The world is undergoing an energy revolution. According to the report of the International Energy Agency, by 2026, renewable energy will account for about 95% of the global energy growth. Solar energy will account for more than half of these 95%.
Nowadays, driven by ambitious clean energy goals and government policies, the adoption of renewable energy in the solar, electric vehicle (EV) infrastructure, and energy storage sectors is accelerating. The gradual popularization of renewable energy also provides more opportunities for deploying power conversion systems in industrial, commercial, and residential applications. The use of broadband gap devices such as silicon carbide (SiC) can help designers balance four major performance indicators: efficiency, density, cost, and reliability.
Advantages of SiC compared to traditional IGBT based power applications in renewable energy systems
SiC power switch and Insulated-gate bipolar transistor (IGBT) are common power switches for high-power applications such as renewable energy systems. Figure 1 shows the typical switching frequencies and power levels of SiC power switches and IGBTs. Both are applicable to power levels of 1kW and above.
Compared with traditional silicon power switches such as IGBT, SiC power switches have many performance advantages in high-power renewable energy applications.
The first performance advantage is that it has lower resistance and capacitance compared to IGBT, which can reduce power loss and help improve efficiency. SiC power switches can support switching speeds much higher than IGBTs, thereby helping to reduce switching losses and improve power conversion efficiency. This means that higher energy output and maximum output of power converter are crucial in renewable energy systems such as Solar inverter, energy storage system or DC fast charging power module.
Many renewable energy applications have a small operating area and generate a large amount of heat, driving designers to continuously explore ways to reduce printed circuit board size and maximize heat dissipation. The working temperature of SiC is higher than that of IGBT, which makes SiC power switches have higher thermal and mechanical stability, enabling more compact power electronic product design.
Using a gate driver to drive SiC
Based on the characteristics of SiC power switches, driving SiC power switches requires special considerations. The selection of gate drivers will have a reasonable impact on the performance of SiC in applications.
SiC power switches require gate drivers capable of handling high voltage and rated current. The gate driver must provide sufficient gate charge to switch the SiC power switch and prevent voltage spikes.
Compared with IGBT, SiC power switches are more susceptible to short circuits, leading to serious damage to power electronic systems. Usually, the short-circuit withstand time of IGBT is about 10 µ s, while the short-circuit withstand time of SiC is about 2 µ s. In view of this, when designing with SiC power switches, it is important to consider adding protective components that provide characteristics such as desaturation or overcurrent protection. Some gate drivers, such as UCC21710 gate drivers, have built-in short-circuit protection features that can detect and respond to short-circuit events.
Although SiC power switches can operate in higher temperature environments, monitoring the thermal performance of SiC power switches and preventing overheating remains crucial. In addition to the built-in short-circuit protection feature, the UCC21710 also has an integrated sensor for monitoring, eliminating the need to deploy discrete temperature sensors.
To fully utilize the power output of renewable energy systems, it is necessary to maximize efficiency while achieving a balance between cost, size, and reliability. SiC power switches have many advantages in high-power applications and are an ideal choice for solar and electric vehicle charging. To maximize the impact of SiC on these applications, TI provides gate driver products optimized for SiC power switches. These gate driver products have multiple power levels and varying degrees of integrated protection, which can help simplify SiC power supply design.
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