Complex Pulse Width Modulation Generation for Motor Controls Application Using Multichannel Sequencer (MCS) of Generic Timer Module (GTM)

The inverter in electric vehicles (EVs) transforms the battery's DC power into a regulated, variable-frequency AC signal, allowing for exact control over the three phase AC motor's speed and torque. The PWM allows for synchronized regulation of pulse widths of all the three phases, resulting in balanced and controlled power output to the motor windings and improves overall performance. The Advance Routing Unit (ARU)Connected Timer Output modules (ATOM) of Generic Timer Module (GTM) incorporate motor control-specific capabilities including fast triggering mechanisms, synchronization, high-resolution (24-bit resolution) and dead-time generation. Whereas other timer modules may be more generic and not optimized for advanced motor control applications. The objective of this paper is to present the strategy to reduce the CPU load in software by utilizing the submodules of GTM called Multi channel sequencer (MCS). It has a minimal amount of software operating on the chip core, resulting in the simulated interface of MCS channels with ATOM channels and consuming no CPU bandwidth. By combining the ARU and Dynamic Memory Allocation (DMA), ATOM generates complex PWM signals at hardware level. The GTM ARU offers a communication interface between the GTM submodules without the CPU intervention. To generate PWM signals without CPU intervention, we can update the PWM Duty Cycle and Period values to ATOM shadow registers concurrently using the GTM MCS, ARU and DMA Interface. This helps in reducing the need for the interrupt service routine to run cyclically to update the PWM duty and Period values in the software algorithms and enhance system performance overall. Keywords: GTM, MCS, ATOM, ARU, DMA, CPU