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US 11,705,834 B2Granted
Sensorless angle estimation for trapezoidal control
AssigneeTexas Instruments Incorporated
InventorsRajan Lakshmi Narasimha, David Patrick Magee
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Abstract
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.
Claims20
A method comprising:
- obtaining measurements of voltage signals and of a total current signal from a brushless direct-current (BLDC) motor having a rotor;
- determining, with processing circuitry, an angular position of the rotor or a commutation state of the motor according to a nonlinear motor model responsive to the measurements, in which the nonlinear motor model provides using a look-up table (LUT) of voltage offsets and at least one of the following as a function of current level and current slope:
- voltage thresholds, or zero-crossing time intervals, the determining further including
- determining a floating gate voltage with respect to a neutral voltage,
- determining an offset based on the total current signal and the voltage offsets of the LUT, and
- adding the determined offset to the determined floating gate voltage;
- and
- controlling, responsive to the determined angular position or the determined commutation state, the motor during a startup of the motor.
5 more elements
A system comprising:
- measurement circuitry adapted to be coupled to a brushless direct-current (BLDC) motor having a rotor, the measurement circuitry configured to:
- measure voltage signals and a total current signal of the BLDC motor;
- processing circuitry coupled to the measurement circuitry, the processing circuitry configured to determine an angular position of the rotor or a commutation state of the motor according to a nonlinear motor model responsive to the measurements, in which the nonlinear motor model provides with reference to a look-up table (LUT) of voltage offsets and at least one of the following as a function of current level and current slope:
- voltage thresholds, or zero-crossing time intervals, the processing circuitry further configured to:
- determine a floating gate voltage with respect to a neutral voltage,
- determine an offset based on the total current signal and the voltage offsets of the LUT, and
- add the determined offset to the determined floating gate voltage;
- and
- control circuitry coupled to the processing circuitry and adapted to be coupled to the BLDC motor, the control circuitry configured to provide motor control signals during a startup of the motor, responsive to the determined angular position or the determined commutation state.
6 more elements
Dependencies are inferred from the claim text.