Abstract: An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

Abstract: An air conditioning system and an air conditioner having the same are provided. The air conditioning system comprises a compressor, an indoor heat exchanger, an outdoor heat exchanger, a directional control assembly, a first throttling element, a second throttling element, a gas-liquid separator and a liquid reservoir. The compressor comprises a first cylinder, a second cylinder, an exhaust port and a gas return port; an exhaust volume ratio of the second cylinder to the first cylinder is less than or equal to 0.1.

Abstract: The present disclosure provides a method and a device for controlling a power factor on motor side and a system having the same, and the method includes: controlling the motor using a control approach of Id?=0 so as to obtain quadrature-axis voltage Uq? and direct-axis voltage Ud? in a virtual coordinate system of a current control cycle; calculating a first control value according to Uq? and Ud?; obtaining a power factor control target value, and calculating a target control value according to the power factor control target value; performing a PI control on a difference between the target control value and the first control value so as to obtain a coordinate deviation angle, and overlapping the coordinate deviation angle to a motor angle of the current control cycle so as to build a virtual coordinate system of a next control cycle, such that the power factor on the motor side is controllable.

Abstract: The present disclosure provides a method and a device for controlling a power factor on motor side and a system having the same, and the method includes: controlling the motor using a control approach of Id?=0 so as to obtain quadrature-axis voltage Uq? and direct-axis voltage Ud? in a virtual coordinate system of a current control cycle; calculating a first control value according to Uq? and Ud?; obtaining a power factor control target value, and calculating a target control value according to the power factor control target value; performing a PI control on a difference between the target control value and the first control value so as to obtain a coordinate deviation angle, and overlapping the coordinate deviation angle to a motor angle of the current control cycle so as to build a virtual coordinate system of a next control cycle, such that the power factor on the motor side is controllable.

Abstract: A method for suppressing a speed fluctuation of a permanent magnet synchronous motor is provided in the present disclosure, including: obtaining a target speed ?_ref, a feedback speed, a fluctuation speed ??, a q-axis inductance Lq and a permanent magnet flux linkage ?f of the permanent magnet synchronous motor; performing a PI adjusting on ?? to obtain a q-axis reference current Iq_ref, and obtaining a q-axis target voltage U*q according to Iq_ref, ?_ref, ?? and ?f; performing a PI control on a q-axis actual voltage according to U*q to obtain a q-axis compensation current Iq_add; obtaining a d-axis target voltage U*d according to Iq_ref, Iq_add, ?_ref, ?? and Lq; performing a PI control on a d-axis actual voltage according to U*d to obtain a d-axis compensation current Id_add; superposing Iq_add and Iq_ref to perform a feedforward compensation on a q-axis current and superposing Id_add and the d-axis reference current to perform a feedforward compensation on a d-axis current.

Abstract: A method for suppressing a speed fluctuation of a permanent magnet synchronous motor is provided in the present disclosure, including: obtaining a target speed ?—ref, a feedback speed, a fluctuation speed ??, a q-axis inductance Lq and a permanent magnet flux linkage ?f of the permanent magnet synchronous motor; performing a PI adjusting on ?? to obtain a q-axis reference current Iq_ref, and obtaining a q-axis target voltage U*q according to Iq_ref, ?—ref, ?? and ?f; performing a PI control on a q-axis actual voltage according to U*q to obtain a q-axis compensation current Iq_add; obtaining a d-axis target voltage U*d according to Iq_ref, Iq_add, ?—ref, ?? and Lq; performing a PI control on a d-axis actual voltage according to U*d to obtain a d-axis compensation current Id_add; superposing Iq_add and Iq_ref to perform a feedforward compensation on a q-axis current and superposing Id_add and the d-axis reference current to perform a feedforward compensation on a d-axis current.