RAPID HILL HOLD AUTO-BALANCE APPARATUS AND METHOD FOR VEHICLES PROPELLED BY MAGNETIC SYNCHRONOUS MOTORS

Abstract

An auto-balance hill-hold apparatus and method for arresting unintentional roll after coming to a stop on a hill or slope in vehicles powered by magnetic synchronous motors by automatically determining and rapidly applying the appropriate balancing counter-torque required to negate torque caused by the acceleration of gravity, and subsequently communicating the magnitude of the determined counter-torque to a speed controller so that it may seamlessly transition to an alternative and more efficient method of generating the equivalent balancing counter-torque and provide a smoother transition to operation mode.

Claims

1. An improved method of rapidly preventing post stoppage wheel roll in electrically propelled vehicles, said method comprising the steps of: receiving notification from position sensors that the rotor of the electric motor has began rotating in the opposite direction of the selected gear; recording the initial position of the rotor; applying an initial current of a pre-determined magnitude in the vector direction of the initial position of the rotor to the electric motor; determining the angle of rotation of the rotor rotation from when said initial current was applied to the motor until rotor ceases rotating or phase angle equals MTPA angle to determine modified current; engaging speed controller to produce torque equal to torque created by initial current of a pre-determined magnitude in the vector direction of the initial position of the rotor to the electric motor.

10. An apparatus for rapidly preventing post stoppage wheel roll in electrically propelled vehicles, said apparatus comprising: a position sensor, integrated with an electrical motor such that it can determine the position of the rotor; activation sensors on the electric vehicles brake and accelerator that can determine when the brake and accelerator is activated; a (traditional) speed control; and power source; a controllable power so;

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0032] The accompanying drawings illustrate various exemplary implementations and are part of the specification. The illustrated implementations are proffered for purposes of example not for purposes of limitation. Illustrated elements will be designated by numbers. Once designated, an element will be identified by the identical number throughout. Illustrated in the accompanying drawing(s) is at least one of the best mode embodiments of the present disclosure. In such drawing(s):

[0033] FIG. 1 is a simple diagram depicting the various current amplitudes that can achieve a given torque and the various torques that can be achieved by and the various torques achieved by the predetermined amplitude I.sub.s as a function of ().

[0034] FIG. 2 is a simple diagram depicting the various inputs required for the speed controller to achieve the equivalent counter balancing torque with lower current.

[0035] FIG. 3 is a high level diagram depicting the basic component of presently disclosed apparatus integrated with the power train of an electrically propelled vehicle.

[0036] FIG. 4 is a flowchart depicting the various steps and logic decisions required to perform an embodiment of the presently disclosed method.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0037] The above described drawing figures illustrate an exemplary embodiment of the presently disclosed apparatus and its many features in at least one of its preferred, best mode embodiments, which is further defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications to what is described herein without departing from its spirit and scope of the disclosure. Therefore, it must be understood that what is illustrated is set forth only for the purposes of example and that it should not be taken as a limitation in the scope of the present apparatus or its many features.

[0038] Described now in detail is an innovative apparatus and method of automatically preventing a vehicle from rolling after coming to a stop on a hill or slope by rapidly calculating and applying the appropriate counter-torque required to balance the torque created by the acceleration due to gravity acting on the mass of the vehicle and subsequently using the minimum necessary power to maintain such torque equilibrium.

[0039] FIG. 1 is an illustration depicting the various torques that can be achieved by the predetermined current I.sub.s as the angle between the current vector and the rotor flux position () increases or decreases. In the illustration, the predetermined current I.sub.s at the angle achieves the torque is T.sub.em_2. If increases to the resulting torque increases to T.sub.em_1, whereas if the torque decreases to then the resulting torque decreases to T.sub.em_3. It is through this immediate response that the auto-balancing system can rapidly provide a counter torque to negate the torque caused by gravity and reach and equilibrium. FIG. 1 also show that the torque of T.sub.em_2 can also be achieved by commanding a lower current in a different vector such as point B which exists along the MTPA curve.

[0040] FIG. 2 illustrates the components necessary to maintain the equilibrium torque determined by the auto-balance system while using less current. An MTPA speed controller can regulate the speed to zero given the torque value calculated by the following equation:

T.sub.em=3/2I.sub.s sin (.sub.f+(L.sub.dL.sub.q)I.sub.s cos .

The motor's resolver, encoder, or equivalent provides the value for and I.sub.s is a predetermined constant.

[0041] FIG. 3 illustrates the high level components of the apparatus. Essentially, the presently disclosed apparatus 300 requires a control unit 320 and a speed controller 320 in communication with the motor's position sensor 330 and brake and accelerator signals 350. When the brake and accelerator signals are indicating that there are insufficient brake or accelerator commands 350 to hold the vehicle still, the controller 320 initially commands a predetermined current I.sub.s and when the motor's position sensor 330 confirms that equilibrium has been reached, the controller 320 calculates the required torque given the rotation as confirmed by the motor's position sensor 330 and commands the speed controller 320 to achieve the equivalent torque at the lowest possible current.

[0042] FIG. 4 is a flowchart depicting the various steps and logic decisions required to perform an embodiment of the presently disclosed method starting with ending of normal drive mode 300 such as when the driver in giving the vehicle instructions to move intentionally. In the illustrated embodiment, the method makes a determination whether a forward oriented gear or a reverse oriented gear is selected 305, whether the brake or accelerator is sufficiently activated to prevent vehicle roll 310 or 315, and whether the vehicle is, in fact, rolling in an opposing direction of the selected gear 320 and 325. If the answer is affirmative to the last questions presented in 320 and 325 hill-hold mode will initiate.

[0043] Hill hold mode begins by immediately assigning to 0 at the rotor flux position at the moment of initiation and commanding a predetermined initial current at the vector =0 335. The vehicle is then allowed to roll and generate proportionate counter balancing torque 340. If equilibrium is successfully reached and the vehicle is no longer rolling 345 then after a predetermined amount of time control is passed to the MTPA speed controller 360. If the auto-balance has not successfully achieved zero roll velocity 345 then the absolute value of is examined to determine if it is greater than 90 degrees 355. If it is greater than 90 degrees then control is passed to the MTPA speed controller 360, if it is not greater than 90 degrees then the auto-balance step is allowed to continue 340.

[0044] The MTPA speed controller 360 commands the equivalent torque determined sufficient to counter balance the torque at the maximum torque per ampere point (MTPA point) and continues until the accelerator or brake is activated by the driver 365 causing hill hold mode to end 370.

[0045] The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of the apparatus and its method of use, and to the achievement of the above-described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material, or acts beyond the scope of the commonly defined meanings. Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specification and by the word(s) describing the element.

[0046] The definitions of the words or drawing elements described herein are meant to include not only the combination of elements which are literally set forth, but all equivalent structures, materials or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements described and its various embodiments or that a single element may be substituted for two or more elements in a claim.

[0047] Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalents within the scope intended and its various embodiments. Therefore, substitutions, now or later known to one with ordinary skill in the art, are defined to be within the scope of the defined elements. This disclosure is thus meant to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted, and also what incorporates the essential ideas.

[0048] The scope of this description is to be interpreted only in conjunction with the appended claims and it is made clear, here, that each named inventor believes that the claimed subject matter is what is intended to be patented.