Claw-Pole Motor Startup Using Reverse Pulse Commutation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Single-phase claw-pole motors in pumps face issues with incorrect start-up due to unfavorable latching positions, low latching torque, or excessive friction, leading to counter-torque during commutation, which can result in reversed rotational direction.
Innovation Solution
A method involving a brief pulse in the opposite direction based on an inverted Hall sensor signal is applied to the stator winding, followed by monitoring the Hall sensor signal to ensure correct start-up, with adjustments for supply voltage and pulse duration to overcome counter-torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor starts up from a favorable latching position, then the start-up reliability is improved, but the device cannot adapt to unfavorable latching positions caused by windmilling effects or friction
Solution Approach 1:
The method applies a preliminary reverse pulse before the main start-up pulse to prepare the rotor for correct rotation. By detecting the initial latching position with the Hall sensor and applying a reverse commutation pulse first, the system ensures the rotor overcomes unfavorable positions and friction before the main drive pulse is applied, thus improving start-up reliability across all latching positions.
Solution Approach 2:
The system uses the Hall sensor to continuously monitor the rotor position and provide feedback to the control unit. Based on this feedback about the current latching position, the control unit dynamically adjusts the commutation strategy, applying reverse pulses when needed and main drive pulses when appropriate, enabling the system to adapt to any initial rotor position.
2Reliability
If the latching torque is increased to overcome counter-torque, then the start-up in correct direction is improved, but the friction losses and energy consumption increase
Solution Approach 1:
Instead of continuously applying high torque, the method uses periodic pulsed commutation with alternating reverse and forward pulses. This periodic action builds up rotational momentum in controlled increments, overcoming counter-torque and friction only when necessary, rather than maintaining continuously elevated torque levels, thus reducing overall energy consumption while ensuring reliable start-up.
Solution Approach 2:
The system dynamically changes the commutation parameters (pulse duration, amplitude, and timing) based on the detected rotor position and load conditions. By adjusting these parameters rather than using fixed high torque, the system achieves reliable start-up with minimum necessary energy input, adapting to varying friction and counter-torque conditions.
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
Prevents incorrect start-up by ensuring sufficient momentum for the rotor to overcome counter-torque, thereby maintaining the correct rotational direction.
Implementation Method 1
a Hall sensor for determining the relative rotor position
Implementation Method 2
generating a pulse for moving the rotor in the direction opposite the running direction by energizing a stator winding
Data Source
AI summary
A method for starting up a rotor of a single-phase claw-pole motor, wherein the claw-pole motor comprises a permanently excited rotor which executes a movement in a running direction in nominal operation, an electronically commutated stator and a Hall sensor for determining the relative rotor position, wherein the method comprises the steps of generating a pulse for moving the rotor in the direction opposite to the running direction by energizing a stator winding on the basis of an inverted Hall sensor signal; and starting up the rotor for movement in the running direction by energizing a stator winding on the basis of a Hall sensor signal.