The energy storage inverter integrates the functions of photovoltaic grid-connected power generation + energy storage power station. When the electric energy is surplus, the electric energy is stored, and when the electric energy is insufficient, the stored electric energy is inverted and output to the grid, which plays the role of peak shaving and valley filling. One of the main development directions in the future.

The photovoltaic inverter is the control center of the photovoltaic power generation system, which can convert the direct current generated by the components into alternating current for grid connection or load use. Photovoltaic inverter is mainly composed of power conversion module, microcomputer control module, EMI module, protection circuit, monitoring module, human-computer interaction module, etc. Its development depends on the development of electronic circuit technology, semiconductor device technology and modern control technology.

(1) Technology Trend 1: Power modularization accelerates string penetration, resonance between new and replacement demands

Photovoltaic inverters can be divided into centralized, string and micro inverters according to their working principles. Due to the different working principles of various inverters, the application scenarios are also different:

(1) Centralized inverters first confluence and then invert, and are mainly suitable for large-scale centralized power plants with uniform illumination. The centralized inverter firstly fuses multiple parallel strings to the DC input end, and after the maximum power peak tracking is performed, it is then converted into AC power centrally, usually with a single unit capacity of more than 500kw. Due to the high integration degree and high power density of the centralized inverter system, the cost is low, and it is mainly used in large-scale workshops with uniform sunshine, desert power plants and other large-scale centralized photovoltaic power plants.

(2) The string inverter first inverts and then fuses, and is mainly suitable for small and medium-sized rooftops, small ground power stations and other scenarios. The string inverter is based on the modular concept. After the individual maximum power peak tracking of 1-4 PV strings is performed, the DC power generated by it is first converted into AC power, and then boosted and connected to the grid. Therefore, the power Relatively centralized type is smaller, but the application scenarios are more abundant. It can be applied to various types of power stations such as centralized power stations, distributed power stations and rooftop power stations. The price is slightly higher than that of centralized power stations.

(3) The micro-inverter is directly inverted and connected to the grid, which is mainly suitable for household and small distributed scenarios. The micro-inverter tracks the maximum power peak value of each photovoltaic module independently, and then merges it into the AC grid through the inverter. Compared with the previous two inverters, it has the smallest volume and the smallest power. It is mainly suitable for distributed household and small distributed industrial and commercial rooftop power stations, but the price is high, and it is difficult to maintain once a fault occurs.

Benefiting from the increase in the proportion of distributed generation and the accelerated penetration of large-scale power plants, the market share of string inverters has gradually increased. According to GTM statistics, the global string inverter market share in 2019 was 52%, an increase of 11 pct compared to 2015. According to CPIA statistics, the market share of domestic string inverters in 2020 is 67%, an increase of 34.5 pct compared to 2016. The specific reasons are as follows:

(1) The string-type solution is the preferred choice for distributed photovoltaic power generation, and the increase in the proportion will directly drive the increase in the share of string-type:

The centralized photovoltaic power station has large investment, long construction period and large area, and is mainly built on large ground with uniform illumination. The centralized photovoltaic power station can make full use of the abundant and stable solar energy resources in the open space. Through the construction of large-scale photovoltaic power stations, it is connected to the high-voltage transmission system to supply long-distance recombination. power and agree to allocate power to users.

Distributed photovoltaic power plants have low investment threshold, fast construction, small footprint and flexible installation, which are the main directions of future photovoltaic development. Distributed power generation refers to the power supply system located near the user's location. In addition to the user's own use and nearby use, the power produced by it can also send excess power to the local distribution network. Due to the characteristics of dispersion and low energy density of solar energy resources, it has the natural advantages of distributed power generation. Due to the low threshold for centralized investment, high electricity price users in parks, large industries, industrial and commercial sectors are increasingly willing to utilize distributed power generation, which directly promotes the gradual increase in the market share of string inverters.

(2) The advantages of string inverter MPPT empowerment and maintenance convenience are significant. With the increase of single-unit power, the gradual reduction of the price difference and the centralized price difference accelerates the penetration of the large-scale power station market:

String inverters have the advantages of high power generation, high reliability, high safety, easy installation and maintenance, etc. When a module is blocked by shadows or fails, but because of the multi-channel MPPT, it will only affect the corresponding few The power generation of the string can minimize the damage, the array mismatch loss is small, and the efficiency is higher, and it is gradually applied in the large-scale power station market.

The main reason why string inverters have not been able to replace centralized inverters on a large scale before is that the cost is high, and the maximum power of a single unit is also limited by power devices and circuit layout. Iterative upgrades, the continuous development of superimposed power module technology, the continuous improvement of the power density of string inverters, the rapid decline in price, and the outstanding cost performance, more and more large-scale power stations choose to use string inverter solutions. According to PV-tech statistics, among the domestic central enterprise inverter centralized procurement projects announced in 2020, the bidding ratio of string inverters has reached a new high, accounting for 74%.

The demand for "addition + replacement" accelerates the outbreak of the photovoltaic inverter market. Different from the 25-30-year service life of photovoltaic modules, the service life of electronic components such as IGBTs used in photovoltaic inverters is generally 10-15 years, so the inverter needs to be replaced at least once during the operating cycle of photovoltaic power plants. In 2010 At that time, the new installed capacity of photovoltaics in the world has reached 17.5GW. As more photovoltaic power plants enter the period of technical transformation of the stock, the replacement demand will continue to grow.

(2) Optimization space 1: The localization of the industrial chain superimposes technology upgrades and iterations, and domestic production accelerates going overseas

The rigid cost of raw materials for photovoltaic inverters is the core focus of cost reduction. The cost of raw materials for photovoltaic inverters accounts for more than 80%, mainly including electronic components, mechanical parts and auxiliary materials. Product pricing is mainly based on cost plus, brand positioning and local market competition.

(1) The localization of the industrial chain promotes the reduction of procurement costs: the domestic manufacturing industry has developed rapidly, most raw materials have been localized, the general-purpose materials market is fully competitive, and the purchase price has dropped year by year, while integrated circuits and semiconductor devices still have high technical barriers. Provided by overseas manufacturers, localization is expected to further reduce procurement costs.

(2) Electronic and circuit technology upgrades help reduce costs and increase efficiency: In photovoltaic power generation applications, the cost of traditional inverters based on silicon-based devices accounts for about 10% of the system, but it is one of the main sources of system energy loss. The conversion efficiency of the photovoltaic inverter of the MOSFET power module can be increased from 96% to more than 99%, the energy loss can be reduced by more than 50%, and the cycle life of the equipment can be increased by 50 times, which can reduce the system volume, increase the power density and prolong the service life of the device.

Market penetration such as the United States and Japan still has potential for improvement, and the domestic inverter has a significant cost advantage, accelerating the optimization of the shipment structure overseas. Overseas markets have relatively high requirements for product performance and after-sales, and the competition atmosphere is relaxed. The inverters of photovoltaic power plants in the United States and Japan are still mainly provided by local brands; for example, two manufacturers, SolarEdge and Enphase, rely on technical and patent barriers, accounting for the US residential reverse. More than 80% share of inverters; Japan has a high entry barrier, and inverter manufacturers are mainly local companies such as TMEIC, Moron, and Panasonic.

Due to the weak price sensitivity of overseas end customers, domestic inverters have a significant cost advantage, product performance is no longer inferior to imported products, and the prices and gross profit margins of products exported overseas are significantly higher than domestic ones. Domestic inverter companies are accelerating their development of overseas markets. , continue to establish overseas channels and expand brand influence, the market share of Chinese inverter manufacturers among the top 10 manufacturers by shipments has rapidly increased from 13% in 2012 to 54% in 2020.

The output value of photovoltaic inverters will more than double in 2025, and the overseas market space will be broader. According to estimates, the global output value of photovoltaic inverters will reach 88.9 billion yuan in 2025, with a CAGR of 18% from 2020 to 2025, of which overseas markets will exceed 70 billion yuan.