New modulation encoding techniques for indirect rotor position sensing in switched reluctance motors

This study deals with the unipolar excitation‐based speed sensorless vector controlled switched reluctance motor drive. For speed sensorless operation, Z‐MRAS (Z‐model reference adaptive system) based speed estimator is proposed where ‘Z’ is a fictitious quantity. This novel structure is completely independent of the stator resistance and DC component of self‐inductance. Also, in the formulation, integrator and differentiator terms are absent. The proposed formulation is perceived as stable in the entire four‐quadrant zone of operation. Detailed stability and sensitivity analysis has been carried out for the proposed estimation scheme. The practicality of the proposed formulation is confirmed through simulation in MATLAB/SIMULINK platform and by carrying out the experimentation on a dSPACE‐1104 based prototype.

Section: Proposed Z-mras Based Speed Estimatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved MRAS based speed estimation for a vector controlled switched reluctance motor drive

Khan

Verma

2020

“…According to the area of application, the strategies could be roughly classified into two categories: position detection for low speed and high speed. The strategies of the first category indirectly access to phase inductance information by: injecting small detecting signal into the inactive phase [12], monitoring chopping current waveforms [13] and frequency modulation technique [14–16]. However, in high‐speed application, the inactive duration of each phase for signal injection is quite limited and the motional electromotive force (EMF) is always ignored which could cause big estimation error.…”

Section: Introductionmentioning

confidence: 99%

Back‐EMF‐based sensorless control system of hybrid SRM for high‐speed operation

Tang

Lee

et al. 2018

Based on the back electromotive force (back-EMF) detection, a novel rotor position estimation strategy with adjustable turn on/off angle is proposed for the high-speed hybrid switched reluctance motor (SRM). The minimum back-EMF position is captured in every electrical cycle for rotor position estimation. The current comparator is employed to send out a turnoff signal for phase winding when the maximum inductance position is detected in the first electrical cycle. By providing sufficient current rise time to the phase winding, the proposed sensorless control system enables the motor to run in high-speed application. Besides the straightforward estimation principle, the proposed strategy has the implemental feasibility by eliminating extensive calculations and complicated look-up tables. The experimental results of a prototype are demonstrated to verify the proposed sensorless control system.

“…The installation of these sensors increases the cost and complexity of the entire drive system. Hence, several sensorless control methods have been proposed containing flux linkage method [3–7], pulse injection method [8, 9], current‐gradient method [10], modulation method [11], state observer‐based method [12], and so on [13–15], some of which applied external circuits. The external flux linkage measurement circuit in [4] is used to obtain the instantaneous flux linkage, and the rotor position can be deduced based on the pre‐stored flux linkage characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…Owing to the challenge posed by the restricted sampling frequency of the digital signal processor (DSP), an analogue integrator is applied to capture the peak of the current pulse for rotor position estimation at high speeds [8]. The modulation and demodulation techniques are used to measure the phase inductance of an idle phase, and then the rotor position can be derived [11], where the external modulator and demodulator circuits are used to obtain the inductance information.…”

Section: Introductionmentioning

confidence: 99%

Circuit‐based flux linkage measurement method with the automated resistance correction for SRM sensorless position control

Liang

Chen

2018

The accuracy of flux linkage measurement is significantly important for a number of sensorless control methods for switched reluctance motor (SRM). This study proposes a novel flux linkage measurement circuit with the automated resistance correction, which comprises only circuit components. During the SRM sensorless operation, the dependence of resistance on temperature leads to the errors in flux linkage measurement and position estimation. The developed scheme is based on the zero-crossing property which asserts that the flux linkage and current pass through zero simultaneously. Hence, the flux linkage error captured at the time when the current falls to zero represents the resistance error and is used for resistance correction. The proposed circuit has been successfully implemented and tested on a sensorless SRM system. Experiment results indicate that the proposed system in sensorless control can be operated stably at different load torques and at the condition of given speed mutation and load mutation, and the speed range in steady state with rated load torque is 0-160 r/min. The overall estimated position error remains within an acceptable margin of 2%. Hence, it significantly improves the sensorless position estimation and thus SRM performance. Δθ e absolute value of the average position error Δθ e max absolute value of the maximum position error