Three-phase-power-based power supply circuit and method for same to realize pfc / voltage boosting / voltage reduction

Abstract

The present application discloses a three-phase-power-based power supply circuit and a method for same to simultaneously realize power factor correction and dynamic voltage boosting / reduction. The circuit comprises an information collection module and a power supply circuit unit, wherein the power supply circuit unit comprises three circuit groups formed by connecting to three phases of three-phase power and a control center used for controlling the working states of the three circuit groups. Each circuit group comprises an input rectification module, an inductor, a capacitor, a switch and a controller thereof, a transformer, and an output half-wave rectification module. Output ends of the three circuit groups comprised in the power supply circuit unit are connected in parallel or in series, thereby solving the ripple problem, and also improving the electric energy conversion rate. The power supply circuit can control the charging and discharging time of an inductor by performing high-frequency adjustment on the magnitude of an input current peak and further adjusting the frequency and duty ratio of a switch, such that the dynamic adjustment of voltage boosting and voltage reduction is realized while realizing power factor correction, the load requirements are met, costs can be effectively saved on, the energy loss is low, and the electric energy conversion rate is high.

Description

Power supply circuit based on three-phase electricity and method for realizing PFC / boost / buck Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a power supply circuit technology for a high-power scenario. Background Art

[0002] In the prior art, power modules used in higher power (generally greater than 200 watts is considered higher power) or high-power scenarios include two-stage circuits, the front-end and the back-end. The front-end generally adopts various topology circuits based on a Boost rectifier or equivalent to a Boost circuit to achieve power factor tracking (also known as PFC). The mainstream PFC topology solution is a three-phase three-wire three-level VIENNA (for example, it also includes: two-way staggered parallel three-phase three-wire three-level VIENNA, a single-phase staggered three-phase three-wire three-level VIENNA), a totem pole topology circuit, and a Boost circuit (for example, it also includes: an interleaved Boost circuit suitable for single-phase power); the rear-stage DC-DC solution generally achieves voltage reduction / voltage regulation through a full-bridge-based circuit topology (for example, two groups of interleaved series two-level full-bridge LLCs, two groups of interleaved parallel two-level full-bridge LLCs, a three-level phase-shifted full-bridge, two groups of two-level LLC full-bridges in series, two groups of two-level three-phase interleaved LLCs in series, a three-level LLC half / full bridge, etc.).

[0003] 1 shows a topology circuit for implementing PFC in the front stage of the power module in the prior art, specifically a connection diagram of a three-phase three-wire three-level VIENNA circuit. FIG2 shows a topology circuit for implementing voltage regulation / isolation of the power module in the prior art, specifically a connection diagram of two groups of interleaved series two-level full-bridge LLCs.

[0004] It can be seen that the power supply module of the existing technology requires two-stage circuits to realize power conversion and transmission. It has many components and complex circuit connections. It has problems such as high cost, large energy loss, poor stability, low conversion rate, and poor scalability. At the same time, it is necessary to solve the ripple problem by increasing the capacitance of the output capacitor.

[0005] Summary of the Invention

[0006] One purpose of the present application is to provide a power supply circuit based on three-phase electricity and a method for the power supply circuit to achieve power factor tracking and boost / buck, so as to solve the problems of complex connection of power supply circuit components, low power conversion rate and weak scalability in the prior art, and at the same time solve the problem of relatively large power frequency ripple caused by single-stage circuit.

[0007] The present application provides a power supply circuit based on three-phase electricity, the power supply circuit including an information acquisition module and a power supply circuit unit, the power supply circuit unit including three circuit groups formed by three phases A / B / C connected to the three-phase electricity and a control center for controlling the working status of the three circuit groups;

[0008] The circuit group includes an input rectifier module, an inductor, a capacitor, a switch and its controller, a transformer, and an output half-wave rectifier module; one end of the inductor is used to connect to the live wire end of one phase of the three-phase electricity, the other end of the inductor is connected to one end of the switch and one end of the capacitor, the other end of the capacitor is connected to one end of the primary winding of the transformer, the other end of the primary winding of the transformer and the other end of the switch are connected to the live wire end or the neutral wire end of the other phase, the two output ends of the secondary winding of the transformer are the output ends for providing electric energy for the circuit group, wherein the end corresponding to the end of the capacitor connected to the primary winding is connected to the output half-wave rectifier module;

[0009] The power supply circuit unit includes three circuit groups whose output ends corresponding to the three-phase electricity are connected in parallel.

[0010] The present application also provides a method for dynamically adjusting the power factor tracking and voltage step-up / step-down of the above-mentioned three-phase power supply circuit, the method comprising:

[0011] Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency;

[0012] Step S2: Compare the current actual output power obtained with the target output power required by the connected load;

[0013] Step S3, adjusting the input current peak value at high frequency according to the comparison result between the current actual output power and the target output power;

[0014] Step S4, determining a target input current value at high frequency according to the input current peak value and the current input phase information;

[0015] Step S5, comparing the current actual input current value with the target input current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result;

[0016] In step S6 , the switch of the power circuit executes the instruction information at a high frequency, and controls the charge and discharge time of the inductor in the power circuit, so that the current actual input current value of the power circuit is as close as possible to the target input current value.

[0017] Compared with the prior art, the power supply circuit based on three-phase electricity of the present application includes an information acquisition module and a power supply circuit unit. The power supply circuit unit includes three circuit groups formed by three phases of three-phase electricity and a control center for controlling the working status of the three circuit groups; the circuit group includes an input rectifier module, an inductor, a capacitor, a switch and its controller, a transformer, and an output half-wave rectifier module; the power supply circuit of the present application simultaneously realizes power factor tracking and a dynamic adjustment method of boost / buck according to output requirements. It can adjust the input current peak size through high frequency, further adjust the frequency and duty cycle of the switch, and control the inductor charging and discharging time. While realizing power factor tracking, it also realizes dynamic adjustment of boost and buck according to the input voltage size and the output voltage requirement of the power supply circuit to meet the load demand.

[0018] This application uses a single-stage circuit to achieve the capabilities of traditional PFC+DC-DC technology, including rectification, power factor tracking, dynamic boost, buck, and high-frequency isolation. This significantly reduces component usage and improves power conversion efficiency. However, the single-stage circuit introduces significant power frequency ripple.

[0019] Due to the operating principle of the circuit groups included in this application, parallel synthesis of the output terminals is supported between circuit groups. This application uses a power supply circuit based on three-phase electricity. After tracking the power factor of each phase of the three-phase electricity, the output terminals of the three-phase electricity are connected in parallel for synthesis, solving the problem of large power frequency ripple caused by single-stage circuits. Furthermore, it does not cause power inconsistency between multiple circuit groups after parallel synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic diagram showing the connection of a three-phase three-wire three-level VIENNA circuit of a front-stage PFC topology circuit of a power module circuit in the prior art;

[0021] FIG2 is a schematic diagram showing the connection of two sets of interleaved series two-level full-bridge circuits in a subsequent DC-DC topology circuit of a prior art power module circuit;

[0022] FIG3 is a connection diagram of a circuit group included in a power circuit unit in an embodiment of the present application;

[0023] FIG4 is a connection diagram of a power supply circuit based on three-phase electricity in an embodiment of the present application;

[0024] Figure 5-1 is a waveform diagram of the input inductance of the power circuit corresponding to a single-phase sinusoidal input power supply;

[0025] Figure 5-2 is the output voltage ripple waveform corresponding to the input 5-1;

[0026] Figure 5-3 is a waveform diagram of the input inductance of the power circuit corresponding to the input power supply being a three-phase sine wave;

[0027] FIG5-4 is a diagram showing the output voltage ripple waveform corresponding to the input of FIG5-3 and a comparison diagram showing the output voltage ripple waveform of FIG5-2;

[0028] FIG6 is a flow chart of a method for simultaneously implementing PFC and voltage boost / buck in a power supply circuit in another embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] The present application provides a power supply circuit based on three-phase electricity to solve the problems of high cost, weak stability, large energy loss, low conversion rate, weak scalability and output ripple caused by the large number of components and complex connections in the power supply circuit of the prior art.

[0032] In the prior art, the power supply circuit is configured with a front / rear two-stage circuit, where the front-stage circuit completes power factor tracking and the rear-stage circuit completes voltage reduction / stabilization. The power supply circuit based on three-phase electricity disclosed in this embodiment includes at least one power supply circuit unit, which includes an inductor, a switch and its controller, a capacitor and a transformer. By configuring three circuit groups connected to three-phase electricity in each power supply circuit unit, the output ends of the three circuit groups are connected in parallel to effectively solve the ripple problem. The power supply circuit of the present application may also include multiple power supply circuit units. In this case, the output ends of the multiple power supply circuit units can be combined in series and parallel to achieve output of a wide range of voltage / power.

[0033] The present application provides a power supply circuit based on three-phase electricity to solve the problems of high cost, weak stability, large energy loss, low conversion rate and ripple caused by the large number of components and complex connections in the power supply circuit of the prior art.

[0034] 3, 4, and 5, the present application provides a power supply circuit based on three-phase electricity, the power supply circuit including an information acquisition module and a power supply circuit unit. The power supply circuit unit includes three circuit groups formed by three phases A / B / C connected to the three-phase electricity and a control center for controlling the working status of the three circuit groups.

[0035] The circuit group includes an input rectifier module, an inductor, a capacitor, a switch and its controller, a transformer, and an output half-wave rectifier module; one end of the inductor is used to connect to the live wire terminal of one phase of the three-phase electricity, the other end of the inductor is connected to one end of the switch and one end of the capacitor, the other end of the capacitor is connected to one end of the primary winding of the transformer, the other end of the primary winding of the transformer and the other end of the switch are connected to the live wire terminal or neutral terminal of the other phase, and the two output ends of the secondary winding of the transformer are the output ends that provide electric energy for the circuit group, wherein the end corresponding to the end of the capacitor connected to the primary winding is connected to the output half-wave rectifier module;

[0036] The power supply circuit unit includes three circuit groups whose output ends corresponding to the three-phase electricity are connected in parallel.

[0037] Specifically, in this embodiment, the power supply circuit includes three circuit groups of power supply circuit units, wherein each circuit group is connected to each phase of the three-phase electricity. The power supply circuit may include multiple power supply circuit units, that is, each phase of the three-phase electricity can be connected to multiple circuit groups. The working modes or working states of the multiple power supply circuit units are consistent, that is, the logic of the controller controlling and adjusting the duty cycle and frequency of the switch in the working group of each power supply circuit unit is the same.

[0038] As shown in Figures 3, 4 and 5, the circuit group includes an input rectifier module, an inductor, a capacitor, a switch and its controller, a transformer, and an output half-wave rectifier module; one end of the inductor is used to connect to the positive output terminal of the power supply after rectification of one phase of the three-phase electricity, the other end of the inductor is connected to one end of the switch and one end of the capacitor, the other end of the capacitor is connected to one end of the primary winding of the transformer, the other end of the primary winding of the transformer and the other end of the switch are connected to the negative output terminal of the rectified three-phase electricity, and the two output ends of the secondary winding of the transformer are the output ends that provide electric energy for the circuit group, wherein the end corresponding to the end of the capacitor connected to the primary winding is connected to the output half-wave rectifier module.

[0039] Specifically, each power supply circuit unit includes three circuit groups, and each circuit group is connected to each phase of the three-phase electricity. There are two specific ways of connecting to each phase. As shown in Figure 4, one is that the three circuit groups of the power supply circuit unit are respectively connected to the AB phase, BC phase and AC phase of the ABC three-phase electricity. At this time, the effective value of the input voltage provided by the three-phase electricity to the power supply circuit is 380 volts; as shown in Figure 5, the other is that the three circuit groups of the power supply circuit unit are respectively connected to the A phase and the neutral line of the ABC three-phase electricity, namely AN, the B phase and the neutral line, namely BN, and the C phase and the neutral line, namely CN. At this time, the effective value of the input voltage provided by the three-phase electricity to the power supply circuit is 220 volts.

[0040] The power supply circuit unit includes three circuit groups whose output ends corresponding to the three-phase electricity are connected in parallel.

[0041] Preferably, the power supply circuit unit includes three circuit groups corresponding to three-phase electricity, which are connected in parallel and then connected to capacitors.

[0042] Specifically, the input of each circuit group of the power supply circuit unit connected to a single-phase or one-phase of the three-phase is a sinusoidal AC power. After rectification by the full-bridge rectifier module, it is converted into a steamed bun wave input to the inductance of the circuit group. Because the inductance of the circuit group has a power factor tracking function (see the introduction to the power factor tracking process below for details), the output voltage of the circuit group at this time is a 100HZ fluctuation superimposed on the DC corresponding to the input. The 100HZ fluctuation is caused by the input steamed bun wave, and the input power varies with the phase of the steamed bun wave. When the input voltage is zero, the output of the secondary winding of the circuit group is also zero. At this time, the output of the circuit group is completely provided by the output capacitor (for example, a filter / electrolytic capacitor) connected to the output end of the circuit group. At this time, the output capacitor voltage connected to the output end of the circuit group will drop, thereby causing the voltage provided by the circuit group to the load, that is, the capacitor voltage, to drop, that is, an obvious ripple problem occurs.

[0043] The three circuit groups are connected to three-phase electricity at the same time. The three phases of the three-phase electricity have a phase difference of 120 degrees. As shown in Figure 4, the output ends of the three circuit groups included in the power circuit unit are respectively connected to three output capacitors C1, C2 and C3. The positive poles of the three capacitors are connected together as the output end of the power circuit unit, and the negative poles are connected together as the other output end of the power circuit unit. That is, the three circuit groups charge the three output capacitors connected in parallel at the same time. The output capacitors C1, C2 and C3 are connected in parallel and then connected to the load to provide power to the load, which can effectively solve the ripple problem. It is also possible to directly connect the output ends of the three circuit groups of the power circuit unit in parallel, and connect one or a group of output capacitors at the same time. The output capacitors are then connected to the load to provide power to the load, which also solves the ripple problem. Among them, the output capacitor can be any one of an electrolytic capacitor, a film capacitor, etc., and its specific form is not limited, as long as it can achieve energy storage and meet the circuit group's output to the load.

[0044] In this embodiment, the circuit group of the present application, due to its reduced number of components and strong circuit stability, can directly combine the output terminals of multiple circuit groups in parallel. Using the power factor tracking and dynamic step-up and step-down methods disclosed in this application to control the switching of each circuit group, it is possible to ensure that the current is evenly distributed among the multiple circuit groups with parallel output terminals, that is, there will be no significant power differences between the multiple circuit groups, which could damage the equipment.

[0045] In practice, the present application provides a method of directly tracking the power factor of the three-phase electricity separately, and connecting the output ends after dynamic boost and step-down in parallel, which ensures the power conversion rate of the power supply circuit while significantly solving the ripple problem.

[0046] Preferably, the control center controls the duty cycle and frequency of the switches in the circuit group by transmitting control information to the switches;

[0047] When the switch in the corresponding circuit group is in the closed state, the switch in the corresponding circuit group forms a loop with the input power supply of the phase connected and the inductor, and charges the inductor; the capacitor forms an LC oscillation loop with the switch and the inductor of the primary winding of the transformer, and the energy stored in the capacitor is transferred between the primary winding of the transformer and the capacitor;

[0048] When the switch is in the off state, an LLC oscillation circuit is formed with the connected phase input power supply, inductor, capacitor and primary winding of the transformer. The connected phase input power supply and the charged inductor charge the capacitor. At the same time, the charged inductor adds its own energy to the energy stored in the primary side of the transformer and induces electrical energy into the secondary winding through the current change of the primary side of the transformer.

[0049] Specifically, referring to Figures 3, 4 and 5, the working principle and process of a circuit group in a power supply circuit unit connected to three-phase power are as follows:

[0050] The control center transmits control information including duty cycle and frequency to the switch, controlling the time ratio of the switch in the circuit group to be closed within the cycle time; when the switch in the corresponding circuit group is in the closed state, the switch in the corresponding circuit group forms a loop with the connected power supply and inductor of that phase, and charges the inductor; the capacitor forms an LC oscillation loop with the switch and the inductor of the primary winding of the transformer; when the switch is in the open state, it forms an LLC oscillation loop with the connected power supply, inductor, capacitor and primary winding of the transformer, and the connected input power supply of that phase and the charged inductor charge the capacitor. At the same time, the charged inductor adds its own energy to the energy stored in the primary side of the transformer and induces the electric energy into the secondary winding through the current change of the primary side of the transformer.

[0051] Specifically, as shown in Figures 3, 4, and 5, the control center controls the frequency and duty cycle of the opening and closing of the switch of each of the three circuit groups according to the demand for the amount of electric energy required by the power circuit unit to provide the electric energy output terminal. As shown in Figure 3, when the switch K of the circuit group is in the closed state, the switch K forms a loop with the input power supply and the inductor L. At this time, the input power charges the inductor L through the loop; the capacitor C of the circuit group forms an LC oscillation loop with the switch K and the inductance of the primary winding of the transformer T; when the switch K is in the open state, the input power supply, the inductor L, the capacitor C, and the inductance of the primary winding of the transformer T form an LLC oscillation loop. The input power supply of this phase and the charged inductor L charge the capacitor C. At the same time, the charged inductor adds its own energy to the energy stored in the primary side of the transformer T and induces electric energy into the secondary winding through the current change of the primary side of the transformer.

[0052] The circuit assembly disclosed in this embodiment controls the operating state of switch K, charging inductor L and then discharging it to capacitor C and the primary winding of transformer T. This allows the primary winding of transformer T to acquire energy, which is then transmitted to the secondary winding of transformer T and subsequently outputted as electrical energy. By controlling the frequency and duty cycle of switch K, the charge / discharge time of inductor L and the charge / discharge time of the primary winding of the transformer are controlled, further controlling the amount of electrical energy outputted by the secondary winding of the transformer. This embodiment achieves electrical energy transfer using a power supply circuit comprising significantly fewer components than conventional circuits, resulting in low cost, enhanced stability, and a high conversion rate.

[0053] Specifically, referring to FIG3 , the detailed working process of the circuit group of the power circuit unit disclosed in this embodiment is as follows: when the switch K is closed, the input power charges the inductor L, and the inductor L stores energy. At the moment the switch K is disconnected, the inductor L generates a high voltage to maintain the current at both ends without sudden change. The electric energy is transferred through the new loop ① [input power + inductor L + capacitor C + transformer T] formed after the switch K is disconnected. The input power is discharged, the inductor L and the primary winding of the transformer T are discharged, and the capacitor C is charged. The current change of the primary winding of the transformer T is sensed to the secondary winding of the transformer T. At this time, the voltage of the input power plus the voltage of the inductor L is equal to the voltage of the capacitor C plus the primary winding of the transformer T, that is: V 输入电源 +V L =V C +V T原; Transformer T induces electric energy into its secondary winding, and the secondary winding outputs the electric energy to the power supply output end of the power circuit unit through the output half-wave rectifier module, and supplies the electric energy to the load; when the switch K is turned from the open state to the closed state, the circuit formed by the power circuit unit and the specific working process are as follows: the power circuit charges the inductor L through the circuit ② [input power supply + inductor L + switch K], and charges the capacitor C and the primary winding of the transformer T through the circuit ① [input power supply + inductor L + capacitor C + transformer T]. After the charging of the capacitor C is completed, in order to maintain the voltage across the capacitor C without sudden changes, the capacitor C charges the primary winding of the transformer T through the circuit ③ [capacitor C + transformer T + switch K]. Because the output half-wave rectifier module is set in the circuit of the secondary winding of the transformer T, the transformer T cannot transfer electric energy to the secondary winding of the transformer T at this time. At this time, it is equivalent to the primary winding of the transformer T and the capacitor C forming an LC resonant circuit to maintain the electric energy of the circuit; at the same time, after the switch K is in the closed state, the power supply is input through the second circuit to charge the inductor L, and the inductor L performs the next energy storage.

[0054] Preferably, the controllers of the three phases A / B / C are connected to the information acquisition module, and are used to generate first control information based on the phase information of the corresponding phase of the input power supply collected by the information acquisition module, and provide the first control information to the control center; the control center adjusts the first control information based on the overall requirements of the load for the power circuit output, and generates second control information including the switch duty cycle and frequency; and provides the second control information to the switch of the corresponding phase.

[0055] Specifically, in this embodiment, the three-phase power includes three phases: A, B, and C. Each phase is connected to a power circuit, which includes a power circuit unit, which includes three circuit groups. The power circuit also includes a controller corresponding to each phase, which is connected to the information acquisition module and the control center and is configured to generate first control information based on the corresponding phase information of each phase of the input power input collected by the information acquisition module and transmit it to the control center. The information acquisition module here can be a sensor, monitor, etc., and the specific implementation form and components are not limited, as long as it can meet the requirements of this embodiment to obtain voltage / current information of each phase input of the power circuit and the overall output of the power circuit; the specific method of generating the first control information here is not limited. The control center receives the first control information carrying the phase information of the corresponding phase sent by the controller, and generates second control information based on the output voltage and current information of the current power supply circuit collected by the information acquisition module and the load's requirements for the voltage and current of the overall output of the power supply circuit, and transmits the second control information to the switch of the circuit group connected to the corresponding phase, thereby controlling the working state of the switch; specifically, the second control information generated by the control center is the duty cycle and frequency information of the switch, and its specific generation method is not limited, as long as it can achieve the implementation of the technical method of this application.

[0056] Preferably, the circuit group realizes power factor tracking through inductance and switch cooperation, and also realizes dynamic adjustment of boost and buck according to input / output voltage, current information and output voltage requirements of connected load.

[0057] Specifically, referring to FIG. 3 , the inductor in the circuit group participates in achieving power factor tracking, and also dynamically adjusts the voltage step-up and step-down according to the input voltage and the required output voltage of the power supply circuit. The principle of the inductor in the circuit group disclosed in this embodiment cooperating with the switch to achieve power factor tracking is as follows:

[0058] When the input power is AC, the voltage period T' after full-wave rectification of the input power is set to the first time interval [if the input power is DC, no rectification is required and the voltage period T' of the input power is directly set to the first time interval]. In this first time interval T', the input voltage changes continuously. Since the inductor does not allow sudden changes in current according to its parameter characteristics, the time period interval corresponding to the switching frequency of switch K is the second time interval T". When the second time interval T" is several orders of magnitude smaller than the voltage period T' of the input power, within the T' voltage period range, switch K has completed hundreds or thousands of times of opening and closing. That is to say, in the process of the voltage period T' provided by the input power itself changing from trough to peak, due to the high on / off switching frequency of switch K, for controlling the working process of the power circuit unit through the working state of switch K, the voltage of the input power does not change much locally and can basically be considered unchanged. That is, the input power voltage corresponding to before and after switch K is switched once is considered unchanged. At the same time, the first time interval T' includes a lot of In the case of the second time interval T", that is, when the input voltage changes significantly, the inductor L has already undergone multiple charge and discharge processes under the control of the switch K. That is, at this time, the inductor L has completed multiple cycles of loop ① [input power supply + inductor L + capacitor C + transformer T], loop ② [input power supply + inductor L + switch K], and loop ③ [capacitor C + transformer T + switch K] in the above working process. The inductor L can obtain electrical energy from the current input power supply corresponding to even a lower voltage, and smoothly transmit the current to the transformer T through the above loop, and further provide it to the power output end. In this way, instead of only using the peak voltage of the input power supply sine wave, even a very low voltage of the input power supply can be effectively transmitted smoothly, thereby achieving power factor tracking.

[0059] In this embodiment, the inductor can realize power factor tracking in the power supply circuit, which means that the inductor can fully utilize the low voltage portion of the input power supply energy, thereby ensuring that the power factor of the power supply circuit can exceed 99%.

[0060] Furthermore, the inductor of the power supply circuit of the present application can achieve the above-mentioned power factor tracking while also realizing a dynamic working process of boosting and bucking the voltage according to the specific conditions of the input voltage and the output voltage required by the power supply circuit load, in conjunction with the working state of the switch K. The specific boosting / buckling process and principle are as follows:

[0061] When the voltage provided by the power supply circuit is insufficient to meet the load's needs and a voltage boost is required, the controller controls switch K to increase its duty cycle or reduce its operating frequency, thereby increasing the charging time of inductor L. When the switch is off, more energy from inductor L can be transferred to the capacitors and primary winding of the circuit components and the transformer, and further induced to the secondary winding of the transformer, thereby achieving a voltage boost. Furthermore, if the voltage provided by the power supply circuit unit is higher and a voltage step-down is required, the controller controls switch K to reduce its duty cycle or increase its operating frequency, thereby reducing the charging time of inductor L and reducing the energy transferred to the capacitors and transformer in the circuit components and achieving a voltage step-down.

[0062] Here, when the period interval T″ corresponding to the operating frequency of switch K is generally higher than the voltage period T' provided by the input power supply, that is, T″>>T', the frequency and duty cycle of switch K are adjusted, and the charging and discharging time of the main inductor are further adjusted to achieve voltage boost / voltage reduction. Specifically, the size of the voltage period T' provided by the input power supply can be set according to the specific situation of the input power supply. Furthermore, if the input power supply is an alternating current with periodic voltage changes, for example, a sinusoidal alternating current, its frequency is 100 Hz, and the corresponding T'=10 ms. If the input power supply does not have obvious periodicity in voltage change, the value of T' can be set by comparing with the change period of the sinusoidal alternating current. The specific setting method only needs to meet the requirements described above and be able to implement the solution of the present application.

[0063] Specifically, as shown in FIG6 , the inductor cooperates with the switch working state in the power circuit unit to achieve power factor tracking and corresponding output required boost and / or buck. The specific working process is as follows:

[0064] Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency;

[0065] Step S2: Compare the current actual output power obtained with the target output power required by the connected load;

[0066] Step S3, adjusting the input current peak value [I_in_peak] at high frequency according to the comparison result between the current actual output power and the target output power;

[0067] Step S4, based on the input current peak value [I_in_peak] and the current input phase information [current input voltage / input voltage peak], the target input current value [I target input current value = I input current peak value * phase information] is determined at high frequency;

[0068] Step S5, comparing the current actual input current value with the target input current value, and determining the duty cycle of the switch and the frequency adjustment instruction information based on the comparison result;

[0069] In step S6 , the switches of the power circuit execute the instruction information at high frequency to control the charge and discharge time of the inductor in the power circuit so that the current actual input current value of the power circuit is as close as possible to the target input current value.

[0070] Specifically, the circuit group of the power supply circuit of the present application can simultaneously realize functions such as boosting, bucking and power factor tracking under AC input conditions. It is necessary to determine the parameters of the components in the circuit group to ensure that the power supply circuit of the present application has an energy conversion rate of up to 98% or even above 98%. With the same energy conversion rate, the power supply circuit of the present application has lower cost and better circuit stability than the existing technology.

[0071] Specifically, the power supply circuit of the present application can simultaneously realize the control of the output power and voltage rise and fall according to the load requirements and the power factor tracking under the condition of periodic fluctuating input. Compared with the existing technology, the power supply circuit of the present application that realizes the same function has fewer components, simple connection relationship, low cost and good stability.

[0072] In this embodiment, three-phase electricity is used in the power supply circuit for parallel synthesis at the output end. For each phase, the power factor of the phase is tracked according to the above steps and the dynamic step-up and step-down of the output voltage after parallel synthesis are simultaneously achieved. In the circuit group disclosed in the present application, during the switch-off period, the inductor and the primary winding of the transformer sense the stored energy to the secondary winding of the transformer through the current change of the primary winding of the transformer, that is, the energy that can be sent to the secondary winding of the transformer depends on the amount of energy stored in the inductor and the primary winding of the transformer during the switch-on period. In this case, it can be ensured that when the three-phase electricity is working, the output end is directly parallel synthesized, and there will be no power imbalance problem between the three circuit groups of the parallel three-phase electricity.

[0073] In order to ensure that the power supply circuit of the present application has good stability, low cost and other advantages, and the power conversion rate is also relatively high, it is also necessary to determine the parameters of the components of the circuit group in the power supply circuit.

[0074] Principles for determining component parameters in a circuit group: The determination of specific component parameters is related to the circuit group's input voltage, output voltage, and output power. First, the maximum input and output voltages, as well as the circuit group's output power, must be determined. Here, for AC power, the maximum voltage refers to its effective value; for DC power, the maximum voltage refers to the maximum value within the input / output voltage range. Based on the ratio of the maximum input and output voltages, as well as the output power of the power supply circuit unit, the circuit group's capacitor and inductor parameters, the transformer's primary / secondary winding inductance and primary / secondary winding ratio, and the switching operating frequency range are determined.

[0075] Specifically, in practice, when determining the inductance of the circuit group and the primary / secondary inductance parameters of the transformer, the following should be considered:

[0076] When parameters such as the switching operating frequency / duty cycle, the primary inductance of the transformer, and the inductance of the inductor do not change, when the input voltage increases, the primary winding inductance of the transformer can store more energy during the switch on period. During the switch off period, the energy stored in the primary winding inductance of the transformer is induced to the secondary winding of the transformer, which can increase the output power of the circuit group; when the input voltage decreases, the output power of the circuit group can be reduced.

[0077] When parameters such as the maximum input voltage, the inductance of the inductor, and the switching operating frequency / duty cycle do not change, and the primary inductance of the transformer decreases, the primary inductance of the transformer can store more energy during the on-state of the switch. During the off-state of the switch, the energy stored in the primary inductance of the transformer is induced into the secondary winding of the transformer, which can increase the output power of the circuit group. Correspondingly, when the inductance of the primary winding of the transformer increases, the output power of the circuit group can be reduced. In the process of determining the inductance of the primary winding of the transformer, it is also necessary to consider that if the primary winding of the transformer stores too much energy, it may cause the transformer to saturate, thereby reducing the power conversion efficiency.

[0078] In practice, changing the ratio of the number of turns of the primary / secondary winding of the transformer will affect the conversion efficiency of the circuit; specifically, when the input voltage, switching operating frequency / duty cycle, load resistance value, transformer primary winding inductance, inductance, etc. are determined, increasing the number of turns of the secondary winding or reducing the number of turns of the primary winding, that is, reducing the primary / secondary winding ratio, can increase the output voltage; correspondingly, reducing the number of turns of the secondary winding or increasing the number of turns of the primary winding, that is, increasing the primary / secondary winding ratio of the transformer, can reduce the output voltage; by determining the parameters of the transformer through specific scenarios and the above-mentioned methods, the conversion efficiency of the power supply circuit can be effectively improved.

[0079] In practice, when the input voltage, switching operating frequency / duty cycle, and inductance of the transformer primary winding are determined, when the inductance of the inductor decreases, the inductor can store more energy during the switch-on period. During the switch-off period, the energy stored in the inductor charges the primary side of the transformer, and the primary winding of the transformer then induces the energy to the secondary winding of the transformer, which can increase the output power of the circuit group; when the inductance of the inductor increases, the output power of the circuit group can be reduced.

[0080] When determining the switching frequency range, consider the following: assuming the parameters of other components in the circuit remain unchanged, lowering the switching frequency increases the energy storage time t during a single switch closure cycle and reduces the frequency f. During the switch closure period, the energy stored in the inductor and transformer primary increases, increasing the circuit's output power. Consequently, increasing the switching frequency reduces the circuit's output power. Furthermore, as the switching frequency increases, switching losses are generated during the switch's turn-on and turn-off transitions. Increasing the switching frequency increases switching losses. The transformer's conversion efficiency also needs to be considered. Different magnetic cores have different inductances and conversion efficiencies at different frequencies. Excessively low frequencies, for example, below 30K, may cause transformer saturation, resulting in a decrease in conversion efficiency. Excessively high frequencies, for example, above 500K, may cause significant changes in the transformer's inductance, reducing conversion efficiency.

[0081] As previously mentioned, the capacitor stores energy during the switch-off period and resonates with the transformer's primary winding during the switch-on period, transferring the stored energy to the transformer's primary winding. If the capacitor's value is too small, the energy stored in the capacitor will be insufficient during operation, reducing the power output of the power supply circuit unit and, consequently, the conversion efficiency. If the capacitor's value is too large, the capacitor's voltage will not be able to keep up with the input voltage changes when the input voltage is AC, making calculations difficult during power factor tracking and reducing energy conversion efficiency.

[0082] Preferably, the maximum input voltage of the circuit group is V 入 With the maximum output voltage V 出 The ratio is V 入 :V 出 =0.2-8.0, when the output power is greater than 200W, the parameter range of the capacitor is 30nF-3μF, the inductance range of the primary winding of the transformer is 10μH-1000μH; the ratio range of the primary winding / secondary winding of the transformer is R 原 :R 副 =1:5-5:1.

[0083] Specifically, when the output power of the circuit group is greater than 200W and the ratio of the maximum input voltage to the maximum output voltage is 0.2-8.0, according to the above parameter selection rules, when the capacitor parameter is less than 30nF, the voltage across the capacitor rises too quickly during the off-cycle of the switch, causing the voltage across the switch to rise too quickly, which may damage the switch, or necessitate the use of a switch with a higher voltage resistance, increasing the cost of the switch. When the capacitor parameter is greater than 3μF, the current in the primary winding inductance of the transformer rises too quickly during the on-time of the switch. At the moment the switch is disconnected, the voltage spike caused by the transformer leakage inductance is too high, which may damage the switch, or necessitate the use of a switch with a higher voltage resistance, thereby increasing the cost of the switch. When the primary winding inductance of a transformer is less than 10μH, transformer parameters are difficult to balance. For example, if the number of turns is too small, saturation is likely to occur, making it unable to carry sufficient power. Alternatively, if the number of turns is sufficient, but the core air gap is too large, magnetic leakage is severe, reducing efficiency. When the primary inductance of a transformer is greater than 1000μH, the energy stored in the transformer's primary inductance decreases during the switch-on energy storage period, requiring a lower frequency to carry sufficient power. At too low a frequency, the transformer conversion efficiency is low and saturation is likely to occur. When the primary / secondary winding ratio is less than 1:5, the transformer manufacturing process is difficult, which can lead to excessive leakage inductance on the secondary winding. This can cause large current fluctuations in the switch when the switch is turned on, significantly reducing efficiency. When the primary / secondary winding ratio is greater than 5:1, the transformer manufacturing process is difficult, which can lead to excessive leakage inductance on the primary winding. This can cause large voltage fluctuations across the switch when the switch is turned off, potentially damaging the switch or requiring a higher voltage switch, which increases the cost of the switch.

[0084] Specifically, in this embodiment, the parameters of the inductor in the circuit group are further determined based on the aforementioned parameter selection principles. Because during operation of the circuit group, electrical energy is dynamically distributed between the inductor and the transformer primary winding based on the relationship between the inductor's value and the inductance of the transformer's primary winding, the inductor parameter needs to have a relatively wide range, specifically 1μH-10mH. When the inductor stores a large amount of energy and participates in a large amount of energy transfer, its parameter value can be set smaller, within a range of 1μH-100μH. When the inductor does not participate in energy transfer or participates in energy transfer less, its parameter value can be set larger, within a range of 2mH-10mH.

[0085] Furthermore, the following considerations must be taken into account when determining the specific values ​​of the inductor parameters:

[0086] If the inductor's inductance is close to that of the transformer's primary winding—for example, and not limitation, if both the inductor and the transformer's primary winding are designed to be between 10μH and 30μH—during the energy storage cycle when the switch is on, the energy stored in the transformer's primary winding and the inductor are the same. This allows the inductor to share the energy transfer burden, balancing the heating points between the inductor and the transformer's primary winding. This also places requirements on the inductor's core material, requiring careful testing of the selected core's losses during energy storage and transfer to avoid inductor saturation, which can increase inductor cost.

[0087] If the inductor's inductance is significantly greater than the transformer's primary winding inductance—for example, but not limited to, if the inductor's inductance is designed between 800μH and 1000μH and the transformer's inductance is designed at 10μH—then the transformer's primary inductance will dominate the energy storage cycle. This approach reduces the inductor's energy transfer and saves on inductor core costs.

[0088] Setting the inductor's inductance much lower than the transformer's primary winding inductance—for example, but not limitation, the inductor's inductance is designed to be 10μH, and the transformer's inductance is designed to be 1000μH. This results in the inductor storing significantly more energy than the transformer's primary winding during energy storage. Setting both the inductor's inductance and the transformer's primary winding inductance relatively high—for example, but not limitation, the inductor's inductance is designed to be between 100μ-1000μH, and the transformer's inductance is designed to be between 100μ-1000μH. This necessitates setting the switching frequency to a very low range to output power above 200W, and can easily lead to saturation of the transformer and inductor, placing very high demands on the transformer and inductor parameter settings. In practice, this circuit group exhibits low power conversion efficiency.

[0089] Specifically, in this embodiment, the operating frequency of the switch is related to multiple parameters. When parameters such as the transformer primary winding inductance, the inductor inductance, the switch duty cycle, the input voltage, and the load remain unchanged, reducing the operating frequency of the switch will increase the output power of the circuit group; increasing the operating frequency of the switch will reduce the output frequency of the circuit group. It should be noted that too low a switching frequency can easily cause saturation of the inductor and transformer, while too high a switching frequency can lead to increased switching losses. Specifically, the switching frequency needs to be adjusted dynamically in real time based on the fluctuations of the input voltage and the dynamic requirements of the output voltage.

[0090] Furthermore, in the process of dynamically adjusting the voltage up and down according to the output requirements of the power supply circuit, it is necessary to calculate and adjust the switch duty cycle and frequency in real time. The process of realizing power factor tracking in the power supply circuit is to adjust the switch duty cycle and frequency so that the actual input current approaches the target input current that is synchronized with the input voltage and shows a regular change in the input voltage in real time. Therefore, the operating frequency range of the switch needs to meet the power factor tracking while being dynamically adjusted. Specifically, its range is about 30K-500K.

[0091] In summary, when the output power of the circuit group is greater than 200W, the ratio of the maximum input voltage to the maximum output voltage is 0.2-8, the capacitor parameters are set to 30nF-3μF, the primary inductance of the transformer is 10μH-1000μH, the inductance parameter range is 1μH-10mH, and the transformer primary / secondary winding ratio is 1:5-5:1, the power conversion rate of the circuit group can reach more than 96%. In certain specific scenarios, the power conversion rate can be as high as 98%. Specific experimental data are detailed in Examples 1 to 64 of Table 1. Compared with the prior art, the power conversion rate is higher. At the same time, the circuit group uses only a few components, achieving an ultra-high power conversion rate at a low cost, and can achieve dynamic voltage boosting and voltage reduction according to the needs of the load. Compared with the circuit with the same power conversion rate in the prior art, the circuit group of the present application has strong stability, low cost, low power loss, and more energy conservation.

[0092] Preferably, the ratio of the maximum input voltage to the maximum output voltage of the circuit group is V 入 :V 出 =0.2-1.0, when the output power is 200W-1000W, the inductance range of the transformer primary winding is 10μH-1000μH, the parameter range of the capacitor is 100nF-3μF, and the transformer primary / secondary winding ratio range is R 原 :R 副 =1:5-1:1.

[0093] Specifically, this embodiment provides parameter ranges for the ratios of capacitors, transformer primary windings, and transformer primary-to-secondary windings in the circuit group components when the circuit group output power is 200W-1000W and the ratio of the calculated input voltage value to the calculated output voltage value is 0.2-1.0. According to the above parameter determination principles and process, after determining the specific maximum input voltage, maximum output voltage, and output power, the specific parameters of the corresponding components are selected and determined within the parameter ranges provided by this embodiment to meet power factor tracking and dynamic adjustment of boost and buck required by the output end, and to achieve an energy conversion rate of up to 98%. Specific parameter experimental data and test results are detailed in Examples 1 to 18 in Table 1. Under the same function and energy conversion rate as the prior art, the power supply circuit of this application has significantly fewer components and less energy loss than the prior art circuit, resulting in lower cost and stronger circuit stability.

[0094] As an example and not a limitation, when the maximum input voltage of the circuit group is 50V, the maximum output voltage is about 250V, and the output power is 200W, according to the above parameter design principles, the inductance parameter is designed to be about 10μ-1mH, the inductance parameter of the primary winding of the transformer is set to about 10μ-1mH, the capacitance parameter is set to about 500nF-3000nF, and the primary / secondary winding ratio of the transformer is set to about 1:2-1:5. At this time, the corresponding power conversion rate is above 97%.

[0095] Specifically, in this embodiment, the transformer primary winding inductance is set to 10 μH, or the inductance of the inductor is set to approximately 10 μH. This is because, at a 50V input voltage, the amount of energy stored in the inductor and the transformer primary during each energy storage cycle is very low. Significantly reducing the transformer primary winding inductance or the inductance of the inductor allows the transformer primary winding and inductor to store sufficient energy during the energy storage cycle, allowing the power supply circuit, including multiple circuit groups, to provide sufficient power to the output terminal or connected load. However, further reducing the transformer primary winding inductance or the inductance of the inductor will significantly increase the transformer excitation current, resulting in a significant decrease in conversion efficiency.

[0096] In this embodiment, the transformer primary / secondary winding inductance ratio range is about 1:5-1:2. Since the maximum input voltage is only 50V, if a 1:1 transformer is used, the duty cycle of the switch operation needs to be increased to increase the output voltage. The required output voltage is 300V, and the duty cycle needs to be increased to about 70% or more to obtain an output voltage of about 300V. At this time, the loss in the switch-on working state decreases too much, resulting in low conversion efficiency of the circuit group. Using a step-up transformer with a primary / secondary winding inductance ratio range of 1:5-1:2 can effectively reduce the duty cycle of the switch and improve the power conversion efficiency.

[0097] Due to the relatively low input voltage, the capacitor requires a relatively large value to ensure sufficient energy is stored in the transformer primary winding during the energy storage cycle. If the capacitor is set below 500nF, insufficient energy can be stored in the capacitor at certain power points when the output voltage changes dynamically, resulting in reduced efficiency. If the capacitor is set above 3000nF, a large voltage spike is observed during the switch disconnection process, requiring a switch with better voltage resistance, which increases cost.

[0098] When the maximum input voltage is 300V, the maximum output voltage is around 300V, and the output power is 1000W, according to the above parameter design principles, the inductance of the primary winding of the transformer is set to around 60μH-1mH, the capacitance parameter is set to around 100nF-500nF, and the primary / secondary winding ratio of the transformer is set to around 1:1. At this time, the energy conversion rate of the corresponding circuit group is above 98%.

[0099] Specifically, by way of example and not limitation, this embodiment can be applied in the field of solar photovoltaics. The input is 300V DC, the output is approximately 300V AC, the circuit group output power is 1000W, the maximum input voltage and the maximum output voltage are approximately 1:1, and the inductance of the inductor and the transformer primary winding are selected to be relatively large. For example, the inductance of the transformer primary winding is set to 60μH, and the inductor is set to 1mH. Since the ratio of the maximum input voltage to the maximum output voltage is 1, the transformer primary / secondary inductance used is approximately 1:1. When the transformer primary / secondary ratio is close, the transformer processing technology can save costs and the leakage inductance is easy to control.

[0100] In the application scenario of this embodiment, if a capacitor smaller than 100nF is selected, the capacitor may not be able to provide enough energy to the primary winding of the transformer during the energy storage period when the switch is closed, resulting in a decrease in the conversion efficiency of the circuit group. If a capacitor larger than 500nF is selected, it is easy to cause a large charging current when charging the primary winding inductance of the transformer during the energy storage period when the switch is closed. At the moment the switch is disconnected, a voltage spike is generated due to the primary leakage inductance of the transformer, resulting in the need to select a switch with a higher voltage resistance, which increases the cost.

[0101] In this embodiment, by way of example and not limitation, it can be applied in the solar photovoltaic field. The input is 300V DC, the output is approximately 300V AC, the circuit group output power is 1000W, and the maximum input voltage and maximum output voltage are approximately 1:1. The inductance of the inductor and transformer primary winding should be relatively large. Smaller inductances will result in reduced power conversion efficiency. In practice, setting the transformer primary winding inductance to 60μH and the inductor to 1mH can achieve a power conversion efficiency of 98% or higher for the circuit group.

[0102] At the same time, you can choose to distribute the energy stored in the energy storage cycle between the transformer and the inductor. Increasing the inductor and decreasing the transformer inductance will result in a greater proportion of energy stored in the transformer primary during the energy storage cycle when the light is on and off, and a smaller proportion in the inductor. Decreasing the inductor and increasing the transformer inductance will result in a smaller proportion of energy stored in the transformer primary during the energy storage cycle when the light is on and off, and a larger proportion in the inductor.

[0103] In the application scenario of this embodiment, the capacitance parameter is about 100nF-500nF; in practice, for capacitors less than 100nF, during the energy storage period when the switch is closed, the energy in the capacitor is too little to provide enough energy to the primary winding of the transformer, resulting in a decrease in the power conversion efficiency of the circuit group; for capacitors greater than 500nF, during the energy storage period when the switch is closed, the capacitor stores too much energy, which charges the inductance of the primary winding of the transformer, easily resulting in a large charging current. At the moment the switch is disconnected, a voltage spike is generated due to the leakage inductance of the primary side of the transformer, resulting in the need to select a switch with a higher voltage resistance, which increases the cost.

[0104] In this embodiment, since the ratio of the maximum input voltage to the maximum output voltage is 1, the primary / secondary inductance of the transformer used is approximately 1:1. When the primary / secondary ratio of the transformer is close, the transformer manufacturing process can be cost-effective and the leakage inductance can be easily controlled.

[0105] Preferably, the ratio of the maximum input voltage to the maximum output voltage of the circuit group is V 入 :V 出=0.5-1.5, when the output power is 1000W-2000W, the transformer primary inductance range is 30μH-1000μH, the capacitance parameter range is 50nF-3μF, and the transformer primary / secondary winding ratio range is R 原 :R 副 =1:2-2:1.

[0106] Specifically, this embodiment provides parameter ranges for the corresponding capacitor, transformer primary winding, and transformer primary-to-secondary winding ratios in the circuit assembly components when the circuit assembly output power is 1000W-2000W and the ratio of the calculated input voltage to the calculated output voltage is 0.5-1.5. Following the aforementioned parameter determination principles and process, after determining the specific maximum input voltage, maximum output voltage, and output power, the specific parameters of the corresponding components are selected and determined within the parameter ranges provided in this embodiment to meet power factor tracking and dynamically adjust the voltage step-up and step-down required by the output terminal. This allows for an energy conversion rate exceeding 96%, or even reaching 98%. Specific parameter experimental data and test results are detailed in Examples 32 to 48 in Table 1. While maintaining the same functionality and energy conversion rate as the prior art, the circuit assembly of this application significantly reduces components and energy loss compared to the prior art circuit, resulting in lower costs and greater circuit stability.

[0107] As an example and not a limitation, when the input voltage is a 220V sine wave, that is, the maximum input voltage is about 311V, the maximum output voltage is about 200V, and the output power is 2000W, according to the above-mentioned parameter design principles, the inductance range of the primary winding of the transformer is set to about 30μH-1mH, the capacitance parameter range is set to about 500nF-3000nF, and the primary / secondary winding ratio of the transformer is set to about 2:1. The power conversion rate of the circuit group can be as high as more than 97%, which is the same as the power conversion rate of the prior art. The circuit group of this application has fewer components, less energy loss, stronger stability, and is more energy-saving.

[0108] As an example and not a limitation, when the input voltage is a 380V sine wave, that is, the maximum input voltage is about 540V, the maximum output voltage is about 1000V, the ratio of the maximum input voltage to the maximum output voltage is about 0.5, and the output power is 1000W, according to the above parameter design principles, the inductance of the primary winding of the transformer is set at about 150μH-1mH, the capacitance parameter is set at about 50nF-500nF, and the primary / secondary winding ratio of the transformer is set at about 1:2. At this time, the corresponding power conversion rate is above 98%.

[0109] In this embodiment, when the output voltage is 1000V, the output voltage is too high. If a 1:1 transformer is used, the output voltage will be induced to the primary side of the transformer, superimposed with the capacitor voltage, resulting in a switch withstand voltage that is too high, damaging the switch. When a 1:2 transformer is used, during the switching period, after the output voltage of 1000V is induced to the primary side, the primary side voltage is only 500V. After the capacitor voltage is superimposed, the withstand voltage during the switch off period is greatly reduced, the choice of switches is increased, and the cost is greatly reduced. Therefore, it is necessary to set the transformer primary / secondary winding ratio to 1:2. This setting can significantly reduce the switch duty cycle and improve the power conversion efficiency of the circuit group. At the same time, the output voltage of 1000V is converted to the primary side through the 1:2 transformer of the primary and secondary sides, which can significantly reduce the withstand voltage of the switch tube during the switching period, increase the choice of switch tubes, and significantly reduce costs.

[0110] Preferably, the ratio of the maximum input voltage to the maximum output voltage of the circuit group is V 入 :V 出 =5.0-8.0, when the output power is 1000W-2000W, the transformer primary inductance range is 50μH-250μH, the capacitance parameter range is 200nF-800nF, and the transformer primary / secondary winding ratio range is R 原 :R 副 =2:1-5:1.

[0111] Specifically, this embodiment provides parameter ranges for the ratios of capacitors, transformer primary windings, and transformer primary-to-secondary windings in the circuit group components when the circuit group output power is 1000W-2000W and the ratio of the calculated input voltage to the calculated output voltage is 5.0-8.0. According to the above parameter determination principles and process, after determining the specific maximum input voltage, maximum output voltage, and output power, the specific parameters of the corresponding components are selected and determined within the parameter ranges provided by this embodiment to meet power factor tracking and dynamic adjustment of the boost and buck required by the output end, and to achieve an energy conversion rate of over 96%, or even 98% or above. Specific parameter experimental data and test results are detailed in Examples 19 to 31 in Table 1. Under the same function and energy conversion rate as the prior art, the circuit group of this application has significantly fewer components and less energy loss than the prior art circuit, resulting in lower cost and greater circuit stability.

[0112] As an example and not a limitation, when the input voltage is a 220V sinusoidal wave, that is, the maximum input voltage is about 311V, the maximum output voltage is about 40V, and the output power is 1000W, according to the above parameter design principles, the inductance of the primary winding of the transformer is set at about 150μH-250μH, the capacitance parameter is set at about 200nF-500nF, and the primary / secondary winding ratio of the transformer is set at about 5:1. At this time, the corresponding power conversion rate is above 96%.

[0113] Specifically, in this embodiment, the output voltage is only 40V, and the output half-wave rectifier module can use a switching device instead of a diode. Under low voltage conditions, the output current is very large, so a switching device with relatively low internal resistance needs to be selected.

[0114] As an example and not a limitation, when the input voltage is a 380V sine wave, that is, the maximum input voltage is about 540V, the maximum output voltage is about 100V, the ratio of the maximum input voltage to the maximum output voltage is about 5:1, and the output power is 2000W, according to the above parameter design principles, the inductance of the primary winding of the transformer is set at about 50μH-150μH, the capacitance parameter is set at about 400nF-800nF, and the ratio of the primary / secondary winding of the transformer is set at about 2:1. At this time, the corresponding power conversion rate is above 97%. Under the conditions of the same function and the same power conversion rate as the prior art, the number of components of the circuit group of this application is far less than that of similar products on the market, the cost is much lower than that of market products, and the circuit stability is higher.

[0115] This embodiment is a situation where the input voltage of the circuit group is high, the output voltage is low, and the output current is large. In practice, if a transformer with a primary winding and a secondary winding of 1:1 is used, the switch duty cycle may be too small and the frequency is too low, resulting in low transformer conversion efficiency, and thus reducing the overall power conversion efficiency of the circuit group. Using a transformer with a primary winding and a secondary winding of about 2:1-3:1 can solve this problem well and improve the circuit conversion efficiency. At this time, it should be noted that the primary leakage inductance of the transformer with a primary winding and a secondary winding of 2:1-3:1 will increase. If the primary leakage inductance is too large, a voltage spike will be generated at the moment the switch is turned off, causing damage to the switch, or a switch with a higher withstand voltage will need to be used, which increases the cost. It is recommended here to use copper foil as the primary and secondary coils, and to use a process of winding the primary and secondary sides in parallel to make a transformer to reduce the leakage inductance of the primary and secondary sides of the transformer.

[0116] In this embodiment, the output voltage is only 100V. It is recommended to use switching components instead of diodes for output half-wave rectification, and it is possible to consider setting the switch of the circuit group to a switching component formed by multiple switching devices in parallel to reduce conduction loss.

[0117] Preferably, the ratio of the maximum input voltage to the maximum output voltage of the circuit group is V 入 :V 出 =2.0-5.0, when the output power is 2000W-10000W, the transformer primary inductance range is 50μH-250μH, the capacitance parameter value range is 200nF-800nF, and the transformer primary / secondary winding ratio range is R 原 :R 副 =1:1-2:1.

[0118] Specifically, this embodiment provides parameter ranges for the ratios of capacitors, transformer primary windings, and transformer primary-to-secondary windings in the circuit group components when the circuit group output power is 2000W-10000W and the ratio of the calculated input voltage to the calculated output voltage is 2.0-5.0. According to the above parameter determination principles and process, after determining the specific maximum input voltage, maximum output voltage, and output power, the specific parameters of the corresponding components are selected and determined within the parameter ranges provided by this embodiment to meet power factor tracking and dynamic adjustment of the boost and buck required by the output end, and to achieve an energy conversion rate of over 96%, or even 98% or above. Specific parameter experimental data and test results are detailed in Examples 49 to 59 in Table 1. Under the same function and energy conversion rate as the prior art, the circuit group of this application has significantly fewer components and less energy loss than the prior art circuit, resulting in lower cost and greater circuit stability.

[0119] As an example and not a limitation, when the input voltage is 600V-1000V, the output voltage is 220V-380V, and the output power is 2000W-10000W, according to the above parameter design principles, the inductance of the primary winding of the transformer is set at about 50μH-250μH, the capacitance parameter is set at about 100nF-800nF, and the ratio of the primary winding to the secondary winding of the transformer is set at about 1:1-2:1. At this time, the corresponding power conversion rate is above 96%. If the inductance of the primary winding of the transformer is lower than 50μH, the switching tube frequency may be too high, and switching tubes such as IGBT cannot be used, thereby increasing the cost; if it is higher than 250μH, the entire circuit may not be able to output enough power, or the switch needs to operate at an extremely low frequency, reducing the transformer conversion efficiency. Compared with the prior art, under the same power and efficiency conditions, the number of components of the circuit group of this application is much smaller than the circuit products of the prior art, and the cost is much lower than the products of the prior art.

[0120] Specifically, referring to FIG4 and in combination with FIG5-1, 5-2, 5-3 and 5-4, when the output ends of the three circuit groups corresponding to the three-phase power included in the power circuit unit are connected in parallel, the process of solving the ripple problem of the power circuit is as follows:

[0121] As shown in Figure 4, three circuit groups are connected to the three-phase power supply. When the switch of the corresponding circuit group is closed, the inductor of each circuit group is charged through the above loop ②. The resonant circuit formed by loop ③ [capacitor C + transformer T + switch K] adjusts the direction of the magnetic field of the primary winding of the transformer. At this time, the circuit group does not transfer energy to the secondary winding of the transformer. When the switch is turned off, the transformer transfers energy to the secondary winding through the above loop ① [input power supply + inductor L + capacitor C + transformer T] and charges the connected output capacitor through the output end of the circuit group. The output capacitor is then connected to the load to provide power to the load.

[0122] As mentioned above, if only the output end of one circuit group is connected to the output capacitor, and the output capacitor is connected to the load to provide power to the load, when the voltage of the input steamed wave is zero or low, the output capacitor needs to use its stored energy to provide power to the load. Otherwise, a large ripple problem will occur, and it is necessary to set an output capacitor with larger parameters to alleviate the ripple problem, which increases the cost.

[0123] The three phases of three-phase electricity have a phase difference of 120°. When the resistive load connected to each phase of the three-phase electricity is the same, the output power is constant. The three circuit groups are connected to the three-phase electricity at the same time, and the output ends of the three circuit groups are connected in parallel, that is, the output ends of the three circuit groups are connected to the positive pole of the output capacitor at the same time, and the other ends are connected to the negative pole of the output capacitor at the same time. In this way, when the input voltage of the first circuit group in the power supply circuit unit is low, the other two circuit groups, due to the 120° phase difference, keep the overall input power of the three-phase power input power circuit unchanged and are not in a state of low input power. The total input power can be guaranteed not to fluctuate due to the 50Hz power frequency phase. Because the inductor has the function of power factor tracking and the power of the three-phase electricity is constant, the output power of the power supply circuit unit is constant at this time, and the voltage ripple is basically eliminated, thereby providing a stable voltage output for the load.

[0124] Taking the input of 380V sinusoidal AC power and the output requirement of 1000V / power of about 40kW as an example, when the input is single-phase power, as shown in Figure 5-1, it is a steamed bun wave with a frequency of 100HZ after full-wave rectification of single-phase power. As shown in Figure 5-2, when the output capacitor has a capacitance of 3mF, the corresponding output voltage has a ripple with a frequency of 100HZ / amplitude of about 28V; when the input is three-phase power, compared with single-phase power, there is an angle of 120° between the three 380V sinusoidal waves. As shown in Figures 5-3 and 5-4, after the output ends of the circuit groups connected to each phase of the three-phase power are connected in parallel, the corresponding output voltage has a ripple with a frequency of 300HZ / amplitude of about 6V. It can be seen that the ripple is significantly reduced, thereby solving the problems of battery overcharge / output overcurrent, heating and shortened life caused by frequent charging and discharging of output capacitors, and output capacitors with smaller parameter values ​​can be selected to reduce costs.

[0125] Preferably, after the output ends of the three circuit groups in the power circuit units in the multiple power circuit units are connected in parallel, the outputs of the multiple power circuit units are connected in series or in parallel.

[0126] Preferably, after the output ends of the three circuit groups corresponding to the three-phase electricity included in the multiple power supply circuit units are connected in parallel, the outputs of the power supply circuit units are connected in series or in parallel.

[0127] Specifically, it can be seen from the above that after the three circuit groups of each power supply circuit unit are respectively connected to three-phase power, the output ends of each circuit group are connected in parallel to solve the ripple problem. When the power supply circuit includes multiple power supply circuit units, the output ends of the multiple power supply circuit units can be combined in series / parallel to provide a wider output voltage / power range to meet the different voltage requirements of various loads.

[0128] In practice, when the power supply circuit includes multiple power supply circuit units, and each power supply circuit unit includes three circuit groups connected to three-phase electricity, the output ends of the three circuit groups in each power supply circuit unit are connected in series / parallel, and the multiple power supply circuit units provide power output ends, which can be connected in series or parallel, or in a combination of series and parallel, through various switch control devices / modules.

[0129] Here, there is no restriction on the specific control device / module for realizing the series / parallel combination of the output terminals of multiple power supply circuit units. Any switch control device / module scheme that can realize the series / parallel combination of the output terminals of multiple power supply circuit units in any current or future existing technology, as long as the scheme can be directly applied to the series / parallel combination of the output terminals of multiple power supply circuit units in this embodiment, or does not require technical personnel in this field to spend creative labor to modify the scheme and then apply it to the series / parallel combination of the output terminals of multiple power supply circuit units in this embodiment, then these schemes that can realize the switch control device / module are all within the scope of protection of this application, such as relays, electromagnetic switches, etc.

[0130] Preferably, the power supply circuit further includes an input rectifier module for providing DC input to the inductor in the circuit group, wherein the multiple circuit groups connected to each phase in the multiple power supply circuit units share one full-wave rectifier module.

[0131] Preferably, the output half-wave rectification module realizes half-wave rectification through a diode.

[0132] Specifically, the output half-wave rectifier module provided in this embodiment is connected to one end of the secondary winding of the transformer, and its specific working principle is as follows:

[0133] After the switch of the circuit group is turned from closed to open, the inductor and the primary winding of the transformer that have been charged during the switch closing period are discharged, the capacitor is charged, and the secondary winding of the transformer is induced by the current change of the primary winding to obtain electrical energy. At this time, the current of the secondary winding of the transformer is output to the output capacitor or the load through the output half-wave rectifier module to provide electrical energy or store energy; when the switch of the circuit group is turned from open to closed, the capacitor in the circuit group forms a loop with the primary winding of the transformer and the switch. Because the capacitor does not allow sudden voltage changes, the capacitor and the primary winding of the transformer resonate at this time, and the current direction in the primary winding of the transformer is opposite to the current direction during the switch-off period. Because the output half-wave rectifier module is set on the secondary winding of the transformer, a loop cannot be formed. When the primary winding of the transformer forms a resonant loop with the capacitor and the closed switch, no induced current is generated in the secondary winding of the transformer.

[0134] It can be seen from this that as long as the output half-wave rectifier module can realize the unidirectional conduction of the secondary winding current of the transformer, there is no restriction on the specific circuit or components for realizing half-wave rectification. Any circuit scheme that can realize half-wave rectification in any current or future existing technology, as long as the scheme can be directly applied to the unidirectional conduction of the secondary winding current of the transformer in this embodiment, or does not require technical personnel in this field to spend creative labor to modify the scheme to be applicable to the unidirectional conduction of the secondary winding current of the transformer in this embodiment, then these circuit schemes that can realize half-wave rectification are all within the scope of protection of this application, such as diodes / MOS tubes with unidirectional conduction function, and switching tubes controlled to be unidirectional conduction, etc.

[0135] Furthermore, diodes are used as output half-wave rectifiers. Connecting these diodes to the corresponding output terminals of the transformer's secondary windings enables unidirectional output from the transformer's secondary windings. Diodes inherently conduct electricity in one direction, and using them to achieve half-wave rectification results in a simple control circuit and stable performance.

[0136] Preferably, the output half-wave rectifier module realizes half-wave rectification through a first switch and a first controller that controls the first switch; preferably, the first controller controls the switching mode of the first switch according to the mode in which the controller of the power supply circuit unit controls the switch to induce electrical energy in the secondary winding of the transformer.

[0137] Specifically, this embodiment implements half-wave rectification of the secondary winding output of the transformer through a switch tube, and at this time the switch tube is controlled by a switch tube controller.

[0138] Furthermore, the working state of the switch tube determines whether the secondary winding of the transformer can form a loop, that is, when the switch tube is disconnected, it cannot form a loop, and when the switch tube is closed, it can form a loop; at the same time, after the switch of the circuit group is closed, the capacitor in the circuit group charges the primary winding of the transformer and the two form resonance, and the secondary winding of the transformer cannot form a loop, that is, at this time the switch tube needs to be disconnected. The switch tube controller needs to control the working state of the switch tube according to the working state of the switch in the power circuit unit. According to the above analysis, when the switch of the circuit group is in the closed state, the switch tube controller needs to control the switch to be in the open state. This embodiment realizes the function of half-wave rectification of the output of the secondary winding of the transformer by setting the switch tube controller and the corresponding switch tube; in some scenarios, the switch has lower energy loss and higher power conversion rate than the diode, such as the scenario with low output voltage, such as less than 160 volts.

[0139] Preferably, the switching of the circuit group of the power circuit is realized by a bidirectional switch or a controllable switching device.

[0140] In practice, the selection of switching components is also related to the switch's operating frequency setting. For ordinary silicon-based MOS transistors, the recommended maximum frequency is limited to 150kHz; for silicon carbide MOS transistors, the recommended maximum frequency is limited to 250kHz; for IGBT switches, the recommended maximum frequency is limited to 40kHz; and for gallium nitride MOS transistors, the recommended maximum frequency is limited to 500kHz. The switch in this embodiment is a common commercially available high-frequency switch with a withstand voltage of 150V, such as the NCEP15T14 high-frequency switch, corresponding to an operating frequency range of 50kHz-200kHz.

[0141] Specifically, the switch of the circuit group of the power circuit unit carries the function of connecting and disconnecting the circuit according to the control information of the corresponding controller. Here, the specific control method of the controller controlling the switch is not restricted, that is, the method or path for the controller to provide the control signal to the switch is not restricted, and it can be wireless or wired. Any scheme that can realize the controller-controlled switch signal transmission in any current or future existing technology, as long as the scheme can be directly applied to the controller in this embodiment to transmit the control signal to the switch it controls, or does not require technical personnel in this field to spend creative labor to modify the scheme and apply it to this embodiment, then these schemes that can realize the controller-controlled switch transmission are within the scope of protection of this application.

[0142] Furthermore, there is no restriction on the specific form of the switch or controller or the switch and its controller that realizes the disconnection and connection of the circuit in the circuit group. Any switch or controller or the scheme of the switch and its controller that can realize the disconnection and connection of the circuit in any existing technology now or in the future, as long as the scheme can be directly applied to the function of disconnecting and connecting the circuit in the scalable power supply circuit of this embodiment, or does not require technical personnel in this field to spend creative labor to modify the scheme and apply it to this embodiment, then these schemes of switches or controllers or switches and their controllers that can realize the disconnection and connection of the circuit are all within the scope of protection of this application.

[0143] Preferably, the leakage inductance value of the transformer in the power supply circuit is less than 1.5%.

[0144] Specifically, during the operation of the power circuit unit, when the switch of the circuit group is closed, the input power supply charges the inductor. At the moment the switch is disconnected, the current of the entire circuit is large. At this time, the leakage inductance of the transformer will cause a large voltage peak to be generated at both ends of the switch. The switch may be damaged by the high voltage breakdown. To ensure that the power circuit can operate normally and stably, the leakage inductance value range of the transformer here needs to be less than 1.5%.

[0145] Furthermore, the specific structure of the transformer that complies with the power supply circuit of this application is not limited here. Any structural scheme of the transformer that can achieve a leakage inductance of less than 1.5% in any current or future existing technology, as long as the scheme can be directly applied to the function of the transformer in the power supply circuit unit of this embodiment, or does not require technical personnel in this field to spend creative labor to modify the scheme and apply it to this embodiment, then these schemes that can achieve a transformer structure with a leakage inductance of less than 1.5% are all within the scope of protection of this application.

[0146] Preferably, the transformer structure in the power supply circuit is copper foil or U-shaped metal sheet, and the winding method is parallel winding.

[0147] Specifically, this embodiment discloses the structure and winding method of the transformer in the circuit group. The magnetic core structure of the transformer is selected to be a thin metal sheet, or it can be a U-shaped copper sheet. The winding method of the primary and secondary sides of the transformer is a parallel winding method, which can reduce the leakage inductance of the transformer and meet the operating needs of the power supply circuit.

[0148] As shown in FIG6 , the present application further provides a method for implementing power factor tracking and output voltage rise and fall control based on the above power supply circuit, the method comprising:

[0149] Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency;

[0150] Step S2: Compare the current actual output power obtained with the target output power required by the connected load;

[0151] Step S3, adjusting the input current peak value [I_in_peak] at high frequency according to the comparison result between the current actual output power and the target output power;

[0152] Step S4, based on the input current peak value [I_in_peak] and the current input phase information [current input voltage / input voltage peak], the target input current value [I target input current value = I input current peak value * phase information] is determined at high frequency;

[0153] Step S5, comparing the current actual input current value with the target input current value, and determining the duty cycle of the switch and the frequency adjustment instruction information based on the comparison result;

[0154] In step S6 , the switches of the power circuit execute the instruction information at high frequency to control the charge and discharge time of the inductor in the power circuit so that the current actual input current value of the power circuit is as close as possible to the target input current value.

[0155] Specifically, in the above step S1, the current actual input current, input voltage, output voltage, and output current values ​​are obtained at high frequency. High-frequency acquisition is required to obtain the current actual input and actual output conditions of the power supply circuit. The specific acquisition or acquisition method is not limited. It can be obtained through the acquisition unit of the controller or through other methods. The acquired information is transmitted to the controller for determining the adjustment instruction information of the switch duty cycle and frequency. The frequency of the high frequency can refer to the frequency of the switch in the power supply circuit. For example, it can be equal to the switching frequency or less than the switching frequency. The frequency of the high frequency here can also change according to actual conditions and is not specifically limited.

[0156] In the above step S2, the current actual output power obtained is compared with the target output power required for the connected load. When the scenario in which the connected load or the power supply circuit is used is determined, the corresponding required target output power and target output voltage / current are relatively determined; the current actual output power is compared with the target output power. When the current actual output power is greater than the target output power, it means that the actual output power is higher than the target output power, and the actual output power needs to be reduced. When the actual output power is less than the target output power, it means that the actual output does not meet the target output power requirements, and the actual output power needs to be increased.

[0157] In the above step S3, the input current peak value [I_in_peak] is determined at high frequency based on the comparison result between the actual output power and the target output power. If the actual output power is less than the target output power, the input current peak value is increased to increase the current actual output voltage or current, and further increase the actual output power to meet the needs of the load; if the actual output power is greater than the target output power, the input current peak value is reduced to reduce the current actual output voltage or current, and further reduce the output power to meet the needs of the load. The increase or decrease amplitude of the input current peak value needs to take into account the difference between the actual output power and the target output power. For example, if the difference between the two exceeds a preset value, the increase amplitude of the input current peak value is increased to quickly meet the needs of the load, etc. The determination of the input current peak value is a high-frequency determination and high-frequency adjustment process. The method for determining the increase / decrease amplitude is not limited, as long as it meets the target output requirement of the load end.

[0158] In the above step S4, the target input current value [I_in_peak] is determined at high frequency based on the input current peak value [I_in_peak] and the current input phase information [current input voltage / input voltage peak value]. The current input phase information is the ratio of the current actual input voltage provided by the current input power supply to the power circuit to the peak value of the periodically fluctuating voltage provided by the input power supply to the power circuit. The target input current value is the product of the input current peak value determined in the above step S3 and the phase information, that is, I 目标输入电流值 =I_in_peak*V 当前实际输入电压 / V 输入电压峰值

[0159] In the above step S5, the current actual input current value is compared with the target input current value, and the duty cycle and frequency adjustment instruction information of the switch are determined at high frequency according to the comparison result. Specifically, when the current actual input current value is less than the target input current value, instruction information for controlling the switch to reduce the frequency and increase the switch duty cycle is generated in the controller, and the working state of the switch is controlled to further control the charging time of the inductor, thereby increasing the input current to meet the needs of power factor tracking. At the same time, the output is controlled by approaching the current actual input current to the target input current value; otherwise, when the current actual input current value is greater than the target input current adjustment value, instruction information for controlling the switch to increase the frequency and reduce the switch duty cycle is generated in the controller, and the working state of the switch is controlled to further control the charging time of the inductor, thereby reducing the input current to meet the needs of power factor tracking. At the same time, the output is controlled by approaching the current actual input current to the target input current value. Specifically, the magnitude of the switch duty cycle reduction or increase, and the magnitude of the switch frequency increase or decrease need to be determined according to the difference between the current actual input current value and the target input current value. The specific implementation method and process are not limited, and ordinary technicians in this field can try to set it according to the actual scenario. At the same time, because the target input current value here includes the phase information of the current input voltage, that is, when adjusting the current actual input current value according to the target input current value, the phase information of the current input power supply is taken into account, ensuring that the current actual input current value always approaches the target input current value and fluctuates around the target input current value, so that the power supply circuit has PFC (power factor tracking) capability.

[0160] In the above-mentioned step S6, the switch of the power supply circuit executes the instruction information at high frequency to control the charge and discharge time of the inductor in the power supply circuit, so that the current actual input current value of the power supply circuit is as close as possible to the target input current value. Specifically, the switch of the power supply circuit executes the instruction sent by the controller at high frequency to adjust the current duty cycle or frequency, and controls the charge and discharge time and frequency of the inductor in the power supply circuit, so that the current actual input current value of the power supply circuit is as close as possible to the target input current value, thereby achieving control of the output power while achieving power factor tracking, that is, dynamic adjustment of the boost and buck according to output requirements.

[0161] The power supply circuit of the present application can simultaneously realize power factor tracking and output voltage rise and fall control methods. Compared with the existing technology, it has fewer components, simpler connection relationships, better circuit stability, lower costs and energy saving.

[0162] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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 specification.

[0163] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A power supply circuit based on three-phase electricity, characterized in that: The power supply circuit includes an information acquisition module and a power supply circuit unit, wherein the power supply circuit unit includes three circuit groups formed by three phases of A / B / C phases connected to three-phase electricity and a control center for controlling the working states of the three circuit groups; The circuit group includes an input rectifier module, an inductor, a capacitor, a switch and a controller thereof, a transformer, and an output half-wave rectifier module; one end of the inductor is used to connect to the live wire end of one phase of the three-phase electricity, the other end of the inductor is connected to one end of the switch and one end of the capacitor, the other end of the capacitor is connected to one end of the primary winding of the transformer, the other end of the primary winding of the transformer and the other end of the switch are connected to the live wire end or the neutral wire end of another phase, and the two output ends of the secondary winding of the transformer are output ends for providing electric energy for the circuit group, wherein the end corresponding to the end of the capacitor connected to the primary winding is connected to the output half-wave rectifier module; The power supply circuit unit includes three circuit groups whose output ends corresponding to the three-phase electricity are connected in parallel.

2. The three-phase power supply circuit according to claim 1, characterized in that: The control center controls the duty cycle and frequency of the switches in the circuit group by transmitting control information to the switches; When the switch in the corresponding circuit group is in a closed state, the switch in the corresponding circuit group forms a loop with the input power supply of the phase connected and the inductor, and charges the inductor; the capacitor forms an LC oscillation loop with the switch and the inductor of the primary winding of the transformer, and the energy stored in the capacitor is transferred between the primary winding of the transformer and the capacitor; When the switch is in the off state, an LLC oscillation circuit is formed with the connected input power supply of this phase, the inductor, the capacitor and the primary winding of the transformer. The connected input power supply of this phase and the charged inductor charge the capacitor. At the same time, the charged inductor superimposes its own energy on the energy stored in the primary side of the transformer and induces electrical energy into the secondary winding through the current change of the primary side of the transformer.

3. The three-phase power supply circuit according to claim 1, characterized in that: The A / B / C three-phase controller is connected to the information acquisition module, and is used to generate first control information based on the phase information of the corresponding phase of the input power source acquired by the information acquisition module, and provide the first control information to the control center; the control center adjusts the first control information according to the overall requirements of the load for the output of the power circuit, and generates second control information including the switch duty cycle and frequency; and provides the second control information to the switch of the corresponding phase.

4. The three-phase power supply circuit according to claim 1, characterized in that: The circuit group realizes power factor tracking through inductance and switch cooperation, and also realizes dynamic adjustment of voltage increase and voltage decrease according to input / output voltage, current information and the requirements of connected load for output voltage.

5. The three-phase power supply circuit according to claim 1, characterized in that: The maximum input voltage of the circuit group is V 入 With the maximum output voltage V 出 The ratio is V 入 :V 出 =0.2-8.0, when the output power is greater than 200W, the parameter range of the capacitor is 30nF-3μF, the inductance range of the primary winding of the transformer is 10μH-1000μH; the ratio range of the primary winding / secondary winding of the transformer is R 原 :R 副 =1:5-5:

1.

6. The three-phase power supply circuit according to claim 1, characterized in that: The output ends of the three circuit groups corresponding to the three-phase electricity included in the power supply circuit unit are connected in parallel, including: the output ends of the three circuit groups corresponding to the three-phase electricity are connected in parallel and then connected to the output capacitors, or the output ends of the three circuit groups are connected to the output capacitors respectively and then the output capacitors are connected in parallel.

7. The three-phase power supply circuit according to any one of claims 1 to 6, characterized in that: The output half-wave rectification module realizes half-wave rectification through a diode.

8. The three-phase power supply circuit according to any one of claims 1 to 6, characterized in that: The output half-wave rectification module realizes half-wave rectification through a first switch and a first controller that controls the first switch.

9. The three-phase power supply circuit according to claim 8, characterized in that: The first controller controls the switching mode of the first switch according to the mode in which the controller of the circuit group controls the switch to sense the electric energy of the secondary winding of the transformer.

10. The three-phase power supply circuit according to any one of claims 1 to 6 and 9, characterized in that: The switching of the circuit group of the power circuit is realized by a bidirectional switch or a controllable switching device.

11. A three-phase power supply circuit according to any one of claims 1 to 6 and 9, characterized in that: The transformer leakage inductance value range of the circuit group in the power supply circuit is less than 1.5%.

12. The three-phase power supply circuit according to any one of claims 1 to 6 and 9, characterized in that: The transformer structure of the circuit group in the power supply circuit is copper foil or U-shaped metal sheet, and the winding method is parallel winding.

13. A method for realizing power factor tracking and voltage boost / voltage reduction dynamic adjustment based on a three-phase power supply circuit according to any one of claims 1 to 12, characterized in that: The method comprises: Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency; Step S2, comparing the current actual output power obtained with the target output power required by the connected load; Step S3, adjusting the input current peak value at high frequency according to the comparison result between the current actual output power and the target output power; Step S4, determining the target input current value at high frequency according to the input current peak value and the current input phase information; Step S5, comparing the current actual input current value with the target input current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result; Step S6, the switch of the power circuit executes the instruction information at a high frequency to control the charging and discharging time of the inductor in the power circuit so that the current actual input current value of the power circuit is as close as possible to the target input current value.

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