Manufacturers and consumers are both trying to break free from their dependence on fossil fuel energy, and electrification solutions are therefore widely favored. This is of great significance for protecting the environment, limiting pollution, and mitigating the destructive trend of global warming. Electric vehicles (EVs) are becoming increasingly popular worldwide, and many companies are entering the market, attempting to transform commercial and agricultural vehicles (CAVs) into electric vehicles.

However, this transformation has led to a rapid increase in electricity demand, putting great pressure on the power grid. Despite their high energy efficiency, applications such as electric vehicles, data centers, and heat pumps still require a significant amount of energy to operate.

New renewable energy sources such as solar energy, wind energy, and wave energy are widely welcomed and gradually becoming mainstream. Only applications that fully utilize renewable energy can be considered truly "clean" applications.

The solar energy market has been developing for many years and is relatively mature. According to a report by Fortune Business Insights, the current solar market size is estimated to be $273 billion and is expected to grow to $436 billion by 2032. In 2023, the North American solar market will account for over 40% of the total market share.

Power Conversion Challenges in Renewable Energy Applications

The amount of solar power generation is rapidly increasing. According to data from the International Energy Agency (IEA), in 2022, solar generated electricity increased by 26% compared to the previous year, reaching 1300 TWh. This marks that solar power has surpassed wind power and become the largest renewable source of electricity.

Solar photovoltaic (PV) panels generate direct current (DC), while the power grid requires alternating current (AC), so central photovoltaic inverters are an indispensable part of large-scale grid connected devices. All the energy generated by photovoltaic panels will pass through the inverter, so the efficiency of the inverter has a significant impact. Although solar energy is inexhaustible, low conversion efficiency can result in very limited energy being transmitted to the grid. The energy wasted during the process will be converted into heat, which in turn poses a serious challenge, as many solar installations are typically located in environments with abundant sunlight and high temperatures, such as deserts.

Cost is also a very important consideration factor, which can directly affect consumers' electricity bills and the profitability of power companies. To achieve higher power, many central inverters use multiple conversion modules in parallel, with the specific number determined by the rated power of each module. The higher the power capacity of each module, the fewer modules are required, thereby reducing costs.

Although electric vehicles have made significant progress, CAVs are still making slow progress in transitioning to electric propulsion. CAVs have a larger body size and consume more fuel and generate more emissions per trip. Although they only account for 2% of the total number of vehicles, their greenhouse gas emissions account for 28% of the total transportation emissions. Although the electrification of commercial passenger vehicles (such as buses) has shown initial results, most large trucks, construction machinery, and agricultural vehicles (such as tractors) still rely on diesel propulsion. Now, the situation is starting to change. To meet the strict zero emission regulations of global markets such as the European Union, China, and California, it is expected that by 2030, the sales proportion of electric trucks (pure electric and hybrid) will increase from the current 5% to 40% -50%.

Compared to fossil fuel commercial vehicles, electric commercial vehicles have a simpler structure and fewer moving parts. Under the same load capacity, electric vehicles have smaller volume, higher reliability, and lower maintenance costs. At present, the cost of batteries has significantly decreased, and the total cost of ownership of electric CAVs is already lower than that of internal combustion engine (ICE) vehicles.

Similar to solar energy applications, efficiency is also a key requirement for electric CAVs. The battery capacity of each vehicle is limited, and the higher the efficiency of the conversion process in the inverter, the longer the distance traveled by the vehicle. Or the amount of electricity required to travel the same distance is even less.

Given our future reliance on solar energy and electric CAVs, reliability naturally becomes very important.

Advanced power technology for inverter applications

In high-power applications such as three-phase solar photovoltaic inverters, three-level active neutral point clamped (ANPC) converters are a common topology. This multi-level topology structure is specifically designed to enhance the performance and efficiency of the system.

A regular neutral point clamp (NPC) converter uses a diode to connect the neutral point of the DC link capacitor to the output terminal. In the ANPC configuration (Figure 1), clamping is performed by switches, which can improve control, reduce switch losses, and increase efficiency, and correspondingly reduce the need for heat dissipation measures, thereby helping to achieve smaller and lower cost solutions.

The arrangement of the topology structure reduces the voltage stress on each switch, thereby improving reliability. In addition, ANPC can also achieve waveforms that are beneficial to the power grid.

Design engineers can create high-performance three-level active neutral point clamping modules by paralleling multiple power modules, such as onsemi's QDual 3 IGBT module, with a system output power of 1.6 MW to 1.8 MW.

The QDual 3 module integrates the new generation of 1200 V Field Cut Off 7 (FS7) IGBT and diode technology, providing superior performance for high-power applications. Compared with previous generations of products, FS7 technology significantly improves conduction loss.

In the FS7 IGBT process, narrow trench platforms bring low VCE (SAT) and high power density, while proton injection multiple buffering ensures robustness and soft switching characteristics (Figure 2). The VCE (SAT) of the Ansen Meizu FS7 device is as low as 1.65V, making it suitable for motion control applications; The EOFF of its FS7 fast product is only 57 μ J/A, making it an ideal choice for high-power applications such as solar inverters and CAVs.

The innovative FS7 technology has reduced the chip size in the new QDual3 module by 30% compared to the previous generation (Figure 3). This miniaturization combined with advanced packaging can significantly increase the maximum rated current. In motor control applications with working temperatures up to 150 degrees Celsius, the output power of QDual3 ranges from 100 kW to 340 kW, which is approximately 12% higher than other products currently on the market.

Reliability is the key to solar and CAV applications, therefore the construction and testing methods of modules are crucial. For example, there are currently many similar solutions that use wire bonding to secure terminals, while Anson Mei chooses to use ultrasonic welding to weld modules. The latter helps to enhance the current carrying capacity, provide a better heat dissipation path, and is more robust than the former (Figure 4).

This method can increase conductivity, thereby reducing power loss and improving efficiency. In addition, it can reduce working temperature, enhance mechanical stiffness, and improve the overall reliability of the module.

Ansenmei's new high-power QDual3 technology

The dedicated QDual 3 half bridge IGBT module NXH800H120L7QDSG is suitable for central solar inverters, energy storage systems (ESS), and uninterruptible power supplies (UPS); SNXH800H120L7QDSG is suitable for CAV. These two devices are both built on FS7 technology, with improvements in VCE (SAT) and EOFF, thereby reducing losses and improving energy efficiency.

Currently, if a 1.725 MW inverter is designed using 600 A IGBT modules with ANPC/INPC architecture, a total of 36 modules will be required. However, if the new NXH800H120L7QDSG and SNXH800H120L7QDSG with a rated working current of 800 A are used, the required number of modules in the design will be reduced by 9. Correspondingly, the size, weight, and cost of the design will save 25%. This is very valuable for both solar energy applications and CAV applications, as weight reduction and efficiency improvement will increase the vehicle's mileage.

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Figure 6: Greater current capability supports the use of fewer modules to build the system

These modules include isolation boards for thermal management and integrated NTC thermistors, and support direct installation of modules onto PCBs through solderable pins, adopting industry standard layouts that help easily upgrade existing designs to the new QDual3 technology.

All QDual3 modules from Ansenmei have undergone rigorous reliability testing, and their reliability level exceeds that of other similar devices on the market. Our humidity testing requires the product to withstand a bias voltage of 960V for up to 2000 hours, while similar devices only need to withstand a bias voltage of 80V for 1000 hours. Vibration testing is crucial for CAV applications, and our product has been tested for up to 22 hours under 30G peak/10G RMS conditions, meeting AQG324 requirements. Other devices are tested under vibration levels as low as 5 G, with a duration as short as 1 hour.

summary

The use of renewable energy is increasing worldwide, and the power grid is under tremendous pressure. Solar power generation has matured and will surpass wind power as the main source of renewable electricity by 2022.

Although fossil fuel powered vehicles remain the main source of pollution, the electrification of CAVs is steadily advancing and is currently showing initial results.

New semiconductor technologies such as Ansenmei FS7 support the development of low loss, high-power devices to meet the efficiency and reliability requirements in these fields. Based on this technology, Anson's new QDual3 device adopts a compact package, which can achieve high power density and excellent energy efficiency. Well soldered terminals and certification testing that surpasses other devices in the industry help ensure the robust performance of QDual3 devices.

The new generation NXH800H120L7QDSG and SNXH800H120L7QDSG modules have a current capacity of up to 800 A. Thanks to this, the number of modules required for inverter design can be reduced by 25%, and the design can be further simplified, reducing its size, mass, and cost.

This is undoubtedly a significant progress, and Anson Mei will continue to focus on exploring the high-performance potential of FS7 technology, striving to launch more modules that exceed existing standards to meet the growing demand of the solar energy industry and CAV manufacturers.