Huibo Lou

Double three-level inverter based variable frequency drive with minimal total harmonic distortion using particle swarm optimization

In this paper, a suitable particle swarm optimization (PSO) is firstly proposed to obtain the pulse width modulation (PWM) switching time which maintaining a required fundamental voltage and a minimal total harmonic distortion (THD) for very high power medium voltage induction motor drives fed by a double three-level inverter (DTI). The simulation results show that double three-level inverter based variable frequency drive system needs switches with lower voltage rating, and performs lower voltage harmonics than one single three-level inverter. After optimizing the PWM switching time by using particle swarm optimization, the motor drive voltage quality improves more.

Nonlinear control of electronic power transformer for distribution system using feedback linearization

In this paper, a mathematical model of electronic power transformer for distribution systems (DEPT) is established, and a nonlinear control scheme is proposed for high performance control of DEPT. The proposed control scheme is based on the state feedback exact linearization technique developed based on differential geometry theory. With this control scheme, the dynamic responses of the system become very fast. The system is tested for dc-link reference voltage, load and input voltages variations respectively. The validity of the proposed model and control strategy is demonstrated by simulation results.

Optimal pulse width modulation for current source converter based static exciter

This paper presents a new optimal pulse width modulation (OPWM) technique for the current source converter (CSC) which is used as part of the static exciter. The reduction of total harmonic distortion (THD) of ac side line current is considered as the control objective of the proposed OPWM. This is formulated as an optimization problem in this paper, and particle swarm optimization (PSO) algorithm is applied to solve the nonlinear transcendental equations. Furthermore, in order to make this CSC based exciter fulfill more roles than the traditional static exciter, a decoupled loop control technique is adopted to design a controller for this exciter. The simulation results demonstrate the effectiveness of the proposed OPWM technique and the control strategy.