When the ORNL did their evaluations of the early Prius drives they analyzed the system and decided to write their own drive software, however none of this is available to the public as far as I know.
The simple minded approach that I thought I could use would be to set up the OEM control system starting with the theft deterrent system and ECU through to the motor just as it exists in the car. The EV mode selector switch would enable operation up into low 30's MPH. Some analysis plus hardware and computer manipulation here might yield higher speeds. A few of the PHEV suppliers claim EV speeds up to 70 MPH and if all else fails, one of their systems could then be installed.
The synergy drive MG2 can maintain electric boost or EV drive at 95 mph.
the problem limiting EV speed in the stock configuration is the1:3 speed increase that the smaller MG1 sees. MG1 can spin up to 10,ooo rpm when the gas input shaft is stopped.This happens at about 40 mph.
My welded planet gears take care of that, and make the synergy drive into an interesting mechanical system. The welded gears couple the three power I/O parts into one drive that runs right into the punkin and final drive
The hylander rear end on the other hand is a single input EV drive, with differential and some final drive gearing, so it is a full speed EV drive right out of the car.
The drive is also a single slave drive, so hacking the Inverter input should be pretty straight forward.
I want the whole rear end and inverter, if anyone sees one for sale at a reasonable price let me know.
Mike: The inverter for the Highlander Hybrid 4wd/LexusRX400h has had pc board and coolant leaking problem recalls. Other cheaper, more compact, and more reliable Toyota inverters are available that should work.
The 2007-2009 Toyota Camry Hybrid inverters are compact, plentiful, relatively cheap and have the necessary 650 volt output that the Highlander/lexus pumpkin requires. In addition, the ORNL has a nice paper describing its construction.
If the assumption is made that the Synergy Drive inverter is slave to the Engine Control Module as many believe, it may be necessary to include the ECM as part of the inverter control and to analyze and recognize the CAN signals received by the ECM during its control of the inverter and be able to synthesize these CAN signals as needed to maintain the ready state of the ECM. Some of these CAN signals would describe the states of the anti-theft system, road speed, SOC, and others.
Then, CAN signals could be applied to the inverter through the ECM which reflect changes such as throttle position, rate of change of throttle position, feedback from traction motor and others.
The ORNL used two computers in their setup to control the inverter.
The beauty of inverters, is that one can dig deeper until you find the gates of the mosfets or IGBTS, then all the complexity is a non issue. A guy ran a civic inverter off of a 3 phase variable frequency circuit 5V logic that ran open loop off a LM555 timer for the frequency.
He was running a rewound 3 phase 5hp induction motor off the civic inverter, at 48V with a nice snappy response and good speed range.
The civic inverter has no intelligence, it is just the HV 3 phase bridge, and the snubber network, with current sensors.
In the car, the MCM of course is required to sync with the gas engine rpm, thus the feedback, but it ran nicely open loop.
He will use it as an electric drive for a sailboat AUX drive.
I expect that the Prius inverter is more complex, but mainly because it needs to sync the two electric motors with the gas in much more complex relationships.
Cant wait till I have some time to just focus on that. I have had what I need in hardware for over a year, just need time.
The 650 volt pumpkin motor requires that battery voltage be boosted which is why the 2007-2009 Camry inverter was selected. While the function of the mosfet switching in the inverter may be pretty straight forward, controlling the boost may be a bit more complex. Hacking the Camry inverter to control the boost appears to be the main problem that needs a solution which is why adhering to Toyota's existing path/solution was suggested.
The 2010 or later Prius inverter appears to be a better choice than the 2007-2009 Camry unit previously selected. Although the Camry inverter is more compact there is no other apparent advantage availability or price wise for selecting it over the later model Prius inverter which also has a 650 volt max. output capability.
The 2010 Prius battery pack voltage, unlike the 2007-2009 Camry 244.8 volt pack, is 201.6 which is similar to Ford Escape and other more readily available packs. Also, Mike will probably have a charger harness available sooner for the GenIII Prius than for the Camry.
I am working with a couple of guys that are rebuilding the 288V Prius packs, to develop a special HV booster/discharger accessory that would allow charging and cycling the packs up to 340V.
I thought the ford escape was over 300V pack?
.........I thought the ford escape was over 300V pack?
You are right about the Ford Escape battery pack voltage (50 x 5 cell sticks). I was thinking about uhtrinity's "Ford Escape Battery Project" where he used the Escape pack as a source for cheap cells to build up his own pack. For an EV project there may be an advantage to using these cylindrical metal encased cells rather than the prismatic tightly assembled cells as used in the Prius application because the cylindrical cell pack structure is easier to keep cool.
Thirty-three of the five cell Escape sticks would build about a 198 volt pack. In a perfect world two Ford Escape packs would provide enough sticks to build three such packs.
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