公开(公告)号：US20240056010A1

公开(公告)日：2024-02-15

申请号：US18449005

申请日：2023-08-14

Applicant: Danfoss (Tianjin) Ltd.

Inventor： Shizhong JI ,  Wanzhen LIU ,  Li YAO

IPC: H02P21/32 ,  H02P25/022

CPC classification number: H02P21/32 ,  H02P25/022 ,  H02P2207/05

Abstract: A method and apparatus for detecting an initial position of a rotor of a motor includes: switching on or off respective switches in respective connecting branches connected to respective phase windings of the motor so as to obtain different switch state combinations capable of supporting different phase states of the motor, wherein the different switch state combinations support inputting voltages for different phases to the motor; for each switch state combination, injecting a voltage and recording a start time; monitoring respective phase currents of the motor, including: stopping the injecting of the voltage in response to determining that at least one of the respective phase currents is greater than a current threshold during the injecting of the voltage; and recording an end time in response to determining that the respective phase currents are all attenuated to zero after stopping the injecting of the voltage; and calculating a time difference between the end time and the start time; and determining the initial position of the rotor based on respective time differences in different switch state combinations.

公开(公告)号：US20240218878A1

公开(公告)日：2024-07-04

申请号：US18400023

申请日：2023-12-29

Applicant: Danfoss (Tianjin) Ltd.

Inventor： Yingke SUN ,  Wanzhen LIU ,  Qingyue MENG ,  Li YAO ,  Shizhong JI

IPC: F04C28/08 ,  F04C18/02 ,  F04C28/28 ,  F04D29/66 ,  G01H1/00

CPC classification number: F04C28/08 ,  F04C18/0215 ,  F04C28/28 ,  F04D29/661 ,  G01H1/003 ,  F04C2270/051 ,  F04C2270/125 ,  F04C2270/86

Abstract: A control method includes: a detection step of: detecting a vibration amplitude of the compressor; a determination step of: determining whether the detected vibration amplitude of the compressor is greater than or equal to a predetermined threshold; and a speed adjustment step of changing a switching frequency of a frequency converter or/and modulate a frequency of the compressor if the detected vibration amplitude of the compressor is greater than or equal to the predetermined threshold. A compressor system is also provided by an embodiment. The control method and the compressor system make it convenient to know whether abnormal vibration of the compressor occurs, and can avoid the resonance frequency range.

公开(公告)号：US20230119389A1

公开(公告)日：2023-04-20

申请号：US17907818

申请日：2021-02-23

Applicant: Danfoss (Tianjin) Ltd.

Inventor： Wanzhen LIU ,  Yan LIN ,  Guangqiang LIU ,  Zhenyu WANG ,  Meng WANG ,  Shizhong JI ,  Li YAO

IPC: H02K1/276 ,  H02K21/14 ,  F25B31/02

Abstract: A rotor for an interior permanent magnet motor, an interior permanent magnet motor, and a compressor includes a rotor core, a plurality of U-shaped permanent magnet accommodating grooves, a plurality of first air grooves, and a plurality of first recesses, wherein the plurality of U-shaped permanent magnet accommodating grooves are arranged inside the rotor core at intervals; the plurality of first air grooves are provided outside the ends of the U-shaped permanent magnet accommodating grooves; and each first air groove is located on an extension line of the end of the corresponding U-shaped permanent magnet accommodating groove and is close to the outer contour of the rotor so as to form a plurality of first magnetic isolation bridges. Each first recess is recessed from the outer contour of the rotor towards the center of the rotor, starts from the end of the corresponding first magnetic isolation bridge at the outermost side of the rotor, and at most, extends to the first intersection point of the connecting line between the bottom center of the U-shaped permanent magnet accommodating groove and the center of the rotor, and the outer contour of the rotor, such that the air gap magnetic density generated between the outer contour of the rotor and the inner contour of a stator of the interior permanent magnet motor approaches a sine curve.