CN-115933805-B - Self-correcting photovoltaic optimizer and photovoltaic system

CN115933805BCN 115933805 BCN115933805 BCN 115933805BCN-115933805-B

Abstract

The invention provides a self-correcting photovoltaic optimizer, which comprises a converter module, an adjusting module, a driving module and a sampling module, wherein a first end of the converter module is connected with an input voltage end, a second end of the converter module is connected with an input end of the sampling module, an output end of the sampling module is connected with the first end of the adjusting module, a second end of the adjusting module is connected with the input voltage end, a third end of the adjusting module is connected with the input end of the driving module, a first output end of the driving module is connected with a fourth end of the adjusting module, a second output end of the driving module is connected with a third end of the converter module, and a second end of the converter module is also connected with an output voltage end.

Inventors

MENG LINGKONG
JIANG ZHONGYA
SHAO BIN
LIU TAO

Assignees

上海数明半导体有限公司

Dates

Publication Date: 20260512
Application Date: 20221222

Claims (10)

1. The self-correcting photovoltaic optimizer is characterized by comprising a converter module, an adjusting module, a driving module and a sampling module; The first end of the converter module is connected with an input voltage end, the second end of the converter module is connected with the input end of the sampling module, the output end of the sampling module is connected with the first end of the adjusting module, the second end of the adjusting module is connected with the input voltage end, the third end of the adjusting module is connected with the input end of the driving module, the first output end of the driving module is connected with the fourth end of the adjusting module, the second output end of the driving module is connected with the third end of the converter module, and the second end of the converter module is also connected with an output voltage end for outputting working voltage; The sampling module is configured to sample the output voltage and the output current in real time and output the current output power; The adjusting module is configured to determine a maximum output power according to the current output power and output a first reference voltage, wherein the first reference voltage is characterized as a corresponding input voltage under the maximum output power; the driving module is configured to output a driving signal to the converter module based on the first reference voltage; The converter module is used for being controlled by the driving signal and outputting the working voltage based on the driving signal, and the adjusting module comprises an integrating circuit, a proportional circuit, a first adder, an MPPT control module and a second adder; The output end of the integrating circuit is connected with the input end of the proportional circuit, the output end of the proportional circuit is connected with the first end of the first adder, the second end of the first adder is connected with the input end of the MPPT control module, the third end of the first adder is connected with the output end of the sampling module, the output end of the MPPT control module is connected with the first end of the second adder, the second end of the second adder is connected with the input end of the driving module, and the third end of the second adder is connected with the input voltage end; the integrating circuit is configured to set an integration coefficient ≡dr for a first driving signal output by the driving module and output the integration coefficient ≡dr to the proportional circuit; the scaling circuit is configured to: performing proportional operation on the integral coefficient [ jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj and-jjjjjjjjjj) by adjusting the proportional coefficient K, so as to output a first proportional amplitude value K, jjjjjjjjjjjjjjjjjjjjjjjjjjjjto the first adder; the first adder is configured to difference the first proportional amplitude K, jjjjjjjjjjjjjjjjjjjjjjjjjjjj from the current output power to output a first difference to the MPPT control module; the MPPT control module is configured to output the first reference voltage to the second adder according to the first difference value; The second adder is configured to difference the first reference voltage from an input voltage to output a second difference to the driving module.
2. The self-correcting photovoltaic optimizer according to claim 1 wherein the regulating module further comprises a first comparator, wherein the non-inverting input of the first comparator is connected to the output of the integrating circuit, the inverting input of the first comparator is connected to a reference voltage terminal for inputting a second reference voltage, and the output of the first comparator is connected to the input of the scaling circuit; The first comparator is configured to compare the integral coefficient ≡dr with the second reference voltage to output a first signal or a second signal.
3. The self-correcting photovoltaic optimizer of claim 2, wherein the first comparator is further configured to: When the integral coefficient ≡dr is above the second reference voltage, the first comparator outputs a first signal; the first comparator outputs a second signal when the integral coefficient ≡dr is smaller than the second reference voltage.
4. A self-correcting photovoltaic optimizer according to claim 3 wherein the scaling circuit is further configured to: When the input signal is the first signal, the proportional circuit outputs a second proportional amplitude; When the input signal is the second signal, the proportional circuit outputs a third proportional amplitude.
5. The self-correcting photovoltaic optimizer according to claim 4, wherein the sampling module comprises a current sampling unit, a voltage sampling unit and a multiplier; the input ends of the current sampling unit and the voltage sampling unit are connected to the converter module, the output ends of the current sampling unit and the voltage sampling unit are connected to the first end and the second end of the multiplier, and the third end of the multiplier is connected to the first adder; The multiplier is configured to multiply the output voltage and the output current to output the present output power.
6. The self-correcting photovoltaic optimizer of claim 5, wherein the drive module comprises a PID control unit, a second comparator and a driver; The input end of the PID control unit is connected with the first end of the second adder, the output end of the PID control unit is connected with the non-inverting input end of the second comparator, the inverting input end of the second comparator is connected with an input waveform end and is used for inputting an input waveform, the output end of the second comparator is connected with the input end of the driver, the first output end of the driver is connected with the input end of the integrating circuit, and the second output end of the driver is connected with the third end of the converter module; The PID control unit is configured to control the second difference value to be infinitesimal and output a PID output value to the non-inverting input terminal of the second comparator; the second comparator is configured to intercept the PID output value with the input waveform to output a second drive signal and a third drive signal; The driver is configured to amplify the second drive signal and the third drive signal to drive the inverter module.
7. The self-correcting photovoltaic optimizer of claim 6, wherein the converter module comprises a first switching tube, a second switching tube, an inductance, a first capacitance, and a second capacitance; The control end of the first switching tube is connected with the first output end of the driver, the first end of the first switching tube is connected with the input voltage end, the second output end of the first switching tube is connected with the first end of the second switching tube and the first end of the inductor, the second end of the second switching tube is connected with the first end of the first capacitor, the second end of the inductor is connected with the second end of the first capacitor, and the second capacitor is connected with the first capacitor and the output voltage end in parallel; the first switching tube and the second switching tube are configured to be controlled by the second driving signal and the third driving signal, and output the working voltage based on the ratio of the second driving signal and the third driving signal.
8. The self-correcting photovoltaic optimizer of claim 7, wherein the converter module comprises a BUCK converter or a BUCK-BOOST converter.
9. The self-correcting photovoltaic optimizer of claim 7, wherein the first and second switching tubes comprise NMOS or PMOS tubes.
10. A photovoltaic system comprising a plurality of photovoltaic modules, an inverter, a power grid, and a plurality of self-correcting photovoltaic optimizers of any of claims 1-9; The photovoltaic modules are connected in series, the output ends of the photovoltaic modules are connected with the input ends of the self-correcting photovoltaic optimizers, the output ends of the self-correcting photovoltaic optimizers are connected with the input ends of the inverters, and the output ends of the inverters are connected with the power grid.

Description

Self-correcting photovoltaic optimizer and photovoltaic system Technical Field The invention relates to the field of photovoltaic power generation, in particular to a self-correcting photovoltaic optimizer and a photovoltaic system. Background The photovoltaic optimizer can realize module-level MPPT, realize decoupling of input and output, and solve the problem of generating capacity loss caused by series-parallel mismatch of a photovoltaic system. At present, after a photovoltaic optimizer is additionally arranged on a photovoltaic system, when the output voltage of the photovoltaic optimizer is lower than the output voltage of a maximum power point, the power is always maintained at the maximum power point, so that the inverter cannot judge the maximum power point of the photovoltaic module, and further the photovoltaic system cannot be in a maximum power state, so that the actual working voltage of the inverter is lower, and the working efficiency is reduced. Disclosure of Invention The invention provides a self-correcting photovoltaic optimizer and a photovoltaic system, which are used for solving the problem that the maximum power point cannot be judged. According to a first aspect of the invention, there is provided a self-correcting photovoltaic optimizer comprising a converter module, an adjustment module, a drive module and a sampling module; The first end of the converter module is connected with an input voltage end, the second end of the converter module is connected with the input end of the sampling module, the output end of the sampling module is connected with the first end of the adjusting module, the second end of the adjusting module is connected with the input voltage end, the third end of the adjusting module is connected with the input end of the driving module, the first output end of the driving module is connected with the fourth end of the adjusting module, the second output end of the driving module is connected with the third end of the converter module, and the second end of the converter module is also connected with an output voltage end for outputting working voltage; The sampling module is configured to sample the output voltage and the output current in real time and output the current output power; The adjusting module is configured to determine a maximum output power according to the current output power and output a first reference voltage, wherein the first reference voltage is characterized as a corresponding input voltage under the maximum output power; the driving module is configured to output a driving signal to the converter module based on the first reference voltage; the converter module is used for being controlled by the driving signal and outputting the working voltage based on the driving signal. Optionally, the adjusting module includes an integrating circuit, a proportional circuit, a first adder, an MPPT control module, and a second adder; The output end of the integrating circuit is connected with the input end of the proportional circuit, the output end of the proportional circuit is connected with the first end of the first adder, the second end of the first adder is connected with the input end of the MPPT control module, the third end of the first adder is connected with the output end of the sampling module, the output end of the MPPT control module is connected with the first end of the second adder, the second end of the second adder is connected with the input end of the driving module, and the third end of the second adder is connected with the input voltage end; the integrating circuit is configured to set an integration coefficient ≡dr for a first driving signal output by the driving module and output the integration coefficient ≡dr to the proportional circuit; the scaling circuit is configured to: performing proportional operation on the integral coefficient [ jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj and-jjjjjjjjjj) by adjusting the proportional coefficient K, so as to output a first proportional amplitude value K, jjjjjjjjjjjjjjjjjjjjjjjjjjjjto the first adder; the first adder is configured to difference the first proportional amplitude K, jjjjjjjjjjjjjjjjjjjjjjjjjjjj from the current output power to output a first difference to the MPPT control module; the MPPT control module is configured to output the first reference voltage to the second adder according to the first difference value; The second adder is configured to difference the first reference voltage from an input voltage to output a second difference to the driving module. Optionally, the regulating module further comprises a first comparator, wherein the non-inverting input end of the first comparator is connected with the output end of the integrating circuit, the inverting input end of the first comparator is connected with a reference voltage end and is used for inputting a second reference voltage, and the output end of the first comparator is connected with