CN117477901A

CN117477901A - Power supply circuit and extended circuit system thereof and implementation method thereof

Info

Publication number: CN117477901A
Application number: CN202311297196.0A
Authority: CN
Inventors: 苏昕; 毕硕威
Original assignee: Shenzhen Yineng Times Technology Co ltd
Current assignee: Shenzhen Yineng Times Technology Co ltd
Priority date: 2023-06-05
Filing date: 2023-10-08
Publication date: 2024-01-30
Also published as: CN116885920A

Abstract

The invention discloses a power supply circuit and an extension circuit system thereof and a method for realizing maximum power point tracking and dynamic boosting/reducing according to output requirements, wherein the power supply circuit comprises an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor, a transformer and an output half-wave rectification module; according to the method, the peak value of the output current can be regulated through high frequency, the frequency and/or the duty ratio of the regulating switch can be further controlled, the charging and discharging time of the inductor is controlled, and meanwhile, the maximum power point tracking and the boosting/reducing and isolating according to output requirements are realized, so that the power maximum value of the power source input to the power source circuit can be detected in the field of unknown power source power size, the electric energy of the input power source can be acquired to the maximum extent, the electric energy conversion rate is improved, few used components and parts can be effectively saved, the cost is effectively saved, the stability is good, the energy loss is low, and the electric energy conversion rate is high.

Description

Power supply circuit and extended circuit system thereof and implementation method thereof

Technical Field

The invention relates to the technical field of power supplies, in particular to a power supply circuit technology in an inversion scene.

Background

At present, a plurality of main power circuit topologies capable of realizing inversion in the prior art are available, for example, a centralized inverter circuit, a group string inverter circuit, a miniature inverter circuit and the like, wherein the centralized inverter circuit belongs to a primary topology circuit DC/AC structure; the series inverter circuit belongs to a two-stage topological circuit structure and consists of a DC/DC front-stage circuit and a rear-stage DC/AC circuit; the miniature inverter circuit is composed of a DC/DC front-stage circuit and a rear-stage DC/AC circuit, and if the system needs isolation capability, a primary isolation circuit is also needed.

The centralized inverter circuit belongs to a primary circuit and has high conversion efficiency, but topology circuits applied in various applications can only reduce voltage, so that the input voltage range is narrow. The isolation capability is not provided, and the characteristics of a single path MPPT (Maximum Power Point Tracking) lead to obvious short-circuit effect in the power generation process, and the power generation capacity of the system is low.

The string inverter circuit can boost voltage while finishing maximum power point tracking due to the fact that one-stage MPPT is added, so that the input voltage range is wide, multi-path MPPT input is achieved, the system generating capacity is higher than that of a centralized inverter circuit, but conversion efficiency is low due to two-stage or multi-stage circuit topology reasons, isolation capability is not achieved, the number of components is large, and reliability is relatively reduced.

The micro inverter circuit has wider input voltage range, and a first-stage isolation circuit is needed to be added if isolation is needed. MPPT may be provided for a single power supply unit (e.g., one solar panel), or a small number of power supply units (e.g., 4 solar panels in series), so the power generation is higher, but because of two or more stage topology, the conversion efficiency is low, and the cost is far from a centralized, string-type inverter circuit.

Disclosure of Invention

An object of the present application is to provide a power supply circuit, which can solve the problems that in the prior art, the power supply circuit cannot realize the tracking of the maximum power point and the boost/buck adjustment and the isolation between input and output according to the actual output requirement, the conversion rate is low, the same conversion rate cost is high, the stability is weak, and the like.

The application provides a power supply circuit, the power supply circuit includes: the device comprises an information acquisition module, an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor, a transformer and an output half-wave rectification module;

the information acquisition module is connected with the controller of the switch and used for acquiring current and voltage information of the input end and the output end of the power circuit and providing the current and voltage information to the controller;

One end of an input power supply is connected with one end of the inductor and one end of the input capacitor, and the other end of the inductor is connected with one end of the capacitor and one end of the switch; the other end of the capacitor is connected with one end of a primary winding of the transformer; the switch, the primary winding of the transformer and the other end of the input capacitor are connected with the other end of the input power supply and grounded; two output ends of the secondary winding of the transformer are output ends of the power supply circuit for supplying electric energy, and one end of the output ends is connected with the half-wave rectification module;

the controller is used for generating control information for controlling the duty ratio and the frequency of the switch according to the information input and output by the power circuit and the electric energy demand of the access load on the output, which are acquired by the information acquisition module;

when the maximum power value of the power supply circuit which can be input currently is unknown, the power supply circuit realizes maximum power point tracking and simultaneously realizes dynamic adjustment and isolation of rising/falling of output voltage according to output requirements.

Preferably, when the input power is a plurality of power supply units whose input power is not determined, at least 2 of the plurality of power supply units are connected in series to the power supply circuit.

Preferably, the power circuit outputsThe ratio of the maximum value of the input voltage to the maximum value of the output voltage is V _{Into (I)} :V _{Out of} When the output power is 200W-1000W, the inductance of the primary winding of the transformer ranges from 10 mu H to 1000 mu H, the parameter of the capacitor ranges from 100nF to 3 mu F, and the ratio range of the primary winding to the secondary winding of the transformer is R _{Original source} :R _{Auxiliary pair} ＝1:1-1:5。

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

Preferably, the half-wave rectification module of the power supply circuit realizes half-wave rectification through a fifth switch and a fifth controller for controlling the fifth switch.

Preferably, the switching of the power supply circuit is implemented by a bi-directional switch or a controllable switching device.

Preferably, the range of leakage inductance values of the transformer in the power supply circuit is less than 1.5%.

Preferably, the transformer in the power circuit is copper foil or U-shaped metal sheet, and the winding mode is parallel winding.

Preferably, the power supply circuit further comprises an output rectifying unit for providing rectification to an output of the power supply circuit.

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

The application also provides the expansion circuit system of the power supply circuit, when the input power is a plurality of power supply units with uncertain input power, the expansion circuit system further comprises a plurality of power supply circuits connected with each power supply unit and a control center connected with a controller of each power supply circuit.

Preferably, the output ends of the power supply circuits are connected in series/parallel according to the requirement of the output of the expansion circuit.

Preferably, the expansion circuit further includes an output rectifying unit for providing rectification for the expansion circuit, and the output rectifying unit is connected to the output terminals of the plurality of power supply circuits.

The application also provides a method for simultaneously realizing maximum power point tracking and dynamic adjustment of output voltage rising/falling according to output requirements by the power supply circuit, which comprises the following steps:

step S1, obtaining the current actual input current, input voltage, output voltage and output current value at high frequency;

step S2, high-frequency adjusting the peak value of the output current, monitoring the input voltage and the input power change caused by the peak value, and determining updated adjusting information of the peak value of the output current according to the input voltage and the input power change;

step S3, determining a target output current value at high frequency according to the output current peak value and the corresponding output target phase information;

s4, comparing the current actual output current value with the target output current value, and determining the duty ratio and the frequency adjustment instruction information of the switch at high frequency according to the comparison result;

And S5, the switch of the power supply circuit executes the instruction information at high frequency, and controls the charge and discharge time of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit approaches the target output current value as much as possible.

Preferably, the step S2 includes:

step S21, increasing the peak value of the output current at high frequency, and monitoring the change condition of the input power; if the input power is increased along with the increase of the output current peak value, continuing to increase the output current peak value at high frequency; if the input power decreases with the increase of the peak value of the output current, step S22 is executed;

step S22, the peak value of the output current is reduced at high frequency, the change condition of the input power is detected, if the response of the input power is rising, the peak value of the output current is continuously reduced at high frequency until the input power starts to be reduced, and the step S21 is performed; if the input power response is decreasing, step S21 is performed.

Compared with the prior art, the power supply circuit comprises an information acquisition module, an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor, a transformer and an output half-wave rectification module; when the switch is in a closed state, the switch, an input power supply and the inductor form a loop and charge the inductor, and at the moment, the capacitor, the switch and the primary winding inductor of the transformer are equivalent to form an LC oscillating loop; when the switch is in an off 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, electric energy is induced into the secondary winding through current change of the primary winding of the transformer, and the output end of the secondary winding is used as an output end of the power supply circuit for providing electric energy, so that electric energy transmission is realized.

The power supply circuit simultaneously realizes maximum power point tracking and dynamic adjustment of output voltage rising/falling according to output requirements, the frequency and/or duty ratio of an adjusting switch can be further controlled by adjusting the peak value of the output current through high frequency, and the charging and discharging time of an inductor is controlled, so that the voltage boosting/dropping and maximum power point tracking according to the output requirements are realized, and therefore, in the field of unknown input power supply power, such as the photovoltaic power generation field of a solar cell panel, the power maximum value of a power supply input to the power supply circuit can be detected, the electric energy of the input power supply can be acquired to the maximum extent, the generated energy is improved, fewer used components can be used, the cost can be effectively saved, the power supply circuit has good stability, low energy loss and high electric energy conversion rate.

When the input power is a plurality of power supply units with uncertain input power, the expansion circuit based on the power supply circuit comprises a plurality of power supply circuits connected with each power supply unit, and the output ends of the power supply circuits are connected in series/parallel according to the output requirement of the expansion circuit; therefore, the electric energy of each power supply unit can be converted by tracking the maximum power point, and the electric energy conversion rate is high; after the output ends of the power supply circuits are combined in series/parallel, the voltage/power in a wider range can be output.

Drawings

FIG. 1 is a schematic diagram of the connection of a power circuit according to one embodiment of the present application;

FIG. 2 is a schematic diagram of the connection of a power circuit according to another embodiment of the present application;

FIG. 3 is a schematic diagram of the connection of a power circuit according to another embodiment of the present application;

FIG. 4 is a schematic diagram of the connection of a power circuit according to another embodiment of the present application;

fig. 5 is a flowchart of a method for simultaneously implementing maximum power point tracking and output voltage up/down adjustment according to actual output requirements by a power supply circuit according to another embodiment of the present application.

Detailed Description

In order to better understand the technical solutions of the present application, the following description will clearly and completely describe the technical solutions of the embodiments of the present application with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The power supply circuit is mainly applied to the field of inverter power supplies, such as the field of solar power generation through a solar panel, is particularly suitable for unknown maximum power values of current input power supplies, namely unknown electric energy values of the input power supplies of the current access power supply circuit, can detect and track out the maximum power points of the input power supplies, and can dynamically adjust rising/falling voltage and isolate input and output according to output requirements, so that electric energy conversion is realized, namely electric energy conversion under different currents, voltages and powers is realized.

Referring to fig. 3, the power supply circuit of the present application includes: the device comprises an information acquisition module, an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor, a transformer and an output half-wave rectification module;

when the switch is in a closed state, the switch, an input power supply and the inductor form a loop and charge the inductor; the capacitor, the switch and the primary winding inductor of the transformer form an LC oscillating loop, and energy stored in the capacitor is transferred between the primary inductor of the transformer and the capacitor;

when the switch is in an off state, the input power supply, the inductor, the capacitor and the primary winding of the transformer form an LLC oscillation loop, the input power supply and the charged inductor charge the capacitor, and meanwhile, the charged inductor superimposes self energy on energy stored on the primary winding of the transformer and induces electric energy into the secondary winding through current change of the primary winding of the transformer; wherein,

when the maximum power value of the power supply circuit which can be input currently is unknown, the power supply circuit realizes the tracking of the maximum power point and simultaneously realizes the dynamic adjustment and isolation of the rising/falling of the output voltage according to the output requirement.

Specifically, referring to fig. 3, a schematic connection diagram of a power circuit of the present application is shown, where the power circuit includes: an input capacitor C ', an inductor L, one end of an input power supply is connected with one end of the inductor L and one end of the input capacitor C', and the other end of the inductor L is connected with one end of the capacitor C and one end of the switch K; the other end of the capacitor C is connected with one end of a 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 with the other end of the input power supply and grounded; two output ends of the secondary winding of the transformer are output ends of the power supply circuit for supplying electric energy, and one end of the output ends is connected with the half-wave rectification module; the controller is used for controlling the time proportion of the switch K in the closed state in the period time according to the electric energy requirement output by the power supply circuit, further, the period time can be changed, namely the period time can be changed, and the controller controls the frequency and the duty ratio of the switch K to be opened and closed.

The working principle of the power supply circuit is as follows:

specifically, the controller controls the frequency and duty cycle of opening and closing the switch K according to the dynamic demand of the power required by the power supply circuit to provide the power output terminal, in combination with tracking 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 the input power supply and the input capacitor charge the inductor L through the loop; the capacitor C, the switch K and the primary winding inductance of the transformer T form an LC oscillating loop; when the switch K is in an off state, the input power supply, the inductor L, the capacitor C and the primary winding inductor 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 induce electric energy to the secondary side of the transformer through current change of the primary side of the transformer.

The power supply circuit disclosed in this embodiment discharges the capacitor C and the primary winding of the transformer T after charging the inductor L by controlling the working state of the switch K, so that the primary winding of the transformer T obtains energy and senses the energy to the secondary winding of the transformer T, and further outputs the electric energy. The frequency and the duty ratio of the switch K are controlled to control the charge/discharge time of the inductor L and the charge/discharge time of the primary winding inductor of the transformer and further control the electric energy output by the secondary winding of the transformer.

Specifically, a loop formed by the power supply circuit disclosed in the embodiment in the working process includes: the circuit (1) [ input power supply parallel input capacitance+inductance L+capacitance C+transformer T ], the circuit (2) [ input power supply parallel input capacitance+inductance L+switch K ], the circuit (3) [ capacitance C+transformer T+switch K ], the circuit (4) [ input power supply+input capacitance ].

Further, the detailed working procedure 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, the input capacitor is charged for the inductor L, the inductor L stores energy, the switch K is disconnected instantly, the inductor L is used for keeping the current at two ends of the inductor L not to be suddenly changed, a high voltage is generated, the electric energy is transmitted through a new loop (1) formed after the switch K is disconnected, the inductor L is charged for the capacitor C, the energy stored in the primary sides of the inductor L and the transformer T is induced to the secondary sides of the transformer through the primary sides of the transformer, and 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 primary side winding of the transformer T at the moment, namely: v (V) _{Input power supply} +V _L ＝V _C +V _{T primary} The method comprises the steps of carrying out a first treatment on the surface of the The transformer T inducts electric energy to a secondary winding of the transformer T, and the secondary winding outputs the electric energy to an electric energy supply output end of the power circuit through the half-wave rectification module to supply the electric energy to a load; when the switch K is switched from the open state to the closed state, the power supply is powered onThe loop formed by the sequence of the loops and the specific working process are as follows: the parallel input capacitor of the power circuit charges the inductor L through the loop (2), and charges the primary winding of the transformer T through the capacitor C of the loop (3), at the moment, the primary winding of the transformer T and the capacitor C form an LC resonant circuit equivalent to the effect of maintaining the electric energy of the loop; meanwhile, after the switch K is in a closed state, the inductance L is charged by the parallel connection of the input power supply and the input capacitor of the (2) th loop, and the inductance L stores energy next time.

And a loop (4) for increasing the input power or decreasing the output power. The input power supply charges the input capacitor through the loop (4), and the voltage of the input capacitor is increased; when the input power decreases or the output power increases, the input power is discharged in parallel with the input capacitor, and the voltage of the input capacitor decreases.

When the maximum power value of the power supply circuit which can be input currently is unknown, the power supply circuit realizes the tracking of the maximum power point and simultaneously realizes the dynamic adjustment of the rising/falling of the output voltage according to the output requirement.

Specifically, the power supply circuit realizes dynamic adjustment of rising/falling of output voltage according to output requirements to obtain alternating current of a target waveform, and the following principle needs to be satisfied:

when the output requirement is periodic alternating current, setting a voltage fluctuation period T 'output by an output half-wave rectification module of the power supply circuit as a first time interval, wherein in the first time interval T', the output voltage required by corresponding output is continuously changed according to the output requirement of a load, for example: a sine wave of 220V is output. Because the inductor is according to the characteristic that the current is not allowed to be suddenly changed, the controller controls the time period interval corresponding to the switching frequency of the switch K to be the second time interval T'; in the case that the second time interval t″ is smaller than the voltage period T ' output by the output half-wave rectification module by several orders of magnitude, in the range of the voltage period T ', the number of times the switch K has completed turning off and on is hundreds or thousands, that is, in the process that the output needs to have the change from trough to crest in the voltage waveform period T ', because the on/off switching frequency of the switch K is higher, for the operation process of the power circuit controlled by the operating state of the switch K, the voltage waveform needed by the output is locally seen to be not changed greatly, basically can be regarded as unchanged, that is, the voltage waveform needed by the output corresponding to the switch K before and after one time is regarded as unchanged, and in the case that the first time interval T ' includes a plurality of second time intervals t″, that is, when the output voltage is obviously changed, the inductor L has been subjected to multiple charging and discharging processes through the control of the switch K, that is, the inductor L has completed the multiple rounds 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-mentioned operation process, the inductor L of the present circuit, and the primary winding of the transformer T can implement accurate control of the output voltage in the period of T "by the above-mentioned method, that is, can well control output even higher or lower voltage waveforms required for output in the period of T", so that can provide very accurate voltage waveforms required for output in the period of T ' by high-frequency control of the output voltage in the period of T ", for example, by controlling the output voltage value in the period of T" =10 μs, realizing accurate output of 50Hz sine wave in the period of T' =20mS.

Specifically, the specific boosting/dropping process and principle of the power circuit are as follows:

when the voltage provided by the power circuit is insufficient and cannot meet the load requirement, and the voltage needs to be boosted, the controller controls the switch K to increase the duty ratio of the switch K, or reduces the working frequency of the switch K, namely increases the charging time of the inductor L and the primary winding of the transformer T, and when the switch is disconnected, more electric energy can be induced to the secondary winding of the transformer T to realize the voltage boosting. Further, if the voltage provided by the power circuit is higher, when the voltage needs to be reduced, the controller controls the switch K, the duty ratio of the switch K is reduced, and the charging time of the inductor L and the primary winding of the transformer T is reduced, so that the electric energy induced by the secondary winding of the transformer T is reduced, and the voltage reduction is realized.

Here, since the power of the input terminal is not determined, the energy storage of the input capacitor is changed with the change of the output power after the step-up or step-down operation is performed, and thus the voltage of the input capacitor is changed.

If the input voltage rises, the energy storage of the primary winding of the inductor L and the transformer T increases, the energy transferred to the secondary winding increases, and the output power rises in the energy storage period when the switch K is closed; if the input voltage drops, the inductance L and the primary winding of the transformer T will store energy during the energy storage period when the switch K is closed, the energy transferred to the secondary winding will also drop, and the output power will drop.

Therefore, the dynamic boosting and reducing process provided by the circuit is a high-frequency working process which is continuously adjusted according to the dynamic requirement of an output load and the dynamic response of an input voltage.

Here, when the period interval t″ corresponding to the operating frequency of the switch K is higher than the output required voltage waveform period T ', that is, T "> T', the frequency and the duty ratio of the switch K are adjusted, and the charge and discharge time of the inductor is further adjusted to achieve voltage boosting/reducing, specifically, the size of the input power supply voltage period T 'may be set according to the specific condition of the output required voltage waveform, further, if the output required voltage waveform is an alternating current with a voltage periodically changed, for example, a sine wave alternating current, the corresponding T' =10ms, and if the output required voltage waveform has no obvious periodicity, the value of T 'may be set to be compared with the change period of the sine wave alternating current, for example, the setting T' is about 10ms, and the specific setting mode only needs to meet the requirement described above, so as to implement the scheme of the present application.

Specifically, the power supply circuit realizes the tracking of the maximum power point and the dynamic adjustment of the step-up/step-down according to the output requirement, and the specific working process is as follows with reference to fig. 5:

Step S1, the current actual input current [ I_in ], input voltage [ V_in ], output voltage and output current value are obtained at high frequency. Wherein, the input current I_in refers to the total current of the input power circuit, including the current for charging the input capacitor. The input voltage [ v_in ] refers to the voltage across the input capacitance.

Specifically, the current actual input current, input voltage, output voltage and output current value are obtained at high frequency, the current actual input and actual output conditions of the power supply circuit are required to be obtained by high-frequency acquisition, wherein the specific acquisition or acquisition mode is not limited, the current actual input and actual output conditions can be obtained through an acquisition unit of the controller, the current actual input current, input voltage, output voltage and output current value can also be obtained through other modes, the obtained information can be transmitted to the controller for determining the adjustment instruction information of the switching duty ratio and the frequency, the frequency of the high frequency can refer to the frequency of a switch in the power supply circuit, for example, the frequency can be equal to the switching frequency or smaller than the switching frequency, the frequency of the high frequency can also be changed according to the actual conditions, and the current actual input and output conditions are not limited.

And S2, high-frequency adjusting the output current peak value (I_out_peak), monitoring the input voltage and input power change conditions caused by the peak value, and determining updated adjustment information of the output current peak value according to the input voltage and input power change conditions.

Step S21 (not shown), the output current peak value is increased at high frequency [ i_out_peak ], and the variation of the input power [ p_in=v_in_i_in ] is monitored; if the input power is also increasing along with the increase of the output current peak value, continuing to increase the output current peak value (I_out_peak) at high frequency; if the input power decreases with the increase of the peak value of the output current, step S22 is performed.

Specifically, referring to fig. 5, when the output power increases, the input capacitance of the input terminal will discharge, and the voltage across the input capacitance of the input terminal, i.e. the input voltage, drops, thereby affecting the input power, for example: the solar photovoltaic panel is used as the input of the circuit, the voltage of the input capacitor is changed, the input power of the solar photovoltaic panel is directly affected, if the input power of the power supply circuit is continuously increased at this time, the output current peak value (I_out_peak) needs to be continuously increased, when the input power starts to be reduced, the step S22 (not shown) needs to be continuously executed, and the high-frequency reduction output current peak value (I_out_peak) is started.

Further, the magnitude of the output current peak value may be increased, and may be set according to a specific practical situation, and the specific manner is not limited, for example, the magnitude may be increased first, and then the magnitude of the increase may be gradually decreased, and when the input power input is decreased, step S22 is performed to reduce the output current peak value at high frequency.

Step S22, detecting the variation of the input power [ p_in=v_in_i_in ] by high-frequency decreasing the output current peak [ i_out_peak ], if the input power response is rising, continuing to high-frequency decreasing the output current peak [ i_out_peak ] until the input power starts to decrease, and proceeding to step S21; if the input power response is decreasing, step S21 is required.

Specifically, as shown in fig. 5, the output current peak value i_out_peak is reduced at a high frequency, and the input power is continuously monitored, at this time, the output power is reduced, more energy of the input power source (for example, 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, the output current peak value i_out_peak needs to be continuously reduced until the input power decreases, step S21 needs to be executed, and the output current peak value i_out_peak needs to be increased at a high frequency.

Further, the magnitude of the peak value of the high-frequency decreasing output current may be set according to the specific practical situation, and the specific manner is not limited, for example, the magnitude may be set to be increased first, and then the magnitude of the decrease may be gradually decreased, and when the input power input is decreased, the step S22 is performed to decrease the peak value of the output current at high frequency.

The steps S21 and S22 in step S2 are repeated at a high frequency, so that the voltage of the input capacitor just can make the input end of the power supply circuit be in the state of maximum power of the input power, for example, the voltage of the input capacitor is maintained at the voltage point required by 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.

Step S3, determining a target output current value [ I target output current value=i output current peak ] at high frequency according to the current adjusted output current peak value [ i_out_peak ] and the corresponding output target phase information.

Specifically, the target phase information of the current output meeting the output requirement is a ratio of the current actual output voltage provided by the current power supply circuit to the load and the periodically fluctuating voltage peak value provided by the current circuit to the load, and the target output current value is a product of the output current peak value and the target phase information determined in the step S2, that is:

I _{target output current value} ＝I _{Peak value of output current} *V _{Current actual output voltage} /V _{Peak value of output voltage}

And S4, comparing the current actual output current value with the target output current value, and determining the duty ratio and the frequency adjustment instruction information of the switch at high frequency according to the comparison result.

Specifically, the current actual output current value is compared with the target output current value, and the duty ratio and the 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 smaller than the target output current value, generating instruction information for controlling the switch to reduce the frequency and improve the switch duty ratio in the controller, and controlling the working state of the switch to further control the charging time of the inductor, so that the output power is improved, the output current is further improved, the output current is enabled to approach the target output current at high frequency, the control of the output waveform is realized, and the inversion capability is further realized; otherwise, when the current actual output current value is larger than the target output current value, generating instruction information for controlling the switch to increase the frequency and reduce the duty ratio of the switch in the controller, and controlling the working state of the switch to further control the charging time of the inductor, so that the output power is reduced, the output current is further reduced, the output current is enabled to approach the target output current at high frequency, and the inversion capability is further realized. Specifically, the control switch reduces, increases the size of the switch duty cycle, increases or decreases the frequency of the switch according to the difference between the current actual output current value and the target output current value, and the specific implementation manner and process are not limited, so that one of ordinary skill in the art can try to set according to the actual scene. Meanwhile, the target output current value covers the phase information of the current output voltage, namely the phase information of the inversion of the target output is considered when the current actual output current value is adjusted according to the target output current value, so that the current actual output current value is ensured to approach the target output current value all the time and to fluctuate around the target output current value, and the power circuit has the inversion capability by matching with the current direction switching component.

Specifically, the switch of the power supply circuit executes the instruction information at high frequency, and controls the charge and discharge time of the inductor in the power supply circuit, so that the current actual output current value of the power supply circuit approaches the target output current value as much as possible; specifically, the switch of the power supply circuit executes the command of adjusting the current duty ratio or frequency sent by the controller at high frequency, and 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 approaches the target output current value as much as possible, and the tracking of the input maximum power point is completed while the output inversion voltage and current are met.

In addition, the power supply circuit of the present application realizes the switching of the current direction by outputting the rectifying unit, for example, an H-bridge, and forms the pulsating direct current generated in the above steps into alternating current, for example, the sinusoidal-conversion-conforming direct current steamed bread wave generated in the above steps, and at the voltage of 0 point, the switching of the current direction is completed according to the period of the steamed bread wave, so that the sinusoidal-conversion-conforming alternating current can be generated.

In one preferred embodiment, when the input power is a plurality of power supply units whose input power is not determined, at least 2 of the plurality of power supply units are connected in series to the power supply circuit.

Specifically, this embodiment is mainly directed to the case where the input power of the power supply circuit includes a plurality of power supply units, where the plurality of power supply units may be connected in series to the power supply circuit to provide a larger input voltage for the power supply circuit; also, a plurality of power supply units herein may be connected in parallel or in series/parallel combinations to the power supply circuit to provide a larger current. By way of example and not limitation, 400 solar photovoltaic cells are combined in series/parallel, 20 are connected together in series, and 20 are connected in parallel and then connected into a 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 supply circuit to provide larger power, and the cost of the overall power supply circuit is saved.

In order to ensure the advantages of good stability, low cost and the like of the power supply circuit, the electric energy conversion rate is high, and parameters of components in the power supply circuit are required to be determined.

Determining principle of component parameters in a power supply circuit: the determination of specific component parameters is related to the input voltage, the output voltage and the output power of the power supply circuit, and the maximum value of the input voltage, the maximum value of the output voltage and the output power of the power supply circuit unit are determined first, wherein the maximum value of the voltage refers to the effective value of the voltage in the case of alternating current, and the maximum value of the voltage refers to the maximum value of the input/output voltage range in the case of direct current. And determining capacitance parameters, inductance values of primary/secondary windings of the transformer, primary/secondary winding ratios, switching operating frequency ranges and the like in the power circuit unit according to the maximum value of the input voltage, the maximum value ratio of the output voltage and the output power of the power circuit unit.

Specifically, in practice, the inductance of the power circuit unit and the primary/secondary inductance parameters of the transformer need to be considered when determining:

when the parameters such as the working frequency/duty ratio of the switch, the primary side inductance of the transformer, the inductance of the inductor and the like are not changed, and the input voltage is increased, the primary side winding inductor of the transformer can store more energy during the switch on period, and the energy stored by the primary side winding inductor of the transformer is induced to the secondary side winding of the transformer during the switch off period, so that the output power of the power circuit unit can be increased; when the input voltage decreases, the output power of the power supply circuit unit can be reduced.

When the input voltage maximum value, the inductance of the inductor, the switching frequency/duty ratio and other parameters are not changed, and the primary side inductance of the transformer is reduced, more energy can be stored in the primary side inductance of the transformer during the switch on period, and the energy stored in the primary side inductance of the transformer is induced to the secondary side winding of the transformer during the switch off period, so that the output power of the power circuit unit can be increased; correspondingly, when the inductance of the primary winding of the transformer is increased, the output power of the power circuit unit can be reduced; in the process of determining the inductance of the primary winding of the transformer, consideration is also needed, and when the energy stored in the primary winding of the transformer is too much, the transformer may be saturated, so that the electric energy conversion efficiency is reduced.

In practice, the conversion efficiency of a circuit can be affected by changing the number of turns ratio of primary side/secondary side windings of the transformer; specifically, when the input voltage, the switching frequency/duty ratio, the load resistance value, the primary winding inductance of the transformer, the inductance of the inductor and the like are determined, the number of turns of the secondary winding is increased or the number of turns of the primary winding is reduced, namely the ratio of the primary winding to the secondary winding is reduced, so that the output voltage can be increased; correspondingly, the output voltage can be reduced by reducing the number of turns of the secondary winding or increasing the number of turns of the primary winding, namely increasing the primary/secondary winding proportion of the transformer; the parameters of the transformer are determined through the specific scene and the mode, so that the conversion efficiency of the power circuit unit can be effectively improved.

In practice, when the input voltage, the working frequency/duty ratio of the switch, the inductance of the primary winding of the transformer and the like are determined, the inductance of the inductor is reduced, more energy can be stored in the inductor during the on period of the switch, the primary winding of the transformer is charged by the energy stored in the inductor during the off period of the switch, and then the primary winding of the transformer induces the energy to the secondary winding of the transformer, so that the output power of the power circuit unit can be increased; when the inductance of the inductor increases, the output power of the power supply circuit unit can be reduced.

The frequency range of the switch is determined taking into account: when the switching frequency is reduced under the condition that parameters of other components in the power circuit unit are unchanged, the energy storage time t for switching on the switch in a single period is prolonged, and the frequency f is reduced; during the closing of the switch, the energy stored in the inductor, the primary side of the transformer, increases and the output power of the power supply circuit unit increases. Accordingly, when the switching frequency is increased, the output power of the power supply circuit unit is reduced. In addition, as the switching frequency increases, the switch generates "switching loss" at the moment of turning on and off, and increasing the switching frequency increases the switching loss. Here, the conversion efficiency of the transformer needs to be considered, and the corresponding inductance is different and the conversion efficiency is different under different frequencies of different magnetic cores. Too low a frequency, for example, below 30K, may lead to saturation of the transformer, causing a decrease in conversion efficiency; too high a frequency, for example, above 500K, may cause a large change in the inductance of the transformer, reducing the conversion efficiency.

The process of determining the parameters of the capacitor, as previously described, stores energy during the off-period of the switch, and during the on-period of the switch, the capacitor resonates with the primary winding of the transformer, transferring the stored energy to the primary winding of the transformer. The capacity value of the capacitor is too small, so that the energy stored on the capacitor is insufficient during the working period, the output power of the power circuit unit is reduced, and the conversion efficiency is further reduced; when the input voltage is alternating current, the voltage of the capacitor cannot follow the change of the input voltage of the alternating current, so that the calculation is difficult in the power factor tracking process, and the electric energy conversion efficiency is reduced.

In practice, the input capacitor needs a larger capacitance value, so that when the input power changes, the input capacitor can be buffered, and the buffer is provided for the whole power circuit to effectively track the maximum power point. If the capacitance of the input capacitor is too small, for example, but not limited to, a 500W output power circuit, the capacitance of the input capacitor is less than 200 μf, and when the input power changes, the voltage changes too fast on both sides of the input capacitor, which results in continuously adjusting the duty cycle and frequency of the switch, so that the overall conversion efficiency of the circuit decreases.

In practice, the input capacitance exceeds a certain threshold value, and is not particularly sensitive, for example, but not limited to, a circuit with 500W power, and the effect of tracking the maximum power point is limited after the input capacitance exceeds 6 mF. The appropriate input capacitance value can be selected according to the actual cost and product requirements.

From the above analysis, it is known that the components and their connection relationships included in the power supply circuit belong to a whole, the parameter settings of the components have relevance, and the parameter settings of all the components have integrity. In practice, according to the input voltage condition of the circuit unit, the requirement of the output voltage and output power of the connected load, the detailed parameter selection principle, the materials and cost of the transformer and the inductor, the saturation condition of the transformer and the inductor caused by the output power, and the inductance of the inductor is designed to achieve the balance of a plurality of parameters. The parameters such as inductance, primary winding inductance of the transformer, switching frequency, capacitance and the like in the power circuit are required to be selected in an independent setting range, and the coordination of the parameters of all components is required to be considered integrally according to the logical relation of parameter setting among the components, so that the power circuit has better electric energy conversion rate on the basis of ensuring good performance.

In one preferred embodiment, the ratio of the maximum value of the input voltage to the maximum value of the output voltage in the power supply circuit is V _{Into (I)} :V _{Out of} When the output power is 200W-1000W, the inductance of the primary winding of the transformer ranges from 10 mu H to 1000 mu H, the parameter of the capacitor ranges from 100nF to 3 mu F, and the ratio range of the primary winding to the secondary winding of the transformer is R _{Original source} :R _{Auxiliary pair} ＝1:5-1:1。

Specifically, the embodiment provides a parameter range of the ratio of the corresponding capacitor, the primary winding of the transformer and the primary and secondary windings of the transformer in the components of the power circuit unit when the output power of the power circuit unit is 200W-1000W and the ratio of the calculated value of the input voltage to the calculated value of the output voltage is 0.2-1.0. According to the parameter determination principle and process, under the condition that the specific input voltage maximum value, the proportion of the output voltage maximum value and the output power of the power circuit are determined, the specific parameters of the corresponding components are selected and determined within the parameter range of the corresponding components provided by the embodiment so as to meet the maximum power tracking, and the dynamic adjustment of the voltage boosting and the voltage reducing according to the requirement of the output end, the electric energy conversion rate can reach 98% or more, the specific parameter experimental data and the test result are shown in the embodiments 1 to 8 in the table 1, and under the condition that the power circuit components have the same functions and the same electric energy conversion rate as those of the prior art, the power circuit components are obviously less than those of the prior art, the energy loss is less, the cost is lower, and the circuit stability is stronger.

By way of example and 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, the inductance sensing parameter is designed to be about 10 μ -1mH, the primary winding sensing parameter of the transformer is set to be about 10 μ -1mH, the capacitance parameter is set to be about 500nF-3000nF, and the primary/secondary winding ratio of the transformer is set to be about 1:5-1:2, at which time the corresponding power conversion rate is 97% or more, according to the above-described parameter design principle.

Specifically, in this embodiment, the inductance of the primary winding of the transformer is set to be 10 μh, or the inductance of the inductor is set to be about 10 μh, because the energy stored in the inductor and the energy stored in the primary winding of the transformer are low each time in the 50V input voltage, so that the primary winding of the transformer and the inductor store enough energy in the energy storage period, and the power supply circuit unit provides enough power for the output terminal or the connected load. However, if the inductance of the primary winding of the transformer is continuously reduced, or the inductance of the inductor is continuously reduced, the exciting current of the transformer is greatly increased, so that the conversion efficiency is greatly reduced.

In this embodiment, a transformer is used with primary/secondary winding inductance ratio in the range of about 1:5 to 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 ratio is increased to more than 70%, so that the output voltage of about 300V can be obtained, and the loss is reduced too much in the on-state of the switch, so that the conversion efficiency of the power supply circuit is low. The booster transformer with the primary side/secondary side winding inductance ratio range of 1:5-1:2 is adopted, so that the duty ratio of a switch can be effectively reduced, and the electric energy conversion efficiency is improved.

Because the input voltage is relatively low, the capacitance needs to be relatively large, so that enough energy can be stored in the primary winding of the transformer in the energy storage period. If the capacitance parameter is set below 500nF, when the output voltage changes dynamically, the situation that the energy stored in the capacitor is insufficient and the efficiency is reduced occurs at part of the power points. If the capacitance is set to 3000nF or more, it is observed that a large voltage spike is generated during the switching off of the switch, and a switch with better withstand voltage is required, which increases the cost.

By way of example, but not limitation, when the maximum input voltage is 300V, the maximum output voltage is 300V, and the output power is 1000W, the inductance of the primary winding of the transformer is set to about 60 muh-1 mH, the capacitance is set to about 100nF-500nF, the primary/secondary winding ratio of the transformer is set to about 1:1, and the power conversion rate of the corresponding power supply circuit is at least 98% according to the above parameter design principle.

By way of example and not limitation, the embodiment may be applied to the solar photovoltaic field, where the input is 300V dc, the output is about 300V ac, the output power of the power circuit unit is 1000W, the maximum input voltage and the maximum output voltage are about 1:1, the inductance 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 60 μh, and the inductance is set to 1mH. Since the ratio of the maximum value of the input voltage to the maximum value of the output voltage is 1, the primary side/secondary side inductance of the transformer used is about 1:1. Under the condition that the primary side/secondary side ratio of the transformer is close, the transformer processing technology can save cost, and leakage inductance is easy to control.

Under the application scene of the embodiment, a capacitor smaller than 100nF is selected, and the capacitor can possibly appear in an energy storage period when a switch is closed, and can not provide enough energy for a primary winding of a transformer, so that the conversion efficiency of a power circuit unit is reduced; the capacitor with the capacitance larger than 500nF is selected, when the primary winding inductance of the transformer is charged in the energy storage period of the switch closing, the charging current is easy to be large, and when the switch is opened, the primary leakage inductance of the transformer generates a voltage spike, so that a switch with higher withstand voltage is required to be selected, and the cost is increased.

At the same time, the energy storage of the energy storage cycle may be selectively divided between the transformer and the inductor. The inductance is improved, the inductance of the transformer is reduced, the energy stored by the primary side of the transformer in the open-close energy storage period is more in duty ratio, and the inductance is less in duty ratio. The inductance is reduced, the inductance of the transformer is improved, the energy stored by the primary side of the transformer in the closed energy storage period of the open light pipe is smaller in proportion, and the inductance is larger in proportion.

Under the application scene of the embodiment, the capacitance parameter is about 100nF-500 nF; in practice, the capacitor less than 100nF has too little energy in the capacitor in the energy storage period of the switch closing, and cannot provide enough energy for the primary winding of the transformer, so that the electric energy conversion efficiency of the power supply circuit is reduced; the capacitor with the capacitance larger than 500nF stores too much energy in the energy storage period of the switch closing, charges the primary winding inductance of the transformer, easily causes large charging current, and at the moment of switch opening, the primary leakage inductance of the transformer generates a voltage spike, so that a switch with higher withstand voltage needs to be selected, and the cost is increased.

In this embodiment, since the ratio of the maximum value of the input voltage to the maximum value of the output voltage is 1, the primary/secondary inductance of the transformer used is about 1:1. Under the condition that the primary side/secondary side ratio of the transformer is close, the transformer processing technology can save cost, and leakage inductance is easy to control.

Preferably, referring to fig. 4, the half-wave rectification module of the power circuit implements half-wave rectification through a diode.

Specifically, the half-wave rectification module provided in this embodiment is connected to one end of the secondary winding in the transformer, and its specific principle of action is as follows: after a switch of a power circuit is turned from closed to open, an inductor charged in the switch closing period charges a capacitor and a primary winding of a transformer, a secondary winding of the transformer is induced by current of the primary winding to obtain electric energy, and at the moment, the current of the secondary winding of the transformer is output to an electrolytic capacitor or a load through the half-wave rectification module to supply or store the electric energy; when the switch of the power circuit is turned from open to closed, the capacitor, the primary winding of the transformer and the switch form an equivalent LC resonant circuit, and the capacitor and the primary winding of the transformer form resonance at the moment because the voltage is not allowed to be suddenly changed by the capacitor.

Therefore, the half-wave rectifying module can only realize unidirectional conduction of the secondary winding current of the transformer, and a circuit or a component for realizing half-wave rectification is not limited, and any scheme of a circuit capable of realizing half-wave rectification in the prior art at present or in the future can be directly applied to unidirectional conduction of the secondary winding current of the transformer in the embodiment, or the scheme is applicable to unidirectional conduction of the secondary winding current of the transformer in the embodiment without creative labor of a person in the field, so that the circuit schemes capable of realizing half-wave rectification are all within the protection scope of the application, such as a diode/MOS tube with unidirectional conduction function, a switch tube controlled to be unidirectional conduction, and the like.

Further, referring to fig. 4, in this embodiment, the unidirectional output of the secondary winding of the transformer T is achieved by connecting a third diode D3 to the corresponding output terminal of the secondary winding of the transformer T. The diode has the property of unidirectional conduction, half-wave rectification is realized through the diode, and the control circuit is simple and has stable performance.

Preferably, referring to fig. 5, the half-wave rectification module of the power circuit implements half-wave rectification through a fifth switch K5 and a fifth controller for controlling the fifth switch K5; the fifth controller controls the switching mode of the fifth switch according to the mode that the controller of the power supply circuit controls the switch to induce electric energy for the secondary winding of the transformer.

Specifically, this embodiment is to implement half-wave rectification of the secondary winding output of the transformer by the fifth switch K5, where the fifth switch K5 is controlled by the fifth controller. Further, since the working state of the fifth switch K5 determines whether the secondary winding of the transformer can form a loop, that is, the fifth switch K5 is opened, which cannot form a loop, and the fifth switch K5 is closed, which can form a loop; meanwhile, when the switch closing capacitor of the power circuit resonates for charging the primary winding of the transformer, the secondary winding of the transformer cannot form a loop, i.e. the fifth switch K5 needs to be opened at the moment. 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, and according to the analysis, when the switch of the power circuit is in the closed state, the fifth controller needs to control the fifth switch K5 to be in the open state.

According to the embodiment, the function of half-wave rectification of the secondary winding output of the transformer is achieved by arranging the fifth controller and the corresponding fifth switch, and in certain scenes, the energy consumption of the switch relative to the diode is lower, and the electric energy conversion rate is higher. For example, and without limitation: under the scene that the output voltage peak value is lower than 100V, a diode is used for half-wave rectification, the voltage drop of the diode is too high, so that the conversion efficiency is reduced, and the output half-wave rectification function of the secondary side of the transformer can be realized by using a switching element. The switching element with fixed internal resistance can be adopted, and a mode of parallel connection of multiple switches can be adopted, so that the power loss of half-wave rectification is reduced, and the electric energy conversion rate is improved.

In practice, the type of the switch element is selected, the switch element is also related to the setting of the working frequency of the switch, the common silicon-based MOS tube is limited to 150K in the highest frequency proposal; the highest frequency suggestion of the silicon carbide MOS tube is limited to 250K; IGBT switching tube, highest frequency suggestion limit 40K; the highest frequency of gallium nitride MOS tube is limited to 500K. The switch of the embodiment is a high-frequency switch with a common withstand voltage of 150V in the market, for example, a high-frequency switch with a model NCEP15T14, and the corresponding operating frequency range of the switch is 50K-200K.

Specifically, the switch in the power circuit carries the on and off functions of the circuit according to the control information of the corresponding controller, where the specific control mode of the controller to control the switch is not limited, that is, the mode or the way of the controller to provide the control signal to the switch is not limited, and the switch signal transmission scheme can be implemented by the controller in any existing or future prior art, so long as the scheme can be directly applied to the control signal transmission of the controller to the switch controlled by the controller in the embodiment, or the scheme is applicable to the embodiment without creative labor of a person skilled in the art after carrying out the change on the scheme, and then the scheme for implementing the control signal transmission of the controller to the switch controlled by the controller is within the protection scope of the application.

Further, the specific form of the switch or the switch and the controller thereof for realizing the circuit opening and closing in the power circuit is not limited, and any scheme for realizing the switch or the switch and the controller thereof for realizing the circuit opening and closing in the prior art now or in the future is within the scope of protection of the present application as long as the scheme can be directly applied to the function of the circuit opening and closing in the power circuit of the present embodiment, or the scheme is applied to the present embodiment without the need of creative labor of a person skilled in the art.

Specifically, in this embodiment, mainly for a scenario that the power supply circuit is used as an inverter and needs to output alternating current, because the current output by the output end of the power supply circuit is direct current, the direct current output by the output end of the power supply circuit needs to be rectified by the output rectifying unit according to the requirement of a final load so as to meet the requirement of the load, and further, the implementation mode of a specific rectifying unit of the output rectifying unit is not limited; any scheme that can be used to implement rectification in the present or future prior art is within the scope of protection of the present application, as long as the scheme can be directly applied to the power supply circuit in the present embodiment, or the scheme is applied to the power supply circuit in the present embodiment without the need for creative effort of a person skilled in the art to change the scheme.

Preferably, referring to fig. 5, the output rectifying unit is an H-bridge.

The output end of the power circuit in fig. 5 outputs direct current, the direct current enters the H-bridge to rectify and transform into alternating current to meet the load requirement of the power circuit, wherein the components composing the H-bridge in fig. 5 are common switches, which are only for example and not for limitation, and the switching devices in the H-bridge do not make any limitation and only need to realize the on/off function.

In one preferred embodiment, the range of transformer leakage inductance values in the power circuit is less than 1.5%.

Specifically, when the switch is closed in the working process of the power circuit, the input power supply charges the inductance, the switch is opened instantly, the current of the whole circuit is larger, leakage inductance existing in the transformer can cause a large voltage peak value to be generated at two ends of the switch, the switch is possibly damaged by the high voltage breakdown, and the leakage inductance value range of the transformer is optimally smaller than 1.5% in order to ensure high electric energy conversion rate and better stability of the power circuit.

Further, the specific structure of the transformer according to the power supply circuit of the present application is not limited, and any transformer structure scheme with leakage inductance less than 1.5% can be implemented in the present or future prior art, so long as the scheme can be directly applied to the function of the transformer in the power supply circuit of the present embodiment, or the scheme is applicable to the present embodiment without the need of creative labor of a person skilled in the art, and then the scheme capable of implementing the transformer structure with leakage inductance less than 1.5% is within the protection scope of the present application.

In one preferred embodiment, the transformer structure in the power circuit is copper foil or U-shaped metal sheet, and the winding mode is parallel winding. Therefore, voltage spike brought by leakage inductance of the transformer T in the switch off period can be effectively reduced, and the switch is protected. Furthermore, the power supply circuit can work under the working condition of higher power.

Specifically, the embodiment discloses a structure and winding mode of a transformer in a power circuit, wherein the magnetic core structure of the transformer is selected to be a sheet metal, or a U-shaped sheet metal, and the winding modes of the primary side and the secondary side of the transformer are parallel winding modes, so that leakage inductance of the transformer can be reduced, and the operation requirement of the power circuit is met.

The application also provides an expansion circuit system based on the power supply circuit, when the input power is a plurality of power supply units with uncertain input power, the expansion circuit system further comprises a plurality of power supply circuits connected with each power supply unit and a control center connected with a controller of each power supply circuit.

Specifically, when the input end of the power supply circuit is connected with a plurality of power supply units, each power supply unit is connected with one power supply circuit, the control center is connected with the controller of each power supply circuit, and synchronously sends control instructions to each controller so as to synchronously control each power supply circuit to realize the tracking of the maximum power point of the connected power supply unit, and meanwhile, the step-up and the step-down are dynamically completed according to the requirements of loads.

Specifically, when the input power is a plurality of power supply units with uncertain input power, the expansion circuit can comprise a plurality of power supply circuits, each power supply circuit is connected to each power supply unit, and the expansion circuit can realize conversion of electric energy of all the power supply units connected to the power supply circuits, namely, the electric energy conversion rate is very high because the power supply circuits have maximum power point tracking and dynamic adjustment of voltage rising/falling according to the output requirement of the expansion circuit; meanwhile, after the output ends of the power supply circuits are combined in series/parallel, the expansion circuit can output a wide range of voltage/power, and the series-parallel combination connection can be performed according to the requirements of loads/power grids and the like accessed by the expansion circuit. After series-parallel connection, the output rectifying unit, such as an H bridge, can be connected according to the specific output requirement to rectify sine waves so as to meet the requirement of an expansion circuit.

Referring to fig. 5, the present application further provides a method for simultaneously implementing maximum power point tracking and dynamic adjustment of output voltage rise/fall according to output requirements based on the above power supply circuit, where the method includes:

step S1, obtaining the current actual input current [ I_in ], input voltage [ V_in ], output voltage and output current value at high frequency.

Specifically, referring to fig. 5, the high frequency increases the output current peak value [ i_out_peak ], and the voltage across the input capacitor of the input terminal, i.e., the input voltage, decreases, thereby affecting the input power, for example: the solar photovoltaic panel is used as the input of the circuit, the voltage of the input capacitor is changed, the input power of the solar photovoltaic panel is directly affected, if the input power of the power supply circuit is continuously increased at this time, the output current peak value (I_out_peak) needs to be continuously increased, when the input power starts to be reduced, the step S22 (not shown) needs to be continuously executed, and the high-frequency reduction output current peak value (I_out_peak) is started.

Specifically, with continued reference to fig. 5, the output current peak value [ i_out_peak ] is reduced at a high frequency, and the input power is continuously monitored, at this time, the voltage across the input capacitor of the input terminal, that is, the input voltage of the power supply circuit, will rise, if the input power of the power supply circuit increases, the output current peak value [ i_out_peak ] needs to be continuously reduced until the input power decreases, step S21 needs to be executed, and the high frequency increase of the output current peak value [ i_out_peak ] is started.

Specifically, comparing the current actual output current value with the target output current value, and determining the duty ratio and frequency adjustment instruction information of a switch at high frequency according to the comparison result, further, when the current actual output current value is smaller than the target output current value, generating instruction information for controlling the switch to reduce the frequency and improve the duty ratio of the switch in a controller, controlling the working state of the switch to further control the charging time of an inductor, thereby improving the output power, further improving the output current, enabling the output current to approach the target output current at high frequency, realizing the control of an output waveform, and further realizing the inverse transformation capability; otherwise, when the current actual output current value is larger than the target output current value, generating instruction information for controlling the switch to increase the frequency and reduce the duty ratio of the switch in the controller, and controlling the working state of the switch to further control the charging time of the inductor, so that the output power is reduced, the output current is further reduced, the output current is enabled to approach the target output current at high frequency, and the inversion capability is further realized. Specifically, the control switch reduces, increases the size of the switch duty cycle, increases or decreases the frequency of the switch according to the difference between the current actual output current value and the target output current value, and the specific implementation manner and process are not limited, so that one of ordinary skill in the art can try to set according to the actual scene. Meanwhile, the target output current value covers the phase information of the current output voltage, namely the phase information of the inversion of the target output is considered when the current actual output current value is adjusted according to the target output current value, so that the current actual output current value is ensured to approach the target output current value all the time and to fluctuate around the target output current value, and the power circuit has the inversion capability by matching with the current direction switching component.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

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Claims

1. A power supply circuit, the power supply circuit comprising: the device comprises an information acquisition module, an input capacitor, an inductor, a switch, a controller for controlling the working state of the switch, a capacitor, a transformer and an output half-wave rectification module;

2. The power supply circuit of claim 1, wherein when the input power is a plurality of power supply units whose input power is not determined, at least 2 of the plurality of power supply units are connected in series to the power supply circuit.

3. The power supply circuit of claim 1, wherein the ratio of the maximum input voltage to the maximum output voltage in the power supply circuit is V _{Into (I)} :V _{Out of} When the output power is 200W-1000W, the inductance of the primary winding of the transformer ranges from 10 mu H to 1000 mu H, the parameter of the capacitor ranges from 100nF to 3 mu F, and the ratio range of the primary winding to the secondary winding of the transformer is R _{Original source} :R _{Auxiliary pair} ＝1:1-1:5。

4. The power circuit of claim 1, wherein the half-wave rectification module of the power circuit implements half-wave rectification by means of diodes.

5. The power circuit of claim 1, wherein the half-wave rectification module of the power circuit implements half-wave rectification via a fifth switch and a fifth controller that controls the fifth switch.

6. The power supply circuit according to claim 1, characterized in that the switching of the power supply circuit is realized by a bi-directional switch or a controllable switching device.

7. The power supply circuit according to any one of claims 1 to 6, wherein the range of transformer leakage inductance values in the power supply circuit is less than 1.5%.

8. The power supply circuit according to any one of claims 1 to 6, wherein the transformer structure in the power supply circuit is copper foil or U-shaped metal sheet, and the winding manner is parallel winding.

9. The power supply circuit according to any one of claims 1 to 6, further comprising an output rectifying unit providing rectification for an output of the power supply circuit.

10. The power supply circuit of claim 10, wherein the output rectifying unit is an H-bridge.

11. An extension circuitry of a power supply circuit according to any one of claims 1 to 10, wherein when the input power is a plurality of power supply units of indeterminate input power, the extension circuitry 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.

12. The expansion circuit system of claim 11, wherein the outputs of the plurality of power circuits are connected in series/parallel combinations according to the requirements of the expansion circuit outputs.

13. The expansion circuit system of claim 11, further comprising an output rectifying unit providing rectification for said expansion circuit, said output rectifying unit being coupled to the output terminals of said plurality of power circuits.

14. A method of simultaneously implementing maximum power point tracking and dynamic adjustment of output voltage rise/fall according to output demand according to a power supply circuit of any one of claims 1 to 13, the method comprising:

15. The method according to claim 14, wherein the step S2 comprises: