Motor Wiring Mode Switching Control Using Inertial Rotor Estimation
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Solution Overview
Problem
Existing motor control methods for air conditioner compressors take a long time to switch between Y and Δ wiring modes, leading to inefficiency and pressure loss due to prolonged motor operation after switching, which increases power consumption and reduces compressor efficiency.
Innovation Solution
A motor control apparatus and method that calculates the rotor's position and speed during inertial rotation after PWM control is stopped, sets these values as initial conditions for the new mode, and adjusts the rotor's speed accordingly to minimize switching time and pressure loss, allowing for faster mode switching and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is stopped completely before switching wiring mode, then the switching can be performed safely, but the switching time becomes long and compressor pressure is lost
Solution Approach 1:
The controller performs preliminary estimation of rotor position and speed during the inertial rotation period (before complete stop) using mathematical models. This preliminary action allows the control system to be prepared with accurate initial values for the new wiring mode before the motor fully stops, eliminating the need to wait for complete cessation of rotation.
Solution Approach 2:
The controller skips the traditional waiting period for complete motor stoppage by rushing through the inertial rotation phase. By estimating rotor parameters during this brief transition period and using them as initial values for the new mode, the system compresses the switching time from a prolonged wait to a rapid transition.
2Reliability
If the motor is stopped completely before switching wiring mode, then the wiring can be switched without damage, but compressor pressure is lost and power consumption increases
Solution Approach 1:
The controller performs preliminary estimation of rotor position and speed during the inertial rotation period using mathematical models. This preliminary action allows the control system to be prepared with accurate initial values for the new wiring mode before the motor fully stops, eliminating the need to wait for complete cessation of rotation.
Solution Approach 2:
The controller skips the traditional waiting period for complete motor stoppage by rushing through the inertial rotation phase. By estimating rotor parameters during this brief transition period and using them as initial values for the new mode, the system compresses the switching time from a prolonged wait to a rapid transition.
3Loss of time
If the motor continues rotating during wiring switching, then switching time is reduced, but the control accuracy may deteriorate without proper initial values
Solution Approach 1:
The controller replaces direct mechanical measurement of rotor position and speed with mathematical estimation models. By using differential equations that model the motor's inertial rotation characteristics, the system calculates rotor parameters without requiring physical sensors or waiting for the motor to stop, maintaining high precision during the transition.
Solution Approach 2:
The controller changes the approach from direct measurement to parameter estimation by solving mathematical models. The system transforms the problem from measuring physical quantities during rotation to calculating them through differential equations that describe the motor's inertial behavior, enabling accurate control during mode switching.
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
The solution enables faster switching between motor wiring modes, reduces compressor pressure loss, and enhances the overall efficiency of air conditioner systems by controlling the motor's rotation based on estimated initial values during inertial states.
Implementation Method 1
a rotor of a motor rotates until a moment of inertia becomes smaller than a load torque
Data Source
AI summary
The present disclosure relates to an apparatus and method for controlling switching of a wiring mode of a motor capable of being operated in a plurality of wiring modes, a motor control apparatus includes a motor including a rotor that rotates according to a motor torque by a pulse width modulation (PWM) control, a switching unit provided at the motor and switching a wiring method inside the motor so that the motor is driven according to another wiring mode, and a controller generating a speed command frequency for controlling a rotation speed of the rotor, and controlling the switching unit so that the wiring mode of the motor is switched according to a result of comparing the speed command frequency with a switching boundary frequency according to the wiring mode of the motor, wherein when the PWM control is stopped in response to the switching of the wiring mode, the controller estimates a rotation state of the rotor that rotates inertially, and when the PWM control is restarted, the controller sets the estimated rotation state of the rotor as an initial value of the rotor, and controls a rotation speed of the motor of which the wiring mode is switched based on the set initial value of the rotor.