摘要:
Methods, systems and apparatus are provided for estimating electrical angular speed of a permanent magnet machine based on two-phase stationary reference frame feedback stator current samples, and a dimensionless gain (K) that is computed based on a sampling time (T) and machine parameters.
摘要:
Systems and methods are disclosed to provide torque linearity in the field-weakening region for an electric (e.g., IPM) machine. The systems and methods implement a field weakening and a torque linearity control loop for linearizing torque generated by an electric machine. First and second voltage commands are used at the field weakening loop to generate a first adjusting current command. The first adjusting current command is then provided to the torque linearity control loop, where it is multiplied by a gain to generate an output current command, which can then be limited to generate a second adjusting current command. The second adjusting current command can then be added to a current command to generate an adjusted current command. The first adjusting current command can also be added to another current command to generate another adjusted current command. The adjusted current commands and feedback currents are then used at a synchronous current regulator to generate new first and second voltage commands. As a result, torque linearity is maintained when the electric machine operates in the field weakening region.
摘要:
A method is provided for controlling an induction motor having a rotor. The method includes receiving a torque command; comparing the torque command to a threshold torque value; generating, with a first estimation module, a first estimated rotor resistance when the torque command is less than or equal to the threshold torque value; generating, with a second estimation module, a second estimated rotor resistance when the torque command is greater than the threshold torque value; and generating control signals for the induction motor based on the first estimated rotor resistance or the second estimated rotor resistance.
摘要:
A temperature estimation controller and methods are provided for controlling a torque command to prevent overheating of one or more of a plurality of phases of a permanent magnet motor. The temperature estimation controller includes a low speed temperature estimation module, a transition module and a temperature dependent torque command derater block. The low speed temperature estimation module determines a stator temperature of each of a plurality of phases of the permanent magnet motor in response to first thermal impedances measured for each of the plurality of phases with respect to a thermal neutral. The transition module is coupled to the low speed temperature estimation module and outputs the stator temperature of each of a plurality of phases of the permanent magnet motor as determined by the low speed temperature estimation module when a detected speed of the permanent magnet motor is less than a first predetermined speed. The temperature dependent torque command derater block is coupled to the transition module and derates the torque command in response to the stator temperature of one or more of the plurality of phases.
摘要:
Methods and systems for controlling an electric motor are provided. An estimated rotor flux angular position error is generated based on estimated back electromotive force (EMF) values, and based on the estimated rotor flux angular position error, an estimated rotor flux angular position, an estimated electrical synchronous frequency and/or an estimated rotor frequency can be generated.
摘要:
A method and system for limiting the operating temperature of an electric motor is provided. A maximum operational temperature of the motor is determined. A current operational temperature within the motor is sensed. A maximum allowable power dissipation of the motor is calculated based at least in part on the maximum operational temperature and the current operational temperature of the motor. A torque command for the motor is generated based on the maximum allowable power dissipation.
摘要:
Methods and apparatus are provided for aligning a control reference axis with a magnetic north of a permanent magnet motor. The method includes the steps of injecting a predetermined stator current on an estimated reference axis of the permanent magnet motor and introducing predetermined error on the estimated reference axis. The method further includes the steps of determining if a speed of the permanent magnet motor is greater than a predetermined threshold speed and setting the control reference axis to 180° added to the estimated reference axis if the speed of the permanent magnet motor is greater than the predetermined threshold speed or setting the control reference axis to the estimated reference axis if the speed of the permanent magnet motor is less than or equal to the predetermined threshold speed.
摘要:
Methods and systems for controlling an electric motor are provided. A signal comprising at least first and second cycles is provided to the electric motor. A first flux value for the electric motor associated with the first cycle of the signal is calculated. A second flux value for the electric motor associated with the second cycle of the signal is calculated based on the first flux value.
摘要:
A temperature estimation controller and methods are provided for estimating stator winding temperature over a full range of motor operating speeds. In one implementation, the angular velocity of a motor is determined along with a total power loss for each phase of said motor. The total power loss in each phase comprises stator winding power loss and a core power loss. Stator winding temperatures for each phase of motor can then estimated based on the total power loss in that phase, and a combined thermal impedance for that phase. The combined thermal impedance comprises a first thermal impedance between the stator winding and the stator core, and a second thermal impedance between the stator core and the motor coolant.
摘要:
Methods, system and apparatus are provided for low speed sensorless rotor angular position estimation that implements reduced switching loss PWM waveforms.