Multiphase Machine Independent Phase Control via Active Star Point
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Solution Overview
Problem
Existing electrical multiphase machines require significant equipment and resources while compromising on dynamics due to the limitations of H-bridge and star point circuits.
Innovation Solution
A multiphase machine design with a stator featuring separate power amplifiers for each strand and a common connection point, where an active control element shifts the potential, allowing independent regulation of phase currents or voltages and reducing the number of power switches and freewheeling diodes needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If H-bridge circuits are used for each strand, then reliable independent control of each phase is achieved, but equipment expenditure and space requirements increase significantly
Solution Approach 1:
Multiple strands are connected to a common connection point, merging their return paths. This allows sharing of power switches and freewheeling diodes among multiple strands, reducing the total number of components while maintaining independent control capability through the active control element that adjusts the connection point potential
Solution Approach 2:
The common connection point serves multiple functions: it acts as a return path for multiple strands, a potential adjustment node for voltage optimization, and a control point for dynamic voltage distribution. This multi-functionality reduces the need for separate dedicated components for each strand
2Device complexity
If bridge arms with star point circuits are used, then equipment expenditure is reduced, but dynamics and maximum available voltage are compromised
Solution Approach 1:
The potential of the common connection point is made dynamically adjustable through an active control element. This allows the system to adapt the voltage distribution in real-time, optimizing the maximum available voltage for each phase according to operational requirements, thereby achieving high dynamics comparable to H-bridge circuits while using fewer components
Solution Approach 2:
The system changes the electrical parameter (potential) of the common connection point dynamically. By adjusting this parameter, the maximum available voltage for each phase can be optimized, enabling the system to achieve high performance with reduced equipment complexity
3Device complexity
If fixed potential star point circuits are used, then circuit simplicity is achieved, but voltage optimization and dynamic performance are limited
Solution Approach 1:
The previously fixed potential star point is transformed into a dynamic potential adjustment node. The active control element enables real-time modification of the connection point potential, allowing the system to optimize voltage distribution and achieve maximum power output while maintaining circuit simplicity
Solution Approach 2:
The electrical parameter (potential) of the common connection point is changed from fixed to variable. This parameter change enables the system to optimize the maximum available voltage for each phase dynamically, resolving the contradiction between circuit simplicity and power optimization
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 achieves a balance of low equipment expenditure and high dynamics, enabling the full potential difference between operating voltages for each phase, surpassing the limitations of conventional circuits.
Implementation Method 1
an additional active control element is provided for shifting the potential of the connection point
Implementation Method 2
a winding having at least three strands for generating an electromagnetic field
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An electric multiphase machine is proposed with a stator (3) comprising a winding (5; 6) having at least two strands (51, 52, 53; 61, 62) for generating an electromagnetic field, wherein each strand (51, 52, 53; 61, 62) belongs to a different electrical phase, further comprising a control device (4) which supplies each strand (51, 52, 53; 61, 62) with a phase current (Ia, Ib, Ic) or with a phase voltage (Ua, Ub, Uc) as a control variable, wherein the control device (4) comprises a separate power amplifier (41a, 41b, 41c, 41d) for each strand (51, 52, 53; 61, 62) such that the control variable for each strand (51, 52, 53; 61, 62) is independent of the control variables for the other strands (51,52,53;61,62) is controllable and wherein at least one common connection point (VP) is provided to which at least two of the strands (51,52,53;61, 62) are connected, and wherein an additional active control element (44) is provided for shifting the potential of the connection point (VP). Furthermore, a method for operating such a machine is proposed.