AC Power Controller for Electromagnetic Switches
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Solution Overview
Problem
Conventional electromagnetic drives for switching devices face challenges in efficiently controlling closing speed and reducing holding power, especially at higher voltages, leading to mechanical shock and self-heating issues, which are costly to address with existing electronic solutions.
Innovation Solution
A device using an AC power controller with anti-series connected transistors and an RC element, controlled by a time function, including negative feedback resistors to balance the transistors, allowing for efficient control of the electromagnetic drive without electronic processes, suitable for high AC voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electromagnetic drives are used with fixed mass ratios and spring forces, then the structure is simple, but the closing speed cannot be efficiently controlled and mechanical shock load increases
Solution Approach 1:
The patent applies dynamics by making the electromagnetic drive system adjustable through electronic control. The mass ratios and spring forces are no longer fixed but can be modified via electronic actuators, allowing the closing speed to be optimized for different operating conditions while maintaining a relatively simple base structure.
Solution Approach 2:
The patent changes physical parameters of the electromagnetic drive system by incorporating electronic control elements that can adjust mass distribution and spring characteristics. This allows the closing speed parameter to be optimized without fundamentally redesigning the mechanical structure, resolving the contradiction between speed control and structural simplicity.
2Power
If DC drives with high holding power are used, then the pull-in power is sufficient, but self-heating occurs in continuous operation
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to control the coil power. Instead of continuous high power application, the drive uses periodic pulses with variable duty cycles, allowing the electromagnetic drive to achieve the required holding power through timed applications of power rather than continuous power, thus reducing self-heating.
Solution Approach 2:
The patent makes the holding power dynamic through electronic control, allowing the power level to be adjusted based on operational requirements. The system can switch between high power for pull-in and reduced power for holding, optimizing performance while minimizing thermal effects during continuous operation.
3Temperature
If PWM modulation or switching regulator is used to reduce holding power, then self-heating is reduced, but electromagnetic compatibility measures increase cost
Solution Approach 1:
The patent applies self-service by designing the electronic control system to inherently manage both power reduction and electromagnetic compatibility. The control architecture integrates EMI filtering and suppression functions within the existing PWM control structure, allowing the system to reduce self-heating while maintaining electromagnetic compatibility without requiring separate, costly EMI mitigation components.
4Productivity
If closing speed is increased to improve switching response, then productivity increases, but mechanical shock load and contact chatter increase
Solution Approach 1:
The patent applies dynamics by enabling real-time adjustment of the closing speed through electronic control of the electromagnetic drive. The system can optimize the closing speed for each switching event, achieving high productivity when needed while controlling the rate of closure to minimize mechanical shock and contact chatter, thus resolving the contradiction between switching response and mechanical stress.
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 effectively reduces mechanical shock and extends service life by adjusting closing speed and holding current, eliminating the need for electronic power reduction, thus being cost-effective and suitable for high AC voltages.
Implementation Method 1
the means for driving the AC power controller have an RC element and the device has negative feedback resistors for balancing the two transistors, the negative feedback resistors also being used to adapt the time function
Implementation Method 2
an electromagnetic drive of a switching device... comprising a valve coil which, when electrical energy is supplied, moves the valve from the basic position to a working position
Data Source
Figure 1~2
Figure 3
AI summary
The device has an alternating current (AC) power controller (220) that operates an electromagnetic drive of a switch gear, where the controller includes two anti-serially connected transistors e.g. MOSFET-transistors and a semiconductor component e.g. thyristor. A control unit e.g. microcontroller, controls the power controller with a time function (240), which is controlled during a power-on process and represents an exponential function. Counter coupling-resistors balance the transistors, where the control unit has a resistor capacitor-unit.