This disclosure features an apparatus including a motor controller to generate control signals to control an electric motor. The motor controller includes a first saturation controller to generate a first saturation controller output based on feedback signals associated with the electric motor. The motor controller further includes a duty ratio modulator coupled to the first saturation controller. The duty ratio modulator is configured to determine activation times for a set of voltage vectors based on the first saturation controller output. The motor controller is configured to generate, at each switching cycle, a control signal based on the set of voltage vectors and the activation times for the set of voltage vectors, and provide the control signal for controlling the electric motor.

A method for controlling a variable speed drive arranged for powering an electric motor, the variable speed drive comprising a power part and a control part. The method comprises a preliminary phase of storing a set of predetermined levels of flux of the electric motor. Then, during a current phase, the method comprises selecting a level of flux from among the set of predetermined levels of flux and controlling the power part of the variable speed drive based on the selected level of flux as reference value.

A method for controlling a variable speed drive arranged for powering an electric motor, the variable speed drive comprising a power part and a control part. The method comprises a preliminary phase of storing a set of predetermined levels of flux of the electric motor. Then, during a current phase, the method comprises selecting a level of flux from among the set of predetermined levels of flux and controlling the power part of the variable speed drive based on the selected level of flux as reference value.

Provides a method for controlling an AC motor, including: receiving a torque command value; generating a command current based on the torque command, and a command voltage by using the generated command current in a current vector controller (CVC) current control mode; switching to a hexagon voltage manipulating controller (HVMC) voltage control mode when the command voltage enters a voltage limit area, and generating a command voltage in the HVMC voltage control mode; and controlling torque of an AC motor by using the command voltage that is generated in the CVC current control mode or the HVMC voltage control mode.

Provides a method for controlling an AC motor, including: receiving a torque command value; generating a command current based on the torque command, and a command voltage by using the generated command current in a current vector controller (CVC) current control mode; switching to a hexagon voltage manipulating controller (HVMC) voltage control mode when the command voltage enters a voltage limit area, and generating a command voltage in the HVMC voltage control mode; and controlling torque of an AC motor by using the command voltage that is generated in the CVC current control mode or the HVMC voltage control mode.

A method for controlling a three-phase electrical converter includes selecting a three-phase optimized pulse pattern from a table of pre-computed optimized pulse patterns based on a reference flux. The method includes determining a two-component optimal flux from the optimized pulse pattern and a one-component optimal third variable. The method includes determining a two-component flux error from a difference of the optimal flux and an estimated flux estimated based on measurements in the electrical converter. A one-component third variable error is determined from a difference of the optimal third variable and an estimated third variable. The optimized pulse pattern is modified by time-shifting switching instants of the optimized pulse pattern such that a cost function depending on the time-shifts is minimized. The method includes applying the modified optimized pulse pattern to the electrical converter.

A direct power conversion device includes a control unit. tb=1/|fdc−n×fL|. fdc is a frequency twice as high as a frequency of an AC power supply, fL is a frequency of periodic load fluctuations, and n is a positive integer that maximizes tb. In a half period of power supply during a period of tb, the half period including a timing at which peaks of a fundamental wave of load torque and an absolute value of a power supply voltage substantially coincide with each other, the control unit being configured to control the switching elements so that two or more local maximum points appear in the half period of power supply, in a waveform obtained by combining a second harmonic, a fourth harmonic, and a sixth harmonic of a power supply frequency contained in a waveform of an absolute value of a motor current vector.

A direct power conversion device includes a control unit. tb=1/|fdc−n×fL|. fdc is a frequency twice as high as a frequency of an AC power supply, fL is a frequency of periodic load fluctuations, and n is a positive integer that maximizes tb. In a half period of power supply during a period of tb, the half period including a timing at which peaks of a fundamental wave of load torque and an absolute value of a power supply voltage substantially coincide with each other, the control unit being configured to control the switching elements so that two or more local maximum points appear in the half period of power supply, in a waveform obtained by combining a second harmonic, a fourth harmonic, and a sixth harmonic of a power supply frequency contained in a waveform of an absolute value of a motor current vector.

A double virtual voltage vectors predictive torque control method without weighting factor for five-phase permanent magnet synchronous motor includes: obtaining the current component in the two-phase stationary coordinate system and the outputting voltage at k interval; one step delay compensation is performed to obtain the current component in the two-phase stationary coordinate system at k+1 interval; predicting the flux and torque of motor at k+1 interval; calculating the reference voltage vector needed by the motor at k±1 interval according to the deadbeat principle and selecting the first virtual voltage vector; selecting the second virtual voltage vector according to the voltage error tracking principle and calculating the duration of the first virtual voltage vector and the second virtual voltage vector respectively and then synthesizing the two vectors and outputting.

A double virtual voltage vectors predictive torque control method without weighting factor for five-phase permanent magnet synchronous motor includes: obtaining the current component in the two-phase stationary coordinate system and the outputting voltage at k interval; one step delay compensation is performed to obtain the current component in the two-phase stationary coordinate system at k+1 interval; predicting the flux and torque of motor at k+1 interval; calculating the reference voltage vector needed by the motor at k±1 interval according to the deadbeat principle and selecting the first virtual voltage vector; selecting the second virtual voltage vector according to the voltage error tracking principle and calculating the duration of the first virtual voltage vector and the second virtual voltage vector respectively and then synthesizing the two vectors and outputting.