What new demands does the rise of renewable energy pose for high-voltage diodes?

 

1, Breakthrough of technical parameters: from kilovolts to tens of thousands of volts

Traditional high-voltage diodes are mainly used in industrial frequency converters, rail transit, and other fields, with operating voltages mostly concentrated in the 600V-1700V range. However, with the expansion of renewable energy grid integration, the power system has put forward new requirements for the withstand voltage level of high-voltage diodes:

Voltage jump in DC transmission system

In the collection systems of photovoltaic power plants and wind farms, DC collection technology is becoming mainstream. Taking the Talatan Photovoltaic Base in Qinghai Province as an example, the ± 800kV ultra-high voltage direct current transmission line used requires the diode to withstand a reverse peak voltage exceeding 10kV. The vertical structure silicon carbide (SiC) diode developed by Taiji Semiconductor has achieved a 12kV withstand voltage level through deep trench etching and epitaxial growth technology, and the reverse recovery time has been shortened to 50 nanoseconds, which is 80% higher than traditional silicon-based devices.

Extreme environmental adaptation of offshore wind power

The floating offshore wind power platform sets strict standards for the salt spray and corrosion resistance of diodes. The metal encapsulated high-voltage diode developed by Weihai Huajie Electronics adopts hydrogen arc extinguishing and ceramic substrate technology, and can still operate stably in environments with 95% humidity and 5% salt spray concentration. Its lifespan has exceeded 200000 hours and it has become the designated component for Dongfang Electric's 15MW offshore wind turbine inverter.

Charge and discharge management of energy storage system

In the energy storage system of Ningde Times, the balancing diode needs to withstand the transient high voltage impact during the charging and discharging of the battery pack. The 5.1V voltage regulator diode used reduces the reverse recovery charge (Qrr) to one-third of that of traditional devices through gold doping technology, extending the battery life by 20% and increasing the equilibrium efficiency to 99.5%.

2, Deep Expansion of Application Scenarios: From Single Function to System Integration

The fluctuation characteristics of renewable energy drive the evolution of high-voltage diodes from traditional rectification functions to system level solutions:

The Efficiency Revolution of Photovoltaic Inverters

In the Huawei SUN2000-50KTL-H1 series inverter, the MUR1680CT ultra fast recovery diode (trr=80ns) is used in anti parallel with IGBT, reducing switching losses by 40%. Under light load conditions, its soft recovery characteristics effectively suppress voltage spikes, increasing Euro Efficiency to 98.7%, which is 1.2 percentage points higher than traditional solutions.

Reliability Upgrade of Wind Power Converter

The SiC Schottky diode used in Goldwind Technology's 2.5MW wind turbine maintains stable characteristics in the temperature range of -40 ℃ to 150 ℃, and the conduction voltage drop (VF) shows a negative temperature coefficient with increasing temperature, avoiding the risk of failure caused by local overheating during parallel use. This device has enabled the MTBF (mean time between failures) of the inverter to exceed 200000 hours and reduced the annual failure rate to below 0.3%.

Key support for the hydrogen energy industry chain

In the electrolysis hydrogen production system, high-voltage diodes need to withstand voltage fluctuations caused by frequent start stop of the electrolysis cell. The TVS (Transient Voltage Suppressing Diode) developed by Silan Microelectronics has a clamping voltage accuracy of ± 1% and a response time of less than 1 picosecond, effectively protecting the membrane electrode components of PEM electrolysis cells and maintaining the efficiency of the hydrogen production system at over 78%.

3, The paradigm shift of material innovation: from silicon-based to wide bandgap

The ultimate pursuit of energy efficiency in renewable energy systems drives the accelerated iteration of high-voltage diode material systems

Large scale application of silicon carbide (SiC)

Infineon CoolSiC ™ The series 1200V diode has a reverse recovery time of only 35 nanoseconds at a junction temperature of 25 ℃, and has a positive temperature coefficient characteristic, making it easy to expand in parallel. In the Tesla V3 Supercharging Station, this device increases the power density of the 350kW charging module to 5kW/in ³, with a charging efficiency of 99.2%, which is 1.5 percentage points higher than the silicon-based solution.

RF Breakthrough of Gallium Nitride (GaN)

In the photovoltaic power supply system of 5G base stations, Wolfspeed's GaN high electron mobility transistor (HEMT) integrates diodes to achieve signal rectification in the 24GHz-52GHz frequency band, reducing power consumption by 30% compared to silicon devices. This technology increases the daily power generation of the solar power supply system for base stations by 18% and reduces carbon dioxide emissions by over 2 tons annually.

Frontier exploration of gallium oxide (Ga ₂ O ∝)

The Ga ₂ O3 based diode developed by the Japan Fluorinated Fluid Technology Research Institute has a breakdown field strength of 8MV/cm, which is more than 10 times that of silicon. Although it is still in the laboratory stage, its theoretical withstand voltage level can exceed 10kV, which is expected to provide a disruptive solution for future ultra-high voltage direct current transmission.

4, Restructuring and Challenges of Market Pattern

The explosive growth of renewable energy is reshaping the market ecology of high-voltage diodes:

Structural changes on the demand side

According to Yole D é evelopment's forecast, the global high-voltage diode market is expected to reach $4.5 billion by 2027, with renewable energy accounting for over 40%. As the world's largest photovoltaic market, China's demand for high-voltage diodes is expected to exceed 8 billion by 2025, driving local enterprises such as Silan Microelectronics and Huatian Technology to occupy more than 60% of the market share.

Supply side technology competition

International giants such as Texas Instruments and Infineon are accelerating the layout of SiC production lines, while Chinese manufacturers are achieving curve overtaking through vertical integration models. For example, Sanan Optoelectronics has built a 6-inch SiC wafer fab with a monthly production of 50000 pieces, and its high-voltage diode yield rate is 95%, with a cost 20% lower than international peers.

The lag risk of standard system

The current IEC 60747 standard still uses silicon-based devices as the benchmark, and there are significant differences in parameters such as thermal expansion coefficient and packaging stress of wide bandgap materials. The industry urgently needs to establish high-voltage diode testing standards for new materials such as SiC and GaN to avoid quality hazards caused by missing standards.