Power Conversion Apparatus Y-Connected Arms Eliminating Reactors
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Solution Overview
Problem
Existing power conversion apparatuses for DC to AC or AC to DC conversion require reactors for each phase, leading to large volume, weight, and reduced controllability of rotary electric machines due to the need for reactors between phases.
Innovation Solution
A power conversion apparatus with three or more arms, each comprising unit converters with energy storage elements connected in series, where the arms are Y-connected to a first node and directly connected to the phase windings of a rotary electric machine, eliminating the need for reactors and enhancing controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactors are provided between each arm and the rotary electric machine, then current circulation through each arm is suppressed, but the volume and weight of the power conversion apparatus increase and the installation footprint enlarges
Solution Approach 1:
The invention extracts and eliminates the reactors from the system by redesigning the connection structure. Instead of connecting each arm to the rotary electric machine through reactors, the arms are directly connected to the phase windings, removing the unnecessary components while maintaining system functionality through the Y-connection configuration
Solution Approach 2:
The invention merges the connection structure by directly linking the arms to the phase windings without intermediate reactors. The Y-connection configuration combines the three arms at a common first node, creating a more compact and integrated structure that eliminates the need for separate reactor components
2Reliability
If reactors are provided between each arm and the rotary electric machine, then current circulation is suppressed, but the controllability of the rotary electric machine is reduced
Solution Approach 1:
The invention removes the reactors that were interfering with the control system. By extracting these intermediate components, the control signals and voltage applications can be transmitted directly from the arms to the phase windings, improving the responsiveness and controllability of the rotary electric machine while alternative methods are used to manage current circulation
3Reliability
If reactors are provided for each phase, then current circulation through each arm is suppressed, but the device complexity increases
Solution Approach 1:
The invention simplifies the device structure by merging the connection topology. Instead of having separate reactor components for each phase, the system uses a unified Y-connection structure where three arms connect to a common first node, and then to the three-phase windings, reducing component count and structural complexity
Solution Approach 2:
The invention extracts and removes the reactor components from the system, eliminating the need for complex reactor design, installation, and maintenance while alternative current suppression methods are implemented in the control and connection architecture
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 volume and weight of the power conversion apparatus, allowing for more compact installations and improved controllability of rotary electric machines, while minimizing energy loss and enabling efficient energy conversion.
Implementation Method 1
one or more unit converters each including an energy storage element and capable of outputting an arbitrary voltage
Implementation Method 2
uses a switching element capable of controlling ON/OFF, such as an IGBT (Insulated-Gate Bipolar Transistor), a GTO (Gate Turn-Off Thyristor) or a GCT (Gate-Commutated Thyristor)
Implementation Method 3
a power conversion apparatus for converting DC power into AC power or AC power to DC power
Data Source
AI summary
A power conversion apparatus includes arms in each of which one or more unit converters each including a capacitor and capable of outputting an arbitrary voltage are connected in series, and a point P as a first node to which one end of the respective arms are Y-connected, and a point N as a second node to which a neutral terminal of the rotary electric machine is connected. The other end of the respective arms are connected to one ends of respective phase windings of a rotary electric machine.