Single Hall Sensor Motor Control Circuit for Phase Commutation
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Solution Overview
Problem
The miniaturization of three-phase motors is hindered by the difficulty in miniaturizing the number of hall sensors required for phase commutation, as existing methods necessitate three hall sensors to determine the position of magnetic poles and control coil current switching.
Innovation Solution
A motor control circuit utilizing one hall sensor to sense the position of magnetic poles and execute phase switching through a full-bridge circuit, start controller, and operation controller, which drives the three-phase motor from a start state to a normal operation state by transmitting digital models sequentially to achieve phase commutation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three hall sensors are used to achieve phase commutation, then the motor operation reliability is improved, but the motor volume increases
Solution Approach 1:
The patent extracts and eliminates two of the three hall sensors from the system, retaining only one hall sensor while achieving the same phase commutation function through a combination of the single sensor, digital models, and microcontroller-based control logic
Solution Approach 2:
The patent changes the control approach from direct three-sensor feedback to a model-based control system where digital models store predetermined phase commutation patterns, and the microcontroller selects appropriate models based on hall signal transitions, thereby reducing sensor count while maintaining control accuracy
2Measurement precision
If three hall sensors are used for position sensing, then the phase commutation precision is improved, but the device complexity increases
Solution Approach 1:
The patent uses digital models as virtual copies of the three-sensor system's functionality. Six digital models store the phase commutation information that would otherwise require three physical sensors, allowing the system to replicate the measurement precision of three sensors using only one physical sensor combined with stored reference data
3Volume of moving object
If the number of hall sensors is reduced to one, then the motor miniaturization is improved, but the control system complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing all possible phase commutation scenarios in six digital models within the microcontroller. This allows the simplified one-sensor system to access predetermined control strategies, compensating for the reduced sensor information and managing control complexity through advance preparation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for the miniaturization of three-phase motors by enabling phase commutation with a single hall sensor, effectively reducing the number of sensors needed while maintaining motor operation efficiency.
Implementation Method 1
The hall sensor is configured close to the three-phase motor, and is configured for sensing a position of magnetic poles of the three-phase motor to generate a hall signal
Data Source
AI summary
A motor control circuit is disclosed, which uses one hall sensor to sense the position of the magnetic poles of three-phase motor, and to execute phase switching mechanism by start controller and operation controller. The motor control circuit drives the three-phase motor from a start state to a normal operation state. In the start state, the start controller controls the switching time and controls storage to transmit the digital models of the phase switching to the operation controller. The operation controller executes the phase switching of the full-bridge circuit according to the received digital models, to drive the three-phase motor. In the normal operation state, the start controller stops transmitting the digital models of the phase switching to the operation controller. The operation controller captures six digital models in sequence once every switching time, and executes the phase switching of the full-bridge circuit, to drive the three-phase motor.