PWM Contactor Coil Circuit for Low-Heat Voltage Step-Down
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Solution Overview
Problem
Existing contactors face challenges in efficiently converting high input voltages to low output voltages for control circuits while minimizing power consumption and size, with current solutions like IGBTs requiring additional heat sinks and being costly or space-consuming.
Innovation Solution
A contactor design incorporating a coil unit, first and second power supply units, current and voltage detection units, and a control unit to adjust switching cycles using pulse width modulation, along with optional components like freewheeling diodes and transient voltage suppressors, to convert high input voltages to low output voltages efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If IGBT buck chopper circuit is used to reduce high voltage to low voltage, then voltage conversion is achieved, but power consumption increases excessively requiring auxiliary heat sink
Solution Approach 1:
The patent replaces the conventional IGBT-based electronic switching system with a magnetic field-based induction system. The primary coil generates a magnetic field that induces voltage in the secondary coil, eliminating the need for high-power electronic switches and their associated heat dissipation requirements.
Solution Approach 2:
The patent utilizes electromagnetic phase transition from electrical energy to magnetic energy and back to electrical energy. The alternating current in the primary coil creates a time-varying magnetic field that couples to the secondary coil, enabling voltage transformation through fundamental electromagnetic principles rather than electronic switching.
2Use of energy by moving object
If Flyback buck circuit is used to reduce high voltage to low voltage, then power consumption is reduced, but cost increases and space occupation increases
Solution Approach 1:
The patent merges the voltage transformation function with the existing contactor coil structure. The primary coil serves dual purposes: actuating the contactor and generating the magnetic field for voltage transformation. This eliminates the need for separate Flyback circuit components, reducing complexity and space.
Solution Approach 2:
The contactor coil is designed to perform multiple functions simultaneously: it acts as both the actuating coil for the contactor mechanism and the primary winding of the voltage transformer. This multi-functionality reduces the overall component count and simplifies the circuit architecture.
3Power
If direct bucking with IGBT is used for high line voltages, then voltage conversion is achieved, but heat generation increases requiring auxiliary heat sink
Solution Approach 1:
The patent replaces high-power electronic switching with magnetic field-based induction. The voltage transformation occurs through electromagnetic coupling between primary and secondary coils, eliminating the need for IGBTs that generate excessive heat at high voltages.
Solution Approach 2:
The magnetic field acts as an intermediary between the high-voltage primary circuit and the low-voltage secondary circuit. Energy is transferred through the magnetic field rather than direct electrical connection, enabling isolation and efficient power transfer without the heat generation problems of direct switching.
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 contactor effectively converts high input voltages to low output voltages with reduced power consumption and size, ensuring safety and reliability of switching devices, while maintaining a simple circuit structure and smaller device count.
Implementation Method 1
a voltage stabilizing diode, the second switch being connected in parallel with the voltage stabilizing diode, and the first power supply unit being connected in series with the coil unit, wherein a cathode of the voltage stabilizing diode is connected to the output of the first power supply unit
Implementation Method 2
the control circuit controls the electromagnetic system to generate a magnetic field, which in turn controls the switching on and off of the contactor contacts
Data Source
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AI summary
The disclosure relates to a contactor, which includes a coil unit including a coil and a first switch; a first power supply unit including a second switch and a voltage stabilizing diode, wherein the second switch is connected in parallel with the voltage stabilizing diode, and the first power supply unit is connected in series with the coil unit; a current detection unit, which is configured to detect a current flowing through the coil; a voltage detection unit, which is configured to detect a first supply voltage at the output; and the control unit, which is configured to control the switching on and off of the first switch according to the current detection signal, and to control the switching on and off of the second switch according to the voltage detection signal, wherein the first supply voltage is less than an input voltage.