Abstract: Power conversion systems and a controller thereof include a processing system that generates inverter switching control signals at a switching frequency, and transitions the switching frequency from a starting frequency to a target frequency over an integer number N blocks. The individual blocks include an integer number M subblocks with a starting frequency subblock in which the processing system generates the switching control signals at the starting frequency, and a target frequency subblock in which the processing system generates the switching control signals at the target frequency. The processing system operates the inverter at multiple demanded voltage values for multiple characterized switching frequencies, measures and records a corresponding inverter output current value for each of the demanded voltage values, creates and stores a lookup table for adjusted demand voltages at each of the characterized switching frequencies, and operate the inverter according to the adjusted demand voltages.

Abstract: A system may include an inverter configured to convert a direct current (DC) voltage to an alternating current (AC) voltage. The system may also include a control system communicatively coupled to the inverter. The control system may receive a torque current feedback from a motor and may generate, based on the torque current feedback, a command torque current and a command flux current. The control system may generate, based on the command torque current and the command flux current, a command torque voltage and a command flux voltage and may generate, based on a slip frequency and a rotor frequency, a command frequency. The control system may determine one or more operating parameters for the inverter based on the command frequency, the command torque voltage, and the command flux voltage and may control the inverter based on the one or more operating parameters.

Abstract: A system may include an inverter configured to convert a direct current (DC) voltage to an alternating current (AC) voltage. The system may also include a control system communicatively coupled to the inverter. The control system may receive a torque current feedback from a motor and may generate, based on the torque current feedback, a command torque current and a command flux current. The control system may generate, based on the command torque current and the command flux current, a command torque voltage and a command flux voltage and may generate, based on a slip frequency and a rotor frequency, a command frequency. The control system may determine one or more operating parameters for the inverter based on the command frequency, the command torque voltage, and the command flux voltage and may control the inverter based on the one or more operating parameters.

Abstract: For counter electromotive force estimation, a disturbance estimator calculates an estimated disturbance as a control function of a quadrature axis current regulator output signal and a quadrature axis current feedback signal of a running permanent magnet motor. A calculator calculates an estimated counter electromotive force of the running permanent magnet motor as a function of the estimated disturbance, a control flux, and an angular velocity.

Abstract: For predicting a load pattern, a method determines a torque error from a torque reference modified by a low pass filter function of the torque reference. The torque reference is one of measured from an induction machine energized by a flux current and a torque current and calculated in an induction machine controller. The method determines a torque increase pulse in response to a torque relative variation calculated from the torque error exceeding an increase threshold. In response to detecting the torque increase pulse, the method determines a change delay time from the torque relative variation and the torque increase pulse. The method further determines a change period from at least two torque increase pulses. The method increases the flux current before a change time that is predicted as a function of the change delay time and the change period.

Abstract: Power conversion systems and a controller thereof include a processing system that generates inverter switching control signals at a switching frequency, and transitions the switching frequency from a starting frequency to a target frequency over an integer number N blocks. The individual blocks include an integer number M subblocks with a starting frequency subblock in which the processing system generates the switching control signals at the starting frequency, and a target frequency subblock in which the processing system generates the switching control signals at the target frequency. The processing system operates the inverter at multiple demanded voltage values for multiple characterized switching frequencies, measures and records a corresponding inverter output current value for each of the demanded voltage values, creates and stores a lookup table for adjusted demand voltages at each of the characterized switching frequencies, and operate the inverter according to the adjusted demand voltages.

Abstract: Power conversion systems and a controller thereof include a processing system that generates inverter switching control signals at a switching frequency, and transitions the switching frequency from a starting frequency to a target frequency over an integer number N blocks. The individual blocks include an integer number M subblocks with a starting frequency subblock in which the processing system generates the switching control signals at the starting frequency, and a target frequency subblock in which the processing system generates the switching control signals at the target frequency. The processing system operates the inverter at multiple demanded voltage values for multiple characterized switching frequencies, measures and records a corresponding inverter output current value for each of the demanded voltage values, creates and stores a lookup table for adjusted demand voltages at each of the characterized switching frequencies, and operate the inverter according to the adjusted demand voltages.

Abstract: Power conversion systems and a controller thereof includes a first processing system that computes phase references for respective phase lines of an inverter according to a feedback value, a setpoint value, and a scaling factor to emulate a scaled frequency that is less than a switching frequency, and a second processing system that generates a carrier waveform having the switching frequency, receives the phase reference from the first processing system for each inverter phase line, and compares each phase reference with the carrier waveform to generate pulse width modulated switching control signals for switching devices of the inverter.

Abstract: Power converters, controllers, methods and non-transitory computer readable mediums are presented, in which a processor operates a switching rectifier in a first mode to regulate a DC bus voltage signal using rectifier switching control for motoring rectifier operation when the measured DC bus voltage value is less than or equal to a first threshold value, operates the switching rectifier in a second mode to regulate the DC bus voltage signal using rectifier switching control for regenerative rectifier operation when the measured DC bus voltage value is greater than the first threshold value and less than or equal to a higher second threshold value, and operates an inverter in a third mode to regulate the DC bus voltage signal using inverter acceleration/deceleration control when the measured DC bus voltage value is greater than the second threshold value.

Abstract: Motor drives, methods and estimation systems are presented for estimating a rotor position of a motor load in which four sets of inverter output current samples obtained at four different sample times in a given inverter PWM cycle are converted into a corresponding stationary reference frame current value pairs, and the rotor position estimate is computed according to the stationary reference frame current values.

Abstract: Methods and apparatus are presented for sampling low side inverter phase currents, in which current sampling is selectively delayed in a given PWM cycle by a non-zero sampling delay time value from a nominal sample time if the middle pulse width value is less than a non-zero first threshold to facilitate adequate signal settling for accurate current measurement, and if a middle total continuous on-time near the end of the given PWM cycle is less than a non-zero second threshold, the middle total continuous on-time is selectively extended by adding a non-zero adjustment offset time value to a middle pulse width value for a next PWM cycle.

Abstract: Methods and apparatus are presented for sampling low side inverter phase currents, in which current sampling is selectively delayed in a given PWM cycle by a non-zero sampling delay time value from a nominal sample time if the middle pulse width value is less than a non-zero first threshold to facilitate adequate signal settling for accurate current measurement, and if a middle total continuous on-time near the end of the given PWM cycle is less than a non-zero second threshold, the middle total continuous on-time is selectively extended by adding a non-zero adjustment offset time value to a middle pulse width value for a next PWM cycle.

Abstract: Motor drives, methods and estimation systems are presented for estimating a rotor position of a motor load in which four sets of inverter output current samples obtained at four different sample times in a given inverter PWM cycle are converted into a corresponding stationary reference frame current value pairs, and the rotor position estimate is computed according to the stationary reference frame current values.

Abstract: Methods, control apparatus and computer readable mediums are presented for controlling a switching inverter in which a controller selectively suspends PWM carrier signals to provide inverter switching control signals using zero vectors in response to a maximal pulse width value for a present PWM half cycle being greater than a threshold value, and accumulates a present output control value for individual output phases for use in a subsequent PWM half cycle for selective effective reduction in switching frequency for low-speed operation while maintaining high frequency control loop sampling.

Abstract: Methods, control apparatus and computer readable mediums are presented for controlling a switching inverter in which a controller selectively suspends PWM carrier signals to provide inverter switching control signals using zero vectors in response to a maximal pulse width value for a present PWM half cycle being greater than a threshold value, and accumulates a present output control value for individual output phases for use in a subsequent PWM half cycle for selective effective reduction in switching frequency for low-speed operation while maintaining high frequency control loop sampling.

Abstract: Motor drives and control methods are presented for sensorless motor speed control in which inverter output currents are sampled from the inverter output and a frequency modulation value is determined based on the current feedback. A speed or frequency setpoint is adjusted at least partially according to the frequency modulation value to provide an adjusted frequency or speed setpoint value that is then used in controlling the inverter to provide stability control to mitigate hunting or motor stoppage.

Abstract: Motor drives and control methods are presented for sensorless motor speed control in which inverter output currents are sampled from the inverter output and a frequency modulation value is determined based on the current feedback. A speed or frequency setpoint is adjusted at least partially according to the frequency modulation value to provide an adjusted frequency or speed setpoint value that is then used in controlling the inverter to provide stability control to mitigate hunting or motor stoppage.

Abstract: A method and apparatus for stopping an AC motor that is controlling a load while detecting mechanical brake slippage of a mechanical brake for holding the load against movement includes a controller for decreasing torque-producing current commands from the drive while a speed regulator is commanding zero speed, sensing movement of the load while the speed regulator is commanding zero speed, detecting movement of the load past a pre-determined distance limit, and increasing torque to support the load and prevent further movement of the load. The controller will again decrease torque-producing current commands from the drive, and again checking for movement of the load, and upon sensing no load movement upon reaching zero torque, then shutting off the motor.

Abstract: A method and apparatus for braking an AC motor in the higher portion of its speed range includes substantially reducing flux before applying reverse torque commands to brake the motor. A DC link bus regulator is employed to prevent increases in bus voltage and frequency.

Abstract: A method and apparatus for maintaining both a DC bus voltage and a motor current within limit values wherein, when a voltage limit condition occurs, a voltage error (i.e. DC bus voltage limit minus DC bus voltage) is used to increase an inverter output frequency until the voltage limit condition subsides, and, wherein during a current limit condition a current error signal (i.e. motor current limit minus motor current) is used to reduce inverter output frequency until the current limit condition subsides, a slew rate used to control the output frequency when neither a current nor a voltage limit condition exists, the slew rate decreased as a function of the voltage limit period durations and increases a function of the current limit period durations.