Microinverters have obvious advantages, and their costs are gradually declining to expand their application markets.

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

Microinverters have obvious advantages, and their costs are gradually declining to expand their application markets.

Posted Date: 2024-02-06

Electronic Enthusiast Network reported (Text/Li Ningyuan) As one of the important pillar industries to achieve carbon peak and carbon neutrality, the photovoltaic and energy storage industry has seen steady growth in market size in recent years. This hot market has also driven the development of the inverter industry. develop. Inverters play an important role in many daily electrical equipment.

In the application of photovoltaic energy storage, there are roughly three types of inverters: centralized inverters, string inverters and micro-inverters. As energy storage applications move into daily life, microinverters are becoming a key technology to make renewable energy more accessible and more scalable.

Expand application scope, micro-inverter accelerates growth

Microinverters are called micro because they are compared to centralized inverters. Centralized inverters connect multiple parallel photovoltaic strings to the same centralized inverter for inversion. The power is very high, usually in the megawatt level, and is used in large photovoltaic systems. The micro-inverter performs independent inverter control on each component, has component-level MPPT, and its power will not exceed 1,000 watts.

MPPT at the microinverter component level brings unique advantages to microinverters. The full name of MPPT is maximum power point tracking. This technology can adjust the output power of the photovoltaic array according to different environmental characteristics of the outside world, so that the output power is always maintained at the maximum state.

The micro-inverter performs independent inverter control on each component, which not only greatly improves the safety of the entire system, but also enables the inversion control of individual photovoltaic modules to achieve the maximum power of each photovoltaic module individually. Point tracking adjusts the power of each photovoltaic module to the maximum before merging, which greatly reduces the power loss caused by the short board effect. Therefore, the micro-inverter has an advantage in the overall power generation efficiency.

However, for a long time, micro inverters have been subject to various factors such as higher cost and applicable scenarios. Compared with centralized inverters and string inverters, their application scope is quite limited and they are often only used. As an option for specific markets and specific household photovoltaics.

According to calculations by relevant agencies, the current installed cost of microinverters per watt is 1.2 yuan/W, which has dropped somewhat from before. The centralized/string type is 0.20 and 0.35 yuan/W. Judging from the shipments in recent years, the annual growth rate of micro-inverter shipments is rising, replicating the development path of string inverters and increasing market share through price reductions. The rapid development of technology has also reduced the cost of microinverters. As the price difference becomes smaller, the replacement process of microinverters will accelerate.

Electronics in microinverters

Micro inverters require many electronic components. Power devices such as IGBT and MOSFET, MCU main control, and driver are definitely indispensable. Magnetic components such as capacitors, resistors, and inductors are also widely used in inverters. And it affects the inverter performance to a considerable extent, in addition to current sensors, DC switches and other components.

Among them, inductors and transformers account for about 10% of the cost of micro-inverters, are used in large quantities in micro-inverters, and have a great impact on performance. The four major types of magnetic devices, main transformer, mutual inductor, differential mode inductor and common mode inductor, are a very classic combination in micro-inverters and are very common in flyback circuit topologies. In micro-inverters, these devices have a wide bandwidth and wide temperature range. Low loss requirements are very high, which can improve the overall conversion efficiency of micro-inversion.

Efficient conversion also requires accurate current measurement to support better power conversion, more precise system control and more effective protection. There are two methods of micro-reverse current measurement, low-side and high-side. The low-side uses shunt detection, which is low-cost but requires a lot of performance trade-offs. The high side can also be detected using a shunt, but it is very complex and costly. Now many use Hall current sensing for high side sensing, which can greatly reduce the difficulty.

The high-side current measurement of the Hall current sensor can accurately detect short circuits, minimize system power consumption, and reduce the impact of heat dissipation, greatly improving the reliability of the microinverter and also contributing to the efficiency of the microinverter.

How can micro-inverters balance high power density and heat dissipation in a small size? These requirements test the upstream hardware design and the technical accumulation of control programs of inverter manufacturers. With the advancement of technology and the decline of costs, micro-inverters are playing an important role in photovoltaic The penetration rate in the market is increasing year by year.


The boom in the photovoltaic industry in the past two years is obvious to all. There are many domestic inverter manufacturers that have doubled their shipments. Among them, the growth rate of micro-inverters is far faster than that of other inverters. Although micro-inverters are currently mainly used in Europe and the United States, the excellent characteristics of micro-inverters will have sufficient domestic application markets in the future with the popularity of domestic household photovoltaics.

#Microinverters #obvious #advantages #costs #gradually #declining #expand #application #markets