CONTROL SYSTEM FOR REVERSING A VEHICLE

Field of invention:

This invention is related to a "Control system for reversing a vehicle" and more particularly for battery operated two and three wheeled vehicles.

Background:

The known battery operated two and three wheelers are generally are very heavy and it is difficult to push the vehicle backwards manually. This difficulty can be experienced when the vehicle is parked in busy and crowed parking locations.

In the present system, the electric vehicle can be run only in one direction. In a typical electric vehicle, (Figure 1) Brushless DC Motor (BLDC) is used for traction. BLDC motor speed and torque is controlled using Power converter. Excitation sequence of phase winding BLDC motor and current direction in the windings determines the direction of rotation of the motor. Traction torque is applied in one direction by commutation of phase windings with the help external switches of the power converter. Commutation signals for the switches of power converter are decoded from signals of 3 Hall sensor (H1, H2, H3), which are mounted on the stator of the BLDC motor. The hall sensors are used for sensing the position of rotor of the motor with respect to stator phase windings- for proper commutation in order to get unidirectional torque. Torque control is achieved by controlling the switches of the power converter based on the TPS signal. Hence the electric vehicle provided with the above circuit has a limitation of running only in the forward direction and manual pushing for reverse.

Hence the objective of the invention is to provide a control device overcoming the above problem of manual pushing for reverse.

Summary of the Invention:

In the light of the state of the art described above, it is an object of the present invention to provide a reverse rotation control system for a battery operated two and three wheeled vehicles.

Another object of the present invention is to provide a selection switch operation of which will determine the direction of rotation of BLDC motor.

Another object of the present invention is to provide easy reversing of the vehicle in congested packing lots.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief description of the Drawings

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

Figure. 1 shows a conventional electric vehicle BLDC system for traction.
Figure.2 shows the reverse control system according to the present invention.
Figure.3 shows the direction controller circuit according to the present invention.

Detail Description of the Invention:

Now description will be made of a reverse control system according to one embodiment of the present invention by reference to the drawings. Figure.2 is an arrangement of the reverse rotation control system, in the figure a throttle position switch (201) provided in the vehicle with an option of selecting the running the vehicle in forward or reverse direction. Direction controller (202) senses the command for the direction of movement of the vehicle from the said switch. When the said direction controller senses the command for a reverse direction, the said controller applies a reverse torque to the motor in order to run the vehicle in the reverse direction. Reverse rotation of the BLDC motor (203) is achieved by logic inversion of the hall sensors of the BLDC motor (203).

The logic conversion of the Hall Effect sensor signal is shown in Figure.3. For forward direction the hall sensors are given without any logic change where as for reverse direction the hall sensors are inverted and given to the said controller (202) to generate decoding signals for controlling the BLDC motor. The direction command is given using a toggle switch (301) which can be controlled by the rider. Direction command is determined by logic state of the toggle switch. Logid is for fonA/ard direction and Logic 0 is for reverse direction. Direction command signal is given to multiplexer select control inputs. When the Sa, Sb, Sc and Sd are Logic 0, the multiplexer selects aO, bO, cO, dO signals and gives to H1a, H2b, H3b and Td when Sa, Sb and Sc are at Logic then the multiplexer selects a1, b1 and c1 and d1 and gives to H1a, H2b, H3b and Td. Output of the said direction controller (202) is given to BLDC motor controller. It is extremely difficult to balance the vehicle in reverse direction. In reverse direction, the TPS (Throttle position switch) signal is limited so that the speed of vehicle does not exceed to a pre determined value in order to have good balance. If reverse direction command is given while the vehicle is moving in forward direction, the vehicle speed is slowly reduced to zero and then the vehicle direction is changed and it moves in reverse direction based on TPS value and speed does, not exceed the limit of predetermined speed.

Although this invention has been described in terms of a certain preferred embodiment, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.

We Claim:

1. A reverse rotation control system of a vehicle comprises:

a variety of switches for selecting forward or reverse direction;

a direction controller which takes the command from the switches;

a motor controller for controlling the direction of rotation of the motor based on direction controller inputs; and

a variety of sensors for generating a variety of information signals in correspondence to motor operation states.

2. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said motor is preferably the brushless DC motor (BLDC).

3. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said sensors are preferably the Hall Effect sensors.

4. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said sensors are mounted on the stator of the motor.

5. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said sensors are used for sensing the position of rotor of the motor with respect to stator phase windings.

6. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said direction controller for reverse rotation of the motor performs a logic inversion of the Hall Effect sensors signal.

7. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the said direction controller for forward rotation of the motor, performs no logic inversion of the Hall Effect sensors signal.

8. A reverse rotation control system of a vehicle as claimed in claim 1, wherein the switch signal for reverse direction is limited thereby the speed of vehicle does not exceed a pre determined value.