DC Pulse Power Supply Duty Control for Reactor Saturation
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Solution Overview
Problem
The existing DC pulse power supply devices face issues with magnetic saturation in DC reactors during pulse generation, leading to excessive current due to insufficient reset of magnetic saturation, especially in the initial stages of pulse mode operation.
Innovation Solution
The DC pulse power supply device incorporates a voltage clamping unit with a capacitor connected in parallel to the DC reactor and a control circuit unit that adjusts the duty cycle of the switching element to prevent magnetic saturation by gradually increasing the pulse width and voltage-time product, ensuring the capacitor voltage is sufficient for resetting the magnetic saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a voltage clamping unit with a capacitor connected in parallel to the DC reactor is added, then the surge voltage generated by leakage inductance is suppressed, but the capacitor voltage is insufficient to reset magnetic saturation in the initial stage of pulse mode operation
Solution Approach 1:
The patent applies dynamics by making the switching element's ON-period variable rather than fixed. The control circuit unit dynamically adjusts the ON-period based on the capacitor voltage level: in the initial stage, a shorter ON-period is used to allow capacitor charging without causing magnetic saturation; in the steady state, a longer ON-period enables the capacitor voltage to reach levels sufficient for magnetic saturation reset. This dynamic adjustment resolves the contradiction between surge voltage suppression and magnetic saturation reset capability.
2Productivity
If the switching element performs repeated ON/OFF operation to generate pulse output, then the pulse waveform is obtained, but the DC reactor reaches magnetic saturation due to insufficient voltage-time product in the OFF state
Solution Approach 1:
The patent applies parameter changes by modifying the voltage-time product parameter in the OFF state through dynamic adjustment of the ON-period. By changing the ON-period duration based on capacitor voltage levels, the voltage-time product balance between ON and OFF states is optimized. This ensures that the OFF state voltage-time product becomes sufficient to reset magnetic saturation while maintaining pulse output generation capability.
3Power
If the duty cycle is increased to improve power supply efficiency, then the pulse output power is enhanced, but the magnetic saturation occurs more easily due to reduced OFF time for reset
Solution Approach 1:
The patent applies dynamics by making the duty cycle variable rather than fixed. The control circuit unit dynamically adjusts the duty cycle based on the capacitor voltage level: in the initial stage, a lower duty cycle allows the capacitor to charge sufficiently; in the steady state, the duty cycle can be increased to improve power supply efficiency while the capacitor voltage remains sufficient to reset magnetic saturation. This dynamic adjustment resolves the contradiction between power output and magnetic saturation prevention.
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 prevents magnetic saturation and excessive current in the DC reactor, maintaining stable operation by ensuring the capacitor voltage is adequate for resetting the magnetic saturation, thereby maintaining efficient power supply to the load.
Implementation Method 1
a voltage clamping unit having a capacitor connected in parallel to the DC reactor of the chopper circuit in order to prevent the rise in a surge voltage generated by a leakage inductance of the DC reactor
Implementation Method 2
The pulse generation circuit repeatedly performs an ON/OFF operation of the switching element to interrupt a DC voltage, thereby obtaining a pulse output with a pulse waveform
Implementation Method 3
A voltage clamping unit having a capacitor connected in parallel to the DC reactor of the pulsing unit and limits a voltage across the DC reactor to a clamp voltage by a capacitor voltage in the capacitor
Implementation Method 4
a step-up chopper circuit comprising a series circuit composed of a DC reactor and a switching element
Data Source
AI summary
In a DC pulse power supply device according to the present invention, at the time of starting pulsing operation, the duty of the pulsing operation of a chopper circuit is controlled, a switching element is set to an ON state, and the pulse width at which the DC reactor is in an energized state is made variable over the period until the capacitor voltage is charged to a sufficient voltage to reset the magnetic saturation of the DC reactor. Gradually increasing the pulse width suppresses the degree of increase in the DC reactor current, and suppresses the DC reactor current below the magnetic saturazion level. As a result, the magnetic saturation of the DC reactor is suppressed at the time of starting pulsing operation.