BOTTOM LINE UP FRONT:
By simply replacing the “passive” rotor assembly and field oriented controller (FOC) of any available electric motor or generator system, which is always with the “asymmetric” circuit and control architecture of “passive” slip induction dependent windings, reluctance saliencies, permanent magnets, or dc field windings, such as the ultra tuned electric machine systems from MAGNAX and MAGNIX, with the “active” rotor assembly and brushless real time emulation controller (BRTEC) of SYNCHRO-SYM providing a “symmetric” circuit and control architecture of directly excited multiphase (or active) winding sets on the rotor and stator, respectively, the power density of the original asymmetric electric machine system will double again, the peak torque per frame size will octuple, and the cost and loss per unit of power rating will halve, all while using the same amount of materials (less rare earth permanent magnets or RE-PM) and the same winding, packaging, and manufacturing techniques!
NOTE: SYNCHRO-SYM attributes have been verified by pre-production prototyping and by the only computer aided designer and simulator, called BEM-CAD, which simultaneously provides equitable side-by-side comparisons between the only symmetric synchronous doubly-fed system as only possible with BRTEC, called SYNCHRO-SYM, and the FOC controlled slip-induction and RE-PM electric machine systems, which are under the same material, winding, packaging, and manufacturing techniques and the same electronic controlled excitation parameters!
SYNCHRO-SYM is a patented “symmetric” electric motor or generator (i.e., electric machine) system with a new, brushless, integrated, magnetic sharing circuit and control architecture, as only possible with a brushless, bi-directional multiphase, sensorless, and automatic (i.e. emulation), and instantaneous (i.e., real time) control means, call Brushless Real Time Emulation Control (BRTEC), that comprises an “active rotor assembly” with another directly excited multiphase winding set (or active winding set) as only practical with BRTEC that similarly contributes additional, continuously stable, electromechanical conversion power in conjunction with the “active stator assembly” found on all electric machine systems. As a result, SYNCHRO-SYM:
- Significantly magnifies the operational performance and the peak torque potential, while reducing the overall cost, of the alternative century old “asymmetric” electric machine circuit and control architectures that comprises a “passive rotor” of rare-earth permanent magnets, field windings, reluctance saliencies, or slip-induction dependent windings that cannot continuously contribute additional electromechanical conversion power from sub-synchronous, such as zero speed, to super-synchronous speeds, such as twice synchronous speed;
- Significantly magnifies the enabling performance of optimizing electromagnetic materials, winding, or packaging techniques (or art) that all other electric machine systems apply for their so-called invention or performance enhancement on the limits of the century old “asymmetric” electric machine circuit and control architectures;
- Conveniently accommodates legacy (or future) electric machine concepts, knowledge, materials, winding, packaging, thermal management, or manufacturing techniques;
- Substitutes electronic and high frequency magnetic control to eliminate extravagantly costly, geopolitically volatile, environmentally unfriendly, limited magnetic life, and supply chain limited rare-earth permanent magnets;
- With the exception of the bearing assembly, the axial-flux rotor and stator assemblies are duplicate components with active winding sets for simplified manufacture, inventory, and field replacement;
- Brings superconductor electric machine systems closer to practical reality by brushlessly relocating superconductor field windings to the stator and by eliminating harmonic heating experienced with the power conditioning of field oriented control. When AC superconductors become a practical reality, the fully electromagnetic SYNCHRO-SYM (without permanent magnets) will become the electric machine system of choice.
Envision the axial flux electric machine footprint of other electric machines with adjacent rotor and stator disks of similar size separated by a single air-gap. In this axial-flux form (e.g, a rotor disk adjacent to a stator disk separated by an axial-flux air-gap surface), SYNCHRO-SYM is a very easy conceptual retrofit: a) remove the “passive” rotor disk and bearing assembly, which always comprises the asymmetry of “passive” RE-PMs, slip induction dependent windings, reluctance saliencies, or field windings, b) replace the passive rotor disk with another “active” stator disk, which comprises a directly excited multiphase winding set or “active” winding set, but fitted with the rotor bearing assembly, and c) replace FOC with the necessary BRTEC for providing synchronous doubly-fed operation by never relying on slip-induction for winding excitation, while automatically and instantaneously compensating for unstable rotor and line perturbations, all of which lead to the classic instability of “synchronous doubly-fed” operation, particularly about synchronous speed where slip-induction is vague or ceases to exist. By reasonably assuming the electrical and core loss (e.g., efficiency), size, and cost between the “active” stator disk and “passive” rotor disk of rare-earth permanent magnets, field windings, reluctance saliencies, or slip-induction dependent windings, then simply replacing the “passive” rotor disk with the same loss, size, and cost of another “active” stator disk (but with the rotor bearing assembly) is tantamount to doubling the power rating of the original package (i.e., doubling the power density) while keeping the same loss, size, and cost of the original asymmetric electric machine system being retrofitted. Since loss, size, and cost of any electric machine are always in proportional relation to the total power rating of the electric machine (i.e., per unit or KW of power rating), the retrofit clearly demonstrates the retrofit provides twice the continuous power density (i.e., synchronous doubly-fed) with half the cost and loss per unit of power rating (i.e., per KW) with the same air-gap flux density, effective air-gap area, and voltage and frequency of excitation and with the same packaging, material (less RE-PMs), construction, winding, thermal management, and manufacturing techniques of the original asymmetric electric machine system. For simplifying convenience, the analysis did not consider the loss component associated with the small orthogonal magnitude of winding magnetizing MMF (e.g., field weakening) that is not associated with any RE-PM electric machine system that is without performance enhancing field weakening capability; nor did it consider the neutralizing effect from the known half power rating attribute of synchronous “doubly-fed” electronic control with even lower “compounded” system loss, cost, and size.
By retrofitting any original axial-flux asymmetric electric machine system with the SYNCHRO-SYM symmetric circuit and control architecture, which includes replacing the field oriented controller (FOC) derivative of the original axial-flux electric machine system with the brushless real time emulation controller (BRTEC) of SYNCHRO-SYM, the performance comparison between the original axial-flux asymmetric electric machine system and SYNCHRO-SYM is an obviously equitable qualitative comparison that shows SYNCHRO-SYM provides at least twice the power density, half the loss per KW, and half the cost per KW as the original axial-flux electric machine system with the same design, packaging, materials (less RE-PMs), manufacturing, thermal management, and winding techniques under the same rated air-gap flux density, speed, and voltage and frequency of excitation because uniquely, both the stator and rotor of only SYNCHRO-SYM actively contribute power to the electromechanical conversion process without issues of instability or dependency on slip-induction. Also, the retrofit of the original electric machine system conveniently shows: 1) SYNCHRO-SYM operation, design, construction, and manufacture are straight-forward ready (like the original electric machine system), 2) SYNCHRO-SYM uses off-the-shelf components without exotic components or materials, such as rare earth permanent magnets (like the original electric machine system), 3) SYNCHRO-SYM is adaptable to legacy, off-the-shelf, fielded, or future electric machine systems with customary engineering and manufacturing (like the original electric machine system), and 4) SYNCHRO-SYM doubles the effective performance of third party legacy or future electric machine design, packaging, material, winding, or construction techniques.
NOTE: BRTEC uniquely guarantees contactless, continuous and symmetrically stable, “synchronous” doubly-fed operation (without relying on slip-induction) during motoring or generating from sub-synchronous to super-synchronous speeds, particularly at absolute or about synchronous speed where slip-induction ceases to exist, or more importantly, automatically and instantaneously compensates for instability due to external perturbations to the rotor shaft or excitation. Effectively, BRTEC uses a magnetic computer (or a compact, magnetic sharing, position-dependent-flux, high frequency transformer) that simultaneously emulates the electromagnetic operation of the symmetric multiphase wound-rotor doubly-fed electric machine entity for brushless and instantaneous (i.e., brushless real time), automatic and sensorless (i.e., emulation) excitation of the active multiphase winding sets (on the rotor or stator) with precision selectable phase angle and frequency in precise synchronism with the rotor speed.
NOTE: For more than a century, electric machine experts have theoretically known that multiphase brushless, instantaneous (i.e., brushless, real time) sensor-less, and automatic (i.e., emulation) control was essential for realizing a true multiphase wound-rotor “synchronous” doubly-fed electric machine system. After all, to satisfy classic electric machine study, brushless real time emulation of currents at the winding terminals of a dual ported (i.e., doubly-fed) multiphase wound-rotor electric machine (or transformer) was intuitively postulated for studying its synchronous operation; but practical enabling technologies for realizing the postulations were not available until the advent of electronic control and high frequency magnetics (circa 1960s) with the eventual invention of brushless real time emulation control (BRTEC) and as a result, slip-induction dependency always introduced an unstable reality in practical applications.
NOTE: SYNCHRO-SYM makes irrelevant any costly advancement in rare-earth permanent magnet materials or electric machine systems, such as provided by the ARPA-E REACT program.
SIMPLE QUALITATIVE METHOD OF PROOF:
The total loss (i.e., electrical and core), cost, and size of an asymmetric electric machine system is the sum of the loss, cost, and size associated with the active stator and the passive rotor assemblies but the total power rating is determined by the single stator active winding set (i.e., singly fed). Without including the associated loss, cost, and size of the characteristic, fully rated electronic power conditioning of singly-fed electric machine control, which shows significant compounding impact to the total system loss, size, and cost, but by normalizing the loss, cost, and size for each rotor or stator assembly to a unit of 1 (per KW of power rating), the reasonable assumption would show 2 normalized units of loss, cost and size per KW of power rating (i.e., 2 x the normalized units of loss, cost, and size for the active stator and for the passive rotor divided by 1 unit of power rating with the rotor and stator reasonably showing similar loss, cost, and size). Similarly, the impossible but best case assumption would show 1 normalized unit of loss and cost but with 2 normalized units of size per KW of power rating (i.e., 2 normalized units of size for the stator and rotor but with 1 normalized unit of loss and cost for the stator and with unrealistic zero loss and cost for the rotor divided by 1 unit of power rating).
By conveniently replacing the passive rotor and bearing assembly of slip-induction dependent windings, rotor saliencies, DC field windings, or RE-PMs of the asymmetric electric machine system with a rotor core and bearing assembly comprising another active winding set as found on its active stator assembly that is under the same air-gap flux density, the same air-gap effective area, the same voltage and frequency of excitation, and the same speed and torque design, the resulting “symmetric circuit and control architecture” of SYNCHRO-SYM (as only possible with BRTEC) comprises an “active winding set” on both the stator and rotor assemblies, respectively, providing double the total power rating (i.e., doubly-fed) as the single “active stator assembly” of the asymmetric electric machine system. Without including the associated loss, cost, and size of the known characteristic of “half rated” electronic power conditioning of doubly-fed electric machine control, which would show significantly lower compounding impact of the characteristic “full rated” controller of the single fed asymmetric electric machine system, but with double the loss, cost, size, and power rating of the single active stator assembly of the asymmetric electric machine system and with the loss, cost, and size of the passive rotor assembly of the asymmetric electric machine eliminated, the reasonable assumption would show 1 normalized unit of loss, cost, and size per KW of power rating (i.e., 2 units of loss, cost, and size for the rotor and stator active winding sets divided by 2 units of power rating), which is half the loss, cost and size of the reasonable case assumptions and still better than the best case assumptions for the asymmetric electric machine system without considering the superior loss, cost, and size performance of BRTEC over FOC.
By a simple qualitative method of proof, it was easily demonstrated that SYNCHRO-SYM will always be smaller, more efficient, and less costly than any asymmetric electric machine system, such as the RE-PM electric machine system, for a given power rating (even with an unfeasible rotor with no loss, cost, or size) but more reasonably, SYNCHRO-SYM will be half as large, half as costly, and half as lossy as any asymmetric electric machine system.
As the only practical brushless and symmetrically stable multiphase wound-rotor “synchronous” doubly-fed electric machine system, SYNCHRO-SYM has ample in-house study and prototyping as well as the century of legacy third-party study and manufacture leveraged from the alternative multiphase slip-ring wound rotor induction doubly fed electric machine systems. In consideration, SYNCHRO-SYM is routine engineering and manufacturing ready (e.g., simplest construction) for power scaling to any customer specification.
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