Field of Invention
[0001] This invention relates to a single regulator system with
switchable input source for a hybrid vehicle.
Background of Invention
[0002] Current two wheelers employ an onboard generator mounted on the engine crankshaft (magneto), which produces an alternating voltage, and this voltage is regulated to feed the DC and AC load of the vehicle.
[0003] A hybrid vehicle sometimes operates in pure electric vehicle mode and the engine doesn't run at that time. In order, therefore, to supply electrical loads during pure electric mode, a separate DC-DC converter is required to generate the necessary voltage from the main high voltage (36/48 or higher) battery pack. [0004] Although the above mentioned arrangement is all right to address the issue of availability of electrical power during the entire zone of operation, it results in large parts count and unnecessary additions to electrical energy sources and power processors (e.g. AC-AC and/or AC-DC regulators). At the same f time, in the known arrangements, at high engine rpm, magneto losses can be significant due to the inherent hysteresis and eddy current losses in the core, even while producing, zero electrical power. [0005] Since hybrid vehicles are generally heavier due to

additional battery and motor, among other components, often the extra weight tends to negate the fuel economy benefit; and any reduction in weight and power loss in a hybrid vehicle is a highly desirable feature. This invention proposes to reduce the part count, weight, cost and power loss in a hybrid vehicle.
Brief Description of Drawings
[0006] Fig. 1 depicts an existing power distribution layout in a
convention vehicle.
[0007] Fig. 2 depicts the proposed power distribution layout for
the hybrid vehicle, in accordance with the embodiments of the
present invention.
Description of Invention
[0008] This invention therefore Proposes the removal of the
magneto and the use of only one regulator in place of two. This
proposal is applicable to any hybrid vehicle employing an AC or
DC machine for traction purposes.
[0009] During electrical mode of operation, entire electrical load
is supplied by the DC-DC converter, which takes the power from
main battery pack and regulates it to 12 V or any other common
operating voltage required by regular loads such as horn, bulbs
among others. During the interval when motor provides no power,

but freewheels and the engine supplies entire traction power, DC-DC converter takes its input from the motor terminals and supplies power at 12 Volt or any other operating voltage as required by the load. During freewheel operation of the motor, a back e.m.f is generated across the motor terminals and that is being supplied to the DC-DC converter as input, so that in engine running condition in hybrid vehicles battery power can be saved.
[00010] For a DC motor, a DC voltage appears across motor terminal and works as input source to the DC-DC converter. [00011] For a permanent magnet AC machine, a voltage appears across the DC bus capacitor of the inverter and works as input source to the regulator.
[00012] For a slip ring induction machine, a DC voltage can be made to appear across the DC bus of the inverter by applying a DC voltage across the rotor terminals of the machine. [00013] This invention removes the need for a separate magneto and the conventional regulator.

We Claim:
1. A single regulator system with switchable input source for a hybrid vehicle employing an AC or DC machine for traction, but no magneto, comprising a main battery pack; a motor and a DC-DC converter in the place of two, characterized in that
the entire electric load, during electric mode of operation, being supplied by the DC-DC converter, which takes the power from the said main battery pack and regulates it to a predetermined voltage required by regular loads, and—during the interval when the motor provides no power, but freewheels and the entire traction power is supplied by the engine, DC-DC converter takes its input from the motor terminals and supplies power at a predetermined operating voltage as required by the load;
wherein for a DC motor, a DC voltage appears across the motor terminal and works as input source to the DC-DC converter; for an AC machine, the voltage appearing across the DC bus capacitor of the inverter works as input source to the DC-DC converter; and for a slip ring induction machine, a DCvoltage can be made to appear across the DC bus of the inverter by applying a DC voltage across the rotor terminals of the machine, thereby dispensing with the need for a separate magneto and the conventional regulator.