Thermal Behavior Improvement of Induction Motors Using Pulse Width Phase Shift Triangle Modulation Technique in Multilevel H-Bridge Inverters

This study investigates the thermal performance of induction motors powered by multilevel H-bridge inverters using a novel Pulse width Phase Shift Triangle Modulation (PSTM-PWM) technique. Conventional PWM methods introduce significant harmonic distortion, which increases copper and iron losses, causing overheating and reduced motor lifespan. Through experimental testing and comparison with standard PWM techniques (LS-PWM and PS-PWM), the proposed PSTM-PWM demonstrates substantial reduction in harmonic distortion and internal motor losses. A first-order thermal model is used to predict motor temperature, validated with direct thermocouple measurements and infrared thermography. Results indicate that PSTM-PWM technique, particularly at a triangular waveform peak value of 3.5 V, minimizes THD and improves thermal performance, offering a practical and compliant solution for industrial motor drive applications. The modulation order has been set to M=7 in purpose of reducing both the losses in the power inverter and to generate very high voltage pulses (high dV/dt) that can deteriorate the insulation of the motor windings with the time in the induction motor.