Multi-Winding Motor Drive Without Transformers for Fault Tolerance
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Solution Overview
Problem
Existing electric fracturing devices face issues with motor reliability due to multiple branches of coil windings being provided with a single variable-frequency current, leading to system failure upon fault, and require transformers to handle high voltage, resulting in large size, weight, and harmonic pollution, which affects motor insulation and efficiency.
Innovation Solution
A multi-winding-motor driving system with independent branches driven by separate power units, including a rectifier and inverter units, eliminates the need for transformers and allows for integration onto the motor, enhancing reliability and reducing size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power element drives the motor with multiple coil winding branches, then the device complexity is reduced, but the reliability deteriorates because a fault in any branch causes the whole motor to fail
Solution Approach 1:
The patent divides the single power element into multiple independent power elements, with each power element dedicated to driving a specific branch of the motor's coil windings. This segmentation allows independent operation of each branch, so that a fault in one branch does not affect the others, thereby improving reliability while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The patent changes the configuration parameter from a single power element to multiple power elements, transforming the system from a centralized control architecture to a distributed control architecture. This parameter change enables the motor to operate with reduced capacity but continued functionality even when some branches fail, thus improving reliability
2Strength
If a transformer is used to reduce high voltage from power supply facilities, then the power element can be protected from overvoltage, but the device volume and weight increase due to the transformer's size
Solution Approach 1:
The patent extracts and removes the transformer from the system by directly connecting the power elements to the high-voltage power supply facilities. The power elements are designed to inherently withstand high voltage through their circuit configuration (series connection of switching elements and diodes), eliminating the need for a separate transformer component and thereby reducing device weight and volume
Solution Approach 2:
The patent introduces a direct electrical connection as an intermediary between the power supply facilities and the power elements, replacing the transformer-mediated connection. This direct connection, combined with the power element's intrinsic voltage handling capability through series configuration, achieves both high voltage protection and weight reduction
3Strength
If a transformer is used for voltage reduction, then the power element can operate at safe voltage levels, but harmonic pollution increases which causes motor heating and insulation aging
Solution Approach 1:
The patent extracts and eliminates the transformer from the system, removing the source of harmonic pollution that transformers generate during voltage transformation. By using power elements with series-connected switching elements and diodes that can directly handle high voltage, the system achieves voltage safety without introducing harmonic distortion, thereby preventing motor heating and insulation aging
Solution Approach 2:
The patent replaces the mechanical/electromagnetic transformation system (transformer) with a solid-state power electronic system (power elements with series-connected switches and diodes). This substitution eliminates the harmonic pollution inherent in transformer-based voltage reduction while maintaining voltage safety through the electronic circuit configuration
4Temperature
If the transducer is placed separately from the motor, then the motor can be cooled more effectively, but the cable requirements increase leading to larger floor area and installation complexity
Solution Approach 1:
The patent merges the transducer and motor into a single integrated unit, eliminating the need for separate placement and extensive cable routing. The power elements are directly connected to the motor's coil windings within the same housing, reducing the floor area required for cable management while maintaining effective cooling through the integrated design that allows proximity to cooling sources
5Adaptability or versatility
If multiple cables are used to connect the motor and transducer, then the motor can be driven by a separate transducer, but the installation complexity and maintenance difficulty increase
Solution Approach 1:
The patent merges the transducer and motor into a single integrated assembly, eliminating the need for multiple external cables and connections. This integration dramatically simplifies installation by reducing the number of connection points and cables required, and simplifies maintenance by reducing the points of potential failure and the complexity of troubleshooting electrical connections
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 system maintains operation even with branch failures, reduces harmonic pollution, and enables compact integration, improving reliability and efficiency while eliminating the need for transformers.
Implementation Method 1
a rectifier unit configured to convert AC power from the power supply facility to DC power
Implementation Method 2
a plurality of inverter units, each of the inverter units corresponds to one branch of the multi-branch windings of the motor, and each of the inverter units is configured to drive the corresponding one branch of the multi-branch windings of the motor with a variable-frequency current
Data Source
AI summary
A multi-winding-motor driving system includes a motor and a power unit. The motor has multi-branch windings independent from each other. The power unit includes a rectifier unit and a plurality of inverter units, wherein the inverter units correspond to the multi-branch windings of the motor one to one, and each of the inverter units supplies power to corresponding one branch of the multi-branch windings of the motor.