Common types of inverters

1. Small and medium power
Small and medium power inverters are one of the important links in household independent AC photovoltaic systems. Their reliability and efficiency are crucial to promoting photovoltaic systems, effectively using energy, and reducing system costs. Therefore, photovoltaic experts from various countries have been working hard to develop inverters suitable for household use to promote the industry to develop better and faster.
2. Multiple series type
Multiple series inverters have many advantages in electric vehicles. The output voltage vector types of the series structure are greatly increased, which enhances the flexibility of control and improves the accuracy of control; at the same time, it reduces the fluctuation of the neutral point voltage of the motor. The bypass feature of the inverter can improve the flexibility of charging and regenerative braking control.
With people's increasing concern for the urban environment, the development of electric vehicles has received a rare opportunity. In urban transportation, electric buses have become the priority development object due to their large load capacity and high comprehensive benefits. Most electric buses use three-phase AC motors. Due to the large power of the motor, the devices in the three-phase inverter need to withstand high voltage and high current stress. The higher dv/dt makes the electromagnetic radiation serious and requires good heat dissipation.
The high-power inverter with multiple series structure reduces the voltage stress of a single device and the requirements for the device; reduces the dv/dt value, reduces electromagnetic radiation, and greatly reduces the heating of the device; due to the increase in the types of output levels, the control performance is better.
Multiple series inverters are suitable for high-power electric vehicle drive systems. The use of multiple series structure can reduce the dangers of multiple batteries in series, reduce the switching stress of the device and reduce electromagnetic radiation. However, the number of batteries required has increased by 2 times.
The output voltage vector types of multiple series structure have increased greatly, thereby enhancing the flexibility of control and improving the accuracy of control; at the same time, the fluctuation of the neutral point voltage of the motor is reduced. In order to maintain the balance of the power of each group of batteries, it is necessary to ensure that the discharge time of the battery is consistent during operation. Through the bypass method, the battery group can be flexibly charged, and the torque of regenerative braking can also be controlled.
According to the nature of the wave chord
It is mainly divided into two categories, one is the sine wave inverter and the other is the square wave inverter.
The sine wave inverter outputs a sine wave AC power that is the same as or even better than the power grid we use in daily life, because it does not have the electromagnetic pollution in the power grid.
Sine wave inverter introduces sine wave inverter technology, explains the working principle of typical inverter mode in the development of sine wave inverter, and the working process of typical inverter circuit. The content includes: basic forms of inverter main circuit, such as voltage type current type... 
Square wave inverter outputs square wave AC of poor quality, and its positive maximum value to negative maximum value are generated almost at the same time, which causes severe instability to the load and the inverter itself. At the same time, its load capacity is poor, only 40-60% of the rated load, and it cannot carry inductive load. If the load is too large, the third harmonic component contained in the square wave current will increase the capacitive current flowing into the load, and in severe cases, it will damage the power supply filter capacitor of the load.
In response to the above shortcomings, quasi-sine wave (or improved sine wave, modified sine wave, simulated sine wave, etc.) inverters have appeared. There is a time interval between the output waveform from the positive maximum value to the negative maximum value, and the use effect is improved, but the waveform of the quasi-sine wave is still composed of broken lines, which belongs to the category of square wave and has poor continuity.
In summary, sine wave inverters provide high-quality AC power and can drive any type of load, but the technical requirements and costs are high. Quasi-sine wave inverters can meet most of our electricity needs, with high efficiency, low noise and moderate price, so they have become the mainstream products in the market. Square wave inverters are made with simple multivibrators, and their technology belongs to the level of the 1950s and will gradually withdraw from the market.
Inverters are divided into coal-fired inverters, solar inverters, wind inverters, and nuclear inverters according to different power sources. According to different uses, they are divided into independent control inverters and grid-connected inverters.
In the world, solar inverters are more efficient in Europe and the United States. The European standard is 97.2%, but the price is relatively expensive. The efficiency of other domestic inverters is below 90%, but the price is much cheaper than imported ones.
In addition to power and waveform, the efficiency of the inverter is also very important. The higher the efficiency, the less energy is wasted on the inverter, and the more energy is used for electrical appliances. This is especially important when you use a small power system.