Transformer Excitation Cycle Control Circuit
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Solution Overview
Problem
Conventional transformers experience coil saturation due to the inertia of current resistance, leading to surge currents and potential damage when load variations cause excitation currents to exceed saturation values, as the existing power supply mechanisms struggle to efficiently manage and reduce excitation currents to prevent saturation.
Innovation Solution
A method and circuit for controlling transformer excitation cycles by modifying the excitation and demagnetization cycles, utilizing a current detection circuit and cycle modification circuit to adjust the duty cycle and ensure the excitation current does not exceed the saturation value, by prolonging the excitation cycle and extending the demagnetization cycle until the current reaches a preset level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse control unit prolongs the conduction cycle of the switch unit to increase the primary side current when load increases, then the secondary side can provide more electric energy, but the excitation current exceeds the saturated excitation value causing transformer saturation and surge current
Solution Approach 1:
The control circuit detects the excitation current before it reaches saturation and proactively extends the demagnetization cycle to prevent saturation. This preliminary action avoids the harmful surge current while still allowing the excitation current to increase during the excitation cycle to meet load demands.
Solution Approach 2:
The invention dynamically adjusts the demagnetization cycle duration based on real-time excitation current levels. When excitation current approaches saturation, the demagnetization cycle is extended proportionally, creating a dynamic balance between energy transfer and saturation prevention.
2Power
If the excitation current is allowed to reach high values to meet heavy load demands, then more electric energy can be provided, but surge voltage damages the switch unit
Solution Approach 1:
The control circuit continuously monitors the excitation current and uses this feedback to determine when to extend the demagnetization cycle. This closed-loop feedback mechanism ensures the excitation current remains below saturation thresholds, preventing surge voltage generation while maintaining adequate power delivery.
Solution Approach 2:
The system applies preliminary anti-action by extending the demagnetization cycle before saturation occurs, creating a safety margin that prevents surge voltage generation. This proactive approach counteracts the tendency toward saturation before it can cause harmful effects.
3Device complexity
If the conventional power supply lacks a mechanism to reduce excitation current to original levels, then the circuit is simpler, but the excitation current approaches saturation state in varying load cycles
Solution Approach 1:
The invention introduces periodic demagnetization cycles that actively reduce the excitation current back to original levels. This periodic action creates a complete cycle of excitation and demagnetization, preventing cumulative current buildup while maintaining relatively simple circuit architecture.
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
Prevents transformer coil saturation by ensuring the excitation current remains below the saturation value, thereby protecting the power supply components from surge voltages and maintaining stable operation during load variations.
Implementation Method 1
The transformer utilizes the electromagnetic induction inside two coils to convert electric energy
Implementation Method 2
According to the Lenz's law, the induced current flowing through the coil will generate an extra magnetic field, and an opposite induced magnetic field is then generated to resist the extra magnetic field
Data Source
AI summary
The present invention discloses a method for controlling transformer excitation cycles and a circuit for controlling the same, wherein the excitation cycle and the demagnetization cycle, which determine the rise and fall of the excitation current, are modified to prevent the coil from being saturated. In the present invention, a sense current is acquired from the excitation current of the transformer coil, and a demagnetization reference value is set. The sense current is used to determine whether the excitation current is lowered to the demagnetization reference value in the demagnetization cycle. A cycle modifying circuit is used to modify the duty cycle signal output by a pulse control unit until the excitation current is lowered to a preset level.