Permanent magnet synchronous motor rotor positioning control system and air conditioner

Abstract

The invention discloses a permanent magnet synchronous motor rotor positioning control system and an air conditioner. The control system comprises: a calculation unit which is used for calculating a target phase theta (i) of motor rotor positioning when i is greater than or equal to 1 and less than N: theta (1) = 0 degree, theta (i + 1) = theta (i) + [delta] theta, wherein N = 360 degrees / [delta] theta and is a multiple of 6, and i is a natural number; a storage unit that stores a target phase theta (i) ( i is greater than or equal to 1 and less than N) for starting a cycle; and a processing unit used for setting the d-axis current of the motor as a first value and setting the q-axis current of the motor as a second value in a motor rotor positioning stage, and controlling the motor rotor to be alternately positioned to a target phase theta (i) which is ranked from small to large in the starting cycle. The thermal stress of the power switch element in the three-phase power inverter is balanced by rotating the target phase positioned by the motor rotor, and the service life of the three-phase power inverter is prolonged.

Description

technical field [0001] The invention relates to the technical field of motor drive, in particular to a permanent magnet synchronous motor rotor positioning control system and an air conditioner. Background technique [0002] Permanent magnet synchronous motors (permanent magnet synchronous motor, PMSM) are mostly used in household appliances (such as air conditioners, refrigerators, washing machines, etc.), and the mainstream control algorithm for permanent magnet synchronous motors is field-oriented control (Field-Oriented Control, FOC). , also known as vector control. [0003] When the permanent magnet synchronous motor starts, the initial position of the rotor needs to be obtained in advance. The accuracy of the initial position of the rotor not only affects the control accuracy of the servo system, but also affects the operation stability of the permanent magnet synchronous motor, which in turn determines the overall control performance of the system. [0004] In fact,...

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Problems solved by technology

[0006] As the number of starts increases, the phase of each rotor positioning is 0 degrees, so the current of the power switching element of the upper bridge arm of the U phase is the largest each time, and the thermal stress it bears is greater than other power switching elements every time. According to normal use, it will fail first, resulting in the failure of the entire three-phase power inverter and shortening its service life

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