Detailed Introduction and Principle of
Electric Compressors
An electric compressor is a crucial component of the air conditioning system in new energy vehicles' comfort systems. Its function is to compress low-pressure gaseous refrigerant into high-pressure gaseous refrigerant, which, through the action of the evaporator and condenser, transfers heat into or out of the passenger compartment.
In traditional gasoline vehicles, the compressor is driven by the engine via an electromagnetic clutch, rotating the compressor body to compress gas. New energy vehicles, lacking an engine, use an electric compressor controller that drives a permanent magnet synchronous motor to provide mechanical energy.
Structure of an electric compressor (scroll type): An electric compressor consists of a top cover, a sealing gasket, a stationary scroll, a moving scroll, cross slip ring, a main bearing housing, a balance weight, a rotor, a stator, a housing, glass terminals, a controller, electrical box cover, connectors, etc. It can be broadly divided into a stationary and moving scroll assembly, a permanent magnet synchronous motor, and a controller assembly, encompassing mechanical, motor, and inverter control boards, making it a complex electromechanical unit. Based on the amount of air compressed per revolution of the stationary and moving scrolls, compressor displacements are 27cc, 45cc, 66cc, etc.
A scroll compressor is a positive displacement compressor, with the compression component consisting of a moving scroll and a stationary scroll. Its working principle utilizes the relative revolution of the moving and stationary scrolls to create a continuous change in the closed volume, thereby compressing the gas.
Two scrolls, one moving and one stationary, with bifunctional equation profiles, are positioned 180° apart and mesh with each other. The moving scroll is driven by a crankshaft with a very small eccentricity and constrained by an anti-rotation mechanism, performing a small-radius planar motion around the stationary scroll. This motion, in conjunction with an end plate, forms a series of crescent-shaped cylindrical working volumes.
