Simulation Model of Hysteresis Current Control-Based FOC for PMSM

In the field of motor control, hysteresis current control combined with Field Oriented Control (FOC) represents a classical method for achieving high-performance drives for Permanent Magnet Synchronous Motors (PMSM). This article presents the design methodology and key implementation aspects of this simulation model. Fundamental Principles of Hysteresis Current Control Hysteresis current control is a nonlinear control strategy that maintains actual current fluctuations within predefined upper and lower limits of the reference current by setting a hysteresis bandwidth. When current exceeds the upper limit, the controller reduces output voltage; when current falls below the lower limit, it increases output voltage, thereby forcing rapid current tracking within the hysteresis band. In code implementation, this typically involves comparator functions that monitor current error and trigger switching actions when boundaries are violated. Role of FOC in PMSM Control The core of FOC lies in transforming three-phase currents into direct-axis (d-axis) and quadrature-axis (q-axis) components to separately control flux and torque. Through hysteresis current control, rapid adjustment of q-axis current enables dynamic torque response while maintaining d-axis current at zero (or adjusted according to field weakening requirements), ensuring optimal operating efficiency. Algorithm implementation requires Clarke and Park transformations to convert stationary reference frame quantities to rotating reference frame components. Key Modules of the Simulation Model Coordinate transformation module: Converts three-phase currents to dq-axis components and performs inverse transformations to generate PWM drive signals. Implementation typically involves mathematical transformation matrices and angle calculation routines. Hysteresis comparator: Switches inverter states based on the deviation between actual current and reference values. Code implementation requires real-time comparison logic with configurable hysteresis bands. Speed/position loop: Outer loop provides speed or position control, outputting q-axis current references. Typically implemented using PI controllers with anti-windup features. PMSM model: Incorporates motor electromagnetic equations, mechanical motion equations, and load characteristics. This involves solving differential equations for electrical and mechanical subsystems. Simulation Verification and Optimization Directions Testing should focus on current tracking speed, torque ripple suppression effectiveness, and stability under dynamic loads. Potential optimizations include adjusting hysteresis bandwidth to balance switching frequency and current ripple, or implementing adaptive strategies to handle parameter variations. Code-level optimizations may involve dynamic band adjustment algorithms and gain scheduling techniques. This model is suitable for applications requiring high dynamic response, such as electric vehicles or industrial servo systems. Future extensions could include sensorless control implementations or integration with other advanced control algorithms.