Bidirectional DC-DC Circuit for Fast High-Voltage Capacitor Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-voltage, fast variable DC voltage sources struggle to provide rapidly changing output voltages with high precision and low loss, especially for capacitive loads, which is crucial for applications like plasma generation and piezo actuators, while maintaining a small physical size and high efficiency.
Innovation Solution
A bidirectional DC-DC converter circuit that varies its voltage amplification factor based on control input signals, using an input capacitor to charge or discharge a load capacitance efficiently, allowing for rapid and precise voltage control without the need for feedback, and minimizing power consumption by recovering energy during voltage decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional DC-DC converter is used to generate high-voltage output, then the output voltage can be controlled, but the voltage variation speed is limited and power losses are high
Solution Approach 1:
The patent employs a bidirectional DC-DC converter that can dynamically switch between charging and discharging modes, allowing the circuit to adapt its operation based on whether the load capacitance needs to be charged or discharged. This dynamic operation enables fast voltage variation while recovering energy during discharge cycles, reducing overall power losses.
Solution Approach 2:
The patent changes the operating parameters of the DC-DC converter by varying the duty cycle of the switching elements and adjusting the voltage amplification factor. This allows rapid adjustment of the output voltage from 0V to several kilovolts while maintaining high efficiency through optimal parameter selection at different operating points.
2Speed
If the output voltage is varied rapidly over a large range, then fast control is achieved, but precision and accuracy are compromised
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor the output voltage and adjust the duty cycle of the switching elements accordingly. This feedback ensures that even during rapid voltage transitions, the output voltage achieves the desired precision and accuracy by continuously correcting any deviations from the target value.
3Adaptability or versatility
If a large voltage range is provided (0V to several kV), then versatility is improved, but device complexity increases
Solution Approach 1:
The patent designs a universal bidirectional DC-DC converter that can operate in both charging and discharging modes, providing a wide voltage range from 0V to several kilovolts. The same circuit topology and switching elements are used for both voltage increase and decrease, eliminating the need for separate circuits and reducing overall device complexity despite the extensive voltage range coverage.
4Measurement precision
If feedback control is implemented for precision, then accuracy is improved, but response time increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating the required duty cycle adjustments based on the desired voltage transition. The control system anticipates the needed changes and prepares the switching elements in advance, allowing the voltage to transition rapidly while still achieving the target precision without waiting for feedback loops to complete full cycles.
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 enables accurate and rapid generation of high-voltage ranges from 0V to several kilovolts with negligible net power consumption, achieving low overall losses and efficient power transfer, suitable for applications requiring fast and precise voltage control.
Implementation Method 1
A bidirectional DC-DC converter is used to vary the output voltage by varying its voltage amplification factor
Implementation Method 2
using an input capacitor to charge or discharge a load capacitance efficiently
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A variable voltage generator circuit is described for generating, from a substantially constant supply voltage VS, a variable high-voltage control voltage VC for a variable power capacitor (1) having a variable-permittivity dielectric. The control voltage generator circuit comprises a top-up circuit (10) for maintaining the voltage VCin on an input capacitor (12) at least at supply voltage VS, and a bidirectional DC-DC converter circuit (20) having a variable voltage conversion factor G controlled by control input signal (27). The bidirectional DC-DC converter (20) is arranged to convert voltage, at the voltage conversion factor G, between the input capacitor voltage VCin and the output voltage VC. When VC < G x VCin, the DC-DC converter circuit (20) uses charge stored in the input capacitor (12) to charge the capacitive load (1). When VC > G x VCin, the DC-DC converter circuit (20) uses charge stored in the load capacitance (1) to charge the input capacitor (12).