DC Pulse Power Supply Frequency Control for Reactor Saturation Reset
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Solution Overview
Problem
The DC pulse power supply devices face the challenge of magnetic saturation in DC reactors during pulsing operations, leading to excessive current due to insufficient reset of magnetic saturation, especially in the initial stages of plasma generation where the capacitor voltage is not adequately boosted to counteract the surge voltage.
Innovation Solution
A DC pulse power supply device with a voltage clamping unit and a control circuit that adjusts the frequency of the switching element's operation to prevent magnetic saturation by varying the time width of the OFF period, ensuring the capacitor voltage is sufficient to reset the magnetic saturation, and using a regeneration unit to clamp the reactor voltage, thereby preventing excessive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching element operates at high frequency to generate pulse output, then productivity is improved, but magnetic saturation occurs in the DC reactor causing excessive current
Solution Approach 1:
The patent applies dynamics by making the OFF period time width variable rather than fixed. The control circuit dynamically adjusts the OFF period duration based on the capacitor voltage level: using a first time width when capacitor voltage is below a threshold and a second time width when the threshold is exceeded. This dynamic adjustment prevents magnetic saturation while maintaining high-frequency pulse operation.
Solution Approach 2:
The patent changes the parameter of OFF period time width based on capacitor voltage conditions. By monitoring the capacitor voltage and switching between different OFF period durations, the system optimizes the balance between productivity and magnetic saturation prevention, ensuring reliable operation at high frequencies.
2Reliability
If the OFF period time width is increased to reset magnetic saturation, then magnetic saturation is prevented, but the pulse output frequency decreases
Solution Approach 1:
The control circuit dynamically adjusts the OFF period duration based on real-time capacitor voltage monitoring. When capacitor voltage exceeds the threshold, the system switches to a shorter second time width, maintaining high pulse frequency. When voltage is below the threshold, it uses a longer first time width to ensure adequate magnetic saturation reset, thus optimizing both reliability and productivity.
Solution Approach 2:
The system changes the OFF period time width parameter conditionally based on capacitor voltage levels, achieving adaptive control that prevents magnetic saturation while minimizing impact on pulse output frequency and maintaining high productivity.
3Reliability
If the capacitor voltage is allowed to rise to reset magnetic saturation, then magnetic saturation is prevented, but surge voltage damages the switching element
Solution Approach 1:
The patent applies preliminary action by providing a clamping circuit that preemptively limits the capacitor voltage before it can reach dangerous surge levels. The clamping circuit activates when capacitor voltage exceeds a predetermined threshold, preventing the voltage from rising further and thus protecting the switching element from damage while still enabling adequate magnetic saturation reset.
Solution Approach 2:
The clamping circuit serves as a protective cushion that absorbs excess voltage energy before it can damage the switching element. By limiting the maximum capacitor voltage to a predetermined safe level, the system prevents surge voltage damage while maintaining sufficient voltage for magnetic saturation reset.
4Object-affected harmful factors
If the clamping circuit limits capacitor voltage to protect the switching element, then surge voltage is prevented, but magnetic saturation cannot be adequately reset
Solution Approach 1:
The control circuit dynamically compensates for the clamping circuit's voltage limitation by adjusting the OFF period time width. When the clamping circuit limits capacitor voltage to a predetermined level, the control circuit increases the OFF period duration to ensure that the area under the voltage-time curve remains sufficient for complete magnetic saturation reset, thus maintaining reliability despite voltage clamping.
Solution Approach 2:
The system changes the OFF period time width parameter in response to clamping circuit activation, ensuring that magnetic saturation reset is maintained even when capacitor voltage is limited by the clamping circuit, thus resolving the contradiction between surge protection and saturation reset.
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 solution effectively prevents magnetic saturation and excessive current in the DC reactor, ensuring stable plasma generation by ensuring the capacitor voltage is adequately charged to reset the magnetic saturation, maintaining a stable discharge and reducing the risk of damage to the switching element.
Implementation Method 1
a voltage clamping unit (30c1) that uses a capacitor voltage (VC) of a capacitor (C) connected in parallel to the DC reactor (21a) to clamp a voltage across the DC reactor (21a) to a clamp voltage
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 control circuit unit (40) that controls a switching operation of the switching element (22), and performs frequency control for making a frequency variable in an initial stage of the pulsing operation until a capacitor voltage (VC) is charged enough to reset magnetic saturation of the DC reactor (21a)
Data Source
AI summary
This DC pulse power supply device comprises a voltage clamper including a capacitor that is connected in parallel to a DC reactor in a chopper circuit provided in a pulsing unit in order to suppress increases in the surge voltage resulting from the leakage inductance of the DC reactor. During the start-up of pulsing operation, which is the initial stage of the pulse mode, the frequency of the pulsing operation of the chopper circuit is controlled over the period until the capacitor voltage is charged to a sufficient voltage to reset the magnetic saturation of the DC reactor.