Design and Implementation of LCL Filter-Based Electric Machine Emulator With Disturbance Compensation

Abstract

The electric machine emulator (EME), using digital simulation and power electronics to emulate the characteristics of actual machines, can greatly accelerate the testing of electric drives. However, most existing EMEs are based on typical L filter and linear controller, which causes control conflicts and bandwidth limitation. To address this issue, this paper presents an EME based on LCL filter with passive damping for a three-phase permanent magnet synchronous motor. To improve the dynamic emulating accuracy, a dual closed-loop deadbeat predictive current control algorithm is proposed, which is computationally efficient and easy to implement. The system stability is analyzed in the discrete domain, and the parameter constraints of the filter are obtained. Then, two unknown input observers are designed to compensate for the disturbance currents and voltages caused by modeling errors. Moreover, instead of the empirical method, a theoretical one considering the harmonic suppression, bandwidth, stability and resonance is presented for filter design. Finally, the performance of the proposed EME is validated through simulation and experimental results under various conditions such as machine start-up, torque step change, and speed reversal.INDEX TERMS Electric machine emulator (EME), LCL filter, dual closed-loop deadbeat predictive current control, unknown input observer. NOMENCLATURE

Design of the electric machine emulator system with interface parameters based on multi-disciplinary cooperative optimization

“…In combination with previous studies 3,5,7,10 , the interface parameters obtained by the conventional design method based on engineering experience are used as preoptimization parameters. Furthermore, a joint Isight-MATLAB simulation is used to construct the MDCO architecture.…”

“…The interface is a key component of the EME system, which determines the stability and simulation accuracy 6 . Compared with the commonly used L-type interface, the LCL-type (consists of inductor-capacitor-inductor) interface has higher bandwidth and better filtering performance, which is a superior interface topology with prominent research value in EME systems 7 . But its complex structure and numerous parameters limit its application in EME systems to some extent 8 .…”

“…The parameter design of the LCL-type interface is one of the key factors of the EME system, especially when a modelbased interface current controller is used 7,9 . Most relevant studies have focused on this.…”