A control method and system for a photovoltaic inverter boost circuit

Abstract

The invention discloses an improved control method and system of a photovoltaic inverter Boost circuit. The control method of the photovoltaic inverter Boost circuit includes the following steps of obtaining a photovoltaic array voltage feedback signal vpvfb, a direct current bus voltage feedback signal vbusfb and an inductive current feedback signal iLfb; obtaining a voltage error signal the value of which is equal to a photovoltaic array voltage reference value vpvref minus the value of the voltage feedback signal vpvfb, making the voltage error signal passes through a voltage loop adjusterGvc to obtain an inductive current reference signal iLref, and substituting the inductive current reference signal iLref and the inductive current feedback signal iLfb into a current loop adjuster Gicto obtain a regulating signal vc1; substituting the voltage feedback signal vpvfb, the direct current bus voltage feedback signal vbusfb and a modulating signal vm of a last switching period into a feedforward adjuster Gff for processing to obtain a regulating signal vc2; adding the regulating signals vc1 and vc2 to obtain a new modulating signal vm, and sending the signal vm into a PWM generatorto generate a PWM driving signal of a Boost switching pipe.

Description

technical field [0001] The invention relates to the field of photovoltaic inverter Boost circuit control, in particular to a control method and system for a photovoltaic inverter Boost circuit. Background technique [0002] Distributed power generation systems represented by wind energy and solar energy, as one of the main ways of renewable energy utilization, can not only dominate the economic operation of the existing power grid, but also be clean and environmentally friendly, and their application proportion in the power system is increasing day by day. Boost converter is a step-up circuit converter with simple structure and wide application occasions. It is widely used in photovoltaic inverters of various power levels to adjust the output voltage of photovoltaic arrays and realize maximum power point tracking (MPPT). . Stable DC voltage control and good MPP tracking are crucial to the safe, stable, efficient and economical operation of the inverter. Therefore, how to r...

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Problems solved by technology

[0005] from figure 2 It can be seen that, although the voltage and current double closed-loop control method is adopted, due to the signal v pv Appearing in the inner and outer loops at the same time, resulting in a strong coupling relationship between the current inner loop and the voltage outer loop, which not only increases the difficulty of regulator design, but also tends to cause system resonance, which cannot effectively improve the system bandwidth.

[0006] also, figure 2 The modeling of the converter in the control block diagram does not take into account the actual operating state of the converter in DCM (Discontinuous Current Mode) mode, resulting in a mismatch between the model and the actual operating state, which in turn leads to a mismatch in control parameters, reduced control accuracy, and even causing system instability

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