.

[0063] Based on this, the core of this application is to reduce the magnetic losses generated by the transformer by controlling the volt-second value of the transformer to be less than the volt-second threshold. Since the DC input is fixed, i.e., the voltage is fixed, and the transformer core is fixed, controlling the transformer's operating time becomes the key to reducing magnetic losses. In the embodiments of this application, the core is to change the effect of the transformer's operating time by controlling the drive time of a portion of the switching circuit.

[0064] Specifically, by stopping the switching circuit of the driving section when the phase of the power frequency AC is in the second phase interval, and only driving the switching transistors in the remaining switching circuit, the primary coil of the transformer connected to the switching circuit without a drive control signal has no input, thereby reducing the magnetic loss generated by the transformer connected to the switching circuit without a drive control signal. This ensures that the volt-second value obtained by multiplying the voltage (which is smaller than the voltage in the first phase interval) by the time does not exceed the volt-second threshold of the transformer connected to the switching circuit with a drive control signal, effectively reducing the magnetic loss generated by the transformer circuit.

[0065] As one implementation method, since the target of the secondary-side switching unit output is to output power frequency AC, the real-time voltage value of the entire power frequency AC is in a state of change. That is, the voltage of the entire power frequency AC (e.g., 220V / 50Hz) will change sinusoidally with the phase. In this application, based on the changing characteristics of the power frequency AC, the real-time voltage value of the boundary between the second phase interval and the first phase interval is determined based on the real-time voltage value of the power frequency AC.

[0066] Then, the phase interval corresponding to the real-time voltage value of the power frequency AC being less than or equal to the boundary real-time voltage value is defined as the second phase interval, and the phase interval corresponding to the real-time voltage value of the power frequency AC being greater than the boundary real-time voltage value is defined as the first phase interval. In this way, the sinusoidal change of the power frequency AC with phase can be divided into two stages: the first phase interval and the second phase interval. These two phase intervals are also relative concepts, depending on the boundary values ​​of the two phase intervals. Based on this, the first phase interval can also be called the high-voltage phase interval, and the second phase interval can be called the low-voltage phase interval. The value of the boundary real-time voltage value depends on the specific transformer model and electrical parameters, and can also be flexibly set based on practical experience.

[0067] In this application, a phase interval refers to the phase variation range of power frequency alternating current, which is a phase range and can be expressed as (lower phase limit, upper phase limit). The phase difference of the entire phase interval can be expressed as: upper phase limit - lower phase limit. Specifically, in this application, the phase difference of the first phase interval is defined as the first interval phase difference, denoted as... The phase difference between the two phase intervals is defined as the second interval phase difference, denoted as . .

[0068] For example, when the phase of the power frequency AC current is in the phase range of 0 to π / 4, as the phase changes from 0 to π / 4, the voltage gradually increases from 0V to... Vmax, where Vmax is the peak voltage of the power frequency AC current. As the phase of the power frequency AC current changes from π / 4 to π / 2, the voltage gradually decreases from... Vmax changes to Vmax. At this time, the first phase interval corresponds to the phase of the power frequency AC current from 0 to π / 4, and the second phase interval corresponds to the phase of the power frequency AC current from π / 4 to π / 2. In this case, the phase difference of the first interval of the first phase interval is... =π / 4, the phase difference of the second phase interval. 2 = π / 4.

[0069] In this application, the division between the second phase interval and the first phase interval depends on the turns ratio of the transformer coil inside the transformer circuit. As one implementation, the ratio between the first and second phase intervals can be determined based on the level of electrical energy converted by the transformer, and then the phase intervals of the power frequency AC current can be divided according to this ratio.

[0070] As one implementation method, if the transformer circuit that performs power conversion in the first phase interval + the second phase interval is denoted as transformer circuit A, and the transformer circuit that performs power conversion only in the first phase interval and not in the second phase interval is denoted as transformer circuit B, then the sum of the coil turns ratio of each transformer circuit A can be denoted as 1:N1, and the sum of the coil turns ratio of each transformer circuit B can be denoted as 1:N2.

[0071] For example, with Figure 3 Taking the isolated inverter circuit shown as an example, if there are 2 transformer circuits and 2 switching circuits, the first switching circuit performs energy conversion in both the first and second phase intervals, while the second switching circuit only performs energy conversion in the first phase interval and not in the second phase interval. In this case, the transformer circuit connected to the first switching circuit is transformer circuit A, and the transformer circuit connected to the second switching circuit is transformer circuit B.

[0072] Since the primary coils of transformer circuits T1 and T2 are connected in parallel and the secondary coils are connected in series, when both transformers have input, the total boosting capacity of transformers T1 and T2 should meet the boosting requirements of the high voltage DC bus voltage HV_BUS.

[0073] Specifically, assuming HV_BUS is N times the low-voltage DC bus voltage LV_BUS, the total step-up ratio of transformer T1 and transformer T2 should satisfy N times. That is, if the first transformer circuit and the second transformer circuit are equivalent to a transformer T, the coil turns ratio of the transformer T should satisfy 1:N=1:(N1+N2), i.e., N1+N2=N.

[0074] Thus, the phase difference of the first phase interval Phase difference with the second phase interval The following relationship must be satisfied:

[0075] Wherein, the interval phase difference is the difference between the upper phase limit and the lower phase limit of the phase interval. It is the inverse ratio of the sum of the turns ratios of the coils of a transformer circuit that performs energy conversion in both the first and second phase intervals. It is the inverse ratio of the sum of the turns ratios of the coils of each transformer circuit that operates only in the first phase interval. .

[0076] In other words, the sum of the width of the second phase interval and the width of the first phase interval equals 90°. Furthermore, the ratio between the width of the second phase interval and the width of the first phase interval satisfies the following condition: the width of the second phase interval is equal to the width of the first phase interval. times.

[0077] In traditional isolated inverter circuits, since there is no driving condition to shut down the switching transistors in the primary-side switching unit, they can operate as usual. Figure 4 As shown, during the entire phase cycle of the power frequency AC, the voltage of the high-voltage side DC bus HV_BUS = Vbat (that is, the DC output of the battery, which is also equal to the low-voltage DC bus voltage LV_BUS).

[0078] And choose the option provided in this application, such as Figure 3 The isolated inverter circuit shown in the diagram, because the second switching circuit only responds to the first drive signal within the first phase interval of (45°~135°] and (225°~315°] to form a full-bridge converter circuit, converts the DC input to AC output to the second transformer circuit. At this time, the full-bridge converter circuit of the first switching circuit and the first transformer circuit are still in the power conversion state, and the full-bridge converter circuit of the second switching circuit and the second transformer circuit are also in the power conversion state. The total coil turns ratio of the entire transformer circuit is 1:N. It can achieve maximum energy conversion according to the coil turns ratio of 1:N, ensuring the power supply needs of the load equipment. However, in the second phase interval, the second switching circuit has no drive signal input, and only the first switching circuit is in the power conversion state.

[0079] To better understand the differences in performance between the solution provided in this application and traditional isolated inverter circuits, please refer to... Figure 5 As shown, for the first phase interval, the DC bus voltage on the high-voltage side can still reach that of a traditional isolated inverter circuit (i.e., Figure 1The inverter circuit shown has a boost effect of HV_BUS=LV_BUS*N. However, for the second phase intervals: (0~45°], (135°~225°], and (315°~360°], since the second switching circuit does not have a second drive signal, the second switching circuit does not need to perform power conversion, and the primary coil of the second transformer circuit has no AC input. At this time, only the first switching circuit + the first transformer circuit is in working state. The primary coil of the second transformer circuit has no AC input, and the secondary coil of the second transformer circuit is equivalent to a copper wire. The high-voltage side DC bus voltage HV_BUS=LV_BUS*N1, and the secondary side switching unit converts the voltage based on the high-voltage side DC bus voltage to obtain the real-time voltage of the power frequency AC power obtained in the second phase interval, which corresponds to the low-voltage section of the power frequency AC power.

[0080] If the turns ratio of transformers T1 and T2 is the same, both being 1:(N / 2), then the DC bus voltage on the high-voltage side, HV_BUS, is equal to LV_BUS*N1. Therefore, it can be calculated as follows: Figure 4 As shown, in the low phase interval, the corresponding high-voltage side DC bus voltage HV_BUS = LV_BUS * (N / 2).

[0081] The first and second transformer circuits are connected in parallel on the low-voltage side and in series on the high-voltage side. As one implementation method, it can be as follows: Figure 3 As shown, the first transformer circuit includes a first transformer T1, a resonant inductor L1, and a resonant capacitor C3. The second transformer circuit includes a second transformer T2. The first terminal of the resonant inductor L1 is connected to one end of the secondary winding of the first transformer T1, and the second terminal of the resonant inductor is connected to the first terminal of the resonant capacitor C3. That is, the resonant inductor L1 and the resonant capacitor C3 are connected in series at one end of the secondary winding of the first transformer T1. The other end of the secondary winding of the first transformer T1 is connected to one end of the secondary winding of the second transformer T2. The input terminal of the secondary-side switching unit is connected to the second terminal of the resonant capacitor C3 and the other end of the secondary winding of the second transformer T2.

[0082] As one implementation method, it can be as follows Figure 3 As shown, the secondary-side switching unit includes a first-side switching circuit and a second-side switching circuit. The first-side switching circuit includes a first high-voltage bridge arm (including switching transistors Q9 and Q10) and a second high-voltage bridge arm (including switching transistors Q11 and Q12). The second terminal of the resonant capacitor C3 is connected to the midpoint of the first high-voltage bridge arm, and the second terminal of the secondary coil of the second transformer T2 is connected to the midpoint of the second high-voltage bridge arm. The midpoint of the high-voltage bridge arm refers to the connection point of the two switching transistors within the bridge arm.

[0083] If the isolated inverter circuit is a unidirectional inverter circuit, then in one implementation, the first-stage switching circuit is similar to a high-voltage rectifier circuit, used to rectify the high-voltage AC output from the first and second transformer circuits into high-voltage DC and output it, that is, to obtain the high-voltage DC bus voltage HV_BUS. Further, the secondary-side switching unit may also include a second-stage switching circuit, which includes a DC bus capacitor C4, a third high-voltage bridge arm (including switching transistors Q13 and Q14), and a fourth high-voltage bridge arm (including switching transistors Q15 and Q16). If the isolated inverter circuit is a unidirectional inverter circuit, then the second-stage switching circuit is used to convert the high-voltage DC bus voltage into power frequency AC, and output it to the live and neutral wires of the power frequency AC through the final bus inductance L2 and bus capacitor C5. The working principle of the secondary-side switching unit is similar to... Figure 1 The working principle of the secondary-side switching unit of the traditional isolated inverter circuit shown is the same. Please refer to the relevant data on the working principle of isolated inverter circuits. It will not be repeated here.

[0084] In some possible embodiments, the isolated inverter circuit can be an isolated bidirectional inverter circuit, used to convert DC input into AC power at power frequency and output it to the corresponding live wire and neutral wire. It can also be used to convert AC power obtained from the live wire and neutral wire into DC input and output it to the DC terminal. Assuming the DC terminal is a battery, the isolated bidirectional inverter circuit can be configured as follows: Figure 3 The conversion process, from left to right, converts the DC power stored in the battery into AC power at industrial frequency and outputs it to the corresponding live and neutral wires, supplying power to load devices connected to both live and neutral wires or feeding power to the power grid. This isolated bidirectional inverter circuit can also be configured as follows: Figure 3 The conversion process, from right to left, converts the AC power to DC power and outputs it to the battery for energy storage.

[0085] In summary, by using the isolated inverter circuit provided in this application, under no-load or light-load conditions, the drive control signal of some switching circuits can be determined by the preset first phase interval and second phase interval, thereby reducing the switching losses of the switched transistors that are turned off.

[0086] For example, such as Figure 3 In the circuit diagram shown, if the load device is in an unloaded or lightly loaded state, turning off the drive control signal of the switching transistor in the second switching circuit can reduce the switching losses of switching transistors Q3, Q4, Q7 and Q8, the switching losses of switching transistors Q13 to Q16, the magnetic loss of the second transformer T2 and the magnetic loss of the bus inductance L2, thereby saving DC power and ensuring the continuity of DC power.

[0087] Secondly, this application provides an inverter circuit driving method, wherein the controller in the isolated inverter circuit provided in the first aspect can, as Figure 6 As shown, the method includes: S61. Obtain the load power of the load device connected to the isolated inverter circuit; S62. Determine the drive control signal for at least one switching circuit in the isolated inverter circuit based on the load power; S63. Based on the drive control signals, control the corresponding switching circuits in the isolated inverter circuit to perform power conversion.

[0088] Using the embodiments of this application, the controller can generate different drive control signals based on the load power of the load equipment connected to the secondary-side switching unit in the isolated inverter circuit, thereby controlling different switching circuits to perform power conversion. All switching circuits do not need to be in a constant power conversion state, which can reduce the additional power consumption of some switching circuits on the DC bus, achieving the effect of saving DC power. Thirdly, this application provides an energy storage converter device, which includes the isolated inverter circuit described in the first aspect. A controller can generate different drive control signals based on the load power of the load device connected to the secondary-side switching unit in the isolated inverter circuit, controlling different switching circuits to perform power conversion. All switching circuits do not need to be in a constant power conversion state, which can reduce the additional energy consumption of the battery in the energy storage converter device by some switching circuits, achieving the effect of saving DC power. Fourthly, exemplary embodiments of this application also provide an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to cause the electronic device to perform a method according to an embodiment of this application.

[0089] An exemplary embodiment of this application also provides a non-transitory computer-readable storage medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform a method according to an embodiment of this application.

[0090] An exemplary embodiment of this application also provides a computer program product, including a computer program, wherein, when executed by a computer's processor, the computer program is used to cause the computer to perform a method according to an embodiment of this application.

[0091] refer to Figure 7The present invention describes a structural block diagram of an electronic device 700 that can serve as a server or client of this application, which is an example of a hardware device that can be applied to various aspects of this application. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the application described and / or claimed herein.

[0092] like Figure 7 As shown, the electronic device 700 includes a computing unit 701, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM 702) or a computer program loaded from a storage unit 708 into a random access memory (RAM 703). The RAM 703 may also store various programs and data required for the operation of the electronic device 700. The computing unit 701, ROM 702, and RAM 703 are interconnected via a bus 704. An input / output interface (I / O interface 705) is also connected to the bus 704.

[0093] Multiple components in electronic device 700 are connected to I / O interface 705, including: input unit 706, output unit 707, storage unit 708, and communication unit 709. Input unit 706 can be any type of device capable of inputting information to electronic device 700. Input unit 706 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of electronic device. Output unit 707 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 708 may include, but is not limited to, disk and optical disk. Communication unit 709 allows electronic device 700 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth™ devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0094] The computing unit 701 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 701 performs the various methods and processes described above. For example, in some embodiments, the aforementioned inverter circuit driving method can be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 708. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 700 via ROM 702 and / or communication unit 709. In some embodiments, the computing unit 701 can be configured to perform the aforementioned inverter circuit driving method by any other suitable means (e.g., by means of firmware).

[0095] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0096] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0097] As used in this application, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0098] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0099] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0100] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other.

Claims

1. An isolated inverter circuit, characterized in that, The isolated inverter circuit includes: a primary-side switching unit, a transformer unit, a secondary-side switching unit, and a controller; wherein: The primary-side switching unit is connected to the primary side of the transformer unit, and the secondary-side switching unit is connected to the secondary side of the transformer unit. The primary-side switching unit includes at least two switching circuits, and the transformer unit includes at least two transformer circuits; one end of one of the switching circuits is connected to the DC bus voltage signal, and the other end is connected to the primary side of one of the transformer circuits. The secondary side of each transformer circuit is connected in series and then connected to one end of the secondary side switching unit, and the other end of the secondary side switching unit is connected to the load device. The controller is connected to each of the switching circuits. The controller is used to output at least one drive control signal to the corresponding switching circuit according to the load power of the load device, so that at least one of the switching circuits performs power conversion in response to the drive control signal.

2. The isolated inverter circuit according to claim 1, characterized in that, The drive control signal includes a first drive signal. The controller is used to output a first drive signal corresponding to the number of switching circuits when the load power of the load device is greater than a preset first power threshold, so that all switching circuits respond to the first drive signal to perform power conversion within a preset first phase interval of the power frequency AC.

3. The isolated inverter circuit according to claim 2, characterized in that, The drive control signal includes a second drive signal. The controller is further configured to output a preset number of second drive signals when the load power of the load device is less than or equal to the first power threshold, so that a portion of the switching circuit responds to the second drive signal to perform power conversion within a preset second phase interval of the power frequency AC power. The first phase interval and the second phase interval are two adjacent phase intervals, and the voltage amplitude of the power frequency AC power in the second phase interval is less than the voltage amplitude of the power frequency AC power in the first phase interval.

4. The isolated inverter circuit according to claim 1, characterized in that, The turns ratio of the transformer coils in each of the aforementioned transformer circuits is the same.

5. The isolated inverter circuit according to claim 3, characterized in that, The transformer circuits have different turns ratios. The controller is used to output the second drive signal to the target switching circuit when the load power of the load device is less than or equal to the first power threshold. The turns ratio of the transformer circuit connected to the target switching circuit is less than a preset turns ratio threshold.

6. The isolated inverter circuit according to claim 5, characterized in that, The turns ratio N of the transformer coils in each of the aforementioned transformer circuits i satisfy: in, This represents the minimum power required for the i-th transformer circuit to operate in its high-efficiency region. U represents the highest power of the i-th transformer circuit operating in its high-efficiency region, and U is the DC bus voltage. The current is the current of the secondary-side switching unit.

7. The isolated inverter circuit according to claim 3, characterized in that, Phase difference in the first phase interval Phase difference with the second phase interval The following relationship must be satisfied: Wherein, the interval phase difference is the difference between the upper phase limit and the lower phase limit of the phase interval. It is the inverse ratio of the sum of the turns ratios of the coils of the transformer circuit that performs power conversion in the first phase interval and the second phase interval. It is the inverse ratio of the sum of the turns ratios of the coils of each transformer circuit that performs power conversion in the first phase interval. .

8. The isolated inverter circuit according to claim 3, characterized in that, The preset quantity is positively correlated with the load power of the load device.

9. A method for driving an inverter circuit, characterized in that, The method is applied to a controller in an isolated inverter circuit as described in any one of claims 1 to 8, and the method includes: The load power of the load device connected to the isolated inverter circuit is obtained, and the drive control signal of at least one switching circuit in the isolated inverter circuit is determined according to the load power. The corresponding switching circuit in the isolated inverter circuit is controlled to perform power conversion based on the drive control signal.

10. An energy storage converter, characterized in that, The energy storage converter includes the isolated inverter circuit as described in any one of claims 1 to 8.

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