This study proposes a novel sliding mode control (SMC) structure for a three-level voltage source inverter (VSI). The proposed controller is implemented in discrete time and is applied for the closed-loop speed control of permanent magnet synchronous motor (PMSM) drive powered from a three-level cascaded H-bridge VSI. The proposed discrete time SMC (DTSMC) has the distinct advantages of control over maximum switching frequency and relatively lower total harmonic distortion compared to that of a conventional hysteresis modulation (HM) control. Unlike HM, the proposed DTSMC relates the maximum switching frequency to sampling time, resulting in better utilisation of the bandwidth of the VSI. Additionally, a procedure to combine the DTSMC with a sliding mode observer to achieve sensor-less operation of the PMSM drive is presented. Verification of the proposed DTSMC is conducted using simulation and experimental tests. The simulation and experimental results are presented.

In this paper, an adaptive proportional-integral (PI) control strategy for nonlinear systems with constrained actuators is discussed. In particular, a variable-structure anti-windup strategy that can be retrofitted onto different control structures is proposed and validated. Both the developed controller and anti-windup method are attuned to an automotive industrial control application: the control of air mass flow-rate and pressure in a fuel cell system using a high speed turbo-compressor and an electromechanical valve. Both the compressor and valve are rate-limited. The results from experimental tests agree with the simulations obtained and showing the effectiveness of the proposed approach by evidencing the fast control dynamics and the proper and desired closed-loop performance of the scheme without windup phenomena.

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