The key role of diodes in inverters

Basic principles and functions of inverters
Inverter is an important component of power electronic equipment, mainly used to convert direct current (DC) into alternating current (AC). Inverters are widely used in fields such as photovoltaic power generation systems, electric vehicles, and wind power generation. Its main function is to convert the direct current generated by solar panels or battery packs into alternating current compatible with the power grid for household or industrial use.

During the operation of an inverter, it involves the switching and regulation of current, as well as the transmission of energy. In this process, diodes, as important semiconductor components, undertake multiple important tasks, from unidirectional current conduction, overvoltage protection, to efficiency optimization, all of which rely on the contribution of diodes.

The role of diodes in inverters
Current rectification and protection
In the working principle of an inverter, direct current needs to be rectified and regulated before being converted into alternating current. A diode is one of the key components in a rectifier circuit, which can rectify the current in an AC power supply into a unidirectional current, providing assurance for subsequent voltage regulation and reverse current control.

In inverters, diodes are often used in rectifier bridge circuits to convert AC input current into DC current. During this process, the diode ensures that the current can only flow in one direction, thereby avoiding damage to the inverter system caused by reverse current. The efficient operation of rectifier diodes directly determines the energy conversion efficiency of inverters.

Prevent backflow and overvoltage protection
During the operation of the inverter, the output terminal of the inverter may experience voltage reversal, especially in solar power generation systems. Due to weather changes or insufficient nighttime lighting, the output current of the inverter may reverse to the solar panel. This situation not only affects the stable operation of the system, but may also cause damage to the equipment.

To address this issue, diodes are typically used in reverse current protection circuits in inverters. Diodes can quickly conduct when the current direction is incorrect, effectively preventing backflow and protecting inverters and other electrical components from damage.
In addition, diodes can also be used for overvoltage protection. When the output voltage of the inverter exceeds the design value, the diode will play a protective role, guiding the excessive voltage to a safe channel to prevent the circuit and equipment from being damaged by overvoltage.

Reduce switch losses and improve efficiency
Inverters usually use high-speed switching to control the on/off of current, and the switching characteristics of diodes have a significant impact on the efficiency of inverters. Traditional diodes may suffer from switching losses and long reverse recovery times, leading to unnecessary energy losses during high-frequency switching operations in inverters.

However, modern diode technology, especially the application of Schottky diodes and Fast Recovery diodes, significantly improves switching efficiency. Schottky diodes, due to their low forward voltage drop and fast switching speed, can effectively reduce switching losses and improve the overall efficiency of inverters. High speed recovery diodes can quickly restore conduction state in environments with high switching frequencies, further reducing energy loss.

Reduce electromagnetic interference (EMI)
The electromagnetic interference (EMI) generated by inverters during operation may affect surrounding electronic devices and even affect the stability of the power grid. The reasonable design and application of diodes in inverter circuits can help reduce the EMI noise of inverters.

For example, by optimizing the selection and layout of diodes, high-frequency noise and voltage spikes in the current waveform can be reduced, thereby suppressing electromagnetic interference. Low loss, high-speed diodes such as Schottky diodes and fast recovery diodes can effectively reduce the interference noise generated by switching moments and improve the electromagnetic compatibility (EMC) of inverters.

The development trend of diode technology
With the development of emerging fields such as renewable energy, smart grids, and electric vehicles, the performance requirements for inverters are constantly increasing, which also puts higher demands on diode technology. The following are the development trends of diode technology in inverters in the future:

Application of wide bandgap semiconductor materials
At present, silicon-based diodes are no longer able to meet the high temperature, high frequency, and high power requirements of efficient inverters. Therefore, diodes based on wide bandgap semiconductor materials are gradually becoming a trend in inverter applications. Silicon carbide (SiC) and gallium nitride (GaN) materials have become the focus of future diode development due to their excellent high-temperature and high-frequency performance.

SiC diodes have high voltage resistance, low conduction loss, and fast switching characteristics, making them very suitable for high-power, high-frequency inverter applications. GaN diodes have higher efficiency and lower losses, making them suitable for inverters that require extremely high switching frequencies, such as DC-AC inverters for electric vehicles.

Integrated and modular design
With the development of inverter design towards integration and modularization, the integration level of diodes is also constantly improving. In the future, more integrated diode modules may be used in inverters, combined with other electronic components such as power MOSFETs, IGBTs, etc., to form an integrated power management system.

Integrated design can reduce the volume and weight of circuits, improve system stability and reliability, simplify manufacturing processes, and reduce costs. Through modular design, the functions of the inverter can be adjusted more flexibly to meet the needs of different application scenarios.

Intelligence and automation
With the advancement of intelligent technology, future inverters will not only rely on hardware upgrades, but also combine artificial intelligence, the Internet of Things, and other technologies to achieve intelligent control and optimization. As an important component in inverters, diodes will also be monitored in real-time for their working status and performance, and feedback and adjustment will be made with other system data.

For example, the working state of diodes may be monitored by sensors and dynamically optimized with AI algorithms for parameters such as current and voltage to improve the efficiency and stability of inverters. This intelligent feedback control system will be widely applied in future fields such as energy management and smart grids.

http://www.trrsemicon.com/diode/smd-diode/high-voltage-switching-diode-bas21h.html