Inverter Rectifier Drive Unit for Rotating Electrical Machine
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Solution Overview
Problem
Existing drive circuits for rotating electrical machines require a large number of switching elements to control both direct and alternating currents, leading to increased costs.
Innovation Solution
A drive unit comprising an inverter to convert direct current into alternating current for the armature winding and a rectifier circuit to convert alternating current back to direct current for the field winding, reducing the number of switching elements needed by using a three-phase configuration with switching arms and rectifier arms connected in series and midpoints for efficient current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bridge-type chopper circuit is used to control direct current to the field winding, then bidirectional current control is achieved, but the number of switching elements increases and cost increases
Solution Approach 1:
The inverter circuit is designed to perform multiple functions: it converts DC to AC for the armature winding and also converts AC to DC for the field winding. By making the inverter multi-functional, the patent eliminates the need for a separate bridge-type chopper circuit, thereby reducing the number of switching elements while maintaining bidirectional current control capability through the rectifier circuit configuration
Solution Approach 2:
The patent combines the DC-to-AC conversion function and AC-to-DC conversion function into a single inverter unit. The inverter includes switching arms for DC-to-AC conversion and rectifier arms for AC-to-DC conversion, merging what would traditionally be separate circuits into one integrated system, thus reducing overall device complexity
2Ease of operation
If separate drive circuits are used for field winding and armature winding, then independent control is achieved, but the number of switching elements and circuit complexity increases
Solution Approach 1:
The inverter is designed as a universal circuit that can independently control both the field winding and armature winding. The switching arms control AC output for the armature while the rectifier arms control DC output for the field winding, allowing independent control of both windings through a single integrated circuit rather than requiring separate drive circuits
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 reduces the number of switching elements, lowering the drive circuit's cost and improving controllability of the rotating electrical machine's field and armature windings, enabling effective field strengthening and weakening control.
Implementation Method 1
an inverter (41) capable of converting a direct current from a direct current power supply (40) into an alternating current and supplying it to an armature winding (28)
Implementation Method 2
a rectifier circuit (42) capable of rectifying the alternating current, that has been converted into the alternating current by the inverter (41), into a direct current and supplying it to a field winding (70)
Implementation Method 3
which generates a field flux when a direct current is supplied to the field winding
Implementation Method 4
which generates a magnetic field that interacts with the field flux when an alternating current is supplied to an armature winding
Data Source
AI summary
An inverter is capable of converting a direct current from a direct current power supply into an alternating current and supplying it to an armature winding. A rectifier circuit is capable of rectifying the current, that has been converted to an alternating current by the inverter, into a direct current and supplying it to the field winding. The amount of the alternating current supplied to the armature winding and the amount of the direct current supplied to the field winding are in a proportional relationship, and implementation of switching control of the inverter controls both the amount of the alternating current supplied to the armature winding and the amount of the direct current supplied to the field winding while this proportional relationship therebetween is maintained.