Controlling power semiconductors with high switching frequency
Miniaturization of power conversion devices by reducing passive components
SiC/GaN power semiconductors have lower conduction and switching losses


The Electronics and Telecommunications Technology Institute (KETI) announced on the 3rd that it has developed a next-generation power semiconductor device high-performance driving technology that enables miniaturization and high-efficiency design of power conversion devices.

A power conversion device is a device that supplies power in the required form, such as AC/DC conversion, with minimal energy loss through switching control of power semiconductors. Switching control, that is, ON/OFF control of power semiconductors, can be used to convert power into the desired form by conducting/blocking the current.

Recently, there has been an increasing demand for designing power converters to be more efficient, smaller, and lighter in order to improve user convenience and energy efficiency.

Controlling power semiconductors at high switching frequencies allows the size of passive components such as inductors and capacitors within power converters to be designed smaller, miniaturizing the power converters.

Existing silicon (Si) series power semiconductors have a large energy loss during switching, so although miniaturization is possible by increasing the frequency, it is difficult to achieve high efficiency. When applying Si series power semiconductors, a trade-off occurs between high efficiency and miniaturization of power conversion devices.

Next-generation power semiconductors based on silicon carbide (SiC) and gallium nitride (GaN), which are currently attracting attention as next-generation materials in the power semiconductor market, have lower conduction loss and switching loss than existing Si series, enabling operation at high switching frequencies.

However, as next-generation power semiconductors are operated at high frequencies, there is a problem that the power semiconductors may malfunction due to parasitic components in the driving circuit, and it is also difficult to implement protection circuits to prevent this.

The next-generation SiC/GaN series drive circuit for power semiconductors developed by Dr. Jin-Hong Kim's research team at KETI this time is capable of switching at frequencies up to several hundred kHz. In the case of existing power semiconductor devices, they were operated at frequencies of several to several tens of kHz due to efficiency degradation issues.

The newly developed drive circuit has a built-in circuit that can detect malfunctions in power semiconductors, enabling the design of high-efficiency, miniaturized power conversion devices. This is because the design of components and current loops in the driving circuit has been optimized to take high-frequency operation into account, and a separate detection circuit has been added to protect next-generation power semiconductors that are relatively vulnerable to malfunction, thereby accelerating the error detection time.

KETI has improved the efficiency of industrial chargers by 6%, which was around 90%, with the developed drive circuit, and reduced the volume and weight by 30%. In addition, it has succeeded in reducing the volume of inverters for electric vehicles and low-voltage chargers by more than 30% compared to mainstream overseas products.

Dr. Kim Jin-hong said, “In order to achieve high efficiency and miniaturization of power conversion devices, circuits that can stably operate next-generation power semiconductors are essential,” and “We will continue to accumulate driving technologies related to SiC and GaN devices to help secure the competitiveness of domestic power conversion devices in the global market.”

Meanwhile, this technology was developed as part of the 'Development of a high-efficiency/high-density 100kW-class battery pack tester based on SiC that can be modularized for ESS/EV' project supported by the 'Energy Technology Development Project' of the Ministry of Trade, Industry and Energy and the Korea Institute of Energy Technology Evaluation and Planning.