Energy-saving retrofit of switched reluctance motor speed control system

The Switched Reluctance Drive (SRD) system comprises a Switched Reluctance Motor (SRM) and an Intelligent SR Controller (ISRD), representing the latest generation of stepless speed control following DC drives and AC variable frequency drives. The motor features a double-salient stator/rotor 12/8 pole structure with concentrated windings on the stator teeth. The rotor, constructed from laminated silicon steel, contains no windings or permanent magnets—only a position sensor. Continuous rotation is achieved by energizing phases in the A-B-C-A sequence; reversing the phase order reverses rotation direction. Retrofitting first addresses the mismatch between the motor's rated power and actual operating load. Existing systems often oversize motors based on peak loads, resulting in prolonged operation at light loads with low efficiency and power factor. SRD utilizes dual closed-loop speed-current control and pulse width modulation to precisely match output torque to actual load, maintaining high efficiency across the entire speed and power range. Second, it resolves starting challenges for heavy-load and high-inertia equipment. SRD delivers a starting torque of 150%~300% of rated torque while drawing only 30% of rated current. In contrast to AC motors requiring 300% current for 100% torque, SRD significantly reduces stress on the power grid and transmission components, offering soft-start capabilities. The controller integrates microcontrollers with digital and analog circuits, ensuring stable operation, strong anti-interference performance, a response time of 0.2 seconds, speed accuracy of ±1.5r/min, and steady-state speed accuracy of 0.15%. It includes comprehensive protection and self-diagnostic functions for overvoltage, undervoltage, phase loss, motor overload, stall, overcurrent, output short circuit, and controller overheating. Status regarding power supply, operation, speed, and protection can be viewed on the display panel. Since the microcontroller program is modifiable, it easily accommodates special user requirements for motor performance. Implementation involves measuring the site equipment load curve and existing motor parameters, then selecting the appropriate model based on four rated speeds (750/1000/1500/3000r/min) and a power range of 0.55~315kW. Installation dimensions are verified against frame sizes 132~355 to achieve 1-for-1 replacement. Following wall-mounted controller installation and parameter tuning, load testing and energy consumption acceptance are performed. Finally, the system connects to a digital IoT motor platform, enabling continuous monitoring of power usage, production capacity, and operational conditions via PC, mobile phones, or tablets. This facilitates immediate detection of idling, frequency reduction, or abnormal shutdowns, providing data support for future energy-saving strategy adjustments.

Use Cases:Oilfield pumping units and well testing machines, injection molding machines and extruders, horizontal boring mills and vertical lathes, screw presses and brick pressing machines, ball mills and crushers, fans and pumps with compressors, etc., under variable load conditions, heavy-load starting, frequent forward/reverse rotation, and frequent start/stop operations.