A Bidirectional Communicating Power Supply Circuit for Smart Gate Driver Boards

Abstract

In power circuits, the gate drivers are required to provide an optimal and safe switching of power semiconductor devices. Nowadays, the gate driver boards include more and more features such as short-circuit detection, soft-shutdown, temperature sensing, on-state voltage monitoring… Research works are in progress on the integration of on-line monitoring features for a predictive maintenance. The instrumentation of the gate drive system supposes the integration of a communication system to transmit the monitoring data. In high power designs, a galvanic isolation is mandatory on the gate driver board. The parasitic capacitance seen on the isolation barrier is critical in these designs as it can lead to the circulation of common mode currents during the switching. Adding extra optocouplers or transformers on the isolation barrier is therefore risky due to ElectroMagnetic Interference (EMI) constraints. In this paper, a new bidirectional data transmission method is proposed for gate drivers used for driving 1.2kV SiC power MOSFETs. The proposed method enables the energy transmission and a bidirectional data exchange on a single power supply transformer. Experimental results are provided demonstrating 1Mb/s for TxD and 16kb/s for RxD. The targeted application is the health monitoring of SiC power MOSFETs using the gate driver board.

Cascaded Smart Gate Drivers for Modular Multilevel Converters Control: A Decentralized Voltage Balancing Algorithm

“…As power plants can reach several kilovolts, industrial built-in two-channel drivers cannot be used to drive MMC submodules. Recently, Smart Gate Drivers had been introduced in the literature [22][23][24][25]. Such drivers are able to realize complex tasks, like power module monitoring, improved fault protection, detailed fault diagnosis, or active gate driving.…”

“…It is also equipped with CPLD logic, allowing communication with the main controller and complex tasks managing like detailed measurement of V DSON for power module monitoring. The gate driver presented in [25] (Figure 5) requires only two planar transformers for bidirectional communications and a power supply. It is a built-in ready-to-plug gate driver for 1.2 kV SiC MOSFET, perfectly suited for DGI-based MMC.…”

“…That work aims to study an innovative structure allowing the use of smart gate drivers for multilevel structures. [25] with FPGAs at each side and bidirectional communication channels between primary and secondaries.…”

“…The algorithm is executed by fast electronics on the primary side. Typically, smart gate drivers equipped with FPGA, like in [25], are perfectly suited for such an application. The overall control structure of the converter is modified, as depicted in Figure 9.…”

“…Only Driver 1 has a slightly different architecture due to the interface between its primary side and the converter main control unit. That low level of model is chosen to accurately represent a CPLD/FPGA device, in order to demonstrate the practical implementation of such algorithms on a real SGD [25].…”