Motor Driving Device Reducing Component Count
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Solution Overview
Problem
Conventional motor driving devices are costly due to the use of multiple comparators and external resistors, which increase component count and reduce detection accuracy.
Innovation Solution
A motor driving device with integrated resistors for voltage-division phase voltage and neutral point voltage generation, a selector, and a comparator to generate comparison signals, reducing the number of components and increasing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three comparators are used to compare voltage-division phase voltages and neutral point voltage for each phase, then detection accuracy is maintained, but device size and cost increase
Solution Approach 1:
The patent merges the functions of three separate comparators into a single comparator by sequentially comparing voltage-division phase voltages with the neutral point voltage. The comparator is reused for each phase comparison through timing control, eliminating the need for three simultaneous comparators and reducing device size while maintaining detection accuracy.
Solution Approach 2:
The patent implements periodic action by sequentially comparing voltage-division phase voltages for each phase in turn rather than simultaneously. The single comparator operates in a periodic manner, switching between phases according to a timing sequence, which allows accurate detection of rotor position while using only one comparator component.
2Measurement precision
If an external resistor is used to generate voltage-division phase voltages and neutral point voltage, then detection accuracy is maintained due to small resistance variations, but component count and cost increase
Solution Approach 1:
The patent extracts the resistor function from external discrete components and integrates it directly into the semiconductor device. By incorporating resistors as integrated circuit elements rather than external components, the patent eliminates the need for separate external resistors while maintaining the voltage division function and detection accuracy.
Solution Approach 2:
The patent uses integrated resistors as intermediary elements within the semiconductor device to perform voltage division. These internal resistors serve as mediators between the power supply and the comparator, providing the necessary voltage-division phase voltages and neutral point voltage without requiring external resistor components.
3Device complexity
If resistors are integrated into the semiconductor device, then component count decreases and cost reduces, but detection accuracy deteriorates due to large resistance value variations
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the resistance values of the integrated resistors to compensate for manufacturing variations. By adjusting resistance parameters and their ratios rather than relying on absolute precision, the patent maintains accurate voltage division and detection performance despite variations in individual resistor values.
Solution Approach 2:
The patent applies local quality by ensuring that the critical parameter is the ratio between resistors rather than their absolute values. The design focuses on maintaining consistent resistance ratios locally within the integrated circuit, which preserves detection accuracy even when individual resistor values vary due to manufacturing tolerances.
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 the size and cost of the motor driving device while maintaining high detection accuracy by integrating resistors and using a single comparator, enabling efficient rotor position detection without sensors.
Implementation Method 1
a voltage-division phase voltage generation portion that divides each of the phase voltages to generate a plurality of voltage-division phase voltages
Implementation Method 2
a neutral point voltage generation portion that combines and divides the phase voltages to generate a neutral point voltage
Implementation Method 3
a comparator that compares the selection voltage-division phase voltage and the neutral point voltage to generate a comparison signal
Data Source
AI summary
A motor driving device of the present invention includes: a driver that receives supply of a power supply voltage to apply a plurality of phase voltages to a motor; a voltage-division phase voltage generation portion that divides each of the phase voltages to generate a plurality of voltage-division phase voltages; a neutral point voltage generation portion that combines and divides the phase voltages to generate a neutral point voltage; a selector that outputs any one of the voltage-division phase voltages as a selection voltage-division phase voltage; a comparator that compares the selection voltage-division phase voltage and the neutral point voltage to generate a comparison signal; and a controller that generates a selection control signal of the selector and an energization control signal of the driver according to the comparison signal.