Common Types of Inverters

- Jan 15, 2019-

The small and medium power inverter power supply is one of the important links in the household independent AC photovoltaic system, and its reliability and efficiency are crucial to popularizing the photovoltaic system, effectively using energy and reducing the cost of the system. As a result, photovoltaic experts in various countries have been working to develop household-friendly inverter power supplies to enable the industry to grow better and faster.

Multiple series type The application of multi-series inverter to electric vehicle has many advantages. The type of output voltage vector of series structure is greatly increased, the flexibility of control is enhanced, the accuracy of control is improved, and the fluctuation of neutral point voltage of motor is reduced.

The bypass characteristics of the inverter increase the flexibility of charging and regenerative braking control. With people's growing concern about the urban environment, the development of electric vehicles has been a rare opportunity. In urban traffic, electric buses have become the target of priority development because of their large load and high comprehensive efficiency.

Electric buses mostly use three-phase AC motor, because of the large power of the motor, the device in the three-phase inverter needs to withstand the role of high voltage and large current stress, the higher dv/dt also makes the electromagnetic radiation serious, and needs good heat dissipation.

The high-power inverter with multiple series structure reduces the voltage stress of a single device, reduces the requirements for the device, reduces the DV/DT value, reduces the electromagnetic radiation, and greatly reduces the heating of the device, and has better control performance due to the increase of the output level type. Multi-series inverter is suitable for high-power electric vehicle drive system. The use of multiple series structure can reduce the danger caused by multiple battery series, reduce the switching stress of the device and reduce electromagnetic radiation.

But the number of batteries required has increased by twice times. The type of output voltage vector of multi-series structure is greatly increased, which enhances the flexibility of control and improves the accuracy of control, and reduces the fluctuation of neutral point voltage of motor. In order to maintain the balance of battery power in each group, it is necessary to ensure that the discharge time of the battery is consistent during operation.

By means of bypass, the battery pack can be flexibly charged, and the torque of regenerative braking can also be controlled.