Technology - Series Hybrids (Breakthrough) July 06, 2008 9:58 AM
There is a technology breakthrough that will bring Series Hybrids to mass market by allowing them to compete DIRECTLY with standard vehicles on price, peformance, and reliability.
Hybrid and pure Electric Vehicles continue to be on the fringe of the mass market due to costs and range, and these disadvantages are not going away, even with $4 gas. The recent introduction of a new type of electric motor/drive from the aerospace industry is posed to move Series Hybrids into the mass market category even before the ultimate battery solution is found. This breakthrough provides more power, better stamina, and increases simplicity which drives down costs for making Series Hybrids, thereby enabling them to move from the fringe to the center of the market.
Until now, there have only been two options for the electric motor for Hybrids, either a Permanent Magnet Motor (used in Toyota and Honda's drive trains) or a 3-Phase AC Induction Motor (used by GM and Tesla). Each presented engineering challenges which are costly.
**Permanent Magnet Motors:**
1. Degrade in performance at higher temperatures. (Must be liquid cooled)
2. Always produce voltage when spinning (safety issue)
3. Use 'rare earths' that come from China (sourcing issues and expensive)
**Standard 3-phase AC Induction Motors:**
1. Have less power density than Permanent Magnet motors
2. Can be either low speed-high torque, or high speed, but not both
3. Can operate at higher temperatures (Better stamina - Can be air cooled)
As you can see, each of these two options has their drawbacks. Permanent Magnet motors require complex engineering solutions to address heating and excess current which add weight, complexity, and therefore cost to the vehicle. The other option, a standard AC Electric Motor, has other drawbacks that must also be offset by larger and heavier motors and will still require complex engineering solutions.
Breakthrough: Chorus Meshcon
Chorus Meshcon is a multiphase (greater than 3 phase) AC Electric Motor/Drive that has nearly TEN TIMES the startup torque of a standard AC electric motor. This new motor/drive system is based on the new Chorus Motor (http://www.ChorusMotors.com) and is presently undergoing FAA certification for use on the nosewheel assemblies
(http://www.Wheeltug.com) to be installed on Boeing 737NGs, starting with Delta Air Lines fleet beginning December 2009. Semikron supplies Chorus' power electronics.
By performing better at high temperatures and having more startup and overload torque than a similar sized permanent magnet motor, Chorus Meshcon gains a significant edge matched by no other motor. A secondary feature of Chorus Meshcon 'seals the deal' and makes it the obvious choice by overcoming the second drawback of 3 phase AC motors - the shift from low speed to high speed operations. Chorus Meshcon provides a virtual transmission between the two speeds that simplifies power train engineering complexity and reduces costs further.
Chorus Meshcon specifically utilizes harmonic drive to "spoof" the drive electronics to think they are operating at a higher speed to get the low speed high torque performance. The net benefit is that the motor drive for this multiphase motor, which cannot output maximum current and voltage to a standard 3 phase motor at low speed, is capable of achieving overload torques nearly TEN TIMES that of what can be achieved in a 3 phase machine.
Starting slow from a dead stop using high torque output, and then shifting to its function as high speed motor that can be air cooled, Chorus Meschon solves otherwise expensive engineering issues; drive train complexity is reduced and the cooling system complexity/weight is reduced, both of which represent tremendous cost savings.
So why Series Hybrids?
Chorus Motors has determined that the optimal market for Chorus Meshcon is Series Hybrids (http://www.ChorusCars.com) which use electric drives powered by a 'single-speed' internal combustion engine to generate the electricity to run the electric motors and to fill the batteries. Hybrids like the Prius rely on a 'variable speed' internal combustion engine when load conditions increase. In comparison, a Series Hybrids internal engine (which is not a part of the drive train) will always be operating at its optimal and most efficient speed.
Series Hybrids using Chorus Meshcon will have the flexibility and range of today's conventional vehicles while providing a simpler drive train and lower component costs than other Hybrid configurations. Series Hybrid vehicles using Chorus Meshcon will surpass conventional vehicles on fuel efficiency, overall performance, and cost. The ability to significantly reduce engineering complexity and weight means that this one technology will bring Hybrids from the fringes of the mass market to the center and will do so without relying on a miracle in battery development.
One day soon you will be able to drive a Series Hybrid to the airport and get on a plane that itself taxis on the ground using Chorus Meshcon.
Chorus Meshcon can even act in both the combination role of a starter/alternator in a conventional vehicle. Replacing two motors with one more efficient unit saves weight and complexity.
To Learn More:
http://www.ChorusCars.com (Series Hybrid Applications)
http://www.wheeltug.com (Aerospace Application - Delta Airlines December 2009 Launch following FAA certification)
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