Simulation of Current Chopper Control for Switched Reluctance Motors

Switched Reluctance Motors (SRM) are widely used in industrial and electric vehicle applications due to their simple structure, high reliability, and superior speed regulation performance. Current Chopper Control (CCC) is a classical control strategy for SRM speed regulation that effectively suppresses torque pulsation and optimizes dynamic motor performance.

The simulation employs a four-phase 8/6 pole SRM model, implementing current chopper control logic through MATLAB. The core methodology includes:

Current Hysteresis Control Sets upper and lower threshold currents - when measured current exceeds the upper limit, power devices are turned off; when current falls below the lower limit, they are reactivated. This creates chopping waveforms that ensure current tracking of reference values. Implementation typically involves real-time current sampling and comparator functions in the control algorithm.

Commutation Strategy Activates phase windings based on rotor position signals (e.g., Hall sensor feedback). For the 8/6 pole configuration, commutation occurs every 15° mechanical angle, requiring precise alignment of conduction intervals with the inductance rising region. Code implementation requires position decoding algorithms and phase sequencing logic.

Key Simulation Modeling Aspects Nonlinear Motor Model: Accounts for flux saturation effects using lookup tables to fit current-flux-angle relationships. The modeling approach involves characterizing magnetic material properties through experimental data or FEA results. Power Circuit: Simplifies the inverter as ideal switching devices, simulating freewheeling diode current paths. Circuit modeling includes semiconductor device on/off states and parasitic components. Mechanical Load: Couples torque equations with kinematic models to analyze speed response. The simulation integrates electromagnetic torque calculation with mechanical system dynamics using ordinary differential equations.

Extension Directions: Can integrate PID regulation of chopping thresholds to optimize dynamic response, or incorporate advanced angle control to reduce commutation noise. This simulation framework can be adapted for analyzing SRMs with other pole configurations through parameter modification and model scaling.