Master-slave charging control method and related renewable energy maximum power tracking power supply system

Abstract

The invention discloses a master-slave charging control method and a related renewable energy maximum power tracking power supply system. The control method is suitable for a renewable energy power supply system comprising a plurality of charging devices. A plurality of input ends and a plurality of output ends of the plurality of charging devices are connected in parallel, and the plurality of charging devices comprise a main charging device. The control method comprises the following steps: calculating the total power of a current system; calculating a plurality of MPPT parameters according to the current total power of the system, and transmitting the MPPT parameters to the plurality of charging devices; calculating a plurality of target powers according to the plurality of current powers; calculating a plurality of control commands respectively according to the plurality of MPPT parameters and the plurality of target powers; and controlling a plurality of output currents and a plurality of output voltages respectively according to the plurality of control commands.

Description

Technical Field

[0001] The present disclosure relates to a charging control method and a renewable energy maximum power tracking power supply system, in particular to a master-slave charging control method and a renewable energy maximum power supply system for multiple charging devices connected in parallel. Background Art

[0002] A renewable energy power supply system includes a renewable energy generating set and a charging device. The renewable energy generating set can be a solar panel or a wind turbine. Generally, the DC power generated by the generating set can be converted into a required DC power through a DC converter and then transmitted to a proximal load or a remote power grid, and a part of the power can be stored in a local battery.

[0003] Maximum Power Point Tracking (MPPT) is a technology commonly used in solar panels or wind turbines, and its purpose is to obtain the maximum power output in various situations. Traditionally, a charging device usually performs MPPT on only one generating set. Considering personnel safety and product reliability, protection devices such as an Impedance Detector (IMD), a Main Circuit Breaker (MCB), and a Surge Protection Device (SPD) are provided at the front end of the charging device. In this architecture, the more the number of charging devices used in the renewable energy power supply system, the more components are required, and the higher the cost. In addition, in order to adapt to different power generation wattages, it is necessary to develop various charging devices with different powers, which is not conducive to engineering development and maintenance.

[0004] In view of the rising environmental awareness, the power supply demand for renewable energy has also increased. How to provide a charging control method and a renewable energy power supply system that do not excessively increase costs and are conducive to development and maintenance is an important issue in this field. Summary of the Invention

[0005] To solve the above problems, the present disclosure proposes a control method applicable to a renewable energy power supply system including a plurality of charging devices, wherein a plurality of input terminals and a plurality of output terminals of the plurality of charging devices are connected in parallel with each other, and the plurality of charging devices include a main charging device, and the control method includes the following steps S31 to S35. S31: Collect a plurality of current powers through the plurality of charging devices to calculate the current total system power. S32: Collect the current total system power through the main charging device, perform maximum power point tracking (MPPT) to calculate a plurality of MPPT parameters, and transmit them to the plurality of charging devices. S33: Calculate a plurality of target powers by evenly dividing according to the plurality of current powers through the plurality of charging devices. S34: Calculate a plurality of control commands through the plurality of charging devices respectively according to the plurality of MPPT parameters and the plurality of target powers. S35: Control a plurality of output currents and a plurality of output voltages through the plurality of charging devices respectively according to the plurality of control commands.

[0006] The present disclosure also proposes a renewable energy power supply system, including a renewable energy generating set and a plurality of charging devices. The renewable energy generating set is configured to generate an input voltage and an input current. A plurality of input terminals and a plurality of output terminals of the plurality of charging devices are connected in parallel with each other, and each of the plurality of charging devices includes a control circuit, and the control circuit is electrically connected to the plurality of input terminals and the plurality of output terminals of the plurality of charging devices and is configured to execute the control method as described above.

[0007] The master-slave charging control method and its renewable energy power supply system of the present disclosure have the following advantages: (1) Connecting a plurality of charging devices in parallel with each other can adapt to different power generation wattages, and there is no need to develop charging devices with different power wattages separately, which can increase the flexibility of system planning; (2) Adopting centralized protection with a single protection device can save system costs; (3) The plurality of charging devices adopt a master-slave control method, and at the same time have the ability of MPPT, input and output power regulation; and (4) Allocating the output power ratio according to the rated power of the charging device can increase the flexibility of system planning.

[0008] It should be understood that the foregoing general description and the following specific description are merely exemplary and explanatory and are intended to provide further explanation of the present disclosure as claimed. Description of the Drawings

[0009] To make the above and other objects, features, advantages and embodiments of the present disclosure more obvious and understandable, the description of the drawings is as follows:

[0010] Figure 1 is a schematic diagram of a renewable energy power supply system according to an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of a charging device according to an embodiment of the present invention;

[0012] Figure 3 is a flowchart of a control method according to an embodiment of the present invention;

[0013] Figure 4 is an operation timing diagram of a control method according to an embodiment of the present invention; and

[0014] Figure 5 is a functional block diagram showing a main control circuit and a slave control circuit connected in parallel according to an embodiment of the present invention.

[0015] Explanation of Reference Numerals in the Drawings

[0016] 10: Renewable Energy Power Supply System

[0017] CG1~CGj, CGi: Charging Device

[0018] 13: Renewable Energy Generator Set

[0019] 15: Protection Device

[0020] 90: Load

[0021] 80: Battery

[0022] VIN: Total Input Voltage

[0023] IIN: Total Input Current

[0024] VIN1~VINj, VINi: Input Voltage

[0025] IIN1~IINj, IINi: Input Current

[0026] VOUT: Bus Voltage

[0027] IOUT: Bus Current

[0028] V1~Vj, Vi: Output Voltage

[0029] I1~Ij, Ii: Output Current

[0030] VM1~VMj, VMi: Relay Voltage

[0031] IM1~IMj, IMi: Relay Current

[0032] 231~23j, 23i: Control Circuit

[0033] 21: First Conversion Circuit

[0034] 22: Second Conversion Circuit

[0035] C1i, C11~C1j: First Control Signal C2i, C21~C2j: Second Control Signal 30: Control Method

[0036] S31, S32, S33, S34, S35: Step 231: Main control circuit

[0037] 232~23j: Slave control circuit

[0038] 50: MPPT unit

[0039] DIR: Direction parameter

[0040] SLP: Slope parameter

[0041] ΔXsys_step: Perturbation amplitude

[0042] M1: Multiplier

[0043] P1~Pj: Current power

[0044] 51: First operation unit

[0045] 52: Second operation unit

[0046] 53, 54, 55, 56, 57: PI controller

[0047] 58, 59: Register

[0048] ΔXconst_step: Fixed amplitude

[0049] ΔX1~ΔXj: Perturbation component

[0050] Vstable: Input voltage stabilization command

[0051] S1, S2, S3, S4, S5: Subtractor

[0052] Y1_prev~Yj_prev: Previous control command

[0053] Y1~Yj: Control command

[0054] Pj_rated: Rated power Detailed implementation manner

[0055] Please refer to Figure 1 , Figure 1 is a schematic diagram of the renewable energy power supply system 10 according to an embodiment of the present invention. The renewable energy power supply system 10 is electrically connected to the load 90 and is configured to supply electrical energy to the load 90. In one embodiment, the renewable energy power supply system 10 is electrically connected to the battery 80 and is configured to supply electrical energy to the battery 80. In one embodiment, the load 90 is a DC communication power supply device.

[0056] Structurally, the renewable energy power supply system 10 includes a renewable energy power generation unit 13, a protection device 15, and a plurality of charging devices CG1 to CGj, where j is a positive integer greater than 1. The renewable energy power generation unit 13 is configured to generate a total input voltage VIN and a total input current IIN. The protection device 15 is electrically connected between the renewable energy power generation unit 13 and the plurality of charging devices CG1 to CGj, and is configured to transfer the total input voltage VIN and the total input current IIN, and protect the plurality of charging devices CG1 to CGj from damage caused by overcurrent, overload, and short circuit. The input terminals and output terminals of the plurality of charging devices CG1 to CGj are connected in parallel with each other, and are configured to convert a plurality of input voltages VIN1 to VINj and a plurality of input currents IIN1 to IINj into output voltages V1 to Vj and output currents I1 to Ij respectively, where the sum of the output voltages V1 to Vj is the bus voltage VOUT and the sum of the output currents I1 to Ij is the bus current IOUT. The total input voltage VIN is approximately equal to each of the plurality of input voltages VIN1 to VINj of the plurality of charging devices CG1 to CGj, and the total input current IIN is equal to the sum of the plurality of input currents IIN1 to IINj of the plurality of charging devices CG1 to CGj.

[0057] In this embodiment, one of the plurality of charging devices CG1 to CGj is a main charging device, and the remaining charging devices are slave charging devices. For example, the charging device CG1 is the main charging device, and the charging devices CG2 to CGj are slave charging devices, but it is not limited thereto.

[0058] Please refer to Figure 2 , Figure 2 is a schematic diagram of the charging device CGi according to an embodiment of the present invention. The charging device CGi is used to represent Figure 1 one of the charging devices CG1 to CGj, where i is a positive integer and 1 ≤ i ≤ j.

[0059] Structurally, the charging device CGi includes a first conversion circuit 21, a relay capacitor, a second conversion circuit 22, and a control circuit 23i. The first conversion circuit 21 is electrically connected Figure 1 to the protection device 15, the second conversion circuit 22, and the control circuit 23i, and is configured to convert the input voltage VINi and the input current IINi into a relay voltage VMi and a relay current IMi according to a first control signal C1i. One end of the relay capacitor is electrically connected between the first conversion circuit 21 and the second conversion circuit 22, and the other end of the relay capacitor is electrically connected to the ground terminal. The relay capacitor is configured to store the electrical energy of the relay voltage VMi and the relay current IMi. The second conversion circuit 22 is electrically connected to the relay capacitor, the control circuit 23i, and Figure 1The load 90 and the battery 80 are configured to convert the relay voltage VMi and the relay current IMi into an output voltage Vi and an output current Ii according to the second control signal C2i. The control circuit 23i is electrically connected to the input end of the first conversion circuit 21, the output end of the second conversion circuit 22, and the input end of the load 90, and is configured to generate a first control signal C1i to the first conversion circuit 21 and generate a second control signal C2i to the second conversion circuit 22 according to the input voltage VINi, the input current IINi, the bus voltage VOUT, and the bus current IOUT. The charging device CGi of this embodiment adopts a two-stage converter, which can simultaneously achieve the regulation of the input end and the output end of the charging device CGi.

[0060] Please refer to Figure 3 , Figure 3 is a flowchart of the control method 30 according to an embodiment of the present invention. The control method 30 is applicable to Figure 1 the renewable energy power supply system 10. The control method 30 can be compiled into code and is configured to instruct a plurality of charging devices CG1~CGj to execute the steps S31 to S34 included in the control method 30.

[0061] Step S31: Collect a plurality of current powers through all the charging devices to calculate the current system total power.

[0062] Step S32: Through the main charging device, perform maximum power point tracking according to the current system total power to calculate a plurality of MPPT parameters and transmit them to all the charging devices.

[0063] Step S33: Through all the charging devices, calculate the target power according to the plurality of current powers respectively.

[0064] Step S34: Through all the charging devices, calculate the perturbation component and the control command according to the plurality of MPPT parameters and the target power respectively.

[0065] Step S35: Through all the charging devices, control the output current and the output voltage according to the control command respectively. Return to step S31.

[0066] In some embodiments, Figure 2 the control circuit 23i may include an application specific integrated circuit (ASIC), a micro control circuit (MCU), a server, or other arithmetic circuits or components with functions such as data access, data calculation, data storage, data transmission and reception, or similar functions, and can be used to execute the control method 30.

[0067] Please also refer to Figure 3 and Figure 4 , Figure 4It is the operation timing diagram of the control method 30 according to the embodiments of the present invention. In this embodiment, it is assumed that the charging device CG1 is the main charging device, and the remaining charging devices CG2 to CGj are slave charging devices.

[0068] In step S31, the main charging device CG1 collects the multiple current powers P1 to Pj of all the charging devices CG1 to CGj in the renewable energy power supply system 10 to calculate the total current power.

[0069] In step S32, the main charging device CG1 performs maximum power point tracking according to the current total system power to calculate multiple MPPT parameters and transmits them to all the charging devices.

[0070] In step S33, all the charging devices CG1 to CGj calculate the target powers P1_target to Pj_target respectively according to the multiple current powers P1 to Pj. In the first embodiment, it is assumed that the rated powers (or maximum operating powers) of the multiple charging devices CG1 to CGj are the same. Then, all the charging devices CG1 to CGj calculate the target power according to the following formula (1).

[0071] Formula (1)

[0072] In formula (1), Pi_target is the target power of the i-th charging device CGi, Pi = VINi × IINi is the current power of the i-th charging device CGi, VINi is the input voltage of the i-th charging device CGi, IINi is the input current of the i-th charging device CGi, j is the number of charging devices, and i and j are positive integers and 1 ≤ i ≤ j. According to formula (1), it can be seen that on the premise that the rated powers are the same, the target powers P1_target to Pj_target of the multiple charging devices CG1 to CGj are the average value of the current total system power.

[0073] For example, assume that there are only two charging devices. The current power of the main charging device CG1 is 200 W (watts), and the current power of the slave charging device CG2 is 100 W. And the rated powers of the charging devices CG1 and CG2 are both 200 W. In this case, the target powers of the charging devices CG1 and CG2 are (200 + 100) / 2 = 150 W to evenly distribute the output power of each charging device.

[0074] In the second embodiment, it is assumed that the rated powers (or maximum operating powers) of the multiple charging devices CG1 to CGj are not all the same. Then, all the charging devices CG1 to CGj calculate the target power according to the following formula (2).

[0075] Formula (2)

[0076] In equation (2), Pi_target is the target power of the i-th charging device CGi, Pi is the current power of the i-th charging device CGi, Pi_rated is the rated power of the i-th charging device CGi, and j is the number of charging devices. According to the above equation (2), the main charging device CG1 calculates the proportion of the rated power of each charging device in the total rated power, and multiplies the total current power by this proportion to calculate the target power of each charging device.

[0077] For example, assume there are only two charging devices. The current power of the main charging device CG1 is 50W, and the current power of the slave charging device CG2 is 100W. Then the total current power is 50 + 100 = 150W. Assume the rated power of the main charging device CG1 is 200W, and the rated power of the slave charging device CG2 is 100W. Then the proportion of the rated power of the main charging device CG1 is And the proportion of the rated power of charging device 110B is According to equation (2), the target power P1_target of the main charging device CG1 can be calculated as And the target power P2_target of the slave charging device CG2 is To distribute the output power of each charging device according to the proportion of the rated power.

[0078] In step S34, all charging devices CG1 to CGj calculate the perturbation component and the control command according to multiple MPPT parameters and the target power. In one embodiment, the multiple MPPT parameters include the perturbation direction parameter DIR, the slope parameter SLP, and the perturbation amplitude ΔXsys_step of the MPPT. The perturbation amplitude ΔXsys_step is the system step size of each MPPT adjustment period, and is set or allocated by the main charging device. In another embodiment, the perturbation amplitude ΔXsys_step is preset in the built-in memory of each charging device.

[0079] All charging devices CG1 to CGj calculate the perturbation component according to the following equation (3).

[0080] Equation (3)

[0081] In equation (3), ΔXi is the perturbation component of the i-th charging device CGi, and Pi_base is the base power of the i-th charging device CGi; if the rated power of each charging device is the same, then the base power Pi_base is the average value of the current total system power; if the rated power of each charging device is not the same, then the base power Pi_base is the rated power Pi_rated.

[0082] Next, step S34 further includes: all the charging devices CG1 to CGj calculate the control command Yi according to the disturbance component, a plurality of MPPT parameters, and the previous control command Yi_prev. Specifically, all the charging devices CG1 to CGj calculate the control command Yi according to the following formula (4).

[0083] Formula (4) Yi = (ΔXi + ΔXconst_step) × DIR × SLP + Yi_prev.

[0084] In formula (4), Yi is the control command of the i-th charging device CGi, ΔXi is the disturbance component of the i-th charging device CGi, ΔXconst_step is the fixed amplitude, DIR is the direction parameter, SLP is the slope parameter, and Yi_prev is the previous control command of the i-th charging device CGi in the previous MPPT cycle.

[0085] In one embodiment, when the renewable energy power supply system 10 uses the perturbation and observation method to find the maximum power point (MPP) output, the disturbance component ΔXi, the disturbance amplitude ΔXsys_step, the fixed amplitude ΔXconst_step, the control command Yi, and the previous control command Yi_prev are all voltage signals.

[0086] In one embodiment, when performing maximum power tracking, if the direction parameter DIR is 1, then the charging device CGi increases the control command Yi; if the MPPT adjustment direction parameter DIR is -1, then the charging device CGi decreases the control command Yi. If the main charging device CG1 determines that the power needs to be increased in the next MPPT cycle, then the slope parameter SLP is 1; if the main charging device CG1 determines that the power needs to be decreased in the next MPPT cycle, then the slope parameter SLP is -1. In addition, various MPPT control methods have been proposed currently, such as the perturbation and observation method, the incremental conductance method, the current scanning method, etc. In this embodiment, taking the perturbation and observation method as an example, the control circuit of the charging device will slightly increase or decrease the voltage in each MPPT adjustment cycle, and measure the current power of the charging device. If the current power increases, the control circuit continues to adjust the voltage in the same direction until the current power does not increase.

[0087] Finally, in step S35, all the charging devices CG1 to CGj respectively control the output currents I1 to Ij and the output voltages V1 to Vj according to the control commands Y1 to Yj. Specifically, step S35 further includes: all the charging devices CG1 to CGj respectively generate first control signals C11 to C1j according to the control commands Y1 to Yj, the input voltages VIN1 to VINj, and the input currents IIN1 to IINj to perform power regulation on the input end; and generate second control signals C21 to C2j according to the input voltage stabilization command Vstable, the relay voltages VM1 to VMj, the output currents I1 to Ij, and the output voltages V1 to Vj to perform power regulation on the output end.

[0088] In an embodiment, step S32 further includes: the main charging device CG1 transmits the synchronization timing to all the charging devices CG1 to CGj. Therefore, in step S35, all the charging devices CG1 to CGj respectively control the plurality of output currents I1 to Ij and the plurality of output voltages V1 to Vj under the synchronization timing to synchronously regulate the power.

[0089] In this way, the control method 30 can be applied to the renewable energy power supply system 10 in which a plurality of charging devices CG1 to CGj are connected in parallel. There is no need to develop different power wattage charging devices separately, which can increase the flexibility of system planning. Moreover, the plurality of charging devices CG1 to CGj simultaneously have the capabilities of MPPT, input end and output end power regulation.

[0090] Please refer to Figure 5 , Figure 5 which is a functional block diagram of the parallel connection of the main control circuit and the slave control circuit according to an embodiment of the present invention. In this embodiment, it is assumed that the control circuit 231 is the main control circuit in the main charging device CG1, and the control circuits 232 to 23j are the slave control circuits in the slave charging devices CG2 to CGj, but it is not limited thereto.

[0091] Structurally, the main control circuit 231 includes an MPPT unit 50, a power detector 501, a first arithmetic unit 51, a second arithmetic unit 52, PI (proportional–integral) control circuits 53 to 57, registers 58 to 59, a multiplier M1, and subtractors S1 to S5. The MPPT unit 50 is electrically connected to a plurality of charging devices CG1 to CGj, and is configured to collect a plurality of current powers P1 to Pj from all the charging devices CG1 to CGj, and generate a direction parameter DIR, a slope parameter SLP, and a perturbation amplitude ΔXsys_step based thereon. Then, the MPPT unit 50 transmits the direction parameter DIR, the slope parameter SLP, and the perturbation amplitude ΔXsys_step to all the first arithmetic units 51. In addition, the MPPT unit 50 transmits synchronous timing to all the first arithmetic units 51 to synchronize power regulation. In one embodiment, only the main control circuit 231 is provided with the MPPT unit 50. In another embodiment, all the control circuits 231 to 23j include MPPT units, but only the MPPT unit 50 of the main control circuit 231 is enabled, and the MPPT units 50 of the remaining slave control circuits 232 to 23j are disabled; in this case, when the main control circuit 231 fails, the MPPT unit 50 of one slave control circuit can be enabled as an alternative main control circuit.

[0092] All the control circuits 231 to 23j adopt the same circuit structure to implement power regulation. Taking the main control circuit 231 as an example, the power detector 501 is electrically connected to the input ends of a plurality of charging devices CG1 to CGj, and is configured to detect the current input voltage VIN1 and input current IIN1. The multiplier M1 is configured to multiply the input voltage VIN1 and the input current IIN1 to calculate the current power P1. The first arithmetic unit 51 is electrically connected to the multiplier M1, and is configured to collect a plurality of current powers P1 to Pj and a plurality of rated powers P1_rated to Pj_rated from all the first arithmetic units 51. In some embodiments, the MPPT unit 50 and the first arithmetic unit 51 transmit information such as a plurality of MPPT parameters, a plurality of current powers P1 to Pj, and a plurality of rated powers P1_rated to Pj_rated to other charging devices through digital signals or analog signals.

[0093] If the rated powers of all the charging devices CG1 to CGj are the same, then the first arithmetic unit 51 is configured to calculate the target power P1_target according to formula (1). If the rated powers of the charging devices CG1 to CGj are not the same, then the first arithmetic unit 51 is configured to calculate the target power P1_target according to formula (2). Then, the first arithmetic unit 51 is configured to calculate the disturbance component ΔX1 according to the current power P1, the target power P1_target, the direction parameter DIR, the slope parameter SLP, the disturbance amplitude ΔXsys_step, and formula (3).

[0094] The register 58 is configured to store the fixed amplitude ΔXconst_step. The second arithmetic unit 52 is electrically connected to the first arithmetic unit 51 and the register 58, and is configured to calculate the control command Y1 according to the disturbance component ΔX1, the fixed amplitude ΔXconst_step, the previous control command Y1_prev, the direction parameter DIR, the slope parameter SLP, and formula (4), and then feedback the control command Y1 to itself and store it as the previous control command Y1_prev. The subtractor S1 is electrically connected to the input end of the charging device CG1, and is configured to subtract the control command Y1 from the input voltage VIN1 to generate a first voltage compensation. The PI controller 53 is electrically connected to the subtractor S2, and is configured to convert the first voltage compensation into a first current value. The subtractor S2 is electrically connected to the input end of the charging device CG1, and is configured to subtract the first current value from the input current IIN1 to generate a first current compensation. The PI controller 54 is electrically connected to the subtractor S2, and is configured to convert the first current compensation into a first control signal C11 and input it to the first conversion circuit 21.

[0095] The register 59 is configured to store the input regulated voltage command Vstable. The subtractor S3 is electrically connected to the register 59, the output end of the first conversion circuit 21, and the relay capacitor, and is configured to subtract the relay voltage VM1 from the input regulated voltage command Vstable to generate a regulated voltage compensation. The PI controller 55 is electrically connected to the subtractor S3, and is configured to convert the regulated voltage compensation into a second current value. The subtractor S4 is electrically connected to the PI controller 55, and is configured to subtract the second current value from the output current I1 to generate a second current compensation. The PI controller 56 is electrically connected to the subtractor S4, and is configured to convert the second current compensation into a first voltage value. The subtractor S5 is electrically connected to the PI controller 56, and is configured to subtract the output voltage V1 from the first voltage value to generate a second voltage compensation. The PI controller 57 is electrically connected to the subtractor S5, and is configured to convert the second voltage compensation into a second control signal C21.

[0096] Therefore, through Figure 5 the circuit architecture in parallel with the control circuit, the control method 30 can be executed Figure 3 of

[0097] In summary, the master-slave charging control method and its renewable energy power supply system according to the embodiments of the present disclosure have the following advantages: (1) Multiple charging devices are connected in parallel with each other, which can adapt to different power generation wattages without the need to develop different power-wattage charging devices separately, increasing the flexibility of system planning; (2) The centralized protection using a single protection device can save system costs; (3) Multiple charging devices adopt the master-slave control method and have the capabilities of MPPT, input and output power regulation at the same time; and (4) Allocating the output power ratio according to the rated power of the charging device can increase the flexibility of system planning.

[0098] Although specific embodiments of the present disclosure have been disclosed regarding the above embodiments, various alternatives and improvements can be implemented by those of ordinary skill in the relevant art without departing from the principles and spirit of the present disclosure. Therefore, the scope of protection of the present disclosure is determined by the scope of the appended claims.

Claims

1. A control method, applicable to a renewable energy power supply system comprising a plurality of charging devices, wherein a plurality of input terminals and a plurality of output terminals of the plurality of charging devices are connected in parallel with each other, the plurality of charging devices include a main charging device, wherein the control method comprises: Step S31: collecting a plurality of current powers through the plurality of charging devices to calculate the current total system power; Step S32: performing maximum power point tracking (MPPT) according to the current system total power through the main charging device to calculate a plurality of MPPT parameters and transmit the parameters to the plurality of charging devices; Step S33: calculating a plurality of target powers according to the plurality of current powers respectively through the plurality of charging devices; Step S34: calculating a plurality of control commands by the plurality of charging devices according to the plurality of MPPT parameters and the plurality of target powers respectively; as well as Step S35 : controlling a plurality of output currents and a plurality of output voltages through the plurality of charging devices according to a plurality of control commands respectively.

2. The control method according to claim 1, wherein if the rated powers of the plurality of charging devices are the same, then step S33 comprises: The multiple target powers are calculated by the multiple charging devices according to the following formula (1): (1) Wherein, Pi_target is the target power of the i-th charging device, Pi=VINi╳IINi is the current power of the i-th charging device, VINi is the input voltage of the i-th charging device CGi, IINi is the input current of the i-th charging device CGi, j is the number of the multiple charging devices, i and j are positive integers and 1≦i≦j.

3. The control method according to claim 1, wherein if the rated powers of the plurality of charging devices are different, then step S33 comprises: The multiple target powers are calculated by the multiple charging devices according to the following formula (2): (2) Wherein Pi_target is the target power of the i-th charging device, Pi is the current power of the i-th charging device, Pi_rated is the rated power of the i-th charging device, j is the number of the multiple charging devices, i and j are positive integers and 1≦i≦j.

4. The control method according to claim 2 or 3, wherein the step S34 comprises: The plurality of disturbance components are calculated by the plurality of charging devices according to the following formula (3): (3) Where ΔXi is the disturbance component of the i-th charging device, Pi_base is the base power of the i-th charging device, and ΔXsys_step is the disturbance amplitude; If the multiple rated powers of the multiple charging devices are the same, then the basic power is the average value of the current system total power; if the multiple rated powers of the multiple charging devices are different, then the basic power is the rated power. 5 . The control method according to claim 4 , wherein the plurality of MPPT parameters include a disturbance direction, a slope parameter and the disturbance amplitude, and the disturbance amplitude is a system step size of each MPPT adjustment cycle.

6. The control method according to claim 5, wherein the step S34 comprises: By means of the plurality of charging devices, a plurality of control commands are calculated according to the plurality of disturbance components, the plurality of MPPT parameters and a plurality of previous control commands respectively: (4)Yi=(ΔXi+ΔXconst_step)×DIR×SLP+Yi_prev Wherein Yi is the control command of the i-th charging device, ΔXi is the disturbance component of the i-th charging device, ΔXconst_step is the fixed amplitude, DIR is the disturbance direction MPPT parameter, SLP is the slope MPPT parameter, and Yi_prev is the previous control command of the i-th charging device in the previous MPPT cycle.

7. The control method according to claim 1, wherein the step S35 further comprises: Generate a plurality of first control signals through the plurality of charging devices according to the plurality of commands, the plurality of input voltages and the plurality of input currents respectively, so as to adjust the power of the input end; and The plurality of charging devices are used to generate a plurality of second control signals according to the input voltage regulation command, a plurality of relay voltages, a plurality of output currents and a plurality of output voltages, so as to adjust the power of the plurality of output terminals.

8. The control method according to claim 1, wherein the step S32 further comprises: Transmitting synchronization timing to the plurality of charging devices through the main charging device; and The plurality of charging devices respectively control the plurality of output currents and the plurality of output voltages under the synchronous timing so as to synchronously adjust the power of the plurality of output ends.

9. A renewable energy power supply system, comprising: A renewable energy generator set configured to produce a total input voltage and a total input current; and A plurality of charging devices, wherein a plurality of input terminals and a plurality of output terminals of the plurality of charging devices are connected in parallel with each other, and each of the plurality of charging devices comprises: The control circuit is electrically connected to the multiple input terminals and the multiple output terminals of the multiple charging devices, and is configured to execute the control method according to claim 1.

10. The renewable energy power supply system according to claim 9, wherein the control circuit comprises: a power detector electrically connected to the plurality of input terminals of the plurality of charging devices and configured to detect an input voltage and an input current; a multiplier configured to multiply the input voltage and the input current to calculate a current power; a first operation unit electrically connected to the multiplier and the plurality of first operation units of the plurality of charging devices, configured to collect a plurality of current powers and a plurality of rated powers, and calculate a target power according to the plurality of current powers and the plurality of rated powers; The total input voltage is approximately equal to each of the multiple input voltages of the multiple charging devices, and the total input current is equal to the sum of the multiple input currents of the multiple charging devices.

11. The renewable energy power supply system according to claim 10, wherein if the rated powers of the plurality of charging devices are the same, the first computing unit is configured to calculate the target power according to the following formula (1): (1) Wherein, Pi_target is the target power of the i-th charging device, Pi=VINi╳IINi is the current power of the i-th charging device, VINi is the input voltage of the i-th charging device CGi, IINi is the input current of the i-th charging device CGi, j is the number of the multiple charging devices, i and j are positive integers and 1≦i≦j.

12. The renewable energy power supply system according to claim 10, wherein if the rated powers of the plurality of charging devices are different, the first computing unit is configured to calculate the target power according to the following formula (2): (2) Wherein Pi_target is the target power of the i-th charging device, Pi is the current power of the i-th charging device, Pi_rated is a rated power of the i-th charging device, j is the number of the multiple charging devices, i and j are positive integers and 1≦i≦j.

13. The renewable energy power supply system according to claim 11 or 12, wherein the first computing unit is configured to calculate the disturbance component according to the current power, the target power, the disturbance amplitude and formula (3): (3) Wherein ΔXi is the disturbance component of the i-th charging device, Pi_base is the base power of the i-th charging device, and ΔXsys_step is the disturbance amplitude; If the multiple rated powers of the multiple charging devices are the same, then the basic power is the average value of the current system total power; if the multiple rated powers of the multiple charging devices are different, then the basic power is the multiple rated powers.

14. The renewable energy power supply system according to claim 13, wherein the control circuit comprises: A first register configured to store a fixed amplitude; and The second operation unit is electrically connected to the first operation unit and the first register, and is configured to calculate a control command according to the disturbance component, the fixed amplitude, the direction parameter, the slope parameter, the previous control command and the following formula (4): (4)Yi=(ΔXi+ΔXconst_step)×DIR×SLP+Yi_prev Wherein Yi is the control command of the i-th charging device, ΔXi is the disturbance component of the i-th charging device, ΔXconst_step is the fixed amplitude, DIR is the direction parameter, SLP is the slope parameter, and Yi_prev is the previous control command of the i-th charging device in the previous MPPT cycle.

15. The renewable energy power supply system according to claim 14, wherein the plurality of charging devices include a main charging device, and the control circuit is a main control circuit, comprising: An MPPT unit electrically connected to the plurality of charging devices and configured to generate a plurality of MPPT parameters according to the plurality of current powers; The multiple MPPT parameters include the direction parameter, the slope parameter and the disturbance amplitude, and the disturbance amplitude is the system step size of each MPPT adjustment cycle. 16 . The renewable energy power supply system according to claim 15 , wherein each of the multiple control circuits of the multiple charging devices comprises the MPPT unit, and only the MPPT unit of the main control circuit is enabled, and the remaining MPPT units are disabled.

17. The renewable energy power supply system according to claim 14, wherein the control circuit comprises: A first subtractor, electrically connected to the input terminals of the plurality of charging devices, configured to subtract the control command from the input voltage to generate a first voltage compensation; a first PI controller, electrically connected to the subtractor, configured to convert the first voltage compensation into a first current value; A second subtractor, electrically connected to the input terminals of the plurality of charging devices, configured to subtract the input current from the first current value to generate a first current compensation; The second PI controller is electrically connected to the second subtractor S2 and is configured to convert the first current compensation into a first control signal.

18. The renewable energy power supply system according to claim 17, wherein the control circuit comprises: a second register configured to store an input voltage regulation command; a third subtractor, electrically connected to the second register, and configured to subtract a relay voltage from the input voltage regulation command to generate a voltage regulation compensation; A third PI controller, electrically connected to the third subtractor, configured to convert the voltage stabilization compensation into a second current value; a fourth subtractor, electrically connected to the third PI controller, configured to subtract the output current from the second current value to generate a second current compensation; a fourth PI controller, electrically connected to the fourth subtractor, and configured to convert the second current compensation into a first voltage value; a fifth subtractor, electrically connected to the fourth PI controller, configured to subtract the output voltage from the first voltage value to generate a second voltage compensation; as well as The fifth PI controller is electrically connected to the fifth subtractor and is configured to convert the second voltage compensation into a second control signal.

19. The renewable energy power supply system according to claim 18, wherein each of the plurality of charging devices further comprises: A first conversion circuit, electrically connected to the renewable energy generator set, configured to convert the input voltage and the input current into the relay voltage and the relay current according to the first control signal; a second conversion circuit, electrically connected to the first conversion circuit, and configured to convert the relay voltage and the relay current into an output voltage and an output current according to the second control signal; as well as A relay capacitor, one end of which is electrically connected between the first conversion circuit and the second conversion circuit, the other end of which is electrically connected to the ground, and the relay capacitor is configured to store the electrical energy of the relay voltage and the relay current.

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