Current Source Inverter Integrated in Motor Housing
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Solution Overview
Problem
Existing electrical machines with integrated voltage source inverters face challenges due to large size DC link capacitors, sensitivity to temperature and current ripple, high electromagnetic interference, and stress on motor insulation, which are not addressed by current source inverters integrated with motor drive coils within a housing.
Innovation Solution
A power architecture that incorporates a current source inverter with a switching network of diodes and switches connected to stator coils and inductors, along with commutating capacitors and a bi-directional DC-DC converter, positioned within a motor housing, allowing for efficient energy storage and conversion between local and central energy storage components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage source inverter with DC link capacitor is used, then the inverter can provide stable voltage output, but the packaging size increases and sensitivity to temperature and current ripple worsens
Solution Approach 1:
The patent changes the fundamental operating parameters of the inverter from voltage-source topology to current-source topology. This parameter change eliminates the need for large DC link capacitors, thereby reducing packaging size while maintaining reliable operation through current control rather than voltage control.
Solution Approach 2:
The patent extracts and removes the DC link capacitor from the inverter structure. By eliminating this component, the packaging volume is significantly reduced and the sensitivity issues associated with capacitor temperature and ripple are resolved, while the current source inverter maintains stable operation through its inherent current control characteristics.
2Ease of operation
If pulse-width modulated voltage waveforms are used, then the inverter can control motor speed, but electromagnetic interference and bearing-leakage currents increase
Solution Approach 1:
The patent substitutes the voltage-based PWM control mechanism with a current-based control mechanism. This substitution fundamentally changes the nature of the output waveforms from high-frequency voltage pulses to controlled current waveforms, thereby reducing electromagnetic interference and bearing-leakage currents while maintaining motor speed control capability through current regulation.
3Length of moving object
If voltage source inverter is integrated with motor housing, then cable length is reduced, but shoot-through concerns and insulation stress increase
Solution Approach 1:
The patent changes the control parameter from voltage to current in the integrated inverter system. This parameter change eliminates shoot-through concerns because current source inverters inherently prevent simultaneous conduction of opposing switches through current control, while maintaining the integration benefits of reduced cable length and improved insulation reliability.
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 packaging issues, minimizes electromagnetic interference, and enhances energy efficiency by integrating the current source inverter and motor drive within a single housing, enabling efficient operation as both a starter and generator while providing fault-tolerant power delivery.
Implementation Method 1
a switching network comprised of a plurality of diodes and switches, the switching network being connected to said set of stator coils and a pair of inductors positioned on DC power rails
Implementation Method 2
a current source inverter including a switching network comprised of a plurality of diodes and switches, the switching network being connected to said set of stator coils and a pair of inductors positioned on DC power rails
Implementation Method 3
a set of commutating capacitors, wherein the commutating capacitors are electrically connected to a line connecting said switching network and each of said set of stator coils
Implementation Method 4
a bi-directional DC-DC converter is positioned between each of said local energy storage components and said central energy storage component
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A machine has a housing (22) that includes a plurality of stator coils (30) to be positioned adjacent to a rotor (31). A switching network (28) includes a plurality of transistors (29) and diodes (131) connected to the coils (30). A current source inverter is provided by a switching network, a pair of inductors (26) positioned on power rails, and commutating capacitors (32). The current source inverter and the coils (30) are all positioned within said housing (22). Power architecture for a vehicle has a source of DC power, which communicates with machines through integrated motor drives. The motor drives include at least three coils positioned adjacent to the rotors for a motor associated with the integrated motor drive. A storage switching network is positioned downstream of the coils, with the storage switching network to be closed to allow power from the coils to drive the rotor, or to be opened to allow power to pass to a local storage component.