Motor Control System Design

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Advanced strategies for precision, reliability, and real-world performance — from control theory to field-proven code.

MarSum Solutions designs and implements motor control systems that deliver adaptability, manufacturability, and performance margins typically reserved for higher-cost platforms. Our team combines deep academic control theory with real-world design experience across industrial automation, HVAC/R, transportation, and high-performance consumer systems.

We specialize in sensorless and sensor-based strategies for a wide range of motor types, optimized control architectures, and scalable firmware deployments. Whether you need trajectory tracking, torque ripple minimization, or safety-qualified motion control, we engineer systems that are mathematically sound and field-proven.

We design for a wide spectrum of motor technologies, each with its own control challenges:

• BLDC (trapezoidal) & PMSM/PMAC (sinusoidal, SPM/IPM): High-efficiency permanent magnet machines with scalar or vector control strategies
• Induction Motors: Scalar (V/f) and vector-controlled, including slip compensation for load stability
• Switched Reluctance Motors (SRM): Current profiling and position estimation for cost-driven platforms — with focus on torque ripple and acoustic noise mitigation
• Synchronous Reluctance Motors (SynRM): Compact, low-inertia, high-efficiency drives for scalable automation platforms
• Stepper & Linear Actuators: Open-loop or closed-loop control for precision motion in constrained geometries
• Ultrasonic Motors: Charge-controlled high-frequency drive techniques for niche actuation use cases
   

We accommodate challenging system constraints such as:

• Tight BOM budgets using low-resolution or sensorless feedback
• Wide speed ranges with fast torque response
• EMI reduction, thermal derating, and extended lifecycle requirements

We match control topology to application needs — balancing performance, complexity, and hardware cost.

Sensor-Based & Sensorless Vector Control

• FOC (Field-Oriented Control): For sinusoidal PMSM/IPM systems
• Flux, voltage, and current-based observers with real-time angle estimation
• Estimators: Luenberger, MRAS, Sliding Mode Observer (SMO), Extended/Unscented Kalman Filter (EKF/UKF), Lyapunov-based
• Zero-speed hold, soft-start, and low-speed merging for high-reliability spin-up
   

Scalar & Simplified Approaches

• V/Hz control: Low-cost, legacy-friendly method for induction machines
• Trapezoidal drive (BLDC): Simple, robust startup in sensorless applications
• Hybrid startup methods: Transition scalar → vector when back-EMF allows

Advanced Dynamic Behavior

• MTPA & Field Weakening: Maximum torque per amp strategies and high-speed extension
• Ripple and resonance suppression: Notch filtering, real-time current shaping
• Adaptive compensation: Online tuning for saturation, temperature, and parameter drift

Sensorless control requires real-time state estimation tailored to bandwidth and EMI.

• Luenberger & MRAS: Fast, lightweight
• Sliding Mode Observer (SMO): Robust in noisy, harsh environments
• Extended/Unscented Kalman Filter (EKF/UKF): Precise, computationally intensive; ideal for advanced systems
• Flux Linkage Estimation: For zero-speed or low back-EMF startup
   

We tune observers for:

• Bias rejection at start-up
• Fast convergence with minimal overshoot
• Load-disturbed speed estimation
• Runtime parameter adaptation

We select the modulation strategy that maximizes system performance, switching efficiency, and EMI resilience.

• SVPWM & BC-SVM (Bus-Clamped SVM): Optimal harmonic profile for vector drives
• 6-Step & Overmodulation: For high-speed and resource-limited systems
• Space Vector Table Lookup: Used in fixed-point DSP/MCUs
• Hysteretic and Peak-Mode Control: For torque-dense, fast-switching drives
   

We also optimize:

• Thermal margin: Minimize I²R loss via real-time MTPA
• Noise shaping: Reduce EMI using phase interleaving and modulation symmetry
• Power factor correction: Where drives interface to grid

We provide complete end-to-end solutions, including production-ready code, comprehensive hardware-in-loop (HIL) test plans, and detailed safety cases, ensuring seamless deployment on production hardware. 

• Model-based design via Simulink®, Stateflow®, and PSIM, with auto code-gen
• Embedded C for DSP, Cortex-M, and FPGA platforms
• Modular architecture: Control Loop → Estimation → Faults → Comms
• Fault handling: Undervoltage, loss-of-sensor, overcurrent, saturation
• Standards-aligned: MISRA C, ISO 26262, IEC 61508, with support for DO-178C, DO-254, IEC 61800-5-2, and UL 61800-5-1 as needed

A full-featured toolchain ensures traceability, repeatability, and rapid iteration.

• Simulation: MATLAB®, Simulink®, Stateflow®, PSIM
• Motor modeling: JMAG-RT, ANSYS Maxwell
• Code generation: Embedded Coder®, HDL Coder™, Simulink Coder™
• Testing: Simulink Test™, Coverage™, HIL (Hardware-in-the-Loop)
• Traceability & validation: Requirements Toolbox™