2results about How to "Reduce common mode voltage" patented technology

This application relates to a common-mode voltage suppression method based on cascaded observers, specifically for high-precision motor drives. The aim is to address the shortcomings of existing CMV suppression methods, which rely heavily on experience and suffer from low robustness. This method utilizes cascaded observers to observe and compensate for the total disturbance in the motor control system, calculating a reference voltage vector. A discrete virtual vector set is constructed, and the vector plane formed by this set is divided into multiple continuous and non-overlapping sub-regions, ensuring that each sub-region uniquely corresponds to a virtual vector in the discrete virtual vector set. The sub-region to which the reference voltage vector belongs in the vector plane is determined, and the virtual vector corresponding to that sub-region is used as the target vector. A PWM signal is generated based on the target vector to control the motor, achieving common-mode voltage suppression. This application demonstrates significant suppression effects on the first, second, and sixth harmonics, reducing the common-mode voltage to one-third of that achieved by traditional methods, while effectively reducing computation time.

This invention discloses a method for interphase battery charge balancing in a three-phase cascaded H-bridge based on model predictive control. A simulation circuit model of a 7-level cascaded H-bridge grid-connected inverter based on model predictive control was built in Matlab / Simulink simulation software, and the simulation results were recorded. The DC-side voltage vo of each H-bridge unit of the inverter is specified. dc The value is 150V, and the mains voltage is v. g The values ​​are set to 220V, the fundamental frequency to 50Hz, the sampling time T for model predictive control to 0.1ms, the grid-connected filter inductor L to 1mH, and the equivalent resistance R of the grid-connected filter inductor to 0.1Ω. The SOC is set... a =70.1%, SOC b =70%, SOC c =69.9%, ε=0.01, the grid-connected filter inductor L is 1mH, the equivalent resistance R of the grid-connected filter inductor is 0.1Ω, the grid-connected current is controlled by model predictive control, and a reward function is introduced to select redundant voltage vectors to balance the phase SoC without affecting the current performance. After the error of the SoC is less than a certain given value, the SoC balancing is stopped to achieve the minimum common mode voltage.