Universal Motor Electrodynamic Braking via Adaptive Firing Angle Control
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Solution Overview
Problem
Existing methods for electrodynamic braking of universal motors do not adapt to changes in rotational speed caused by external influences such as wear, aging, or tool variations, leading to inconsistent braking times and increased loading on the motor.
Innovation Solution
A method that continuously monitors the rotational speed of a universal motor and adjusts the firing angles of a semiconductor switch to match a target rotational speed profile, using a regulating device to minimize deviations and account for varying operating conditions, thereby ensuring more uniform braking and reduced loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed firing angles are used for electrodynamic braking, then the braking control is simple, but the braking time varies and motor loading increases due to external influences
Solution Approach 1:
The patent applies dynamics by making the firing angle adjustable and adaptive rather than fixed. The control device dynamically adjusts the firing angle of the semiconductor switch based on feedback from the rotational speed sensor, allowing the braking process to adapt to changing motor conditions and maintain consistent braking time despite external influences.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual rotational speed of the motor during braking and comparing it to the target rotational speed profile. The control device uses this feedback information to adjust the firing angle in real-time, ensuring that the motor follows the desired speed profile and achieving consistent braking performance.
2Device complexity
If fixed firing angles are used for electrodynamic braking, then the control system is simple, but the motor collector experiences increased loading
Solution Approach 1:
The patent reduces collector loading by dynamically adjusting the firing angle to optimize the braking current waveform. By adapting the firing angle to the actual motor speed, the system minimizes harmful induction currents and ensures smoother current flow through the collector, reducing wear and loading on this critical component.
Solution Approach 2:
The feedback mechanism allows the control device to detect deviations from the target speed profile and adjust the firing angle accordingly. This real-time adjustment prevents excessive current surges and optimizes the braking current, thereby reducing harmful effects on the motor collector and extending its service life.
3Reliability
If the rotational speed is continuously monitored and firing angles are adjusted, then the braking uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent uses feedback from a rotational speed sensor to continuously monitor the motor speed during braking. This feedback is processed by the control device, which adjusts the firing angle to maintain the target speed profile, thereby achieving uniform and reliable braking performance despite the added control complexity.
Solution Approach 2:
The patent replaces mechanical or fixed electrical braking methods with an electronically controlled system using semiconductor switches and microprocessor-based control. This substitution allows for precise, programmable control of the braking process, achieving uniform braking through software algorithms rather than mechanical adjustments.
4Duration of action of stationary object
If the firing angle is adapted to rotational speed changes, then the motor operating life is extended, but the measurement and control difficulty increases
Solution Approach 1:
The patent extends motor life by implementing continuous rotational speed monitoring with feedback control. The rotational speed sensor provides real-time data to the control device, which adjusts the firing angle to optimize braking conditions and reduce stress on motor components, thereby extending operational life despite the increased measurement and control requirements.
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 approach results in more uniform braking operations, reduced wear, and extended motor lifespan by adapting to individual operating conditions and external influences, while also ensuring safe handling of maximum load scenarios.
Implementation Method 1
electrodynamic braking of a universal motor... temporarily, periodically short-circuiting an armature of the universal motor by means of a semiconductor switch
Data Source
AI summary
A method and device for electrodynamic braking of a universal motor. The method comprises the steps of continuously ascertaining a rotational speed of the universal motor, temporarily, periodically short-circuiting an armature of the universal motor with a semiconductor switch, and regulating firing angles of the semiconductor switch with a regulating device. The regulating device regulates firing angles of the semiconductor switch such that the rotational speed of the universal motor is adapted with minimal deviation to a rotational speed of a target rotational speed profile.