Motor Drive Device for Electric Compressor Startup Control
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Solution Overview
Problem
Existing motor drive devices consume high power during startup and impose a significant operational load due to the need for angular position determination and complex current switching processes, especially when the rotor's initial position is unknown or misaligned.
Innovation Solution
A motor drive device for a multi-phase synchronous motor that calculates the initial angular position of the rotor using a voltage pulse, rotates the d-axis and q-axis by a predetermined angle, accelerates the rotor by flowing torque component current, and transitions to sensorless control once a predetermined speed is reached, reducing power consumption and operational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angular position determination phase with current flowing through coils is executed to determine rotor position, then rotor angular position can be determined, but large amount of power is consumed
Solution Approach 1:
The patent applies periodic action by executing the angular position determination phase only once at motor startup rather than continuously. The rotor angular position is determined initially using voltage pulse and current detection, then the system transitions to sensorless control using estimated angular velocity, eliminating the need for repeated high-power position determination operations.
Solution Approach 2:
The patent applies preliminary action by determining the rotor angular position once at the beginning before motor operation. The initial angular position is calculated using voltage pulse application and current detection, and this preliminary determination enables subsequent sensorless control to proceed with reduced power consumption.
2Reliability
If current switching processing between Id and Iq is executed while rotor is rotating, then motor control can be maintained, but high operational load is imposed on controller
Solution Approach 1:
The patent applies preliminary action by calculating the initial rotor angular position before motor rotation begins. This preliminary position determination allows the system to establish the initial d-axis and q-axis orientations, enabling smooth transition to sensorless control without requiring complex real-time current switching processing during rotor rotation.
Solution Approach 2:
The patent replaces the mechanical/current-switching control method with a sensorless control approach that uses voltage application and current detection to estimate rotor position and angular velocity. This substitution eliminates the need for complex current switching processing between Id and Iq while maintaining reliable motor control.
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 reduces power consumption and operational load by accurately determining the initial rotor position and smoothly transitioning to sensorless control, enhancing the robustness and efficiency of motor operation.
Implementation Method 1
detecting a d-axis and a q-axis as an initial angular position of the rotor based on a current flowing in response to a voltage pulse applied to the coils of the stator
Implementation Method 2
flowing through the stator the torque component current determined based on a d-axis and a q-axis... accelerating the rotation of the rotor
Data Source
AI summary
A motor drive device drives a multi-phase synchronous motor in an electric compressor. The multi-phase synchronous motor includes a rotor that is provided with a permanent magnet and a stator having coils of different phases. The motor drive device includes an inverter that supplies current to the coils and a control unit that controls the inverter. The control unit executes an initial angular position calculation processing of detecting a d-axis and a q-axis as an initial angular position of the rotor, a rotating processing of rotating the d-axis and the q-axis in a direction opposite to rotation of the rotor, an acceleration processing of accelerating the rotation of the rotor, and a sensorless control processing of controlling the rotation of the rotor.