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By simply removing the “passive rotor” circuit and control architecture of any electric motor or generator system, which consumes precious real estate with the non-optimal asymmetry of passive slip-induction dependent windings, reluctance saliencies, DC or single phase field windings, or rare-earth permanent magnets that do not contribute additional working power to the electromechanical energy conversion process, and then by replacing with the “active rotor” circuit and control architecture of SYNCHRO-SYM, which contributes additional working power to the electromechanical energy conversion process with the optimal symmetry of another multiphase (or active) winding set on the rotor as found on the stator that is directly excited without contacts or slip-induction (i.e., active rotor), the continuous power density of the original asymmetric electric motor or generator core will obviously double, the cost will halve, the loss will halve, and the peak torque will octuple by at least effectively eliminating the entire loss, cost, and size of the “passive rotor.”
All electric motor and generator systems (i.e., electric machine systems) follow the classic textbook study that begins with the symmetric electromagnetic relationships (see 4.1.19 – 4.1.23 of Figure 1) of the classical multiphase wound-rotor [synchronous] doubly-fed electric machine system, which comprises the symmetry of two “directly excited multiphase winding sets (i.e., active winding sets)” on the rotor and stator, respectively, but only by postulating a multiphase excitation means that is brushless, instantaneous (i.e., real time), sensor-less & automatic (i.e., emulation), and bi-directional (i.e., brushless real time emulation excitation control or BRTEC TM) in order to: a) avoid the instability of relying on slip-induction excitation, particularly about synchronous speed where slip-induction ceases to exist, b) provide continuously stable operation throughout its double constant-torque speed range (i.e., double Maximum Load RPM) for a given frequency of excitation (e.g., sub-synchronous to super-synchronous speeds, including synchronous speed), and c) provide automatic compensation to random rotor shaft or line perturbations without electronic processing delays. The same symmetric electromagnetic relationships become the follow-on study for the asymmetric (or all other) electric machine system by deoptimizing their symmetry with the relational asymmetry of a passive rotor assembly of slip-induction dependent windings, rotor saliencies, permanent magnets (PM), or DC field windings under a derivative of Field Oriented Control:
- In accordance to the classic textbook study, there are only two electric machine circuit and control architectures (EM-CCA) for comparative convenience: 1) the optimal symmetric EM-CCA with the symmetry of an “active” rotor assembly, which comprises another directly excited multiphase winding set with the “active” stator assembly as only possible with BRTEC, and 2) the non-optimal asymmetric EM-CCA with the asymmetry of a passive rotor assembly, which comprises slip-induction dependent windings, reluctance saliencies, pm, or DC field windings under field oriented excitation control (FOC).
- Today, all EM-CCAs incorporate electronic excitation control for optimum performance or operation and therefore, an equitable comparison between competing electric machines should always be a “system” comparison with at least including the Maximum Load RPM and the compounding loss, cost, and size of the electronic controller.
- Commonly confused with the asynchronous (or slip-induction) doubly-fed electric machine system or asymmetric EM-CCA, a practical “synchronous” doubly-fed electric machine system or symmetric EM-CCA, because of the formidable challenges of realizing the essential BRTEC for “contiguous stability” from sub-synchronous to super synchronous speeds, including synchronous speed, has never materialized, although early symmetric EM-CCA research began with the advent of high speed electronic and magnetic control (circa 1960’s).
- With over a century of legacy practice, electric machine design knowledge and manufacture are straight-forward, regardless of the EM-CCA. Coupled with the past elusiveness of BRTEC for implementing the most “optimum” EM-CCA, which is the symmetric EM-CCA, the unswaying inertia of huge public and private R+D investment in alternatives, such as in the RE-PM electric machine, and the common belief that everything that can be invented has been invented, electric machine research was conveniently redirected to the development and strategic application of readily available electric machine material, winding, packaging, high speed electronic control, and manufacturing techniques for enhancing the performance of the century old asymmetric EM-CCA, such as the permanent magnet (PM) EM-CCA after the advent of a high energy product rare-earth (RE) PM (circa 1980’s) that provided a practical means of eliminating the provisioning of Magnetizing Magneto-Motive-Force (MFF). But ironically, the loss, cost, and size of Magnetizing MMF provisioning is being re-instituted into the RE-PM EM-CCA to regain the coveted attribute of field weakening.
- With equally rated active winding sets on the rotor and stator, respectively, the symmetric EM-CCA shows twice the loss and cost but provides twice the power rating as the active stator within the same package of materials as the asymmetric EM-CCA, which normalizes per unit of power rating to the same loss, cost, size as just the active stator of the asymmetric EM-CCA but with the entire loss, cost, and size of its “passive rotor” of slip-induction dependent windings, reluctance saliencies, permanent magnets, or DC field windings completely eliminated. Therefore, the symmetric EM-CCA shows up to half the loss, half the cost, and half the size as the asymmetric EM-CCA per unit of power rating by reasonably assuming the rotor of any EM-CCA consumes up to the same size, loss, and cost as the stator, particularly if the EM-CCA is an axial flux slip-induction asymmetric EM-CCA.
- With the magnifying contribution of two active winding sets on the rotor and stator, respectively, the symmetric EM-CCA doubles the performance gain expected from the same readily available electric machine material, winding, packaging, and electronic control techniques strategically applied to the asymmetric EM-CCA.
- The symmetric EM-CCA brings superconductor electric machine systems closer to practical reality by contactless relocation of the superconductor field windings to the stator assembly while eliminating harmonic heating experienced with the power conditioning of FOC; but when AC superconductors become a practical reality, the fully electromagnetic SYNCHRO-SYM, which is without delicate and limited lifetime permanent magnets, will become the electric machine system of choice.
- In accordance with the classic study of electric motors, generators, and transformers, the pinnacle of electric motor or generator circuit and control technology is the symmetric electric machine system of SYNCHRO-SYM.
With a simple qualitative method of demonstration of: a) simply removing the field oriented controller (FOC) and the passive rotor disk (and rotor bearing) assembly of any axial-flux (i.e., adjacent active stator disk and passive rotor disk) electric motor or generator system, which does not contribute working power to the electromechanical energy conversion, and then b) replacing with another “active” stator disk (with the addition of the rotor bearing) assembly, which contributes additional working power to the electromechanical energy conversion, the original axial-flux asymmetric electric machine system, such as the performance enhanced electric motor system from MAGNAX or MAGNIX, becomes a symmetric electric machine circuit and control architecture as only provided by the patented SYNCHRO-SYM circuit and control architecture with brushless real time emulation control (BRTEC), which: 1) doubles the contiguous constant-torque speed range (i.e., Maximum Rated Load RPM) for a given torque, a pole-pair count, and a frequency and voltage of excitation, which is tantamount to double the power density, half the cost, and half the loss of the original core (per unit of power rating) by the symmetric power magnification of two active winding sets on the rotor and stator, respectively, instead of the one active winding set of the original non-optimal asymmetric electric machine system, 2) effectively eliminates the entire size, cost, and loss of the original asymmetric rotor of “passive” rare-earth permanent magnets, slip-induction dependent windings, reluctance saliencies, or DC field windings, 3) halves the Magnetizing MMF loss by sharing Magnetizing MMF between the rotor and stator active winding sets on each side of the airgap, 4) provides octuple the peak torque (and peak power density) by holding the air-gap flux density constant below the core flux saturation with increasing torque current in accordance with the conservation of energy physics of a dual ported transformer topology, and 5) effectively doubles the expected gain from strategically applying the same performance enhancing material, windings, packaging, thermal management, electronic component, and manufacturing techniques to the asymmetric electric machine system.
For over a century, SYNCHRO-SYM‘s leap in performance was verified during classic electric machine study with postulating BRTEC but now has been verified by lengthy analytical analysis, by several progressive stages of prototyping by retrofitting off-the-shelf electric machines, including pre-production prototyping, and more importantly, by the evolution of a SYNCRO-SYM customized computer aided design tool (BEM-CAD) that simultaneously provides side-by-side RE-PM and Induction electric machine system comparisons, all of which are designed to the same electrical and mechanical parameters with the same winding, material, packaging, thermal management, and control techniques for competitive fairness. SYNCHRO-SYM is routine engineering and manufacturing ready for power scaling to any customer specification; all without considering the BEM-CAD interface to the only 3D Printer method of axial-flux electric machine systems, such as SYNCHRO-SYM, with amorphous or nanocrystalline ribbon.
SIMPLE QUALITATIVE PROOF:
SIMPLE QUALITATIVE METHOD OF PROOF:
In accordance to Lorentz Force Law, all electric machines produce force with two orthogonal flux (or current) vectors, which are the Torque magneto-motive-force (MMF) and the Magnetizing Flux produced by a) Magnetizing MMF, b) the product of rare-earth permanent magnet (RE-PM) coercivity and its depth, or c) the magnetic path reluctance change. Only RE-PMs produce Magnetizing Flux without electrical power and as a result, the RE-PM asymmetric electric machine is without Magnetizing Flux electrical loss, which has driven its application. In contrast, the reluctance, slip induction, and dc field wound asymmetric electric machines shows similar Magnetizing Flux electrical loss but only the Symmetric Electric Machine, which operates with half of the Magnetizing MMF on the rotor and stator, respectively, shows half the electrical loss associated Magnetizing MMF or reluctance. All electric machines have a degree of core loss, including RE-PM electric machines, and as a result, all are constructed with lamination of low reluctance material to reduce hysteresis and eddy current losses.
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, and by normalizing the loss, cost, and size for each rotor or stator assembly to a unit of 1 (per KW of power rating), the asymmetric electric machine system would reasonably 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 for the passive rotor divided by 1 unit of power rating). Similarly, the impossible but best case assumption for the asymmetric electric machine system, such as the RE-PM electric machine system without assuming rotor core loss, would show 1 normalized unit of loss but with 2 normalized units of cost and size per KW of power rating (i.e., 2 normalized units of cost and size for the stator and rotor but with 1 normalized unit of loss for the stator and with the unrealistic zero loss 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 symmetric electric machine system would reasonably 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 without considering the superior loss, cost, and size performance of BRTEC over FOC.
By a simple qualitative method of proof and without introducing the significant compounded loss, cost, and size associated with the electronic controller (system), it was easily demonstrated that SYNCHRO-SYM will always be at least smaller, as efficient, and less costly than any asymmetric electric machine system, such as the rare-earth permanent magnet (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 following table of cross normalized loss, cost, and size shows. By introducing the significant compounded loss, cost, and size associated with the electronic controller (system), SYNCHRO-SYM will always show significant performance over any asymmetric electric machine system, including the RE-PM electric machine system.
OTHER RETROFIT COMPARISONS:
OTHER RETROFIT COMPARISONS:
The same SYNCHRO-SYM retrofit comparison can be applied to any asymmetric electric machine circuit and control architecture that always comprises a “passive asymmetric rotor assembly” of rare earth permanent magnets (RE-PM), slip-induction dependent windings, reluctance saliencies, or DC field windings:
- The Magni250 and the EMRAX348 are by far, the most optimized asymmetric electric machine circuit and control architectures. Both use rare-earth permanent magnets and are axial flux form, which is a stator disk adjacent to a rotor disk configuration, with strategic application of material, winding, and packaging techniques. The comparative BEM-CAD design results show SYNCHRO-SYM provides twice the power density at half the cost and half the loss of the Magni240 and the EMRAX348, while providing up to 8x more peak torque.
- The “Synchronous Reluctance” electric machine system is sometimes described as a simple performance improving retrofit to the common slip-induction electric machine system by keeping the “active” power producing stator assembly but by replacing the “passive” slip-induction dependent squirrel cage rotor assembly with a reluctance (SyncR) rotor assembly that may include embedded rare-earth permanent magnets and a sophisticated waveform shaping field oriented controller (FOC) derivative for smoothing out the traditional issues of torque ripple and cogging of synchronous reluctance electric machine systems. Similarly to the slip-induction electric machine system retrofit, the complex passive rotor assembly and sophisticated FOC of any synchronous reluctance electric machine system can be replaced with an active rotor assembly and BRTEC to provide the circuit and control architecture of SYNCRO-SYM, which will double again the overall performance of the synchronous reluctance electric machine system while eliminating the extravagant cost, safety and handling issues of rare-earth permanent magnets.
Note: Tesla’s IPM-SyncR electric machine system shows the complicated SyncR rotor assembly of rare earth permanent magnets and reluctance saliencies placement but without emphasizing the complexities and ramifications of the essential electronic shaping controller to provide a practical IMP-SyncR motor with up to 96% efficiency or without emphasizing similar performance trade space of an optimized slip-induction motor comprising a less complex copper wound rotor assembly and electronic controller. Also overlooked, the essential electronic controller has compounding effects on the overall loss, cost and size of any electric machine “system.” For instance, if the efficiency of the motor is 96% and if the efficiency of the essential electronic controller is also an impressive 96%, the actual compounded efficiency of the Tesla’s IMP-SyncR motor “system” for practical operation is only 92% (i.e., 96% x 96%).
- LinearLabs’ Hunstable Energy Turbine (HET) rare-earth permanent-magnet (RE-PM) electric machine system (RE-PM-EMS) recently advertised a four rotor concept providing twice the torque density and triple the power density as other RE-PM-EMS, but after reviewing the video, the four rotor concept is actually a single rotor assembly (of the century old asymmetric circuit and control architecture) with four rotor segments completely surrounding the directly excited stator multiphase (or active) winding set (i.e., so-called circumferential flux of HET) and as admirably claimed, the winding end-turns are seemingly eliminated with the effective air-gap area doubled. Without critiquing the practicality of a completely air-gap surrounded (or floating) active stator assembly without the necessary means to directly excite the multiphase (active) winding set, which would disrupt the crucial circumferential flux of HET, a SYNCHRO-SYM retrofit (as done with MAGNAX) would double the performance claims of LinearLabs’ HET motor while eliminating the cost, safety and handling issues of RE-PMs.
- By retrofitting the Nidec motor with the patented symmetric circuit and control architecture of SYNCHRO-SYM while using the same materials, winding, packaging, manufacturing, and thermal management techniques, Nidec’s electric motor performance would again be doubled and its production cost halved, all without including the additional savings of eliminating expensive rare earth permanent magnets or without transforming Nidec’s manufacturing with MOTORPRINTER, which is the only high speed 3D Printer of amorphous or nanocrystalline axial-flux electric motors and generators.
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