For users, the most concern is the use of the inverter. According to different uses, the inverter can be divided into general-purpose inverter and Dedicated inverter.
1. Universal inverter
Universal inverter is the largest number of inverter family, the most widely used one. As the name suggests, the general characteristics of universal inverter is universal. With the development of frequency conversion technology and the continuous expansion of market demand, general purpose inverters are moving in two directions: First, a low cost simple general purpose inverter which simplifies some system functions with energy saving as the main purpose, which is mainly used in Pumps, fans, blowers and other occasions for the system speed performance is not high demand, and has the advantages of small size, low prices and other advantages; the second is fully considered in the design process needs a variety of high-performance, versatile When in use, the inverter can be set by the user according to the characteristics of the load selection algorithm, and various alternative options provided by the manufacturer can be selected according to the needs of the system to meet the special needs of the system. In addition to all the applications of the simple inverter, the high-performance multi-functional universal inverter can also be widely used in occasions where the performance of the speed regulation system has high requirements such as elevators, numerical control machine tools and electric vehicles.
In the past, the universal inverter basically adopted a U / f control method with simple circuit structure, which was inferior to the VC method in terms of torque control performance. However, with the development of frequency conversion technology, some manufacturers have already introduced the universal frequency converter adopting VC in order to meet the demand of the increasingly competitive frequency converter market. This multi-function universal inverter can be switched to "U / f control operation" or "VC operation" mode according to user's requirements, but the price is in line with U / f universal inverter. Therefore, with the development of power electronic technology and computer technology, the cost-effective inverter will continue to improve in the future.
2. Dedicated inverter
(1) high-performance dedicated inverter.
With the development of control theory, AC speed regulation theory and power electronics, the VC of asynchronous motor has been developed. The AC servo system composed of VC inverter and its special motor has reached and surpassed the DC servo system. In addition, asynchronous motors have many advantages not found in DC servo systems, such as high environmental adaptability and easy maintenance. They are gradually replacing DC servo systems in high-speed and high-precision control.
(2) high-frequency inverter.
In the ultra-precision machining often use high-speed motor. In order to meet the requirements of its drive requirements, the use of PAM-controlled high-frequency inverters has resulted in output frequencies up to 3 kHz and a maximum speed of 18,000 r / min when driving a two-pole asynchronous motor.
(3) high-voltage inverter.
High-voltage inverters are generally high-capacity inverters with a maximum power of 8000 kW and voltage classes of 3 kV, 6 kV and 10 kV.