Motor driving apparatus and home appliance including the same
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Solution Overview
Problem
Existing motor driving apparatuses, particularly sensorless types, face challenges in accurately calculating stator resistance and inductance during motor alignment, which affects efficient motor operation and load management.
Innovation Solution
A motor driving apparatus comprising an inverter, an output current detector, and a controller that supplies specific current patterns with DC and high-frequency components during distinct periods to calculate stator resistance and inductance, enabling efficient motor alignment and load management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sensorless type motor driving apparatus is used to reduce manufacturing cost, then manufacturing cost is reduced, but measurement precision of stator resistance and inductance deteriorates
Solution Approach 1:
The patent applies preliminary action by performing stator resistance and inductance calculations during the motor alignment period before normal operation begins. The controller calculates these parameters using current and voltage data obtained during the alignment period, ensuring accurate measurements are obtained in advance without requiring additional sensors during normal operation.
Solution Approach 2:
The patent uses the alignment period as an intermediary phase to obtain accurate stator resistance and inductance values. During this intermediate period between power-on and normal operation, the controller intentionally measures electrical parameters that would be difficult to measure accurately during normal motor operation, thereby solving the measurement precision problem without adding sensors.
2Measurement precision
If multiple currents with different components are supplied during alignment periods, then measurement precision of stator resistance and inductance is improved, but device complexity increases
Solution Approach 1:
The patent segments the alignment period into distinct phases: a first alignment period where only flux current is supplied to calculate stator resistance, and a second alignment period where both flux current and torque current are supplied to calculate inductance. This segmentation allows separate, simplified measurements for each parameter rather than attempting to measure both simultaneously, reducing control complexity while maintaining measurement precision.
Solution Approach 2:
The patent employs periodic action by using two distinct alignment periods with different current patterns. The first period uses a specific current pattern for resistance calculation, and the second period uses a different current pattern for inductance calculation. This periodic approach with clearly defined phases simplifies the control logic compared to continuous complex measurements during normal operation.
3Measurement precision
If stator resistance and inductance are calculated during motor alignment, then measurement precision is improved, but loss of time in normal operation increases
Solution Approach 1:
The patent merges the parameter measurement function with the motor alignment function. During the alignment period, the motor is brought to its aligned position while simultaneously measuring the electrical parameters needed for stator resistance and inductance calculations. This merging allows the alignment process to serve dual purposes: mechanical alignment and electrical parameter measurement, thereby avoiding additional time loss.
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
Enables precise calculation of stator resistance and inductance during motor alignment, facilitating efficient motor operation and load management, thereby improving motor performance and efficiency.
Implementation Method 1
an inverter to convert a direct current voltage into an alternating current voltage through a switching operation and to output the AC voltage to the motor
Implementation Method 2
a stator resistance and inductance of the motor based on the first current and the second current is determined
Data Source
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AI summary
A motor driving apparatus (220) includes an inverter (420) to convert a direct current (DC) voltage into an alternating current (AC) voltage through a switching operation and to output the AC voltage to a motor (230), an output current detector (E) to detect an output current flowing in the motor (230), and a controller (430) to control the inverter (420), wherein, at the time of starting the motor (230), the controller (430) controls a first current, including a DC component and a high-frequency component, to be supplied to the motor (230) during a first period for alignment of the motor (230), and controls a second current, including a DC component and a high-frequency component, to be supplied to the motor (230) during a second period for alignment of the motor (230), and the controller (430) calculates the stator resistance and inductance of the motor (230) based on the first current and the second current. Consequently, it is possible to easily calculate the stator resistance and inductance of the motor (230) during the alignment of the motor (230).