Real-time random delay compensation with prediction-based digital redesign

Inverter synchronization control with Internal Model Principle

“…Since the digital controller is working in discrete-time domain, the afore-mentioned continuous-time s-domain controller needs to be converted into the corresponding zdomain function. Other than the direct digital design method in z-domain only, advantages of digital redesign approach are: (i) Continuous-time design theory and tools are well developed, and intuitively more familiar to most engineers; (ii) Digital redesign separates the problems of basic controller design from that of sampling and calculating period selection and adjustment [8][9][10][11].…”

“…In order to reduce the calculation rate, closed-loop global digital redesign techniques are better suited since it takes into account the closed-loop nature of the whole system [8][9][10][11]. Among them, the prediction-based digital redesign method in [8,9] is utilized in this paper, which can shift the discrete-time control signal to defined inter-sampling instant to minimize the A/D conversion error by means of "equivalent area" principle.…”

“…Among them, the prediction-based digital redesign method in [8,9] is utilized in this paper, which can shift the discrete-time control signal to defined inter-sampling instant to minimize the A/D conversion error by means of "equivalent area" principle.…”

“…Following the idea in [8,9], the desired PAM digital control signal to H-bridge can be predicted as following, in which the subscript d represents discrete-time,…”

“…Since proposed controller will have three poles on complex axis, Linear Quadratic Regulator (LQR) in [7] is introduced to enhance stability. Based on the continuous-time controller in s-domain, digital redesign in [8,9] is then conducted to obtain the corresponding discrete-time controller in zdomain. Other than the direct digital design method in zdomain only, advantages of digital redesign approach include: (i) Continuous-time design theory and tools are well developed, and intuitively more familiar to most engineers; (ii) Digital redesign separates the problems of basic controller design from that of sampling and calculating period selection and adjustment [10]; (iii) Compared with conventional redesign method like bilinear transform, proposed global digital redesign method can effectively enlarge the sampling period while maintaining the essential performance [11].…”