Control of a Three-Level T-Type Inverter-Fed PMSM With Regenerative Braking Tested With Dynamometer Test Bench Emulation and EV Load

To maximize energy recovery during deceleration of electric vehicles (EVs) powered by three-level T-type inverters (3L-TNPCI), this study introduces a novel regenerative braking technique (RGB). The proposed method selectively switches the inverter device according to the expected back EMF of the motor, thereby optimizing the pulse width modulation (PWM) control. The integrated four-wheel (4W) electric vehicle system achieves smooth transitions between acceleration and deceleration by controlling the brake force distribution using the vehicle dynamics principles. A DC machine as a dynamometer is connected to a permanent magnet synchronous motor (PMSM) as part of the experimental test bench. A four-quadrant chopper controls the DC motor to replicate braking forces, vehicle inertia, and road loads. The proposed control method simulates various driving situations and evaluates the performance of the braking system and power losses, reliability, and thermal stress under different loads using hardware-in-the-loop (HIL) emulation. The proposed 3L-TNPC-based regenerative braking strategy can improve the recovery rate of the regenerative braking energy by 27.975%, improve the SoC of the battery by 3.3%, reduced the torque ripple to 1.9-2.4% and reduced the THD to 8–12%. An experimental study is conducted in various environments to evaluate the effectiveness of the proposed RGB method under up- and down-ramp conditions for a 60 V, 2.25 kW PMSM driven by a 3L-TNPCI with an EV load to validate the proposed method. The results show that the proposed technique provides significantly better energy recovery, especially when braking downhill in hilly terrain.