MM32SPIN360PF

The hardware cordic (COordinate Rotation DIgital Computer) is a hardware accelerator for trigonometric and vector calculations: (1) Functions supported - Sine, cosine, arctangent, vector magnitude, and vector rotation. (2) Performance - Completes calculations in approximately 20 clock cycles vs hundreds of cycles for software implementation. (3) FOC applications - Accelerates Park transformation (3 sine/cosine), inverse Park, and SVPWM calculations. (4) Precision - 16-bit precision suitable for motor control applications. (5) CPU offload - Frees CPU for other tasks like observer calculations and communication. In FOC algorithms, the cordic accelerates the most time-critical calculations. For example, a typical sensorless FOC loop requires 4-6 trigonometric calculations. With hardware cordic, these complete in ~120 cycles vs ~600 cycles in software, enabling higher control loop frequencies or lower CPU utilization. This is essential for high-performance servo applications requiring fast current loops.

Contact LiTong for cordic utilization in FOC algorithms and performance optimization.

MM32SPIN360PF supports various sensorless FOC algorithms through its processing power and peripherals: (1) Sliding Mode Observer (SMO) - Robust observer estimating rotor position from current measurements. Good dynamic performance and parameter robustness. (2) Extended Kalman Filter (EKF) - Optimal state estimator providing accurate position and speed estimates. Higher computational load but excellent performance. (3) Flux Linkage Observer - Estimates rotor flux position directly. Simple implementation with good low-speed performance. (4) High-Frequency Injection (HFI) - Injects high-frequency signal for position detection at standstill and low speeds. Useful for startup and low-speed operation. MindMotion provides reference implementations of SMO and flux linkage observers in their motor control library. The 96MHz Cortex-M3 with hardware cordic can execute these algorithms with control loop frequencies of 10-20kHz. For startup from standstill, high-frequency injection or open-loop startup sequences are typically used.

Contact LiTong for sensorless FOC algorithm selection and implementation support.

The MM32SPIN360PF includes a hardware quadrature encoder interface (QEI) with the following capabilities: (1) Resolution - Can decode quadrature signals up to 1MHz edge rate per channel, supporting high-resolution encoders at high speeds. (2) 4x decoding - Counts on both edges of both channels providing 4 counts per encoder line. (3) 32-bit position counter - Wide counter range eliminating overflow concerns. (4) Index pulse handling - Optional index pulse input for absolute position reference. (5) Velocity calculation - Hardware velocity capture or software delta-position calculation. (6) Direction detection - Automatic direction detection from quadrature phase relationship. For a 1000-line encoder at 4x decoding, this provides 4000 counts per revolution. At 6000 RPM (100 rev/s), the edge rate is 400kHz, well within the 1MHz capability. The hardware QEI significantly reduces CPU overhead compared to software decoding, freeing processor cycles for control algorithms.

Contact LiTong for encoder interface configuration and high-speed encoder applications.

The MM32SPIN360PF can achieve high control loop frequencies suitable for high-performance motor control: (1) Current loop - Typically 10-20kHz for FOC applications. At 96MHz with hardware cordic, current loop execution time is approximately 5-10μs leaving significant headroom. (2) Speed loop - Typically 1-5kHz, easily achievable with the available processing power. (3) Position loop - Typically 100Hz-1kHz for servo applications. (4) PWM frequency - Usually matched to current loop at 10-20kHz. The achievable loop frequency depends on algorithm complexity: (1) Simple BLDC six-step - Current loop possible at 50kHz+. (2) Sensored FOC - Current loop at 20kHz typical. (3) Sensorless FOC with SMO - Current loop at 10-15kHz typical. (4) Sensorless FOC with EKF - Current loop at 5-10kHz due to higher computational load. Higher loop frequencies provide better dynamic response and lower current ripple but require more CPU time.

Contact LiTong for control loop frequency optimization and algorithm tuning.

Yes, MM32SPIN360PF supports single-shunt current sensing for cost-effective motor drives: (1) Single-shunt principle - Reconstructs three-phase currents from DC bus current measurement using PWM state information. (2) ADC timing - Fast 2Msps ADC with precise PWM synchronization captures current during active vectors. (3) Sampling windows - Hardware identifies valid sampling windows when current flows through shunt. (4) Current reconstruction - Software algorithms reconstruct phase currents from samples. (5) Limitations - Some PWM states don't provide valid current information, requiring special handling at high modulation indices. Single-shunt sensing reduces hardware cost by eliminating two current sensors but requires more complex software. It works well for most applications but may have limitations at very high speeds or high modulation indices. For highest performance and simplest software, dual-shunt or triple-shunt sensing is preferred. The MindMotion motor control library includes single-shunt current reconstruction algorithms.

Contact LiTong for current sensing scheme selection and implementation guidance.