Power Supply Device Voltage Input Adaptation
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Solution Overview
Problem
Existing power supply devices for arc machining face instability and biased magnetism issues when using pulse width modulation control, particularly when switching between different voltage inputs, leading to inefficiencies and output instability.
Innovation Solution
The power supply device incorporates a DC converter circuit, an inverter circuit, an auxiliary switching circuit, a pulse width modulation control unit, a phase shift control unit, and a control switching unit to manage switching elements and control pulse signals, allowing for soft switching and phase shift control to stabilize output across varying input voltages of 200 V and 400 V series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse width modulation control is used to adjust output to extremely small level, then output control precision is improved, but switching elements may not activate properly leading to output instability and biased magnetism
Solution Approach 1:
The patent dynamically adjusts the control strategy based on output level. For extremely small output requests, it transitions from conventional PWM control to phase shift control, where the phase difference between switching elements is adjusted to achieve stable operation. This dynamic adaptation of control methodology resolves the contradiction between precision and stability.
Solution Approach 2:
The patent changes the control parameters from pulse width modulation to phase shift modulation when operating at extremely small output levels. By varying the phase difference between switching elements instead of pulse width, the system maintains reliable switching element activation while achieving precise output control.
2Adaptability or versatility
If switching switch connects first node and second node for 400 V series input, then voltage matching is improved, but soft switching control becomes more complex requiring coordination of fifth to eighth switching elements
Solution Approach 1:
The patent segments the switching circuit into multiple independently controllable switching elements (fifth to eighth switching elements) with distinct functions. This segmentation allows each element to be controlled separately to achieve soft switching while maintaining the ability to handle different voltage inputs through coordinated operation.
Solution Approach 2:
The auxiliary switching circuit with multiple switching elements serves multiple functions: it enables soft switching control, accommodates different voltage inputs (200V and 400V series), and maintains output stability. This multi-functionality resolves the contradiction between adaptability and complexity by making the additional circuit elements serve multiple purposes.
3Loss of energy
If auxiliary switching circuit is added for soft switching control, then switching loss is reduced, but device complexity increases with additional switching elements and control circuits
Solution Approach 1:
The auxiliary switching elements (fifth to eighth) are activated in advance before the main switching elements (first to fourth) to prepare the circuit for soft switching. This preliminary action ensures that voltage and current are properly managed during the switching transition, reducing switching loss while the control system coordinates all elements efficiently.
Solution Approach 2:
The auxiliary switching elements act as intermediaries between the DC converter circuit and the inverter circuit, facilitating soft switching by temporarily managing energy transfer. This intermediary function reduces the stress on main switching elements and minimizes switching loss, while the added complexity is justified by the energy efficiency gains.
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 configuration ensures stable output and reduced switching loss by adjusting pulse widths and phase differences, maintaining efficient operation even during low output requests, and automatically switching between voltage modes without manual intervention.
Implementation Method 1
a rectifier circuit, which rectifies commercial power (three phase AC power)
Implementation Method 2
a smoothing capacitor, which smoothes the rectified DC voltage
Implementation Method 3
The inverter circuit synchronously controls the activation and deactivation of a predetermined combination of the switching elements to convert the DC voltage from the DC converter circuit into a predetermined high frequency AC voltage
Implementation Method 4
a soft switching control is performed to deactivate predetermined ones of the fifth to eighth switching elements before deactivation of the first to fourth switching elements of the inverter circuit. This switches each element with a zero voltage and zero current thereby reducing switching loss
Data Source
AI summary
A power supply device that is applicable to both 200 V and 400 V series input power by switching the operation of an auxiliary switching circuit with a switching switch. When a relatively large output is requested, PWM control is performed to adjust the on pulse width of a control pulse signal provided to switching elements of an inverter circuit and an auxiliary switching circuit, which is operated in cooperation with the inverter circuit. When a relatively small output is requested, PSM control is performed to adjusting a phase difference of two control pulse signals provided to the same set of switching elements in the inverter circuit.