Silicon Carbide IGBT and Power MOSFETs

Silicon carbide igbt technology holds great promise to transform power systems by increasing efficiency, reliability and size. The wide bandgap material dissipates heat much more effectively while operating reliably at higher temperatures – as well as being capable of withstanding higher voltages and offering reliability at increased temperatures.

An experimental system was devised and used to measure the turn-on and off delay times of Si-IGBT hybrid power switches under RL load conditions, and results indicate lower energy losses at switching times.

Power

Silicon carbide semiconductors have found widespread application in electronic devices. One device that stands out among them is silicon carbide power MOSFETs; often referred to as SiC MOSFETs or FETs. They offer significant power performance benefits over their silicon counterparts.

Silicon carbide’s significant advantage over silicon is its higher breakdown electric field strength, enabling MOSFETs fabricated from this material to have lower on state resistance than their silicon counterparts, leading to lower switching losses that are especially beneficial in electronic circuit designs such as voltage converters.

Another advantage is that silicon carbide MOSFETs can be manufactured to operate at higher temperatures than their silicon counterparts, enabling higher current densities as well as quicker switching on and off rates, which reduce switching losses and can further lower switching losses.

Silicon carbide power devices find widespread application in electrical motor drives. Silicon carbide MOSFETs can drastically enhance performance by reducing switching losses and increasing efficiency – one of the key applications for silicon carbide MOSFETs.

As demand for electromechanical devices such as switches, solenoids and encoders increases across fields like advanced manufacturing and electric vehicles, so does their need to convert digital signals to physical actions. Power conversion plays a pivotal role here and breakthroughs in power electronics can have profound effects on efficiency, controllability and performance of these devices.

One breakthrough in power conversion innovation is using silicon carbide MOSFETs (SiC MOSFET) instead of silicon IGBTs (Si IGBT), which can lead to significant increases in their performance by enabling higher speeds and greater control.

Semikron Danfoss has developed a selection of silicon carbide IGBT replacement modules with industry-standard housings and advanced packaging technologies, to fully exploit the benefits offered by these devices. One such IGBT module, the CoolSiC MOSFET-based CIPOS Maxi IPM IM828 series is an industry standard TO-247 package incorporating an optimized 6 channel SOI gate driver and six CoolSiC MOSFETs into one TO-247 package to create low module commutation inductance that allows full take-up of benefits from reduced on-state resistance and switching losses.

Efficiency

Silicon carbide is far superior to silicon in terms of power conversion efficiency. This is due to the fact that it dissipates heat much better and can withstand higher voltages than traditional silicon components – ideal for high performance power applications like railway traction. Furthermore, silicon carbide’s higher durability makes it suitable for high voltage systems like railway traction.

Silicon carbide not only increases efficiency but offers additional advantages as well. These include lower switching losses, smaller magnetic filter components and improved reliability – helping designers reduce system size and weight as well as maintenance and operational costs. Plus, silicon carbide’s high power density is perfect for medium voltage power systems reducing space requirements and costs further.

SiC MOSFETs are ideal for hard and resonant switching topologies, and can be driven just like IGBTs or standard power MOSFETs with easy-to-use drivers. Furthermore, this technology delivers maximum efficiency at switching frequencies that enable reduced system size and increased power density.

Silicon Carbide IGBTs can be optimized by selecting appropriate gate drive circuitry that will minimize parasitic effects during power on/off operations and power losses associated with switching themselves; also important are factors like inductance strayance of gate drives as well as power losses associated with switches as these factors could dramatically change device performance.

Silicon Carbide (SiC) MOSFETs provide superior critical breakdown strength, higher switching frequency and reduced switching loss than their IGBT counterparts. Furthermore, these more rugged devices operate at lower temperatures to reduce system size, weight and costs as well as be more cost effective due to lower temperature operations and greater robustness when faced with transient events found commonly within medium voltage power systems.

Wolfspeed’s Gen3 3300 V Bare Die SiC MOSFET power modules are specifically tailored to meet these stringent standards, boasting superior performance at both chip and module levels. Their low commutation inductance makes them suitable for even the most stringent power converter applications found on trains and trams, as well as providing packaging optimizations designed to minimize thermal resistance between chip and heat sink, thereby increasing power density densities while optimizing system efficiency.

Switching

Silicon carbide (SiC) is an advanced semiconductor material used to fabricate power devices. SiC devices can be found in various applications, from inverters and motors to providing energy in the power grid. SiC chips offer superior switching times over traditional silicon devices, making them suitable for power conversion applications such as switching faster during power conversion processes.

SiC power devices can handle higher currents than silicon MOSFETs while being integrated into smaller packages, as well as being more durable, resistant to high temperatures, and possessing much lower switching losses than their silicon counterparts.

SiC power devices offer many advantages that make them ideal for applications ranging from grid-connected AC inverters and single-phase pulse test (SPT) systems to three-phase inverters and replacement IGBTs in existing power converters, including reduced power losses and enhanced reliability.

In this experiment, three SiC-IGBT power modules were compared with traditional IGBT power modules for performance comparison. The results of the comparison demonstrated that SiC-IGBT modules had significantly lower switching losses and higher efficiency as well as shorter turn-on delay time and lower negative overshoot than IGBTs.

SiC-IGBT power modules were subjected to load tests with resistances of 42 ohms (RL = 42ohms, L = 290uH), including turning duration (rise-time and fall-time), overshoot current and voltage measurements as well as collector-to-emitter resistance Rceon which was measured using a handheld multifunctional oscilloscope from MICsig while gate-to-emitter voltage and its overshoot voltage were obtained via Hantek clamp meters.

SiC-IGBT power devices used in this experiment had rise times of less than 261 nanoseconds and fall times of around 617 nanoseconds, along with low overshoot current levels and small negative overshoot losses that reduced switching losses overall. Furthermore, SiC-IGBT modules proved more energy-efficient than IGBTs when operating under RL loads, due to lower on-state gate-to-emitter resistances and currents than their IGBT counterparts.

Transistors

Silicon Carbide transistors offer distinct advantages over their silicon counterparts due to their wider bandgap properties. SiC transistors can switch at much higher frequencies with reduced switching loss for an energy-efficient circuit design with less heat dissipation and improved thermal performance, which allows for smaller circuit designs with increased energy savings and better thermal performance.

This allows for the use of larger gate capacitance, increasing power density. Furthermore, faster on/off switching times reduce losses; further improving efficiency by decreasing collector-to-emitter resistance (Rceon).

The p-channel SiC-IGBT is also ideal for hard and resonant-switching topologies like LLC and ZVS that require high blocking voltage capabilities, with existing drivers easily driving it and high switching frequencies being easily handled resulting in smaller peripheral components, greater power density, and improved reliability.

To demonstrate the superior performance of SiC-IGBTs, they were pitted against conventional silicon devices in an AGPU-based system for comparison purposes. Both single phase and three phase experiments were performed to examine their operating performances.

SiC-IGBTs were found to show significantly less negative overshoot than their silicon counterparts during this experiment, along with shorter gate-to-emitter switching time with reduced overshoot and ringing; and lower conduction power losses.

These characteristics make the SiC-IGBT an excellent replacement for silicon devices in existing AGPU-based power systems, although its physical limitations could limit its full potential in this application.

Future devices should provide greater performance and efficiency, yet current devices already boast high levels of both features. Applications of the technology currently include charging batteries for electric vehicles, converting solar energy into DC power, optimizing server power efficiency optimization. This is achieved using advanced fabrication processes which create SiC MOSFETs with low parasitics while offering features such as high current capability, low on resistance resistance and high gate drive current; which allow for improved power density with reduced overall system costs.