Low-power two-phase alternating current frequency conversion system and electromotor thereof

Abstract

The invention discloses a low-power two-phase alternating current frequency conversion drive system. A power supply from a power grid is converted into a frequency conversion power supply to drive a three-phase electromotor.; the converted frequency conversion power supply is a two-phase power supply, which is provided with a common terminal, has the time lag equal to 1 / 6 of a period and has the same amplitudes; the two-phase power supply is connected to a three-phase terminal of a three-phase electromotor by the way that the common terminal is connected to a phase terminal of the electromotor and two output terminals of the two-phase power supply are connected to another two phase terminals of the electromotor; and the three-phase electromotor is provided with such a three-phase impedance that two-phase impedances of the two output terminals connected to the two-phase power supply are equal and are greater than a one-phase impedance of the common terminal. A two-phase impedance phase of the two output terminals of the two-phase power supply, which is connected to the electromotor, is 1.5 to 4.5 times of the one-phase impedance phase of the common terminal which is connected to the electromotor. The design can achieve the effect of improving asymmetry of the system, so the system improves efficiency and reduces noise caused by vibration.

Description

technical field [0001] The invention relates to a variable frequency drive system and its motor. In the International Patent Classification Table, the functional classification can belong to H02P7 / 00. Background technique [0002] The three-phase inverter drive three-phase motor system has been widely used in industrial equipment, but it is used for electric appliances powered by single-phase power supply with relatively small power. The inverter circuit appears to have too many units and insufficient component capacity. Complicated circuits have also become the weak link of the system. Usually, it is necessary to select better unit components or set up more complex protection circuits and control programs, and even use relatively expensive intelligent power modules (IPM) and 16-bit single-chip microcomputers, etc., which obviously affect the cost. . For this reason, the designer of the present invention proposes to drive a two-phase motor or a three-phase motor with a two-...

AI Technical Summary

Problems solved by technology

[0002] The three-phase inverter drive three-phase motor system has been widely used in industrial equipment, but it is used for electric appliances powered by single-phase power supply with relatively small power. The inverter circuit appears to have too many units and insufficient component capacity.

But when the actual circuit is running, the test result of the effective value of the voltage on the three input terminals of the motor is that the voltage U of the two-phase inverter output terminals A and B to the common terminal C CA and U CB Roughly equal, but lower than the fundamental voltage U between the two output terminals AB Small; the test result of the effective value of the current entering the three input terminals of the motor is that the output current I of the two-phase inverter output terminals (controlled terminals) A and B A and I B Roughly equal, but higher than the current I of the common terminal (non-controlled terminal) sub-C C The ratio is larger, which means that it is still undersymmetrical, which has an impact on efficiency and vibration and noise levels

Images