Improving Control Dynamics of PMSM Drive by Estimating Zero-Delay Current Value

Abstract

Dynamic performance of current control loop still remains crucial for position-, speed-, and torque-controlled drives. In the study, a current loop solution has been designed for field oriented control of permanent magnet synchronous motors (PMSM). It enhances typical PI controller with an estimator of zero-delay current (ZDC) value. The ZDC estimation allows for selecting substantially higher controller gain. It reduces control loop step response rise time to a single control cycle, which is the shortest technically possible value, while avoiding overshoot. The method does not require any hardware changes and it needs only negligible processing overhead. Both simulations made and experimental results obtained in the study have proved the effectiveness of the proposed solution.

Frequency and time domain characteristics of digital control of electric vehicle in-wheel drives

“…The results even for relatively low frequencies indicate that the sampling variant substantially influences the electric drive control dynamics, as expected from [14] and [15]. For the Bode plots, the corner frequency at which the magnitude drops to 3 dB (0.71 p.u.)…”

“…The model comprises a continuous model of an electric motor and a discrete controller model describing field-oriented control, which is usual in drive control research [23,24]. The reference model has been thoroughly verified and validated by Jarzebowicz [15,25], indicating a very good representation of real digitally controlled drive behavior. 5 and m = 1).…”

“…1, constitutes a torque control loop as well. A digitally imlemented PI controller is usually used to drive motor torque [13,15]. While an electric motor can be represented well in continuous time, the control algorithm cannot, because it is performed digitally as a series of discrete control events.…”

“…4, Table 1), whose technical parameters are provided in [15]. The model comprises a continuous model of an electric motor and a discrete controller model describing field-oriented control, which is usual in drive control research [23,24].…”

“…Replacing an analog control with a sampled one negatively influences the electric drive control dynamics [14] if the control cycle, which also influences the power electronic converter switching frequency, is not radically shortened. Moreover, the exact instant of motor currents sampling within the control period influences the control characteristics significantly, as researched for both PMSM and DC drives [15,16].…”