Electronic Expansion Valve Drive Control with Secondary Positioning
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Solution Overview
Problem
The existing drive techniques for electronic expansion valves in inverter air conditioners face issues with insufficient starting torque and positional deviations between the rotor and stator, leading to ineffective operation and misalignment, which affects the accurate control of the valve body opening.
Innovation Solution
A drive control method and device that performs secondary positioning on the motor before and after starting, using holding currents and additional pulse signals to enhance torque and maintain correct rotor positioning, ensuring accurate valve body opening control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electronic expansion valve is directly turned on and off at normal operating rate without secondary positioning, then the control is simple and fast, but the starting torque is insufficient and the rotor-stator alignment is incorrect
Solution Approach 1:
The patent applies preliminary action by performing secondary positioning before the motor starts rotating. A holding current is applied to the coil to generate a magnetic field that aligns the rotor with the stator magnetic poles, ensuring correct rotor-stator alignment before normal operation begins. This preliminary alignment prevents starting failures and ensures reliable operation from the beginning.
Solution Approach 2:
The patent segments the motor control process into distinct phases: a positioning phase with holding current applied before rotation, and a normal rotation phase with pulse signals. This segmentation allows the system to address the specific requirement of rotor-stator alignment separately from the rotation control, improving starting reliability without compromising overall control efficiency.
2Measurement precision
If holding current is applied for a long duration to maintain rotor position, then the positional accuracy is improved, but the energy consumption increases
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to apply holding current intermittently rather than continuously. The holding current is applied in periodic pulses during the positioning phase, maintaining rotor-stator alignment while reducing average energy consumption compared to continuous current application.
Solution Approach 2:
The patent applies partial action by using a holding current that is sufficient to maintain positioning during the critical phase before rotation, but not continuously throughout operation. The holding current is applied only when needed for positioning and during specific phases of operation, avoiding excessive energy consumption while maintaining adequate positioning precision.
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 approach effectively addresses the issues of insufficient starting torque and positional deviations, ensuring the electronic expansion valve can be correctly driven and maintained in the desired opening state, enhancing the reliability and performance of the air conditioning system.
Implementation Method 1
a current is applied to the coil, the magnetic field between the stator and the rotor of the motor forms a holding torque
Implementation Method 2
the controller sends a pulse control signal to the driving circuit to thereby drive the step motor to rotate to make the valve body reach a corresponding opening
Implementation Method 3
a current is applied to the stop pulse signal of the electronic expansion valve, thereby making the magnetic field between the stator and the rotor of the motor of the electronic expansion valve form a holding torque
Data Source
AI summary
A drive control method for an electric expansion valve is disclosed. In the disclosure, before applying a drive pulse signal corresponding to a rotary pulse number to a motor of the electronic expansion valve, a secondary positioning is performed on a relative position between stator magnetic field of the motor and rotor magnetic field of the motor by applying a holding current of a first duration time to the motor, applying an pulse signal of an additional pulse number to the motor, and applying a holding current of a second duration time to the motor, and a same secondary positioning operation is also performed on the motor after applying the drive pulse signal corresponding to the rotary pulse number to the motor of the electronic expansion valve, which ensures that the electronic expansion valve operates according to the drive pulse signal corresponding to the rotary pulse number.