Sensorless Motor Inverter Control Using Zero-Voltage Vector Pulses
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Solution Overview
Problem
Existing motor driving apparatuses for sensorless motors face inefficiencies and instability in current and speed control due to the reliance on pulse width modulation control, especially when a position sensor is omitted.
Innovation Solution
A motor driving apparatus that stops pulse width modulation control when a predetermined condition is met and applies a zero-voltage vector pulse to the switching signal to estimate current position and speed, stabilizing control when modulation is resumed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse width modulation control is continuously performed in sensorless motor control, then the motor can be driven, but efficiency is reduced and current/speed control stability deteriorates
Solution Approach 1:
The patent applies periodic action by alternately performing pulse width modulation control and zero-voltage vector pulse control. The controller switches between these two control modes periodically, using zero-voltage vector pulses at specific intervals to estimate rotor position and speed without continuous PWM control, thereby improving efficiency while maintaining control stability through periodic measurement updates.
2Device complexity
If position sensor is omitted for sensorless control, then device complexity is reduced, but measurement precision of rotor position and speed deteriorates
Solution Approach 1:
The patent uses zero-voltage vector pulses as an intermediary mechanism to indirectly measure rotor position and speed without direct sensor input. By injecting zero-voltage vector pulses and measuring the resulting current responses, the controller can estimate rotor state with sufficient precision, using the current measurement as an intermediary to obtain position information without physical sensors.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with an electrical measurement system. Instead of using physical position sensors that directly detect rotor position, the system uses electrical current measurements during zero-voltage vector pulses to infer position and speed through mathematical estimation, substituting mechanical detection with electrical sensing and computation.
3Measurement precision
If zero-voltage vector pulse is applied during pulse width modulation pauses, then position and speed estimation accuracy is improved, but control complexity increases
Solution Approach 1:
The patent applies universality by making the zero-voltage vector pulse serve multiple functions: it acts as both a control element for motor operation and a measurement probe for position/speed estimation. The same control hardware and switching elements used for motor control are utilized to generate measurement pulses, eliminating the need for separate measurement apparatus and reducing overall system complexity despite the enhanced measurement capability.
Data Source
AI summary
A motor driving apparatus and a method of driving the same are disclosed. The motor driving apparatus includes a motor, an inverter configured to drive the motor based on a switching signal, and a controller configured to output the switching signal when pulse width modulation control is performed, to stop the pulse width modulation control when a predetermined condition is satisfied, and to apply a zero-voltage vector pulse to the switching signal in a period in which execution of the pulse width modulation control is stopped, for determination of a current speed estimation value of the motor.