Texas Instruments Corporation

Rajan Lakshmi Narasimha

David Patrick Magee

In described examples of methods and control systems to control a position and/or velocity of a machine, control circuitry is coupled to receive and dither a control signal, and to compute a control output value according to the dithered control signal and a control function. An inverter is coupled to the control circuitry, to control the position and/or velocity according to the control output value.

Position or velocity control system and method

Systems and methods for sensorless trapezoidal control of brushless DC motors provide effective high-torque startup and low speed operation without the use of Hall effect sensors or encoders during motor operation. The systems and methods also provide the ability to boost signal-to-noise ratio for motor startup and low speed operation via an augmenting supply voltage. Sampling architectures and current-dependent inductance modeling architectures for the control systems are also described.

Sensorless angle estimation for trapezoidal control

A motor controller includes current measurement circuitry and estimation circuitry. The current measurement circuitry is adapted to be coupled to a motor, and configured to measure current in the motor. The estimation circuitry is coupled to the current measurement circuitry, and includes a memory, current computation circuitry, and summation circuitry. The memory stores coefficients of a function for estimating current related to variation of inductance of the motor. The current computation circuitry is coupled to the memory, and is configured to compute a compensation current value based on the coefficients. The summation circuitry is coupled to the current compensation circuitry, and is configured to generate a position error signal by subtracting the compensation current value from a measured current value generated by the current measurement circuitry.

Rotor position estimation

A permanent magnet motor controller injects a periodic signal into a field oriented controller of the brushless motor. Phase currents in stator windings of the brushless motor are measured. A d-axis current and a q-axis current are determined with a transform of the phase currents. The d-axis current and the q-axis current are demodulated to extract an angle dependent current signature that includes a sine component of a rotor angle estimate and a cosine component of the rotor angle estimate. The rotor angle estimate is determined by processing the sine component and cosine component.

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Dallas, TX, United States of America

Rajan Lakshmi Narasimha