Abstract: Devices are provided for field weakening control of a compressor, including the compressor and a main circuit unit providing power for the compressor. The devices include a compressor rotational speed obtaining unit, and a control unit that compares the rotational speed ? of the compressor with a rotational speed threshold ?1 of the compressor, and controls the main circuit unit according to comparison results. When the rotational speed ? is less than ?1, an output voltage of the main circuit unit is controlled at a fixed value. When the rotational speed ? is greater than or equal to ?1, the compressor is controlled not to enter the field weakening control temporarily and the output voltage of the main circuit unit is controlled to rise, the compressor is controlled to enter the field weakening control when the output voltage of the main circuit unit cannot continue to rise.

Abstract: A surge absorption circuit for a single-phase air conditioning system, including: an L line and an N line, where one end of each of the two is connected to a power source, and the other end of each is connected to one pin of a rectifier bridge; a common mode inductor, which includes a magnetic ring, and first and second common mode coils that are connected in series in the L line and the N line, respectively; a first surge absorption unit, which is connected to the side of the common mode inductor close to the power source and which comprises first and second varistors and a first discharge tube, where one end of each of the first and second varistors is connected to the L line and the N line respectively, and the other end of each is connected to each other and grounded by the first discharge tube.

Abstract: Devices are provided for field weakening control of a compressor, including the compressor and a main circuit unit providing power for the compressor. The devices include a compressor rotational speed obtaining unit, and a control unit that compares the rotational speed ? of the compressor with a rotational speed threshold ?1 of the compressor, and controls the main circuit unit according to comparison results. When the rotational speed ? is less than ?1, an output voltage of the main circuit unit is controlled at a fixed value. When the rotational speed ? is greater than or equal to ?1, the compressor is controlled not to enter the field weakening control temporarily and the output voltage of the main circuit unit is controlled to rise, the compressor is controlled to enter the field weakening control when the output voltage of the main circuit unit cannot continue to rise.