Rotary Electric System Neutral-Point Powering
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Solution Overview
Problem
Existing rotary electric systems with star-connected multiphase stator windings face challenges in reducing third harmonic wave components in direct current, which complicates the application of inter neutral-point powering systems in in-vehicle electric systems with vehicle body ground, leading to potential issues with DC terminal potential differences.
Innovation Solution
A rotary electric system with a pair of star-connected multiphase stator windings and inverters, where the stator windings are wound with a predetermined phase difference, and a capacitor is connected between the high-side and low-side terminals of the inverters, allowing for the intermittent supply of phase currents to charge electromagnetic energy and reduce higher harmonic wave components, thereby achieving common potential at the DC input terminals of the inverters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an inter neutral-point powering system is used to reduce third harmonic wave components, then the third harmonic wave components are reduced, but the DC terminal potentials cannot be made common, making it difficult to apply to in-vehicle electric systems with vehicle body ground
Solution Approach 1:
A neutral point potential control device is introduced as an intermediary component between the power supply source and the star-connected multiphase stator windings. This device actively controls and stabilizes the neutral point potential, enabling the DC terminal potentials to be made common while still allowing the system to reduce third harmonic wave components through the neutral-point powering mechanism.
2Power
If a specific booster is used to boost battery voltage, then higher output power with low loss is achieved, but the system complexity increases
Solution Approach 1:
The neutral-point powering system serves multiple functions simultaneously: it acts as a voltage boosting mechanism for the inverter, provides third harmonic wave component reduction, and enables DC terminal potential commonality for vehicle body ground compatibility. By integrating these functions into a single system architecture, the patent avoids the need for separate booster devices, thereby reducing overall system complexity while maintaining high output power capability.
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 effectively reduces third harmonic wave components and simplifies the circuit structure by ensuring common potential at the DC terminals of the inverters, facilitating the use of the system in in-vehicle electric systems with vehicle body ground, and reduces electromagnetic emissions and battery lifetime issues.
Implementation Method 1
a capacitor (5) connected between the common high-side terminal and the common low-side terminal of the first and second multiphase inverters
Implementation Method 2
the first multiphase inverter to intermittently supply a first phase current to the first star-connected multiphase stator windings per phase to charge first electromagnetic energy in the first star-connected multiphase stator windings per phase
Data Source
AI summary
In a rotary electric system, a controller works to turn high-side and low-side switching elements of first and second multiphase inverters on and off to thereby cause:the first multiphase inverter to intermittently supply a first phase current to the first star-connected multiphase stator windings per phase to charge first electromagnetic energy in first star-connected multiphase stator windings per phase, the first electromagnetic energy charging a capacitor;the second multiphase inverter to intermittently supply a second phase current to the second star-connected multiphase stator windings per phase to charge second electromagnetic energy in the second star-connected multiphase stator windings per phase, the second electromagnetic energy charging the capacitor. The first phase current for each phase and the second phase current for a corresponding one phase have a predetermined second phase difference from each other, and the first phase difference is matched with the second phase difference.