High Load Fast Startup Sensorless Control of Wheel BLDC Motor with Line-to-Line Back EMF Extraction Using Least Pth-Norm IIR Digital Filter

Abstract

In this paper, an effective scheme of on-load startup with reduced current has been proposed for BLDC motor and the steady as well as dynamic performance in all four quadrants was verified. Hysteresis band-limited back EMF noise provides the starting pulses, the frequency of which depends on the threshold factor in speed proportional threshold. Scheme is quite fast, comparatively to the state-of-the art schemes of startup and less complex than time-consuming initial position detection (IPD) algorithm. Second-order least [Formula: see text]th-norm infinite impulse response (IIR) digital low pass filter realized in MATLAB/Simulink has been used for extraction of line-to line back EMF from line-to-line terminal voltages measured with two voltage sensors. Proposed filter has wide flexibility of online variation of cut-off frequency, gain and phase without any circuit-based modification due to variability of filter coefficients. This enables the smooth filtering with minimized phase delay in low speed range irrespective of any duty cycle and PWM frequency. Linear compensation of phase error or phase advancement for desired current profile can easily be achieved by the varying the threshold factor. In this experiment, the threshold factor of 1/1460 has been found most suitable for smooth sensorless startup without jerk, vibration and reverse rotation, as the motor operates in advanced mode with this value. First, the performance of Hall sensor-based drive was studied using open loop variable duty cycle speed control. The controller was designed in MATLAB/Simulink platform and implemented using TMS320F28069M DSP control stick with Code composer Studio V5. Later on, a complete controller for proposed sensorless scheme was developed in MATLAB/Simulink environment and was implemented using NI-PCI6221 Controller installed in PC. The proposed sensorless drive has been found capable of operating at very low speed of 50[Formula: see text]rpm in voltage control mode and 85[Formula: see text]rpm in current chopping PWM mode. Approximately 85[Formula: see text]ms less time was taken by sensorless drive to reach the same speed when compared with Hall-based control for identical loading. Also less overshoots during startup was observed. Overlap time of 0.05[Formula: see text]ms between phase currents has been achieved during commutation period.

Sensorless control of high‐speed BLDC motor using equal area criterion based precise commutation scheme with Fuzzy based phase delay compensation

“…An initial back EMF noise band based strategy is used to start the motor from standstill. 43 High filtering delay does not much affect the commutation process during…”

“…Complete drive system has been shown in Figure 4. An initial back EMF noise band based strategy is used to start the motor from standstill 43 . High filtering delay does not much affect the commutation process during operation at low speed and current does not rise too high.…”

“…In proposed sensorless scheme, the back EMF noise band based startup technique 43 has been implemented. The proposed startup scheme works from startup to steady state operation and it is not required to shift the commutation modes unlike conventional startup schemes.…”

“…The instantaneous frequency , matching to the load at startup is given by, 34,43 where, T o is load torque during startup, θ s is the angle between rotor position and axis of energized phases. For safe starting, load current at start up should be very low ( 5 .…”

An enhanced sensorless control based on active disturbance rejection controller for a PMSM system: design and hardware implementation

“…An infinite impulse response (IIR) filter is another alternative filter, which can attenuate the high frequency noise to satisfy the requirements of the signal acquisition. Therefore, the IIR filter is widely applied to the practical engineering systems due to the efficiency and rapidity (Agrawal et al , 2020; Soni and Tripathi, 2020). However, it is a relatively novel research field to introduce IIR filter to the speed sensorless vector control system.…”