Inverter boost current-loop vector auxiliary control method

Abstract

The present invention provides an inverter boost current-loop vector auxiliary control method. The method comprises the step of providing a first acquisition unit to acquire the deviation current in real time. The method further comprises an acquisition step: providing a second acquisition unit to acquire bus ripples in real time; a decomposition step: providing a first orthogonal extractor to conduct the orthogonal decomposition of the deviation current so as to obtain a first real component and a first imaginary component; providing a second orthogonal extractor to conduct the orthogonal decomposition of the bus ripples so as to obtain a second real component and a second imaginary component; an operation step: providing a first vector-synthesis unit to generate a first control current; and a control step: providing an integral controller to respectively conduct the integration control for the first control current and a second control current so as to enable the first control current and second control current to be zero respectively. According to the technical scheme of the invention, bus ripples and acquiring error currents are acquired, and the closed loop control process is conducted simultaneously. In the case of frequency changes, the control method is more stable compared to a proportional resonance controller.

Description

technical field [0001] The invention relates to the technical field of photovoltaic inverter control, in particular to an inverter Boost current loop vector auxiliary control method. Background technique [0002] As the key equipment for photovoltaic power generation, distributed photovoltaic grid-connected inverters mostly adopt DC-DC boost and DC-AC inverter two-level grid-connected topology (boost side 1 and inverter side 2). figure 1 As shown, the inverter side 2 controls the grid-connected current and the DC bus voltage, and the boost side 1 controls the input current and voltage of the battery panel to complete the tracking of the maximum power point; [0003] Since the average bus voltage is constant for Boost, and the soft voltage characteristics of solar panels make it possible to control the battery input voltage simply by fixing the Boost duty cycle, but in single-phase grid-connected inverters There is a power pulsation with a larger amplitude twice the power on...

AI Technical Summary

Problems solved by technology

[0003] Since the average value of the bus voltage is constant for Boost, and the soft voltage characteristics of solar panels make it possible to control the battery input voltage simply by fixing the Boost duty cycle, but in single-phase grid-connected inverters There is a power pulsation with a larger amplitude twice the power on the middle bus. The control method with a fixed duty ratio is adopted. The higher the output power, the lower the bus capacitance, the smaller the Boost inductance, and the higher the oscillation amplitude of the Boost current. The higher the value, the higher the Boost inductance loss and the lower the system stability.

[0004] refer to figure 2 As shown, the existing control method is to realize the Boost current loop through PI control by extracting the control deviation current Ie, which can meet the requirements when the power is small and the bus ripple is small, but when the output power increases, the bus voltage ripple becomes After the increase, the Boost current ripple also increases. If the DC input is a photovoltaic panel, the input voltage will also fluctuate with the current pulsation, which will inevitably affect the maximum power point tracking of the panel.

Images