Fixed-frequency current prediction control method for secondary ripple suppression circuit of single-phase PWM rectifier
A secondary ripple and suppressing circuit technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve the problem of short life of electrolytic capacitors, increase the difficulty of system design, and increase system instability sexual issues
Active Publication Date: 2021-04-20
SOUTH CHINA UNIV OF TECH
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Problems solved by technology
Passive filtering is to connect a large-capacity electrolytic capacitor or a parallel LC resonant circuit on the output side, but the parallel connection of a large-capacity electrolytic capacitor will increase the volume of the system, and the life of the electrolytic capacitor is short, and the LC resonant circuit will increase the instability of the system.
Most active filtering schemes use SPWM or SVPWM control methods, but these control methods require at least four PI regulators or PR regulators, the control process is complicated, which increases the difficulty of system design and reduces the robustness and stability of the system , and the switching frequency is not constant
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[0074] figure 1 It is the secondary ripple suppression circuit diagram of the single-phase PWM rectifier. The secondary ripple suppression circuit of the single-phase PWM rectifier includes 6 MOS transistors, two filter inductors, a filter capacitor, an energy storage capacitor and resistors, among which, each 2 After the MOS tubes are connected in series, they respectively form the first bridge arm, the second bridge arm and the third bridge arm connected in parallel. The first bridge arm, the second bridge arm and the third bridge arm form a bridge structure, and a filter in the input end of the circuit One end of the inductor is connected to the midpoint of the first bridge arm, the other end of the filter inductor is connected to one end of the input voltage, and the other end of the input voltage is connected to the midpoint of the second bridge arm; the input end of the circuit also includes an energy storage capacitor and An energy storage branch composed of another fil...
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The invention discloses a fixed-frequency current prediction control method for a secondary ripple suppression circuit of a single-phase PWM rectifier. The method comprises the following steps: calculating an energy storage capacitor power given value and an energy storage capacitor current given value at a next sampling moment according to an input voltage angle obtained by a phase-locked loop; selecting three switching states in one sampling period, including an effective switching state and two zero switching states, to realize fixed-frequency control, calculating an input current predicted value, an energy storage capacitor current predicted value and an energy storage capacitor power predicted value corresponding to each switching state at the next sampling moment according to a discretization mathematical model of a circuit, deriving the time by the objective function, and enabling the derivative of the time to be 0 to obtain the optimal action time of different effective switching states and the action time of a zero switching state; and substituting the calculated given value and the predicted value into a target function, selecting an effective switching state enabling the value of the target function to be minimum as the switching state of the next moment, and calculating the upper tube conduction time of each bridge arm.
Description
technical field [0001] The invention relates to the technical field of single-phase PWM rectifier control, in particular to a constant-frequency current prediction control method for a secondary ripple suppression circuit of a single-phase PWM rectifier. Background technique [0002] With the increasingly serious energy crisis and environmental problems, the research of new energy technology has received more and more attention. In small and medium power applications, single-phase PWM rectifiers are widely used. However, the output DC voltage of the single-phase rectifier will contain the secondary ripple voltage, which will not only bring the third harmonic to the input current, but also adversely affect the load, especially when charging the battery. Ripple voltage will introduce additional low-frequency ripple current, which affects battery performance and reduces battery life. [0003] The method of suppressing the secondary ripple of single-phase PWM rectifier can be ...
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IPC IPC(8): H02M7/219H02M1/15
Inventor 康龙云周海兰张健彬于玮
Owner SOUTH CHINA UNIV OF TECH