Three-phase Bi-directional Voltage-source High Frequency Link Inverter

In recent years, DC/AC inverter is applied in many fields. Also is used in new energy sources, such as photovoltic cell, fuel cell. The conventional inverter adopts line-frequency transformer, so it has many disadvantages, such as big size, heavy weight. Line-frequency transformer was quit from many fields going with the development of high frequency technology. For overcoming such disadvantages, the concept of high-frequency inverter technology was proposed by Mr. Espelage in 1977. The high-frequency link inverter offers significant reduction in size and weight due to the absence of line-frequency transformer. The merits of HF link are widely recognized. Its application has covered areas such as Uninterruptible Power Supply (UPS), and renewable energy source systems. The two well-known HF link inverters are the "cycloconverter" and "DC-DC converter" types. The HF link inverter topology has been attracting special interests all over the world.There are some developmental directions about modern inverters, such as HF power transformation, unit power factor, low electro-magnetic interference, and bi-directional power flow. Single-phase HF link inverter has been used widely. Three-phase HF link inverter is being studied. By improving the circuit topology and control methods, the inherent problems are resolved, such as voltage surge, high power loss. Its development makes the progress of inverters, such as high power density, high efficiency, high reliability, no pollution, and intelligence.It is introduced that the development and application of high frequency link in...