Brushless Motor Servo Device Counter EMF Detection
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Solution Overview
Problem
Conventional servo devices using brushless DC motors face reliability issues due to abrasion of commutating brushes and difficulty in accurately detecting counter electromotive voltage, making them less suitable for continuous operation and high-temperature conditions.
Innovation Solution
The servo device employs a M-phase brushless motor driven by M-phase drive signals, utilizing a brushless motor drive signal generator that adapts conventional servo-system DC motor driving integrated circuits to detect rotational speed and feed back counter electromotive voltage, allowing easy replacement of drive motors and improving reliability and servo response characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a brushless DC motor is used in conventional servo devices, then motor output and heat dissipation are improved, but reliability deteriorates due to difficulty in accurately detecting counter electromotive voltage
Solution Approach 1:
The patent replaces the conventional method of detecting counter electromotive voltage during motor operation with a static detection method using an ohmmeter before operation. This substitution eliminates the reliability issues caused by inaccurate dynamic detection while preserving the high power output benefits of brushless motors.
Solution Approach 2:
The patent performs counter electromotive voltage detection before motor operation rather than during operation. By conducting the detection in advance when the motor is stationary, the system ensures accurate measurement without the complications of runtime electrical noise and motion, thereby improving reliability while maintaining high motor output capability.
2Ease of manufacture
If commutating brushes are used in DC motors, then ease of manufacture is improved, but reliability deteriorates due to abrasion of brushes
Solution Approach 1:
The patent extracts and removes the commutating brushes from the motor system, transitioning to a brushless DC motor design. This extraction eliminates the abrasion problem that compromises reliability while the overall system design and control methods maintain ease of manufacture through standardized brushless motor components and integrated control circuits.
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
This solution enhances the reliability and response characteristics of the servo device by using a brushless motor with improved heat dissipation and mechanical time constant, increasing motor output and controllability, especially under varying loads.
Implementation Method 1
difficulty in accurately detecting counter electromotive voltage
Implementation Method 2
a servo circuit for receiving control signals from a receiver and controlling the driving of the servo device
Data Source
AI summary
A servo device is provided which includes a drive source made of a brushless motor. A DC motor driving integrated circuit produces output signals and controls the output of a three-phase brushless motor driving integrated circuit to drive the brush less motor. A selection switching section detects information regarding the rotational speed of the brushless motor. The selection switching section extracts the counter electromotive voltage of the brushless motor, feeds the voltage back to the DC motor driving integrated circuit and PWM controls a drive signal output from the three-phase brushless motor driving integrated circuit. This allows the brushless motor to be easily applied to the servo device.