Power supply circuit, expanded circuit system thereof and implementation method of expanded circuit system

Abstract

The invention discloses a power supply circuit, an expanded circuit system thereof and a method for realizing maximum power point tracking and dynamic step-up / step-down according to output requirements. The power supply circuit comprises an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor and a transformer, the peak value of the output current can be adjusted through high frequency, the frequency and / or duty ratio of the adjusting switch can be further controlled, the charging and discharging time of the inductor can be controlled, meanwhile, maximum power point tracking and voltage boosting / reducing and isolation according to the output requirement are achieved, and therefore in the field with the unknown input power source power, the application range is wide. The maximum power value of the power supply input to the power supply circuit can be detected, the electric energy input to the power supply can be obtained to the maximum extent, the electric energy conversion rate is improved, the number of used components is small, the cost can be effectively saved, the stability is good, the energy loss is low, and the electric energy conversion rate reaches up to 96% or above.

Description

Technical Field

[0001] The present invention relates to the field of power supply technology, and in particular to a power supply circuit technology in an inverter scenario. Background Art

[0002] There are many main power supply circuit topologies that can be used to achieve inverters in the existing technology, such as centralized inverter circuits, string inverter circuits and micro inverter circuits, among which the centralized inverter circuit belongs to a one-level topology circuit DC / AC structure; the string inverter circuit belongs to a two-level topology circuit structure, which is composed of a DC / DC front-stage circuit and a rear-stage DC / AC circuit; the micro inverter circuit belongs to a multi-level topology circuit structure, which is composed of a DC / DC front-stage circuit and a rear-stage DC / AC circuit. If the system requires isolation capability, an additional level of isolation circuit is required.

[0003] The centralized inverter circuit is a primary circuit with high conversion efficiency, but the topology circuits of various applications can only step down the voltage, resulting in a narrow input voltage range. There is no isolation capability, and the single-channel MPPT (Maximum Power Point Tracking) feature leads to an obvious short board effect during the power generation process, resulting in low system power generation.

[0004] The string inverter circuit has an additional MPPT stage, which can perform maximum power point tracking and voltage boosting at the same time. Therefore, the input voltage range is wide and can be multi-channel MPPT input. The system power generation is higher than that of the centralized inverter circuit. However, due to the two-stage or multi-stage circuit topology, the conversion efficiency is low, there is no isolation capability, and the number of components is large, so the reliability is relatively reduced.

[0005] Micro inverter circuits have a wider input voltage range, and if isolation is required, an additional isolation circuit must be added. MPPT can be provided for a single power unit (for example, a solar panel) or a small number of power units (for example, 4 solar panels in series), so the power generation is higher, but due to the two-level or multi-level topology, the conversion efficiency is low, and the cost is much higher than that of centralized and string inverter circuits. Summary of the invention

[0006] One purpose of the present application is to provide a power supply circuit that can solve the problems in the prior art that the power supply circuit cannot simultaneously achieve maximum power point tracking and step-up / step-down adjustment according to actual output requirements and isolation of input and output, the conversion rate is low, the same conversion rate has high cost and weak stability, etc.

[0007] The present application provides a power supply circuit, which includes: an information acquisition module, an input capacitor, an inductor, a switch, and a controller, a capacitor, and a transformer for controlling the working state of the switch;

[0008] The information acquisition module is connected to the controller of the switch and is used to collect current and voltage information of the input and output ends of the power supply circuit and provide the information to the controller;

[0009] One end of the input power supply is connected to one end of the inductor and one end of the input capacitor, and the other end of the inductor is connected to one end of the capacitor and one end of the switch; the other end of the capacitor is connected to one end of the primary winding of the transformer; the switch, the primary winding of the transformer and the other end of the input capacitor are connected to the other end of the input power supply and grounded; the two output ends of the secondary winding of the transformer are output ends for providing electric energy to the power supply circuit;

[0010] The controller is used to generate control information for controlling the duty cycle and frequency of the control switch according to the information of the power circuit input and output collected by the information collection module and the power demand of the connected load for the output;

[0011] In the power supply circuit, the ratio of the maximum input voltage to the maximum output voltage is V 入 :V 出 =0.3-0.9, when the output power is 200W-1000W, the inductance range of the primary winding of the transformer is 15μH-950μH, the parameter range of the capacitor is 105nF-2.9μF, and the ratio range of the primary / secondary winding of the transformer is R 原 : R 副 =1∶5-1∶1.

[0012] Preferably, when the input power source is a plurality of power supply units with uncertain input power, at least two of the plurality of power supply units are connected in series to the power supply circuit.

[0013] Preferably, when the maximum power value that can be currently input into the power supply circuit is unknown, the power supply circuit realizes maximum power point tracking while also realizing dynamic adjustment and isolation of output voltage increase / decrease according to output requirements.

[0014] Preferably, the power supply circuit also includes an output half-wave rectifier module, one end of the output half-wave rectifier module is connected to one end of the secondary winding of the transformer, wherein the other end of the output half-wave rectifier module and the other end of the secondary winding of the transformer are the output ends of the power supply circuit.

[0015] Preferably, the half-wave rectification module of the power supply circuit realizes half-wave rectification through a diode.

[0016] Preferably, the half-wave rectification module of the power supply circuit realizes half-wave rectification through a fifth switch and a fifth controller that controls the fifth switch.

[0017] Preferably, the switch of the power supply circuit is realized by a bidirectional switch or a controllable switching device.

[0018] Preferably, the transformer leakage inductance value range in the power supply circuit is less than 1.5%.

[0019] Preferably, the transformer structure in the power supply circuit is copper foil or U-shaped metal sheet, and the winding method is parallel winding.

[0020] Preferably, the power supply circuit further comprises an output rectification unit for providing rectification for an output end of the power supply circuit.

[0021] Preferably, the output rectifying unit is an H-bridge.

[0022] The present application also provides an extended circuit system based on the above-mentioned power supply circuit. When the input power supply is a plurality of power supply units with uncertain input power, the extended circuit system also includes a plurality of power supply circuits connected to each of the power supply units and a control center connected to the controller of each of the power supply circuits.

[0023] Preferably, the output ends of the multiple power supply circuits are connected in series / parallel combination according to the output requirements of the expansion circuit.

[0024] Preferably, the expansion circuit further comprises an output rectifier unit for providing rectification for the expansion circuit, and the output rectifier unit is connected to the output ends of the plurality of power supply circuits.

[0025] The present application also provides a method for the above-mentioned power supply circuit to simultaneously realize maximum power point tracking and dynamic adjustment of output voltage up / down according to output requirements, the method comprising:

[0026] Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency;

[0027] Step S2, adjusting the output current peak value at high frequency, monitoring the input voltage and input power changes caused thereby, and determining update adjustment information of the output current peak value according to the input voltage and input power changes;

[0028] Step S3, determining the target output current value at high frequency according to the output current peak value and the corresponding output target phase information;

[0029] Step S4, comparing the current actual output current value with the target output current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result;

[0030] Step S5, 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 output current value of the power circuit is as close as possible to the target output current value.

[0031] Compared with the prior art, the power supply circuit of the present application includes an information acquisition module, an input capacitor, an inductor, a switch, and a controller, a capacitor, and a transformer for controlling the working state of the switch; when the switch is in a closed state, the switch, the input power supply, and the inductor form a loop, and charge the inductor. At this time, the capacitor, the switch, and the primary winding inductor of the transformer are equivalent to form an LC oscillation loop; when the switch is in an open state, the input power supply, the inductor, the capacitor, and the primary winding of the transformer are equivalent to form an LLC oscillation loop, the input power supply and the charged inductor charge the capacitor, and the electric energy is induced into the secondary winding through the current change of the primary winding of the transformer, and the output end of the secondary winding serves as the output end of the power supply circuit to provide electric energy, thereby realizing the transmission of electric energy, and the ratio of the maximum input voltage to the maximum output voltage of the power supply circuit is V 入 :V 出 =0.3-0.9, when the output power is 200W-1000W, the inductance range of the primary winding of the transformer is 15μH-950μH, the parameter range of the capacitor is 105nF-2.9μF, and the ratio range of the primary / secondary winding of the transformer is R 原 : R 副 =1:5-1:1, which can make the power conversion rate of the power circuit reach 96% or above.

[0032] The power supply circuit described in the present application realizes the method of simultaneously realizing maximum power point tracking and dynamic adjustment of output voltage up / down according to output requirements. The output current peak value can be adjusted by high frequency, and the frequency and / or duty cycle of the adjustment switch can be further controlled to control the inductor charging and discharging time, thereby realizing voltage boost / down and maximum power point tracking according to output requirements. Therefore, in the field of unknown input power supply power, such as photovoltaic power generation through solar panels, the maximum power value of the power input to the power supply circuit can be detected to obtain the electric energy of the input power supply to the maximum extent, improve the power generation, use fewer components, can effectively save costs, have good stability, low energy loss, and high power conversion rate.

[0033] When the input power source is a plurality of power supply units with uncertain input power, the expansion circuit based on the above-mentioned power supply circuit described in the present application includes a plurality of power supply circuits connected to each of the power supply units, and the output ends of the plurality of power supply circuits are connected in series / parallel combination according to the output requirements of the expansion circuit; thereby, the electric energy of each power supply unit can be converted in a maximum power point tracking manner, and the electric energy conversion rate is high; after the output ends of the plurality of power supply circuits are combined in series / parallel, a wider range of voltage / power can be output. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A connection diagram of a power supply circuit in one embodiment of the present application;

[0035] Figure 2 is a connection diagram of a power supply circuit in another embodiment of the present application;

[0036] Figure 3 is a connection diagram of a power supply circuit in another embodiment of the present application;

[0037] Figure 4 is a connection diagram of a power supply circuit in another embodiment of the present application;

[0038] Figure 5 This is a flow chart of a method for a power supply circuit to simultaneously implement maximum power point tracking and increase / decrease output voltage according to actual output requirements in another embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0040] 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 sequence. 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 an order 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.

[0041] The power supply circuit described in the present application is mainly used in the field of inverter power supplies, such as the field of solar power generation through solar panels, and is particularly suitable for the case where the maximum power value of the current input power supply is unknown, that is, the electrical energy of the input power supply currently connected to the power supply circuit is unknown. The maximum power point of the input power supply can be detected and tracked, and dynamic adjustment of the voltage increase / decrease and isolation of the input and output can be performed according to the output requirements, thereby realizing the conversion of electrical energy, that is, realizing the conversion of electrical energy under different currents, voltages, and powers.

[0042] Ginseng Figure 3 As shown, the power supply circuit of the present application includes: an information acquisition module, an input capacitor, an inductor, a switch, and a controller, a capacitor, and a transformer for controlling the working state of the switch;

[0043] The information acquisition module is connected to the controller of the switch and is used to collect current and voltage information of the input and output ends of the power supply circuit and provide the information to the controller;

[0044] One end of the input power supply is connected to one end of the inductor and one end of the input capacitor, and the other end of the inductor is connected to one end of the capacitor and one end of the switch; the other end of the capacitor is connected to one end of the primary winding of the transformer; the switch, the primary winding of the transformer and the other end of the input capacitor are connected to the other end of the input power supply and grounded; the two output ends of the secondary winding of the transformer are output ends for providing electric energy for the power supply circuit, and one end of each end is connected to the half-wave rectifier module;

[0045] The controller is used to generate control information for controlling the duty cycle and frequency of the control switch according to the information of the power circuit input and output collected by the information collection module and the power demand of the connected load for the output;

[0046] When the switch is in a closed state, the switch, the input power supply, and the inductor form a loop and charge the inductor; the capacitor, the switch, and the transformer primary winding inductor form an LC oscillation loop, and the energy stored in the capacitor is transferred between the transformer primary inductor and the capacitor;

[0047] When the switch is in the off state, the input power supply, inductor, capacitor and transformer primary winding form an LLC oscillation loop, the input power supply and the charged inductor charge the capacitor, and 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; wherein,

[0048] When the maximum power value that can be currently input into the power supply circuit is unknown, the power supply circuit realizes maximum power point tracking while also realizing dynamic adjustment and isolation of output voltage increase / decrease according to output requirements.

[0049] Specifically, refer to Figure 3 As shown, a connection schematic diagram of the power supply circuit of the present application is shown, and the power supply circuit includes: an input capacitor C', an inductor L, one end of the input power supply is connected to one end of the inductor L and one end of the input capacitor C', and the other end of the inductor L is connected to one end of the capacitor C and one end of the switch K; the other end of the capacitor C is connected to one end of the primary winding of the transformer T; the other end of the switch K, the other end of the primary winding of the transformer and the other end of the input capacitor C' are connected to the other end of the input power supply and grounded; the two output ends of the secondary winding of the transformer are the output ends of the power supply circuit for providing electric energy, one end of which is connected to the half-wave rectifier module; the controller is used to control the time ratio of the switch K in the closed state within the cycle time according to the electric energy demand output by the power supply circuit. Furthermore, the cycle time here can be changed, that is, the cycle time can be variable, and the controller controls the frequency and duty cycle of the switch K opening and closing.

[0050] The working principle of the power supply circuit is:

[0051] Specifically, the controller controls the frequency and duty cycle of the switch K being opened and closed according to the dynamic demand of the power output terminal provided by the power supply circuit, combined with the tracking of the maximum power point of the input power. When the switch K is in a closed state, the switch K forms a loop with the input power supply and the inductor L, and at this time, the input power supply and the input capacitor charge the inductor L through the loop; the capacitor C forms an LC oscillation loop with the switch K and the primary winding inductance of the transformer T; when the switch K is in an open state, the input power supply, the inductor L, the capacitor C and the primary winding inductance of the transformer T form an LLC oscillation loop, and the input power supply, the input capacitor and the charged inductor L charge the capacitor C, and the electric energy is induced to the secondary side of the transformer through the current change of the primary side of the transformer.

[0052] The power supply circuit disclosed in this embodiment controls the working state of the switch K so that the inductor L is charged and then discharged to the capacitor C and the primary winding of the transformer T, so that the primary winding of the transformer T obtains energy and induces it to the secondary winding of the transformer T, and further outputs the electric energy. By controlling the frequency and duty cycle of the switch K, the charge / discharge time of the inductor L and the charge / discharge time of the primary winding inductance of the transformer are controlled, and the amount of electric energy output by the secondary winding of the transformer is further controlled. Compared with the prior art, this embodiment can realize the transmission of electric energy through a power supply circuit including very few components, with low cost, strong stability, and high conversion rate.

[0053] Specifically, the power supply circuit disclosed in this embodiment forms a loop during operation including: loop ① [input power supply in parallel with input capacitor + inductor L + capacitor C + transformer T], loop ② [input power supply in parallel with input capacitor + inductor L + switch K], loop ③ [capacitor C + transformer T + switch K], and loop ④ [input power supply + input capacitor].

[0054] Furthermore, the detailed working process of the power supply circuit disclosed in this embodiment is as follows: when the switch K is closed, the input power supply is connected in parallel with the input capacitor to charge the inductor L, and the inductor L stores energy. At the moment when the switch K is disconnected, the inductor L will generate a high voltage to keep the current at both ends from changing suddenly. The electric energy is transmitted through the new loop ① formed after the switch K is disconnected. The inductor L charges the capacitor C. The energy stored in the inductor L and the primary side of the transformer T is induced to the secondary side of the transformer through the primary side of the transformer. At this time, the voltage of the input power supply plus the voltage of the inductor L is equal to the voltage of the capacitor C plus the voltage of the primary winding of the transformer T, that is: Transformer T senses electric energy to its secondary winding, and the secondary winding is output to the power supply circuit's power supply output terminal through a half-wave rectifier module, and supplies electric energy to the load; when switch K changes from an open state to a closed state, the loops and specific working processes formed in the power supply circuit are as follows: the parallel input capacitor of the power supply circuit charges the inductor L through loop ②, and charges the primary winding of transformer T through loop ③ capacitor C. At this time, it is equivalent to the primary winding of transformer T and capacitor C forming an LC resonant loop to maintain the electric energy of the loop; at the same time, after switch K is in a closed state, the input power supply and input capacitor are connected in parallel through loop ② to charge the inductor L, and the inductor L performs the next energy storage.

[0055] Loop ④, when the input power increases or the output power decreases, the input power charges the input capacitor through loop ④, and the voltage of the input capacitor increases; when the input power decreases or the output power increases, the input power discharges in parallel with the input capacitor, and the voltage of the input capacitor decreases.

[0056] When the maximum power value that can be currently input into the power supply circuit is unknown, the power supply circuit realizes maximum power point tracking and also realizes dynamic adjustment of output voltage increase / decrease according to output requirements.

[0057] Specifically, the power supply circuit realizes dynamic adjustment of the output voltage up / down according to the output demand to obtain the AC power of the target waveform, which needs to meet the following principles:

[0058] When the output requirement is periodic alternating current, the voltage fluctuation period T' output by the output half-wave rectifier module of the power supply circuit is set to the first time interval. In this first time interval T', the output voltage required by the corresponding output is constantly changing according to the output requirement of the load, for example: outputting a sine wave with an effective value of 220V. Due to the characteristic of the inductor that it does not allow sudden changes in current, the time period interval corresponding to the switching frequency of the switch K controlled by the controller is the second time interval T". When the second time interval T" is several orders of magnitude less than the voltage period T' output by the output half-wave rectifier module, within the T' voltage period range, the switch K has completed hundreds or thousands of times of closing and closing, that is, in the process of the output voltage waveform period T' itself changing from the trough to the peak, due to the high on / off switching frequency of the switch K, for controlling the working process of the power supply circuit through the working state of the switch K, the output voltage waveform required locally does not change much, and can basically be considered unchanged, that is, the output voltage waveform required before and after the switch K is switched once is considered unchanged. At the same time, when the first time interval T' includes a large number of second time intervals T", that is, the output voltage produces a clear When the voltage changes significantly, the inductor L has been charged and discharged for many times through the control of the switch K, that is, at this time, the inductor L has completed the 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 of this circuit and the primary winding of the transformer T can realize the precise control of the output voltage within the T” period through the above method, that is, the output voltage waveform required to be output within the T” period can be well controlled, even if it is higher or lower, so that a very precise voltage waveform that meets the output requirements within the T' period can be provided through high-frequency control of the output voltage within the T” period. For example, by controlling the output voltage value within the period of T”=10μS, a 50Hz sine wave can be accurately output within the period of T'=20mS.

[0059] Specifically, the specific voltage boost / voltage reduction process and principle of the power supply circuit of the present application are as follows:

[0060] When the voltage provided by the power supply circuit is insufficient to meet the load requirements and a voltage boost is required, the controller controls the switch K to increase the duty cycle of the switch K or reduce the operating frequency of the switch K, that is, to increase the charging time of the inductor L and the primary winding of the transformer T. When the switch is disconnected, more electric energy can be induced to the secondary winding of the transformer T by the inductor L and the primary winding of the transformer T to achieve a voltage boost. Furthermore, if the voltage provided by the power supply circuit is high and a voltage reduction is required, the controller controls the switch K to reduce the duty cycle of the switch K, reduce the charging time of the inductor L and the primary winding of the transformer T, and thus reduce the electric energy induced to the secondary winding of the transformer T to achieve a voltage reduction.

[0061] Here, since the power at the input end is uncertain, after a step-up or step-down operation is performed, as the output power changes, the energy storage of the input capacitor will also change, thereby causing a change in the input capacitor voltage.

[0062] If the input voltage rises, during the energy storage period when the switch K is closed, the energy stored in the inductor L and the primary winding of the transformer T will increase, the energy transferred to the secondary winding will also increase, and the output power will increase; if the input voltage drops, during the energy storage period when the switch K is closed, the energy stored in the inductor L and the primary winding of the transformer T will decrease, the energy transferred to the secondary winding will also decrease, and the output power will decrease.

[0063] Therefore, the dynamic step-up and step-down process provided by this circuit is a high-frequency working process that is continuously adjusted according to the dynamic needs of the output load and the dynamic response of the input voltage.

[0064] Here, when the period interval T" corresponding to the working frequency of switch K is higher than the period T' of the voltage waveform required by the output as a whole, that is, T">>T', the frequency and duty cycle of switch K are adjusted, and the charging and discharging time of the 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 voltage waveform required by the output. Furthermore, if the voltage waveform required by the output is an alternating current with periodic voltage changes, for example, a sinusoidal alternating current, the corresponding T'=10ms. If the change in the voltage waveform required by the output does not have obvious periodicity, the value of T' can be set by analogy with the change period of the sinusoidal alternating current. For example, T' is set to about 10ms. The specific setting method only needs to meet the requirements described above and can implement the solution of the present application.

[0065] Specifically, the power supply circuit realizes maximum power point tracking and also realizes dynamic adjustment of voltage boost / voltage reduction according to output requirements. Figure 5 As shown, the specific working process is as follows:

[0066] Step S1, Step S1, high frequency acquisition of the current actual input current [I_in], input voltage [V_in], output voltage, and output current values. Among them, the input current [I_in] refers to the total current of the input power circuit, including the current charging the input capacitor. The input voltage [V_in] refers to the voltage across the input capacitor.

[0067] Specifically, 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 of the power supply circuit. There is no restriction on the specific acquisition or acquisition method. It can be obtained through the acquisition unit of the controller or through other methods. The acquired information is transmitted to the controller to determine the switch duty cycle and frequency adjustment instruction information. 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 the actual situation and there is no specific restriction.

[0068] Step S2, high frequency adjustment of the output current peak value [I_out_peak], monitoring the input voltage and input power changes caused thereby, and determining update adjustment information of the output current peak value according to the input voltage and input power changes.

[0069] Step S21 (not shown), increase the output current peak value [I_out_peak] at high frequency, and monitor the change of input power [P_in = V_in*I_in]; if the input power increases with the increase of the output current peak value, continue to increase the output current peak value [I_out_peak] at high frequency; if the input power decreases with the increase of the output current peak value, execute step S22.

[0070] Specifically, refer to Figure 5 As shown, high frequency increases the output current peak value [I_out_peak]. At this time, the output power increases, the input capacitor at the input end will be discharged, and the voltage across the input capacitor at the input end, that is, the input voltage, drops, thereby affecting the input power. For example, the solar photovoltaic panel is used as the input of the circuit. Changing the voltage of the input capacitor directly affects the input power of the solar photovoltaic panel. If the input power of the power supply circuit continues to increase at this time, the output current peak value [I_out_peak] needs to be continued to increase. When the input power begins to decrease, it is necessary to continue to execute step S22 (not shown) to start high frequency to reduce the output current peak value [I_out_peak].

[0071] Furthermore, the amplitude of increasing the output current peak can be set according to the actual situation, and the specific method is not limited. For example, it can be set to first increase the increase amplitude and then gradually reduce the increase amplitude. When the input power input decreases, enter step S22 to reduce the output current peak at high frequency.

[0072] Step S22, reduce the output current peak value [I_out_peak] at high frequency, detect the change of input power [P_in=V_in*I_in], if the input power response is rising, continue to reduce the output current peak value [I_out_peak] at high frequency until the input power begins to decrease, then enter step S21; if the input power response is decreasing, it is necessary to execute step S21.

[0073] Specifically, continue to Figure 5 As shown, the high frequency reduces the output current peak value [I_out_peak] and continuously monitors the input power. At this time, the output power is reduced, and more energy of the input power source (such as a photovoltaic panel) enters the input capacitor. The voltage across the input capacitor at the input end, that is, the input voltage of the power supply circuit, will rise. If the input power of the power supply circuit increases, it is necessary to continue to reduce the output current peak value [I_out_peak] until the input power decreases. In this case, it is necessary to execute step S21 to start the high frequency to increase the output current peak value [I_out_peak].

[0074] Furthermore, the amplitude of the high frequency reduction of the output current peak value can be set according to the actual situation, and the specific method is not limited. For example, it can be set to first increase the reduction amplitude and then gradually reduce the reduction amplitude. When the input power input decreases, enter step S22 to reduce the output current peak value at high frequency.

[0075] Step S21 and step S22 in step S2 are repeatedly executed at a high frequency, so that the voltage of the input capacitor can just make the input end of the power supply circuit be in the maximum power state of the input power supply. For example, the voltage of the input capacitor is maintained at the voltage point required for the maximum power output of the solar photovoltaic panel, so that the power supply circuit can track the maximum value of the input power of the solar photovoltaic panel.

[0076] Step S3, according to the currently adjusted output current peak value [I_out_peak] and the corresponding output target phase information, the target output current value [I target output current value = I output current peak value * target phase information] is determined at high frequency.

[0077] Specifically, the target phase information of the current output that meets the output requirements is the ratio of the current actual output voltage provided by the current power supply circuit to the load to the peak value of the periodically fluctuating voltage provided by the circuit to the load, and the target output current value is the product of the output current peak value determined in the above step S2 and the target phase information, that is:

[0078] I 目标输出电流值 =I 输出电流峰值 *V 当前实际输出电压 / V 输出电压峰值

[0079] Step S4, comparing the current actual output current value with the target output current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result.

[0080] Specifically, the current actual output current value is compared with the target output current value, and the duty cycle and frequency adjustment instruction information of the switch are determined at high frequency according to the comparison result. Further, when the current actual output current value is less than the target output current value, the instruction information for controlling the switch to reduce the frequency and increase the switch duty cycle is generated in the controller, and the switch working state is controlled to further control the charging time of the inductor, thereby increasing the output power, thereby increasing the output current, allowing the output current to approach the target output current at high frequency, realizing the control of the output waveform, and thereby realizing the inverter capability; otherwise, when the current actual output current value is greater than the target output current value, the instruction information for controlling the switch to increase the frequency and reduce the switch duty cycle is generated in the controller, and the switch working state is controlled to further control the charging time of the inductor, thereby reducing the output power, thereby reducing the output current, and allowing the output current to approach the target output current at high frequency, thereby realizing the inverter capability. Specifically, the magnitude of the switch duty cycle is controlled to be reduced or increased, and the amplitude of the switch frequency is increased or decreased according to the difference between the current actual output current value and the target output 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, the target output current value here includes the phase information of the current output voltage, that is, when adjusting the current actual output current value according to the target output current value, the phase information of the target output inversion is considered, ensuring that the current actual output current value is always close to the target output current value, and fluctuates around the target output current value, and cooperates with the current direction switching component to enable the power supply circuit to have the ability of inversion.

[0081] Step S5, 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 output current value of the power circuit is as close as possible to the target output current value.

[0082] Specifically, the switch of the power supply circuit executes the instruction information at high frequency, controls the charging and discharging time of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit is as close as possible to the target output current value; specifically, the switch of the power supply circuit executes the instruction sent by the controller to adjust the current duty cycle or frequency at high frequency, controls the charging and discharging time and frequency of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit is as close as possible to the target output current value, thereby achieving the tracking of the input maximum power point while meeting the output inverter voltage and current.

[0083] In addition, the power supply circuit of the present application realizes the switching of current direction through an output rectifier unit, for example, an H-bridge, and converts the pulsating DC generated in the above steps into AC power. For example, the DC steamed bun wave that conforms to the sinusoidal transformation generated in the above steps, when the voltage is 0, completes the current direction switching according to the period of the steamed bun wave, and can generate sinusoidal transformed AC power.

[0084] In one of the preferred embodiments, when the input power source is a plurality of power supply units with uncertain input power, at least two of the plurality of power supply units are connected in series to the power supply circuit.

[0085] Specifically, this embodiment is mainly aimed at the case where the input power supply of the power circuit includes multiple power supply units. At this time, the multiple power supply units can be connected to the power circuit in series to provide a larger input voltage for the power circuit; at the same time, the multiple power supply units here can also be connected to the power circuit in parallel or in series / parallel combination to provide a larger current. As an example and not a limitation, 400 solar photovoltaic cells are connected in series / parallel, 20 in series, and 20 in parallel, and then connected to the power circuit. In this embodiment, the series connection can increase the input voltage of the power circuit, thereby making the power circuit more efficient; the parallel connection can enable the power circuit to provide more power and save the cost of the overall power circuit.

[0086] 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 in the power supply circuit.

[0087] Principles for determining the parameters of components in the power supply circuit: The determination of specific component parameters is related to the input voltage, output voltage and output power of the power supply circuit. First, the maximum input voltage, the maximum output voltage, and the output power of the power supply circuit unit must be determined. Here, in the case of AC, the maximum voltage refers to its effective value, and in the case of DC, the maximum voltage refers to the maximum value of the input / output voltage range. According to the ratio of the maximum input voltage and the maximum output voltage and the output power of the power supply circuit unit, the capacitance parameters, inductance parameters, the inductance of the primary / secondary winding of the transformer and the ratio of the primary / secondary winding, the switching operating frequency range, etc. in the power supply circuit unit are determined.

[0088] Specifically, in practice, the inductance of the power circuit unit and the primary / secondary inductance parameters of the transformer need to be determined by considering:

[0089] When parameters such as the switch operating frequency / duty cycle, the primary inductance of the transformer and the inductance of the inductor do not change, when the input voltage increases, during the switch-on period, the primary winding inductance of the transformer can store more energy, and 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 power circuit unit; when the input voltage decreases, the output power of the power circuit unit can be reduced.

[0090] When parameters such as the maximum input voltage, the inductance of the inductor, the switching operating frequency / duty cycle, etc. do not change, when the primary inductance of the transformer decreases, during the switch-on period, the primary inductance of the transformer can store more energy, and during the switch-off period, the energy stored in the primary inductance of the transformer is induced to the secondary winding of the transformer, which can increase the output power of the power supply circuit unit; accordingly, when the inductance of the primary winding of the transformer increases, the output power of the power supply circuit unit can be reduced; in the process of determining the inductance of the primary winding of the transformer, it is also necessary to consider that when the primary winding of the transformer stores too much energy, it may cause the transformer to saturate, thereby reducing the energy conversion efficiency.

[0091] 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 aforementioned methods, the conversion efficiency of the power circuit unit can be effectively improved.

[0092] In practice, when the input voltage, switch operating frequency / duty cycle, transformer primary winding inductance, etc. are determined, when the inductance of the inductor decreases, the inductor can store more energy during the switch-on period, and 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 senses the energy to the secondary winding of the transformer, which can increase the output power of the power circuit unit; when the inductance of the inductor increases, the output power of the power circuit unit can be reduced.

[0093] When determining the frequency range of the switch, it is necessary to consider: when the parameters of other components in the power circuit unit remain unchanged, when the switching frequency is lowered, the energy storage time t of the switch closure in a single cycle becomes longer and the frequency f decreases; during the switch closure period, the energy stored in the inductor and the primary side of the transformer increases, and the output power of the power circuit unit increases. Correspondingly, when the switching frequency is increased, the output power of the power circuit unit will decrease. In addition, as the switching frequency increases, the switch will generate "switching losses" at the moment of turn-on and turn-off. Increasing the frequency of the switch will increase the switching losses. Here, the conversion efficiency of the transformer also needs to be considered. Different magnetic cores have different corresponding inductances and conversion efficiencies at different frequencies. Too low a frequency, for example, below 30K, may cause the transformer to saturate, resulting in a decrease in conversion efficiency; too high a frequency, for example, above 500K, may cause a huge change in the inductance of the transformer, reducing the conversion efficiency.

[0094] The process of determining the parameters of the capacitor, as mentioned above, is that the capacitor stores energy during the switch-off period, and during the switch-on period, the capacitor resonates with the primary winding of the transformer and transfers the stored energy to the primary winding of the transformer. If the capacitance of the capacitor is too small, the energy stored on the capacitor will be insufficient during operation, reducing the output power of the power circuit unit and thus reducing the conversion efficiency; if the capacitance of the capacitor is too large, when the input voltage is AC, the voltage of the capacitor cannot keep up with the changes in the input voltage of AC, resulting in calculation difficulties during the power factor tracking process and reduced power conversion efficiency.

[0095] In practice, the input capacitor needs to have a relatively large capacitance value so that when the input power changes, it can be buffered by the relatively large input capacitor, providing a buffer for the entire power circuit to effectively track the maximum power point. If the input capacitor capacitance value is too small, for example, not limitation, for a circuit with a 500W output power, the input capacitor capacitance value is less than 200μF. When the input power changes, the voltage on both sides of the input capacitor changes too quickly, causing the duty cycle and frequency of the switch to be continuously adjusted, resulting in an overall decrease in the circuit conversion efficiency.

[0096] In practice, when the input capacitance exceeds a certain threshold, it is no longer particularly sensitive. For example, but not limited to, for a 500W power circuit, when the input capacitance exceeds 6mF, the effect of tracking the maximum power point is limited. You can choose the appropriate input capacitance value based on actual cost and product needs.

[0097] From the above analysis, it can be seen that the components and their connection relationships included in the power supply circuit belong to a whole, the parameter settings between the components are related to each other, and the parameter settings of all components are integrated. In practice, according to the input voltage of the circuit unit, the output voltage of the connected load, the output power requirements, the above-mentioned detailed parameter selection principles, the materials and costs of the aforementioned transformers and inductors, and the saturation of the transformers and inductors caused by the output power, the inductance of the inductor is designed to achieve a balance of multiple parameters. That is, it is necessary to select the individual setting ranges of the inductance, primary winding inductance of the transformer, switching frequency, capacitance and other parameters in the power supply circuit, and it is necessary to consider the coordination of all component parameters as a whole based on the logical relationship between the parameter settings of the above-mentioned components to ensure that the power supply circuit has a better performance and a better energy conversion rate.

[0098] In one preferred embodiment, the ratio of the maximum input voltage to the maximum output voltage of the power supply circuit is V 入 :V 出 =0.3-0.9, when the output power is 200W-1000W, the inductance range of the primary winding of the transformer is 15μH-950μH, the parameter range of the capacitor is 105nF-2.9μF, and the ratio range of the primary / secondary winding of the transformer is R 原 : R 副 =1∶5-1∶1.

[0099] Specifically, this embodiment provides a parameter range of the corresponding capacitor, transformer primary winding, and transformer primary secondary winding ratio in the power circuit unit components when the output power of the power circuit unit is 200W-1000W and the ratio of the input voltage calculated value to the output voltage calculated value is 0.3-0.9. According to the above parameter determination principle and process, after determining the specific input voltage maximum value, the ratio of the output voltage maximum value and the output power of the power circuit, the specific parameters of the corresponding components are selected and determined within the parameter range of the corresponding components provided in this embodiment to meet the maximum power tracking and the dynamic adjustment of the boost and buck required by the output end, and the electric energy conversion rate can be as high as 98% or more. The specific parameter experimental data and test results are shown in Examples 1-11 in Table 1. Under the same function and the same electric energy conversion rate as the prior art, the power circuit components of the present application are obviously less than the components of the prior art circuit, and the energy loss is less, the cost of the present application is lower, and the circuit stability is stronger.

[0100] As an example but not limitation, when the maximum input voltage of the power supply circuit 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 15μ-950μH, the capacitance parameter is set to about 500nF-2900nF, and the primary / secondary winding ratio of the transformer is set to about 1:5-1:2. At this time, the corresponding power conversion rate is above 97%.

[0101] Specifically, in this embodiment, the transformer primary winding inductance is set to 10μH, or the inductance of the inductor is set to about 10μH, because under the condition of 50V input voltage, the energy storage of the inductor and the primary energy storage of the transformer are very low in each energy storage cycle. The transformer primary winding inductance or the inductance of the inductor is greatly reduced, so that the transformer primary winding and the inductor can store enough energy in the energy storage cycle, so that the power supply circuit unit can provide enough power to the output end or the connected load. However, if the transformer primary winding inductance is further reduced, or the inductance of the inductor is further reduced, the excitation current of the transformer will be greatly increased, resulting in a significant decrease in conversion efficiency.

[0102] 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 power supply circuit. 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.

[0103] Since the input voltage is relatively low, the capacitor needs to have a relatively large capacitance value to ensure that enough energy is stored in the primary winding of the transformer during the energy storage cycle. If the capacitor parameter is set below 500nF, when the output voltage changes dynamically, the energy stored in the capacitor is insufficient at some power points, and the efficiency decreases. If the capacitor is set above 2900nF, it is observed that a large voltage spike is generated during the switch disconnection process. At this time, a switch with better voltage resistance is required, which increases the cost.

[0104] Specifically, by way of example but not limitation, this embodiment can be applied in the field of solar photovoltaics. When the maximum input voltage is 300V, the maximum output voltage is about 300V, and the output power is 1000W, according to the above parameter design principle, the inductance of the primary winding of the transformer is set to about 60μH-950μH, the capacitance parameter is set to about 105nF-500nF, the ratio of the primary winding to the secondary winding of the transformer is set to about 1:1, and the inductance of the primary winding of the transformer and the inductance of the primary winding of the transformer are selected to be relatively large. For example, the inductance of the primary winding of the transformer is set to 60μH, and the inductance is set to 1mH. Since the ratio of the maximum input voltage to the maximum output voltage is 1, the primary / secondary inductance of the transformer used is about 1:1. When the ratio of the primary / secondary side of the transformer is close, the transformer processing technology can save costs, and the leakage inductance is easy to control. At this time, the power conversion rate of the corresponding power supply circuit is above 98%. ,

[0105] In the application scenario of this embodiment, if a capacitor smaller than about 105nF 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 power circuit unit; 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.

[0106] Preferably, the power supply circuit also includes an output rectifier module, one end of the output rectifier module is connected to one end of the secondary winding of the transformer, wherein the other end of the output rectifier module and the other end of the secondary winding of the transformer are the output ends of the power supply circuit.

[0107] Specifically, the output rectifier module is connected to one end of the secondary winding of the transformer, which corresponds to the end of the primary winding connected to the capacitor, and rectifies the current output by the power circuit unit to meet the needs of the load connected to the power circuit.

[0108] Preferably, Figure 4 As shown, the half-wave rectification module of the power supply circuit realizes half-wave rectification through a diode.

[0109] Specifically, the half-wave rectifier module provided in this embodiment is connected to one end of the secondary winding in the transformer, and its specific working principle is as follows: after the switch of the power supply circuit is turned from closed to open, the inductor that has been charged during the switch closing period charges the capacitor and the primary winding of the transformer, and the secondary winding of the transformer is induced by the current of the primary winding to obtain electrical energy. At this time, the secondary winding current of the transformer is output to the electrolytic capacitor or the load through the half-wave rectifier module to provide electrical energy or store energy; when the switch of the power supply circuit is turned from open to closed, the capacitor, the primary winding of the transformer and the switch form an equivalent LC resonant circuit. Because the capacitor does not allow sudden voltage changes, the capacitor and the primary winding of the transformer resonate at this time. Because the 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 circuit with the capacitor, no induced current is generated in the secondary winding of the transformer.

[0110] It can be seen from this that as long as the 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 the technical personnel in this field to make creative efforts 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 protection scope of this application, such as diodes / MOS tubes with unidirectional conduction function, and switching tubes controlled to be unidirectional conduction.

[0111] Further, Figure 4 As shown, this embodiment realizes unidirectional output of the secondary winding of the transformer T by connecting a third diode D3 to the corresponding output end of the secondary winding of the transformer T. The diode itself has the property of unidirectional conduction, and half-wave rectification is realized by the diode, the control circuit is simple, and the performance is stable.

[0112] Preferably, Figure 5 As shown, the half-wave rectifier module of the power supply circuit realizes half-wave rectification through the fifth switch K5 and the fifth controller that controls the fifth switch K5; the fifth controller controls the switching mode of the fifth switch according to the mode in which the controller of the power supply circuit controls the switch to induce electric energy of the secondary winding of the transformer.

[0113] Specifically, this embodiment realizes half-wave rectification of the output of the secondary winding of the transformer through the fifth switch K5, and at this time, the fifth switch K5 is controlled by the fifth controller. Furthermore, the working state of the fifth switch K5 determines whether the secondary winding of the transformer can form a loop, that is, when the fifth switch K5 is disconnected, it cannot form a loop, and when the fifth switch K5 is closed, it can form a loop; at the same time, when the power circuit switch is closed and the capacitor charges the primary winding of the transformer to form resonance, the secondary winding of the transformer cannot form a loop, that is, at this time, the fifth switch K5 needs to be disconnected. The fifth controller needs to control the working state of the fifth switch K5 according to the working state of the switch in the power circuit. According to the above analysis, when the switch of the power circuit is in a closed state, the fifth controller needs to control the fifth switch K5 to be in an open state.

[0114] This embodiment realizes the function of half-wave rectification of the output of the secondary winding of the transformer by setting a fifth controller and a corresponding fifth switch. In some scenarios, the use of a switch has lower energy consumption and higher power conversion efficiency than a diode. For example, by way of example and not limitation: in a scenario where the output voltage peak is lower than 100V, a diode is used for half-wave rectification, and the diode voltage drop accounts for too high a proportion, resulting in a decrease in conversion efficiency. At this time, switch components can be used to realize the output half-wave rectification function of the secondary side of the transformer. Switch components with fixed internal resistance can be used here, and multiple switches can also be connected in parallel to reduce the power loss of half-wave rectification and improve the power conversion rate.

[0115] Preferably, the switch of the power supply circuit is realized by a bidirectional switch or a controllable switching device.

[0116] In practice, the selection of switch components is also related to the setting of the switch operating frequency. For ordinary silicon-based MOS tubes, the maximum frequency is recommended to be limited to 150K; for silicon carbide MOS tubes, the maximum frequency is recommended to be limited to 250K; for IGBT switch tubes, the maximum frequency is recommended to be limited to 40K; for gallium nitride MOS tubes, the maximum frequency is recommended to be limited to 500K. The switch in this embodiment is a general high-frequency switch with a withstand voltage of 150V on the market, such as a high-frequency switch with a model of NCEP15T14, and the corresponding switch operating frequency range is 50K-200K.

[0117] Specifically, the switch in the power supply circuit 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 limited, that is, the method or path for the controller to provide the control signal to the switch is not limited, and it can be wireless or wired. Any scheme that can realize the signal transmission of the controller controlling the switch in any existing technology now or in the future, 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 the technical personnel in this field to make creative efforts to modify the scheme and apply it to this embodiment, then these schemes that can realize the control signal transmission from the controller to the switch it controls are within the protection scope of this application.

[0118] Furthermore, there is no restriction on the specific form of the switch or switch and its controller for realizing circuit disconnection and connection in the power supply circuit. Any scheme of the switch or switch and its controller that can realize circuit disconnection and connection in any existing technology now or in the future, as long as the scheme can be directly applied to the function of circuit disconnection and connection in the power supply circuit of this embodiment, or does not require technical personnel in this field to make creative efforts to modify the scheme and apply it to this embodiment, then these schemes of switches or switches and their controllers that can realize circuit disconnection and connection are all within the protection scope of this application.

[0119] Preferably, the power supply circuit further comprises an output rectification unit for providing rectification for an output end of the power supply circuit.

[0120] Specifically, this embodiment is mainly aimed at the scenario where the power supply circuit needs to output AC power as an inverter. Since the current output from the output end of the power supply circuit is DC, the DC power output from the output end of the power supply circuit needs to be rectified through an output rectifier unit according to the needs of the final load to meet the needs of the load. Furthermore, the specific implementation method of the output rectifier unit is not limited; any scheme that can achieve rectification in any current or future existing technology, as long as the scheme can be directly applied to the power supply circuit in this embodiment, or does not require technical personnel in this field to spend creative labor to modify the scheme and apply it to the power supply circuit in this embodiment, then these schemes that can achieve rectification are all within the protection scope of this application.

[0121] Preferably, Figure 5 As shown, the output rectification unit is an H bridge.

[0122] Figure 5 The output end of the power supply circuit outputs DC power, which enters the H bridge for rectification and is converted into AC power to meet the load requirements of the power supply circuit. Figure 5The components that make up the H-bridge are ordinary switches. This is only an example and not a limitation. There is no restriction on the switch devices in the H-bridge. They only need to realize the on / off function.

[0123] In one of the preferred embodiments, the transformer leakage inductance value in the power supply circuit is less than 1.5%.

[0124] Specifically, during the operation of the power supply circuit, when the switch is closed, the input power is used to charge the inductor. At the moment the switch is disconnected, the current in 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. In order to ensure the high energy conversion rate of the power supply circuit and better stability, the leakage inductance value range of the transformer here is preferably less than 1.5%.

[0125] Furthermore, the specific structure of the transformer that complies with the power supply circuit of the present 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 of this embodiment, or does not require technical personnel in this field to make creative efforts to adapt the scheme to this embodiment, then these schemes that can achieve a transformer structure with a leakage inductance less than 1.5% are all within the scope of protection of the present application.

[0126] In one preferred embodiment, the transformer structure in the power supply circuit is copper foil or U-shaped metal sheet, and the winding method is parallel winding. Thus, the voltage spike caused by the leakage inductance of the transformer T during the switch off period can be effectively reduced, so that the switch is protected. Furthermore, the power supply circuit of the present application can work under higher power conditions.

[0127] Specifically, this embodiment discloses the structure and winding method of the transformer in the power supply circuit. The magnetic core structure of the transformer is selected to be a thin metal sheet, or it can be a U-shaped metal sheet. The winding method of the primary and secondary sides of the transformer is a parallel winding method. This can reduce the leakage inductance of the transformer and meet the operating needs of the power supply circuit.

[0128] The present application also provides an extended circuit system based on the above-mentioned power supply circuit. When the input power supply is a plurality of power supply units with uncertain input power, the extended circuit system also includes a plurality of power supply circuits connected to each of the power supply units and a control center connected to the controller of each of the power supply circuits.

[0129] Specifically, when the input end of the power supply circuit is connected to multiple power supply units, each power supply unit is connected to a power supply circuit, and the control center is connected to the controller of each power supply circuit. The control center synchronously sends control instructions to each controller to synchronously control each power supply circuit to achieve maximum power point tracking of the power supply unit connected to it, while dynamically completing voltage boost and voltage reduction according to load requirements.

[0130] Preferably, the output ends of the multiple power supply circuits are connected in series / parallel combination according to the output requirements of the expansion circuit.

[0131] Preferably, the expansion circuit further comprises an output rectifier unit for providing rectification for the expansion circuit, and the output rectifier unit is connected to the output ends of the plurality of power supply circuits.

[0132] Specifically, when the input power is a plurality of power supply units with uncertain input power, the expansion circuit may include a plurality of the power supply circuits, each of which is connected to each power supply unit. Since the power supply circuit has the maximum power point tracking and the dynamic adjustment of the voltage rise / fall according to the output requirements of the expansion circuit, the expansion circuit can realize the conversion of the electric energy of all the power supply units connected to the power supply circuit, that is, the electric energy conversion rate is very high; at the same time, after the output ends of the plurality of power supply circuits are combined in series / parallel, the expansion circuit can output a wide range of voltage / power, and can also be connected in series and parallel combination according to the requirements of the load / power grid connected to the expansion circuit. After the series and parallel connection, the output rectifier unit, such as the H bridge, can be connected according to the specific output needs to rectify the sine wave to meet the needs of the expansion circuit.

[0133] Ginseng Figure 5 As shown, the present application also provides a method for realizing maximum power point tracking and dynamic adjustment of output voltage up / down according to output requirements based on the above power supply circuit, the method comprising:

[0134] Step S1, high frequency acquisition of current actual input current [I_in], input voltage [V_in], output voltage, and output current values.

[0135] Specifically, 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 of the power supply circuit. There is no restriction on the specific acquisition or acquisition method. It can be obtained through the acquisition unit of the controller or through other methods. The acquired information is transmitted to the controller to determine the switch duty cycle and frequency adjustment instruction information. 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 the actual situation and there is no specific restriction.

[0136] Step S2, high frequency adjustment of the output current peak value [I_out_peak], monitoring the input voltage and input power changes caused thereby, and determining update adjustment information of the output current peak value according to the input voltage and input power changes.

[0137] Step S21 (not shown), increase the output current peak value [I_out_peak] at high frequency, and monitor the change of input power [P_in = V_in*I_in]; if the input power increases with the increase of the output current peak value, continue to increase the output current peak value [I_out_peak] at high frequency; if the input power decreases with the increase of the output current peak value, execute step S22.

[0138] Specifically, refer to Figure 5 As shown, high frequency increases the output current peak value [I_out_peak], and the voltage across the input capacitor at the input end, that is, the input voltage, decreases, thereby affecting the input power. For example, the solar photovoltaic panel is used as the input of the circuit. Changing the voltage of the input capacitor directly affects the input power of the solar photovoltaic panel. If the input power of the power supply circuit continues to increase at this time, it is necessary to continue to increase the output current peak value [I_out_peak]. When the input power begins to decrease, it is necessary to continue to execute step S22 (not shown) to start high frequency to reduce the output current peak value [I_out_peak].

[0139] Furthermore, the amplitude of increasing the output current peak can be set according to the actual situation, and the specific method is not limited. For example, it can be set to first increase the increase amplitude and then gradually reduce the increase amplitude. When the input power input decreases, enter step S22 to reduce the output current peak at high frequency.

[0140] Step S22, reduce the output current peak value [I_out_peak] at high frequency, detect the change of input power [P_in=V_in*I_in], if the input power response is rising, continue to reduce the output current peak value [I_out_peak] at high frequency until the input power begins to decrease, then enter step S21; if the input power response is decreasing, it is necessary to execute step S21.

[0141] Specifically, continue to Figure 5 As shown, the high frequency reduces the output current peak value [I_out_peak] and continuously monitors the input power. At this time, the voltage across the input capacitor at the input end, that is, the input voltage of the power supply circuit, will rise. If the input power of the power supply circuit increases, it is necessary to continue to reduce the output current peak value [I_out_peak] until the input power decreases. Then, it is necessary to execute step S21 to start the high frequency to increase the output current peak value [I_out_peak].

[0142] Furthermore, the amplitude of the high frequency reduction of the output current peak value can be set according to the actual situation, and the specific method is not limited. For example, it can be set to first increase the reduction amplitude and then gradually reduce the reduction amplitude. When the input power input decreases, enter step S22 to reduce the output current peak value at high frequency.

[0143] Step S21 and step S22 in step S2 are repeatedly executed at a high frequency, so that the voltage of the input capacitor can just make the input end of the power supply circuit be in the maximum power state of the input power supply. For example, the voltage of the input capacitor is maintained at the voltage point required for the maximum power output of the solar photovoltaic panel, so that the power supply circuit can track the maximum value of the input power of the solar photovoltaic panel.

[0144] Step S3, according to the currently adjusted output current peak value [I_out_peak] and the corresponding output target phase information, the target output current value [I target output current value = I output current peak value * target phase information] is determined at high frequency.

[0145] Specifically, the target phase information of the current output that meets the output requirements is the ratio of the current actual output voltage provided by the current power supply circuit to the load to the peak value of the periodically fluctuating voltage provided by the circuit to the load, and the target output current value is the product of the output current peak value determined in the above step S2 and the target phase information, that is:

[0146] I 目标输出电流值 =I 输出电流峰值 *V 当前实际输出电压 / V 输出电压峰值

[0147] Step S4, comparing the current actual output current value with the target output current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result.

[0148] Specifically, the current actual output current value is compared with the target output current value, and the duty cycle and frequency adjustment instruction information of the switch are determined at high frequency according to the comparison result. Further, when the current actual output current value is less than the target output current value, the instruction information for controlling the switch to reduce the frequency and increase the switch duty cycle is generated in the controller, and the switch working state is controlled to further control the charging time of the inductor, thereby increasing the output power, thereby increasing the output current, and making the output current approach the target output current at high frequency, so as to achieve the control of the output waveform, and thus achieve the inverter capability; otherwise, when the current actual output current value is greater than the target output current value, the instruction information for controlling the switch to increase the frequency and reduce the switch duty cycle is generated in the controller, and the switch working state is controlled to further control the charging time of the inductor, thereby reducing the output power, thereby reducing the output current, and making the output current approach the target output current at high frequency, so as to achieve the inverter capability. Specifically, the magnitude of the switch duty cycle is controlled to reduce or increase, and the amplitude of the switch frequency is increased or decreased according to the difference between the current actual output current value and the target output 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, the target output current value here includes the phase information of the current output voltage, that is, the phase information of the target output inversion is taken into account when adjusting the current actual output current value according to the target output current value, ensuring that the current actual output current value always approaches the target output current value and fluctuates around the target output current value, and cooperates with the current direction switching component to enable the power supply circuit to have the ability of inversion.

[0149] Step S5, 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 output current value of the power circuit is as close as possible to the target output current value.

[0150] Specifically, the switch of the power supply circuit executes the instruction information at high frequency, controls the charging and discharging time of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit is as close as possible to the target output current value; specifically, the switch of the power supply circuit executes the instruction sent by the controller to adjust the current duty cycle or frequency at high frequency, controls the charging and discharging time and frequency of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit is as close as possible to the target output current value, thereby achieving the tracking of the input maximum power point while meeting the output inverter voltage and current.

[0151] In addition, the power supply circuit of the present application realizes the switching of current direction through an output rectifier unit, for example, an H-bridge, and converts the pulsating DC generated in the above steps into AC power. For example, the DC steamed bun wave that conforms to the sinusoidal transformation generated in the above steps, when the voltage is 0, completes the current direction switching according to the period of the steamed bun wave, and can generate sinusoidal transformed AC power.

[0152] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0153] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0154]

Claims

1. A power supply circuit, characterized in that: The power supply circuit includes: an information acquisition module, an input capacitor, an inductor, a switch, and a controller, a capacitor, and a transformer for controlling the working state of the switch; The information acquisition module is connected to the controller of the switch and is used to collect current and voltage information of the input and output ends of the power supply circuit and provide the information to the controller; One end of the input power supply is connected to one end of the inductor and one end of the input capacitor, and the other end of the inductor is connected to one end of the capacitor and one end of the switch; the other end of the capacitor is connected to one end of the primary winding of the transformer; the switch, the primary winding of the transformer and the other end of the input capacitor are connected to the other end of the input power supply and grounded; the two output ends of the secondary winding of the transformer are output ends for providing electric energy to the power supply circuit; The controller is used to generate control information for controlling the duty cycle and frequency of the control switch according to the information of the power circuit input and output collected by the information collection module and the power demand of the connected load for the output; In the power supply circuit, the ratio of the maximum input voltage to the maximum output voltage is V 入 :V 出 =0.3-0.9, when the output power is 200W-1000W, the inductance range of the primary winding of the transformer is 15μH-950μH, the parameter range of the capacitor is 105nF-2.9μF, and the ratio range of the primary / secondary winding of the transformer is R 原 :R 副 =1:5-1:

1.

2. The power supply circuit according to claim 1, characterized in that: When the input power source is a plurality of power supply units with uncertain input power, at least two of the plurality of power supply units are connected in series to the power supply circuit.

3. The power supply circuit according to claim 1, characterized in that: When the maximum power value that can be currently input into the power supply circuit is unknown, the power supply circuit realizes maximum power point tracking while also realizing dynamic adjustment and isolation of output voltage increase / decrease according to output requirements.

4. The power supply circuit according to any one of claims 1 to 3, characterized in that: The power supply circuit also includes an output rectifier module, one end of which is connected to one end of the secondary winding of the transformer, wherein the other end of the output rectifier module and the other end of the secondary winding of the transformer are the output ends of the power supply circuit.

5. The power supply circuit according to claim 4, characterized in that: The half-wave rectification module of the power supply circuit realizes half-wave rectification through a diode.

6. The power supply circuit according to claim 4, characterized in that: The half-wave rectification module of the power supply circuit realizes half-wave rectification through a fifth switch and a fifth controller that controls the fifth switch.

7. The power supply circuit according to any one of claims 1 to 3 and 5 and 6, characterized in that: The transformer structure in the power supply circuit is copper foil or U-shaped metal sheet, and the winding method is parallel winding.

8. The power supply circuit according to any one of claims 1 to 3 and 5 and 6, characterized in that: The power supply circuit also includes an output rectifying unit for providing rectification for an output end of the power supply circuit.

9. The power supply circuit according to claim 8, characterized in that: The output rectifying unit is an H bridge.

10. An expansion circuit system of a power supply circuit according to any one of claims 1 to 9, characterized in that: When the input power source is a plurality of power supply units with uncertain input power, the expansion circuit system further comprises a plurality of power supply circuits connected to each of the power supply units and a control center connected to a controller of each of the power supply circuits.

11. The expansion circuit system according to claim 10, characterized in that: The output ends of the multiple power supply circuits are connected in series / parallel combination according to the output requirements of the expansion circuit.

12. The expansion circuit system according to claim 10, characterized in that The expansion circuit further includes an output rectification unit for providing rectification for the expansion circuit, and the output rectification unit is connected to output ends of the plurality of power supply circuits.

13. A method for realizing maximum power point tracking and dynamic adjustment of output voltage up / down according to output requirements in a power supply circuit according to any one of claims 1 to 12, characterized in that: The method includes: Step S1, obtaining the current actual input current, input voltage, output voltage, and output current values ​​at high frequency; Step S2, adjusting the output current peak value at high frequency, monitoring the input voltage and input power changes caused thereby, and determining update adjustment information of the output current peak value according to the input voltage and input power changes; Step S3, determining the target output current value at high frequency according to the output current peak value and the corresponding output target phase information; Step S4, comparing the current actual output current value with the target output current value, and determining the duty cycle and frequency adjustment instruction information of the switch at high frequency according to the comparison result; Step S5, 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 output current value of the power circuit is as close as possible to the target output current value.

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