A low-cost model predictive control method for dual-pwm power converters

Abstract

The invention discloses a low-cost model prediction control method of a dual-PWM power converter. The low-cost model prediction control method comprises the following steps of estimating stator flux linkage and rotor flux linkage of an induction machine according to measured phase current and a rotational speed; forecasting absolute values of the stator flux linkages corresponding to four voltage vectors and a torque of an inversion side and active power and reactive power of a rectification side at a next sampling moment, and forecasting capacitance voltage according to switch states of four bridge arms; adopting a proportion integral (PI) regulator by a speed outer ring and a bus voltage outer ring, and outputting an active power given value and a motor flux linkage given value by the regulator; and building target functions of the system according to a forecast value, a measurement value and the given values, and applying rectification corresponding to the relatively small target function and switch combination of the inversion side to the power converter. The low-cost model prediction control method is applicable to a low-cost dual-PWM variable frequency speed regulation system; and with the adoption of an optimal target function determination method used by the invention, the forecast and iteration frequency of model forecast control can be greatly reduced, the calculation complexity is reduced, and the low-cost model prediction control method can be achieved in actual engineering.

Description

technical field [0001] The invention belongs to the technical field of medium and high power frequency conversion speed regulation, and more specifically relates to a low-cost dual PWM power converter model predictive control method. Background technique [0002] The rectification and controllable frequency conversion speed regulation system has been widely used in wind power generation, metallurgy and other medium and high power occasions due to its high efficiency and energy saving characteristics. Its power converter is mainly figure 1 The three-phase six-leg structure shown includes a rectification link (that is, an AC / DC converter) and an inverter link (that is, a DC / AC converter). The rectification link realizes the bidirectional flow of electric energy; the inverter link connects the DC side and the AC side. The motor converts electrical energy into mechanical energy output. The high-performance control of the system can be realized by controlling the opening and clo...

AI Technical Summary

Problems solved by technology

However, due to the limitation of control technology, the linear control method based on pulse width modulation strategy (PWM) is difficult to achieve good performance control.

Moreover, the low-cost power converter reduces the control degree of freedom of the system due to the reduction of switching tubes. At the same time, the nonlinear components in the system also pose challenges for the control strategy.

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