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While “Innovating for Our Clean and Sustainable Energy Future,” Best Electric Machine (BEM) leveraged patents and patents pending for Synchro-Sym Electric Machine Systems (SS-EMS), which is an advanced Brushless Variable Speed Wound-Rotor Doubly-Fed [Synchronous] Electric Motor or Generator System that [symmetrically] motors and generates with five intrinsically unique attributes that significantly improve efficiency, power density, and cost over all other electric machine systems as known by experts from the wound-rotor doubly-fed electric machine research community since the 1960s but only with the invention of instantaneous control means.


The five unique attributes of SS-EMS are:  


  1. Only Electric Motor or Generator System (EMS) With Brushless "Real Time" Control (BRTC):

  • Eliminates reliance on speed-based induction for efficient synchronous operation;

  • Stable, controllable, and continuously "synchronous" wound-rotor doubly-fed operation (e.g., torque) at any speed with the simplest and highest resolution of brushless control (even at  absolute zero speed or about synchronous speed);

  • Automatically phase locks to a predefined steady-state condition with no additional need for offline measurements or compensatory responses with their associated inaccuracies and time delays;

  • Leading, Lagging, or Unity Power Factor adjustment and correction.

  1. Only EMS With Rotor Real-Estate Actively Participating In The Energy Conversion Process:

  • Eliminates extraneous rotor components that contribute real-estate without participating in the electromechanical energy conversion process by replacing the "passive" components, such as permanent magnets (PM), reluctance saliencies, or squirrel-cage windings, with a similar "active" multiphase winding set as the stator active winding set (or armature);

  • Produces the sum of the power of the two armatures on the rotor and stator in the same package size (with loss, size, and cost always normalized to total power) by "actively" occupying the otherwise passive rotor real-estate;

  • Up to twice the continuous power density of any other electric machine in the same size package (by reasonably assuming rotor volume is equal to stator volume, particularly in an axial-flux (or disk shape) footprint);

  • Any loss associated with a "passive" rotor, which is substantial with a squirrel cage winding rotor, is eliminated.

  • Up to half the loss;

  • Up to half the cost.

  1. Only EMS With A "Continuous" Constant-Torque Speed Range To Twice Synchronous Speed For A given Pole-Pair Count, Voltage, And Frequency of Excitation:

  • Fulfills the criteria for true doubly-fed operation, which is: 1) at least super-synchronous motoring (and generating) operation; and 2) no control discontinuity at synchronous speed;

  • 7200 rpm with 2 poles @ 60hz versus 3600 rpm for all other electric machines with the same torque and within the same package;  

  • Highest efficiency;

  • Highest power density;

  • Lowest cost.

  1. Only EMS With A True Dual-Ported (or Symmetrical) Transformer Circuit Topology:

  • Allows "factors" higher peak torque current (and torque) without leading to core flux saturation, increasing air-gap flux density, inductive  reactance effect, or misalignment of rotating fields;

  • Core and air-gap flux density remain relatively constant with increasing torque current;

  • No permanent magnets to potentially damage;

  • Experts have shown peak torque density (and power) at least eight times constant-torque design;

  • Exceptional Field Weakening control.

  1. Only EMS That Electronically Controls Less Than Half of The Total System Power For Continuous And Symmetrical Motoring or Generating Control Over Any Speed (Including Absolute Synchronous Speed):

  • Lowest cost;

  • Highest efficiency;

  • Highest power density.



Whether the focus of present or future electric machine research is on making permanent magnet assemblies denser and better, concentrating the windings, improving the core material performance, introducing dual air-gap footprints, introducing axial-flux (or disk shape) footprints, etc., the result of this traditional research is always directed in some way towards reducing the footprint of the “passive” rotor real-estate that never actively participates in the energy conversion process.


With a totally different approach from all other electric machine research, SYNCHRO-SYM Technologies makes the rotor real-estate an “active” participant in the energy conversion process for providing additional electromechanical power with brushless real time control as hypothesized by electric machine experts since the 1960's; and as a result, SYNCHRO-SYM shows up to twice the power density, up to quadruple the torque density, down to half the electrical loss (e.g., higher efficiency), and down to half the cost of any other type of electric machine system (EMS) with at least the same constant-torque power rating and packaging techniques while still compounding any improvements that may result from traditional electric machine research that could be years away from practical reality if even successful!



With a symmetrical transformer electric machine system (e.g., fully electromagnetic and no permanent magnets) where electronic control supports only one-half the power of other EMSs, Synchro-Sym Electric Machine System (SS-EMS) can be scaled to at least twice the power capability of any EMS based simply on the power limits of today's electronic control!



[Simple Perspective]

[Hot Rodders: Double Teslamotors' Roadster's Performance With A Drop-in SS-EMS Retrofit]

[Just The Facts For Comparisons]

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Note: The Radial Flux prototyping of the Advanced Brushless Wound-Rotor Synchronous Doubly-Fed Electric Motor Or Generator System is shown as our Icon, which predates the axial-flux SS-EMS Technology.


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