BOTTOM LINE UP FRONT:
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, automatic, and instantaneous 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) 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, or 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;
- 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.
As a conceptual demonstration of SYNCHRO-SYM, 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 an axial-flux format (e.g, a rotor disk adjacent to a stator disk separated by an axial-flux air-gap surface), SYNCHRO-SYM is a very easy retrofit: a) remove the “passive” rotor disk and bearing assembly, which comprises the “passive” RE-PMs, slip induction dependent windings, reluctance saliencies, or field windings, b) replace with another “active” stator disk, which comprises a similar directly excited multiphase winding set or “active” winding set, but fitted with the rotor bearing assembly, and of course, c) replace FOC with the necessary BRTEC for synchronous doubly-fed operation that never relies on slip-induction. By reasonably assuming the electrical and core loss (e.g., efficiency), size, and cost are predominantly determined by the “active” stator disk but are similar between the “active” stator disk and the “passive” rotor disk of rare-earth permanent magnets, field windings, reluctance saliencies, or slip-induction dependent windings, then simply replacing the loss, size, and cost of the “passive” rotor disk with another “active” stator disk (with the rotor bearing assembly) is tantamount to doubling the power rating (with the symmetry of two “active” disks instead of the asymmetry of an active disk and a passive disk) within the same package of loss, size, and cost as the original electric machine system. 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 KW), the retrofit clearly demonstrates a conversion to twice the continuous power density (i.e., doubly-fed) with half the cost and loss per power rating (i.e., per KW) under 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, and manufacturing techniques (without considering the small orthogonal magnitude loss associated with magnetizing MMF that is easily offset by the even lower compounding system loss, cost, and size associated with the known half power rating attribute of “doubly-fed” electronic control).
By retrofitting any original axial-flux electric machine system with SYNCHRO-SYM, 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 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), and winding techniques under the same rated air-gap flux density, speed, and voltage and frequency of excitation because both the stator and rotor, together, of only SYNCHRO-SYM actively contribute power to the electromechanical conversion process. 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 becomes unstable, in particular due to external perturbations to the excitation or to the rotor shaft. Effectively, BRTEC uses a magnetic computer (or a compact, magnetic sharing, position-dependent-flux, high frequency transformer) that simultaneously emulates in real time 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 set (on the rotor or stator) with precision phase angle and frequency in synchronism with the rotor speed and with a selectable phase and frequency component.
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 understanding 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).
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:
With the “symmetric circuit and control architecture” of SYNCHRO-SYM as the only exception, all electric machine systems have an “asymmetric circuit and control architecture,” which comprises an active stator assembly with at least one directly excited multiphase winding set (i.e., stator “active winding set”), and a passive rotor and bearing assembly of slip-induction dependent windings, rotor saliencies, DC field windings, or RE-PMs with no “direct” multiphase electrical port for contributing electromechanical (i.e., electrical versus mechanical) power conversion (i.e., passive rotor component). 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 full rated electronic power conditioning of singly-fed electric machine control, which show significant compounding impact to the total system loss, size, and cost, and by normalizing the loss, cost, and size for the rotor or stator assembly to a unit of 1 (per KW of power rating), the reasonable but worst case assumption would show 2 normalized units of loss, cost and size per KW of power rating (i.e., 2 normalized units of loss, cost, and size for the active stator and the passive rotor, together, with the rotor and stator realistically having similar loss, cost, and size divided by 1 unit of power rating) and the impossible but best case assumption would show 1 normalized unit of loss, cost, and size per KW of power rating (i.e., 1 normalized unit of loss, cost, and size for the stator and rotor but with the rotor impossibly having zero loss, cost and size 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 under the same air-gap flux density, which is determined by the same core material available to all, the same air-gap effective area, the same voltage and frequency of excitation, and the same speed 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, with 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 characteristic half rated electronic power conditioning of doubly-fed electric machine control, which would show significantly lower compounding impact than the characteristic full rated controller of the single fed asymmetric electric machine system, with double the loss, cost, and size of the single active stator assembly of the asymmetric electric machine system but with double the power rating, 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 active winding set divided by 2 units of power rating), which is the best case assumption for the asymmetric electric machine system with the rotor unrealistically showing zero loss, cost, and size.
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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