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wattage of DC-DC converter ?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by HeadsUp, Nov 22, 2009.

  1. HeadsUp

    HeadsUp New Member

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    does anybody know the wattage of the high voltage DC-DC converter ?

    i mean the one that converts 200 volts DC up to 500 volts DC on the 2003 > models
     
  2. ias513

    ias513 New Member

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    I saw this yesterday online. I think this was a Gen2. Does anyone know the wattage for a gen 1?


    In the Prius, the DC-DC converter (which is equivalent to the alternator in a normal car) is limited to 100 amps. Power = volts × amps, so in the Prius, we can get a total of 13.7 × 100 = 1,370 watts out of the 12-volt system. From the online forums, it turns out that the internal Prius electronics take about 300 watts, which leaves about 1,000 watts available for external use,

    Here is the link...

    Pressed for Details: Hybrid car powers home during blackout > The Harvard Press
     
  3. HeadsUp

    HeadsUp New Member

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    thanks but you didnt read the question

    i want the wattage of the converter which converts 200 VOLTS UP TO 500 VOLTS

    that 500 volts is then fed to the motor controller

    the one you are talking about is for accessories only


    :)

    cheers
     
  4. dogfriend

    dogfriend Human - Animal Hybrid

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    Its a little more complicated than that.

    VH boost
     
  5. Ct. Ken V

    Ct. Ken V Active Member

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    HeadsUp,

    I'm not any form of electrical engineer, so I can't answer your question for you & I'm not trying to be critical here of you. But the heading of your thread asks for the "wattage of the DC-DC converter". The DC-DC CONverter changes your 202 VDC from your HV (traction) battery to about 14 VDC to charge your little 12 VDC battery (which I think ias513 was answering for you).

    But in the text of your post you seem to ask a different question (about the conversion of 200 volts to 500 volts). That is actually the INverter which changes the 202 VDC from the HV (traction) battery to 500 VAC (alternating current) for the AC electric 50KW traction (drive) motor.

    And the model year(s) you are asking about seems to say 2003 and newer models, but it should be 2004 & up models because the 2003 model year was still the smaller "Echo" sized "Classic" Prius with the trunk instead of the hatchback. I believe the 2003 "Classic" had a 375 volt battery & drive system (& NOT the 202 VDC to 500 VAC system).

    I hope an electrical engineer can read your question better & provide you with the answer you're really looking for.

    Ken (in Bolton,Ct)
     
  6. HeadsUp

    HeadsUp New Member

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    no

    the DC-DC converter is separate from the AC motor controller , it steps up 202 volts DC to 500 volts DC and then that is connected to the VFD motor controller which converts it to AC as a variable speed drive.

    it is also bi-directional , it acts in reverse , carrying the regen current and converting 500 VDC back down to 200 VDC to charge the battery

    i want the wattage of the DC-DC converter as mentioned correctly in my first post
     
  7. hobbit

    hobbit Senior Member

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    First of all, the boost converter is in 2004+, not 2003. I don't
    know how much power it's rated for, but consider this: the nominal
    max battery current in and out is 100 amps. [Rarely we see
    peaks slightly above that but not for long, and the pack is
    fused at 120A.] At full regen when the pack is around 250V
    instantaneous that's 25 kilowatts on the "200V" side; obviously
    less current but higher voltage at the motor for equivalent
    power. Now, MG2 [the big one] is rated for 50 kW peak, I believe,
    which presumably would have to be fed by the doubled-up side of the
    inverter rack, but there's no way the battery is going to deliver
    or accept that on its own. What's probably more important than
    "power handling" in terms of the buck/boost converter is just how
    much current it can handle without getting too warm or blasting the
    bejeezus out of some transistor dies. The power dissipated *across*
    the circuit is probably very low by comparison, and we count on the
    mass of the inverter frame and that always-running coolant loop to
    whisk that excess away from the important bits in short order.
    .
    I haven't answered the question, but hopefully have gotten your
    thinking into the right order of magnitude. At a very outside guess
    I'd say somewhere between 25 and 50 kW to have a nice safe envelope.
    Compare the die and bond-wire sizes of the inverter-rack vs. the
    boost-switch transistors, consider the real-life feed current at
    up to a 300V delta, and you can probably get close.
    .
    _H*
     
  8. ken1784

    ken1784 SuperMID designer

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    The (boost) DC-DC converter is located between HV battery and MG1/MG2 DC-AC inverters.
    The max wattage depends on the max power of the HV battery which is 25kW. (27kW on the Gen3)

    Ken@Japan
     
  9. HeadsUp

    HeadsUp New Member

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    thankyou Ken

    that tells me the maximum battery wattage but the DC-DC converter could be rated with a large safety factor

    it is still guess work , the converter could be 50 kW for all i know

    but thats why i am asking the question , if i am going to use the Prius DC-DC step up converter in another project i need to know its rating , i wouldnt be using the Prius battery pack.

    i hoped somebody would have a spec sheet , or be able to look at theirs and read the information off the plate , the plate should say ;

    minimum operating voltage cuttoff level
    maximum input voltage
    max current
    max continuous power
    max intermittant power
    and temperature range

    if battery max current drain is 100 amps then the rating could be 150 A x 202 V = 30 kilowatts or more

    i am still guessing


    thanks people. :)
     
  10. patsparks

    patsparks An Aussie perspective

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    AS the DC - DC converter is an integral part of the HSD I doubt it has any spec plates.
     
  11. ken1784

    ken1784 SuperMID designer

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    As patsparks wrote, there is no specification plate. Toyota never published the official specification.
    No one can exceed 25kW wattage.
    A safety margin is another story.

    Ken@Japan
     
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  12. Mike Dimmick

    Mike Dimmick Active Member

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    The waveforms of three-phase alternating current (AC) going to the main drive motor MG2, main generator MG1 when driven as a motor (heretical mode), and to the air-conditioning compressor (also a three-phase alternating current motor), have to exactly follow the current position of the rotor so that the correct magnetic field is being produced in the correct coils at the right time, in order to actually drive the motor. Basically, from the perspective of any magnet on the rotor, the coil directly overhead must be more-or-less neutral, the one ahead must be attracting, and the one behind repulsing, in order that the magnet is pulled and pushed forwards.

    Let's say we're accelerating hard at 30mph (48km/h). 72% of the torque produced by the engine goes straight to the ring gear whereupon it goes to the reduction gear (via the chain in Gen 1 and 2), differential and front wheels. 28% of the torque goes to drive MG1 to produce power which goes to MG2. To get more acceleration we also add the power from the battery to MG2.

    However, MG1 and MG2 are rotating at different rates. According to a Prius simulator, MG2 (which is directly related to the road speed) is turning at 1,800rpm. The highest speed we can set the engine to and keep MG1 within the ±6,500rpm bracket is 3,000rpm. If the engine is rotating at this speed MG1 must turn at about 6,100rpm. Clearly we can't just take the waveform directly from MG1 and apply it to MG2, the wrong coils would be driven.

    So that all the voltages and timings work out, the power generated by MG1 - which due to the setup of the coils and magnets is also three-phase, at high voltages - has to be converted back to around 200V DC. That allows power to be directly taken off from or returned to the battery. The MG2 inverter must be able to handle the entirety of the power capability of MG2 itself - a full 50kW for Gen 2, 60kW for Gen 3.

    I believe that the inverter is actually a pulse-width-modulated variable-frequency drive as described at Variable-frequency drive - Wikipedia, the free encyclopedia.

    From what I recall of Gen 3 marketing materials, the battery supplies up to 25kW on Gen 2, up to 27kW on Gen 3. The remaining power for large outputs from MG2 comes from MG1.
     
  13. hobbit

    hobbit Senior Member

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    No, MG1 and MG2 share the same 500V power rail, both post-boost.
    .
    _H*