Power stations of wind and solar hybrid power generation systems are generally installed in remote areas far away from the power grid: such as forests and jungles, coastal watersheds, rivers and lakes, highways, desert areas, mountain areas, mining areas, offshore platforms, etc.; the inverter part of the power generation system belongs to As an important output component, the inverter operates continuously 24 hours a day when the system is running. If the selection is unreasonable, it can easily cause after-sales risks. Because the system is deployed in remote scenes, maintenance requires a lot of manpower and material resources, causing a lot of damage. Maintenance costs. There are various common inverters on the market, and the two common ones are high-frequency inverters and power frequency inverters. How to select the inverter used in Guangzhou Shanneng wind and solar hybrid power generation system?
High frequency inverter features:
Since the high-frequency inverter uses high-frequency magnetic core materials that are small in size and light in weight, the power density of the circuit is greatly improved, so that the no-load loss of the inverter power supply is very small and the inverter efficiency is improved. High-frequency inverters are composed of complex electronic component circuits, and the life of electronic components is designed to be about 1 to 2 years (depending on the frequency of use).
Features of power frequency inverter:
The power frequency inverter first inverts the DC power into power frequency low-voltage AC power, and then boosts it through the power frequency transformer into 220V, 50Hz AC power for the load. Various protection functions can be implemented at lower voltages. Because there is a power frequency transformer between the inverter power supply and the load, the inverter operates stably and reliably, has strong overload capability and impact resistance, and can suppress high-order harmonic components in the waveform. The iron loss of the power frequency transformer is basically unchanged during operation, but the operation loss is larger and the efficiency is lower.
Weight comparison between high frequency inverter and power frequency inverter
Inverters with the same power, power frequency inverters are much heavier than high-frequency inverters. High-frequency inverters are small in size, light in weight, high in efficiency, and low in no-load load, but they cannot be connected to full-load inductive loads, and Poor overload capability.
Comparison of the working principles of high frequency inverters and power frequency inverters
The high-frequency inverter circuit is more complex. The high-frequency inverter usually consists of an IGBT high-frequency rectifier, a battery converter, an inverter and a bypass. IGBT can be turned on and off by controlling the drive applied to the gate. The switching frequency of IGBT rectifier is usually from a few kilohertz to tens of kilohertz, or even as high as hundreds of kilohertz, which is much higher than that of a power frequency inverter. Therefore it is called high frequency inverter.
The power frequency inverter is designed based on the traditional analog circuit principle and consists of a thyristor (SCR) rectifier, IGBT inverter, bypass and power frequency boost isolation transformer. Because the working frequency of the rectifier and transformer is 50Hz, As the name suggests, it is called a power frequency inverter.
Comparison of conversion efficiency between high frequency inverter and power frequency inverter
The conversion efficiency of power frequency inverters is not as high as that of high-frequency inverters because complex hardware simulation circuits are burned into the microprocessor and the operation of the inverter is controlled by software programs. In addition to greatly reducing the size of high-frequency inverters, their conversion efficiency has also been improved.
Applied to comprehensive evaluation of wind and solar hybrid power generation systems:
For applications in power generation systems, it is recommended to use power frequency inverters as the leading product. The IGBT high-frequency rectifier used in high-frequency machines has a higher switching frequency, has strict voltage and current working areas, and has low impact resistance. After more than half a century of development and innovation, the technology of industrial frequency machine SCR rectifier has become very mature and its ability to withstand current shock is very strong. Since SCR is a semi-controlled device, there will be no faults such as shoot-through and false triggering. Therefore in terms of overall reliability, IGBT rectifiers are lower than SCR rectifiers. Considering the complexity of the installation environment (humidity, temperature, altitude) and the impact of after-sales cost issues, the system output is also a 24-hour continuous output, so the key issue of stability has to be considered more carefully.
Job Wang（Mr）
Shenzhen Lolsolar New Energy Technology Co.,Ltd
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