Parallel Voltage Multiplier for High Temperature Oil Well Logging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current oil well logging devices using Cockroft-Walton series voltage multiplier circuits face limitations at temperatures above 150 degrees C due to excessive electrical leakage in semiconductors and voltage regulation issues, which restrict the number of stages and lead to inefficient power conversion.
Innovation Solution
Implementing a voltage multiplier circuit with a parallel or combination parallel and series multiplication scheme, utilizing high voltage capacitors with a novel construction that fits within the small diameters required for oil well logging devices, allowing for a larger number of stages to reduce reverse voltage across semiconductor rectifiers and minimize power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If Cockroft-Walton series voltage multiplier circuit is used, then high voltage multiplication is achieved, but excessive electrical leakage occurs at temperatures above 150 degrees C due to semiconductor rectifier breakdown
Solution Approach 1:
The voltage multiplication is divided into multiple stages, with each stage handling a portion of the total voltage multiplication. This segmentation reduces the reverse voltage across individual rectifiers, allowing them to operate reliably at higher temperatures without excessive leakage currents.
Solution Approach 2:
The patent transitions from a traditional series voltage multiplier topology to a parallel or combination parallel-series topology. This topological transformation changes how voltage and current are distributed across components, enabling better high-temperature performance while achieving the same voltage multiplication factor.
2Stress or pressure
If the number of stages in Cockroft-Walton multiplier is increased to provide higher output voltage, then voltage multiplication factor increases, but output voltage droop increases proportionally to the cube of the number of stages
Solution Approach 1:
The voltage multiplication process is segmented into parallel paths, where multiple capacitor-rectifier stages work simultaneously rather than sequentially. This segmentation reduces the cumulative voltage droop effect, as the droop from each parallel path is less severe than a single long series path.
Solution Approach 2:
Multiple parallel voltage multiplication paths are merged at the output to achieve the desired high voltage. The combining of parallel paths provides redundancy and reduces the overall voltage droop, as the load is distributed across multiple active stages rather than a single series chain.
3Stress or pressure
If the number of stages in Cockroft-Walton multiplier is increased, then higher output voltage is achieved, but ripple voltage increases proportionally to the square of the number of stages
Solution Approach 1:
The voltage multiplication is segmented into parallel stages, each contributing to the total output voltage. The ripple voltage from each parallel stage is independent and can be filtered more effectively, rather than accumulating quadratically as in series configurations.
Solution Approach 2:
Capacitors are strategically placed at intermediate stages to perform preliminary voltage smoothing before the final output stage. This preliminary action reduces the ripple voltage that would otherwise propagate through all subsequent stages and accumulate at the output.
4Stress or pressure
If standard high voltage capacitors are used in parallel multiplier circuit, then sufficient voltage rating is achieved, but the capacitors do not fit within the small diameter constraints of oil well logging devices
Solution Approach 1:
Multiple capacitor elements are nested or stacked in a compact configuration, with smaller capacitors arranged within the spatial envelope of larger structural components. This nesting approach achieves the required total capacitance and voltage rating while fitting within the constrained cylindrical housing of the logging device.
Solution Approach 2:
The capacitor arrangement transitions from a horizontal side-by-side layout to a vertical stacked configuration along the cylindrical axis. This dimensional change exploits the length dimension of the cylindrical housing rather than the limited radial dimension, allowing standard voltage-rated capacitors to fit within the device's overall form factor.
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 enables oil well logging devices to operate at higher temperatures with improved voltage regulation and reduced ripple, increasing efficiency and allowing for deeper well logging by reducing the reverse voltage across rectifiers and minimizing power dissipation.
Implementation Method 1
a voltage multiplier circuit which transforms electrical energy from an AC voltage to a high DC voltage by successively raising up the voltage in a step wise fashion
Implementation Method 2
utilizing a voltage multiplier circuit with a parallel or combination parallel and series multiplication scheme
Data Source
AI summary
A high voltage power supply for use in small diameter spaces such as in oil well logging devices includes an AC voltage source which provides an AC voltage to a voltage multiplier circuit that converts the AC voltage to a high DC voltage. A parallel or combination parallel-series multiplication circuit is used, rather than a series multiplication circuit, to reduce the reverse voltage across each semiconductor rectifier in the multiplication circuit. The lower reverse voltage reduces leakage currents allowing such circuits to operate at temperatures over 150 degrees C. A special construction of high voltage capacitors allows the power supply to fit small spaces. A piece of elongate conductive material, such as a metal cylinder, forms a common capacitor electrode and is coated with a high voltage dielectric. Separate individual capacitor electrodes are formed around the common electrode and dielectric.