Jingfuyuan Company: Driving the development and application of photovoltaic off-grid systems with technological innovation

The "Inverter Technology Seminar" sponsored by Shenzhen New Energy Industry Association, Shenzhen Solar Energy Society and organized by China Renewable Energy Society was held at Shenzhen Vocational and Technical College on September 19. Ou Haihui, technical director of Jingfuyuan, delivered a speech on "Driving the development and application of photovoltaic off-grid systems with technological innovation" at the conference. Ou explained in detail the difficulties currently encountered by photovoltaic off-grid systems and a series of solutions proposed by Jingfuyuan to solve these difficulties.

At present, there are two typical applications of photovoltaics, grid-connected systems and off-grid systems. The grid-connected system relies on the power grid and adopts the working mode of "self-generation and self-use, surplus power to the grid" or "full power to the grid", which is the role of "icing on the cake"; photovoltaic grid-connected power generation has national subsidies, and building photovoltaic power stations is an investment behavior. Customers are most concerned about the return on investment. The off-grid system does not rely on the power grid, and relies on the working mode of "storage while using" or "storage first and then use", which is a "helping hand in time". Photovoltaic off-grid is a rigid consumer demand, and customers are most concerned about product prices and product quality.

In modern daily life, we usually take electricity for granted. However, there are still more than 2 billion people living in areas with or without electricity in the world today. Take our country as an example. Due to differences in economic development levels, some people in remote areas in the west still have not solved the basic electricity problem and cannot enjoy modern civilization. Photovoltaic off-grid power generation can not only solve the basic electricity problem of residents in areas without or with little electricity, but also use local renewable energy in a clean and efficient manner, effectively solving the contradiction between energy and the environment. From the current point of view, the research on grid-connected technology has received enough attention, but the off-grid system still faces many difficulties, which restricts the application and development of photovoltaic off-grid.

Problems faced by off-grid photovoltaic

1. High initial investment: The photovoltaic off-grid power generation system is mainly composed of photovoltaic components, brackets, controllers, inverters, batteries and distribution systems, among which components and batteries account for the vast majority of the cost. Whether the proportion of the above two can be reduced has become an important factor in the off-grid mass application.

2. Complex system: The off-grid system must comprehensively consider the user's load type, power consumption, and local climate conditions. Complex calculations are required to reasonably configure the components, inverters, and batteries to maximize benefits. The system has many circuit points and is difficult to construct.

3. Single function and poor performance indicators: The product has single function, uses PWM controller, has no intelligent battery management, no AC interface, cannot be expanded, has weak load capacity, and poor impact resistance.

4. Poor reliability: Due to the instability of photovoltaic power generation, large changes in load power, long working hours, short life of lead-acid batteries, and many impact loads, the reliability of the off-grid system is poor, which affects the large-scale application of photovoltaic off-grid systems.

Shenzhen Jingfuyuan Company has launched a series of solutions to solve the problems of high investment, complex system and poor reliability of photovoltaic systems. The solutions mainly include the following core parts:

1. Functional integration, simplifying the complex: Jingfuyuan Company launched the XPI, ESS, and ETS series of off-grid inverter products. The inverter integrates solar controller, DC-AC inverter, AC-DC charger and other functions, which can reduce system investment, simplify system design, facilitate construction, and reduce initial investment costs.

2. Modular design and efficient use: XPI, ESS, ETS series off-grid products and solar controllers all adopt efficient modular design and multi-MPPT technology (up to 16 channels). On the one hand, they make full use of solar energy and greatly reduce the investment cost of solar panels. On the other hand, they can be flexibly expanded and easy to maintain.

3. Complete specifications, close to demand: The off-grid system is decentralized and independent, and the user load characteristics and power consumption environment are different. Jingfuyuan has launched 10 models including XPI, ESS, ETS, iPS, HSC, and more than 50 specifications of off-grid products to meet the actual needs of users to the greatest extent.

4. Multiple energy access and multiple energy storage methods: Supports access to mains electricity or diesel generators, forming complementary advantages between photovoltaics and other energy sources, and can significantly extend the battery life. Energy storage supports lead-acid batteries and lithium batteries (optional).

5. Powerful functions and flexible expansion: For medium and large power off-grid systems, it adopts full digital control technology and DZ transformer, fully supports three-phase 100% unbalanced load, and has multiple working modes, solar energy/mains power priority, and a built-in bidirectional converter in the system. It can support AC charging and multi-machine parallel operation, which is convenient for expansion.

6. Safe operation and reliability are fundamental: The inverter has a built-in isolation transformer and two-level overcurrent and overload protection, which can greatly reduce the damage to the equipment caused by impact loads. The intelligent battery charge and discharge management system effectively prolongs the battery life.

Jingfuyuan's various off-grid solutions have effectively promoted the application and development of photovoltaic off-grid systems. The company has achieved fruitful results in domestic photovoltaic poverty alleviation projects. Jingfuyuan's Sunaura500S series models have shipped more than 100,000 sets, accounting for more than 60% of the market share. Medium and large off-grid machines occupy more than 40% of the domestic market share. It is the company with the largest shipments of domestic photovoltaic off-grid inverters.