Design Note #127
The control of high voltage inductive loads requires careful design discipline. Multiphase 240 VAC control of inductive loads presents a number of challenges. Current and voltage switching transients together with efficient circuitry cooling and heat management are essential design elements.
PWM control of high voltage inductive loads is supervised by an NXP LPC11 class ARM Cortex-M class microcontroller. PWM generation, current monitoring, voltage monitoring, set point programming, remote communications and switching time supervision are all part of the activities of the ARM Cortex-M microcontroller.
High voltage eld effect transistors (FET) from ST Microelectronics together with high voltage drive circuitry makes this design possible. Today’s high-voltage eld effect transistors (FET) from ST Microelectronics, together with high-voltage drive circuitry make operation to 600 volts possible. Proper design de-rating achieves high reliability at the actual operating point.
Highly inductive, elevator brake devices present a triple phase delta connected load to the controller. With inductances in the hundreds of millihenries, current and voltage transients must be carefully considered.
High speed, full duplex RS422 Serial Communications makes this controller flexible to install. Low wire count RS422 communication is robust in harsh environments.
Running OTEC’s proprietary non-preemptive real time operating system, data acquisition and processing are accomplished in real time. Small and efficient, OTEC’s proprietary non-preemptive real time operating system securely performs safety-critical tasks.
The development of custom electronic products for our OEM clients is OTEC’s entire business. The design of high voltage PWM controllers with rapid design cycles, demanding technical requirements, and unforgiving schedules sets us apart. Contact OTEC today!