Online control method with time-delay compensation for hybrid active power filter with Injection Circuit

This paper proposes a novel online control method with time-delay compensation for HAPF with Injection Circuit. It includes two closed-control loops: the lower closed-control loop contains a conventional proportional-integral (PI) controller and HAPF with Injection Circuit model, whereas the upper closed-control loop is composed of predictive neural network, generalised predictive control and HAPF with Injection Circuit model. The purpose of the upper closed-control loop is to find a set of optimal PI parameters for the lower closed-control loop. A pi-Smith predictive compensator is established to generalised current time-delay compensate and makes a 180 degrees delay between the output current of HAPF with Injection Circuit and load harmonic current. The proposed control method is analysed for stability by 'Lyapunov' theorem. Compared with the conventional PI control method, the proposed control method shows the advantages of shorter response time, effectiveness in reducing harmonics and able to online control very well. It is implemented in HAPF with Injection Circuit with a 100 kVA active power filter installed in a copper mill in Northern China. The simulations and experiments as well as industrial applications have verified the effectiveness of this control method.