Initial position detection of an electric motor
AssigneeNXP USA, Inc.
InventorsJianqiu Hu, Huabiao Tang
Life of this patent
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Abstract
A method for initial position detection of an electric motor includes determining a delta voltage for each of three pairs of stator windings by sequentially energizing and deenergizing each pair. The delta voltage is measured through a non-energized stator winding connected to a center tap of each respective pair. A minimum delta voltage is determined from an absolute value of a minimum of the three delta voltages. The minimum delta voltage is associated with a remaining stator winding not included in the respective pair. The two delta voltages not associated with the minimum delta voltage are compared to determine the proximity of the remaining stator winding to one of a D-axis of a rotor of the electric motor and a Q-axis of the rotor.
Claims20
A method for initial position detection of an electric motor comprising:
- for each of a respective pair of stator windings selected from two of three stator windings, wherein each of the three stator windings are connected to a neutral node, determining a respective stator delta voltage, each respective stator delta voltage being one of a plurality of delta voltages determined by applying a first voltage pulse across the respective pair while measuring a respective first voltage of the neutral node, applying a discharge path across the respective pair while measuring a respective second voltage of the neutral node, and determining the delta voltage by subtracting the respective first voltage from the respective second voltage;
- determining a minimum delta voltage from a minimum of an absolute value of each of the three respective stator delta voltages, the minimum delta voltage associated with a remaining stator winding of the three stator windings not included in the respective pair;
- determining a proximity of the remaining stator winding corresponding to the minimum delta voltage to one of a D-axis of a rotor of the electric motor and a Q-axis of the rotor by comparing the stator delta voltages of the two stator windings not associated with the minimum delta voltage;
- and
- determining a rotor polarity of the rotor by comparing a first rotor delta voltage to a second rotor delta voltage, wherein the first rotor delta voltage and the second rotor delta voltage are each one of the plurality of delta voltages determined from a pair of stator windings including the remaining stator winding associated with the minimum delta voltage.
An apparatus comprising:
- a rotor of an electric motor, the rotor comprising a Direct (D)-axis and a Quadrature (Q)-axis, wherein the D-axis defines a first path of maximum reluctance of the rotor and the Q-axis defines a second path of maximum generated torque;
- and
- a plurality of stator windings of the electric motor, wherein three pairs of stator windings are chosen from the plurality of stator windings;
- and
- a controller configured to:
- determine a delta voltage for each pair of stator windings by sequentially energizing and deenergizing each pair, wherein the delta voltage is measured through a non-energized stator winding connected to a center tap of each respective pair,
- determine a minimum delta voltage from a minimum of an absolute value of each of the three delta voltages, wherein the minimum delta voltage is associated with a remaining stator winding not included in the respective pair, and
- compare the two delta voltages not associated with the minimum delta voltage to determine the proximity of the remaining stator winding to one of the D-axis of the rotor and a Q-axis of the rotor.
A method for initial position detection of an electric motor comprising:
- determining a delta voltage for each of three pairs of stator windings by sequentially energizing and deenergizing each pair, wherein the delta voltage is measured through a non-energized stator winding connected to a center tap of each respective pair;
- determining a minimum delta voltage from a minimum of an absolute value of each of the three delta voltages, wherein the minimum delta voltage is associated with a remaining stator winding not included in the respective pair;
- and
- comparing the two delta voltages not associated with the minimum delta voltage to determine the proximity of the remaining stator winding to one of a Direct (D)-axis of a rotor of the electric motor and a Quadrature (Q)-axis of the rotor, wherein the D-axis defines a first path of maximum reluctance of the rotor and the Q-axis defines a second path of maximum generated torque.
Dependencies are inferred from the claim text.