Brushless Motor Drive Advanced Angle Control
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Solution Overview
Problem
Existing motor drive systems for brushless motors face challenges in controlling the advanced angle, leading to voltage increases due to counter electromotive voltage, especially at low speeds and high speeds, which can result in motor shutdown, and require additional timers to manage phase shifts, increasing costs.
Innovation Solution
A motor drive apparatus with detection sensors and a control part that determines the rotor position and power distribution timing by shifting the stage number and adjusting the advanced angle, allowing for optimal advanced angle control without increasing the number of timers, using a combination of mechanical and software-based angle adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-free rectangular wave drive is performed to allow counter electromotive voltage to escape, then voltage increase is prevented at low speeds, but voltage increase cannot be prevented at high speeds when current phase becomes later than advanced angle
Solution Approach 1:
The patent dynamically adjusts the advanced angle based on motor rotation speed. At low speeds, a larger advanced angle is used to prevent voltage increase from counter electromotive voltage. At high speeds, the advanced angle is reduced to prevent current phase delay. This dynamic adjustment resolves the contradiction by adapting the control strategy to operating conditions.
Solution Approach 2:
The patent changes the advanced angle parameter according to rotation speed thresholds. When rotation speed exceeds a predetermined threshold, the advanced angle is modified to prevent current phase from becoming later than the advanced angle, thereby preventing voltage increase while maintaining reliable operation.
2Object-affected harmful factors
If advanced angle is mechanically shifted by 30 degrees to reduce current phase delay, then delay angle is reduced, but advanced angle control flexibility is lost
Solution Approach 1:
The patent implements dynamic advanced angle control where the advanced angle is not fixed but varies based on rotation speed. The control unit adjusts the advanced angle within a range including 0 degrees, allowing flexible adaptation to different operating conditions while preventing current phase delay through software-based timing adjustment rather than fixed mechanical shifting.
3Measurement precision
If timer-based advanced angle control is implemented to achieve precise angle control, then operational precision is improved, but device complexity increases due to additional timers
Solution Approach 1:
The patent replaces mechanical timer-based angle control with software-based timing adjustment. The control unit performs timing control through software algorithms that calculate and adjust the advanced angle based on rotation speed and position, eliminating the need for additional hardware timers while maintaining precise angle control.
Solution Approach 2:
The control unit performs multiple functions including rotation speed detection, position detection, timing control, and advanced angle adjustment using a single integrated controller. This multi-functional approach eliminates the need for separate timer hardware while achieving precise angle control through coordinated software management.
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 the motor to operate at an optimal advanced angle, reducing voltage increases and preventing motor shutdown, while maintaining cost-effectiveness by avoiding the need for additional timers, thus improving operational reliability and efficiency.
Implementation Method 1
a detection sensor (for example, a Hall IC) that detects a rotation position of a motor
Implementation Method 2
a counter electromotive voltage due to regeneration is generated
Data Source
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AI summary
A motor drive apparatus includes: a stage determination part that determines a position of the rotor based on a combination of states of a plurality of the output signals; and a power distribution timing determination part which determines that a power distribution timing when power is distributed to the coil is a timing obtained by advancing an angle by an amount that corresponds to a predetermined electric angle in a startup time of the motor, wherein, when a rotation speed of the motor becomes a predetermined rotation speed or more, the power distribution timing determination part determines that a timing when a predetermined period of time elapses since a position of the rotor arrives at a position of an electric angle that corresponds to a displacement amount of an electric angle which is arbitrarily advanced with respect to a predetermined electric angle that is advanced in the startup time is a power distribution timing.