Improved deadbeat control method for single-phase PWM rectifier

Abstract

The invention discloses an improved deadbeat control method for a single-phase PWM rectifier. The method comprises steps that an expression of a current loop in deadbeat current prediction control isobtained, a second-order generalized integrator follows a grid-side input voltage signal to obtain an orthogonal voltage signal in a two-phase stationary coordinate system, in this way, an AC side voltage at the time k+1 is predicted; a compensation parameter is introduced in the current loop, in a two-phase rotating coordinate system, a value of a virtual axis current iq is a reference, the compensation parameter is adjusted to be an optimal value, a power factor is increased to be close to 1, moreover, a prediction error is reduced, and the current THD is reduced; in a voltage loop, an active-disturbance-rejection controller is analyzed and introduced to improve dynamic performance of sudden change in a load.

Description

technical field [0001] The invention relates to the control field of power electronics technology, in particular to an improved dead-beat control method for a single-phase PWM (pulse width modulation) rectifier. Background technique [0002] In recent years, with the emergence of energy crises such as the reduction of fossil fuels and the intensification of environmental problems such as air pollution, distributed generation (DG) using new energy sources has been increasingly used. Among them, the micro-grid composed of small-capacity distributed power sources has attracted more attention due to its high energy utilization rate, convenient and flexible installation and other advantages. Among them, single-phase PWM rectifiers are widely used due to their high efficiency, small size, low cost and high reliability, such as in photovoltaic energy storage systems, uninterruptible power systems, wind power generation and electric vehicle charging. Compared with uncontrolled rect...

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Problems solved by technology

However, its control effect is sensitive to circuit parameters and is easily affected by control delay, which will increase the harmonic component in the input current and reduce the power factor of the AC side.

In the prior art, in the predictive current control, the influence of the control delay is compensated by predicting the current at time k+2, and the influence of the error between the actual value and the calculated value of the inductance parameter on the reactive power of the system is analyzed, but the inductance parameter still needs to be solved The error influence method; another method proposes an online input side inductance calculation method, which improves the system robustness and reduces the control error, but the influence of control delay is not considered in the algorithm; in addition, a The online input-side inductance and resistance calculation method calculates the corresponding active power and reactive power by predicting the current at time k+2 in predictive power control, but in this algorithm, the value function is used to judge the direct output of the switching vector instead of the pulse wide modulation; there is also an improved dead-beat current predictive control, through the correction of the inductance parameter, the control effect is more accurate and the current ripple is reduced, but in theory the correction of the inductance parameter cannot fully compensate the control delay, and there is no Larger inductance parameters in the beat control current loop will lead to an increase in harmonic components in the input current

At the same time, the traditional deadbeat control voltage outer loop generally uses a proportional-integral (PI) controller. Due to the secondary pulsation on the DC side of the single-phase rectifier, the bandwidth of the PI controller is low when designing, so its dynamic response speed under sudden load changes is relatively slow. slow

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