FIELD OF THE INVENTION
The present invention relates to dual input electrical operated platform truck, for movement of heavy goods within the factory premises, having a motor operated by battery charged by either solar photovoltaic power or utility power.
BACKGROUND OF THE INVENTION
Transportation of large goods weighing few hundred kilograms over long distances within a factory premises is a difficult process because of the problems associated with their movements. Transportations of various types are required for the movement of the goods from one place to the another. In a factory, such situations occur during, movement of raw materials from storage yards to production shops; inter shop movement of unfinished goods; loading and unloading of goods between trucks and containers; movement of goods over a long distance in areas with space constraints or areas where trucks cannot directly load or unload goods etc. Hence, the transportation of goods within a factory premises is carried out by powered vehicles including small platform trucks, fork lifts, tractors, powered trolleys and similar equipment. These vehicles are powered by variety of methods depending on their load characteristics and design.
In recent years, electric vehicles are preferred over the internal combustion engine vehicles due to its environment friendly nature and good technical characteristics. There have been considerable amount experimentations that were carried out in the electric vehicles and have been known for many years. For internal movement of goods inside the factories, electric powered platform trucks are put in use by many industries. These electric powered platform trucks include a direct current motor as the main drive which is connected to the truck wheels by means of gear arrangements. The direct current motor is powered by storage type electrochemical batteries connected in series or parallel combinations to meet the electric power requirement of the direct current motor. These batteries are charged by plugging them to an electrical charger overnight. The electrical charger

is simply an alternating current (ac) to direct current (dc) rectifier formed using rectifier diodes.
The discharge of battery is directly proportion to the operation hours of the motor drive fitted in the platform truck. Thus, for high duration operation of the platform truck the limited charge available in the batteries are not enough. The normal working duration of a shift in factories is about eight hours, during which the goods movement take place and therefore, chance of intermittent charging is more and it will definitely have high level of impact on the operations. However, solutions to the battery charging problem for such platform trucks available at present are not universal and are not applicable for all cases.
In the past, a probable solution to the charging problem of batteries that discharge too frequently is that to charge the battery often in the day time by plugging it to the electrical charger. However, the availability of such tailor made electrical chargers is sporadic in nature. It is not possible for the truck operator to gain access to electricity, for example, in the areas where no electricity is available or on the way between two factories having long distances, say few kilometers etc. the electrical terminals may not be available. Even if the electrical terminals are available, the charging unit may not be available and even if the charging unit is available, the charging terminals and the potential may not match.
One more solution to this problem described in the prior art is to carry spare batteries along the truck, but this add extra burden on the truck and will limit the space availability for carrying the goods.
The US patents for mobile power system US7230819B2 granted in 2007 to Muchow et al. and US8254090B2 granted in 2009 to Eldon Prax and Stan Waldrop and US8492645B1 in 2009 to Michael Strahm explains about a self-contained solar power system, however, this is not suitable for compact open type platform truck having lesser space for module mounting and the weight of the modules will become an extra load for the truck and the goods load need to be compromised.

Also, the above inventions do not have technology to interface of different energy sources to charge the batteries.
One or more drawbacks of conventional systems and process for a method for improving yield strength of a workpiece and an apparatus are overcome, and additional advantages are provided through the apparatus and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are part of the claimed disclosure.
OBJECT OF THE INVENTION
Considering the above criteria, following analysis have been envisaged to determine the objective of invention:
It is therefore an object of the invention to propose a platform truck charged overnight by electrical charger from an electrical point and also having a compact charging system that is having less space and weight requirements and able to charge the batteries on the go.
The other object of the invention is to design a dual input technology for charging the energy storage device of a platform truck where the primary source of energy for battery charging is the electrical utility and the secondary source is the solar photovoltaic charging.
Another object of the invention is to design a constant current charging system using power semiconductor switches that are highly efficient and exhibiting less power loss.
Yet another object of the invention is to provide a safe interlocking arrangements and automatic changeover between the primary and secondary energy sources.

SUMMARY OF THE INVENTION
Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and 10 embodiments may be combined to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
The invention is dual input technology for charging the energy storage device of a platform truck. One input is a direct current supply sourced from a rectified power source and the second one is from solar photovoltaic cell. Overnight charging of the energy storage device is done by the rectified direct current supply. Whereas solar photovoltaic supply is used while in movement and during parking.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with

embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which
Figure 1 : Shows the general schematic of dual input solar platform truck
Figure 2 : Shows the electrical drawing of the solar charging circuit.
Figure 3: Shows the mounting arrangement of the photovoltaic module.
The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the

following description when considered in connection with the accompanying figures.
As used in the description herein and throughout the claims that follow, the meaning of “a”, “an” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in”' includes “in” and “on” unless the context clearly dictates otherwise.
The terms "comprise", “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system, apparatus or device.
These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
The general schematic of dual input solar platform truck is shown in figure 1. Solar photovoltaic module [1] comprising of crystalline cells that convert light energy into electrical energy is employed in this invention to power the platform truck. Solar photovoltaic modules are selected to meet the capacity, in ampere hour, of the battery [2] for charging. One more factor to be considered while selection of solar photovoltaic module is the size limitation. Being mobile unit, more space and weight cannot be added to the platform truck, hence, there should be trade-off between the ampere hour capacity required by the battery [2] and the space required for installing the solar photovoltaic module.

A typical design that is required for charging three twelve-volt batteries connected in series to form a thirty-six-volt direct current power supply is shown in figure 1. There are three solar photovoltaic modules whose positive terminal and negative terminal are connected to the positive terminal and negative terminal of the battery through a solar charge controller [3] respectively. It is to be noted that one solar photovoltaic module is connected to one battery though the batteries are in series connection. The advantage of this type of connection over combined connection is that the increase in charging efficiency. The three batteries [2] connected in series can be charged overnight, by connecting them to a thirty-six-volt rectified direct current supply unit [4] by a double pole single throw switch means [5] . The direct current supply unit produces direct current by rectifying a regular alternating current supply means available in an industry or a commercial establishment. The direct current supply unit [4], being a fixed voltage source, the commonly known switched mode power conversion technique is used to rectify the alternating current supply to direct current supply. This invention comprises of a direct current motor drive unit [6] for driving a direct current series motor [7] having the magnetizing field coil [8] in series to the main winding of the motor [7]. The advantage of using direct current series motor [7] for a platform truck is well explained in the prior art that it can provide better torque characteristics as compared to other electrical motors. The direct current series motor [7] is connected to the motor drive unit [6] using another double pole single throw switch means [9]. The motor drive unit [6] comprises of current contactors and relay means to drive the motor [7] in a proper manner. A mechanical interlock is provided between the double pole single throw switch means [5] for battery charging and double pole single throw switch means [9] for motor driving in such a way that either one operation is carried out at a time.
The electrical drawing of the solar charging circuit of the system is shown in figure 2. The positive terminal of the solar photovoltaic module [1] is connected to a semiconductor diode [10] which will allow flow of direct current from the solar photovoltaic module [1] to the circuit only. Accidental flow of current from the

circuit to the solar photovoltaic module [1] is not allowed by the semiconductor diode [10]. The light energy from the sun is converted into electrical energy by the solar photovoltaic module [1] and fed to a metal oxide semiconductor field effect transistor popularly called as MOSFET [11]. MOSFET is a high frequency switch means which will conduct upon providing a firing signal at the gate terminal [12] and will not conduct in the absence of firing signal. The conducting time of the MOSFET [11] is called ‘ON’ period and the non-conduction time is called the ‘OFF’ period. The purpose of using MOSFET in this charging circuit for stepping down the available direct current supply to a desired magnitude of direct current supply. For example, if the available voltage at the solar photovoltaic module [1] is sixteen volt and the required voltage to charge the battery [2] is twelve volt; the MOSFET [11] is made to ‘ON’ and ‘OFF’ at high frequency of few kilohertz in such a manner to provide an average output voltage of twelve volt and the balance four volt is dissipated by the MOSFET itself during the ‘OFF’ period. The firing signal to the gate terminal [12] is supplied a programmable microcontroller [13], where the logical instructions are pre-programmed to generate the output signal. The microcontroller [13] is a silicon chip discussed in the prior art deliberately perform mathematical operations to produce desired output signals based on the input signals. The microcontroller [13] in this system is used to process two main input signals; one is the voltage at the terminals of the solar photovoltaic module [1] and the second is voltage at the terminals of the battery [2]. The magnitude of the voltages cannot be fed to the microcontroller [13] as such, as it may harm the microcontroller [13] causing failures. Hence, a voltage divider [14] made up of resistors of high ohmic values is used to reduce the voltage in proportion to the voltage available at the terminals of solar photovoltaic module [1]. Similarly, another voltage divider [15] made up of resistors of high ohmic values is used to reduce the voltage in proportion to the voltage available at the terminals of the battery [2]. The two voltage signals provided by the voltage divider [14] and voltage divider [15] respectively are compared by the mathematical operations performed within the microcontroller [13] and the required firing signals are

produced as output by the microcontroller [13]. Thus produced firing signals are fed to the gate terminal [12] of the MOSFET [11]. It is ensured by the microcontroller [13] that only the required voltage is provided to charge the battery [2]. Since there could be undesired voltage ripples present in the input and output terminals of the MOSFET [11], input capacitive filter [16] and output capacitive filter [17] are used to smoothen the input voltage and output voltage respectively. The positive and negative terminals of the series connected batteries are connected to positive terminal [18] and negative terminal [19] of the direct current supply unit [4] respectively for overnight charging of the battery bank. Thus, the series connected batteries form the required thirty-six-volt direct current supply to the direct current motor drive unit [6] through double pole single throw switch means [9] for driving the motor.
The mean operational current drawn by the 36-volt motor used in this embodiment is around 53 amperes measuring to 706 kilo joules of energy requirement to travel one kilometer at a truck speed of ten kilometers per hour. The solar installation will provide a mean daily energy of about 3456 kilo joules of energy sufficient enough to travel 5 kilometers a day. The rest of the energy requirement shall alone be met by utility powered rectifier charger. Thus the platform truck can travel additional distance of five kilometers under sunlight without any requirement of charging from utilities.
The mechanical arrangement of the solar photovoltaic module [1] is shown in figure 3. The three solar photovoltaic modules are installed on top of the platform truck by a rigid mechanical frame work [20]. The advantage of this structure is that it exposes the solar photovoltaic module [1] to the sun always and provide shading to the driver for comfort while driving. Four vertical supports [21] made up of steel angles are formed to provide support for the frame work [20] accommodating the three solar photovoltaic modules. The supports are firmly fitted to the platform [22] of the truck by welding. The solar charge controller [3] of each solar photovoltaic module [1] is installed just below the mechanical frame

work [20] by firmly fitting it by mechanical screw means on the supporting structure [21]. The insulated wires from the solar charge controller [3] to the battery [2] are made to run through a poly vinyl chloride conduit along the steel channels to ensure personnel safety. The three batteries are kept safely inside a rigid metallic enclosure [23] below the driver seat.
Each of the appended claims defines a separate invention, which for infringement purposes is “reorganized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention” will refer 1o to subject matter recited in one or more, but not necessarily all, of the claims.
Groupings of alterative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted form, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
With respect to the use of substantially plural and/or singular terms herein, those having skill in the art can translate form the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It still be understood by takes within the art that in general, terms used herein, and especially in the appended claims (e.g, bodies of the appended claims) are generally intended as “open” terms (eg, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least”, the term “includes” should be interpreted as “includes but is not

limited to” etc.)- It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claim may contain usage of the introductory phrases “at least one” and “one or more” to introduce claims recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claims includes the introductory phrases “one or more” or “at least one” and indefinite articles such a “a” or “an” (e.g, “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite article used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g the bare recitation of “two recitation,” without other modifiers, typically mean at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of the A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (eg. “a system having at least one A, B and C etc. would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B and C together etc.). In those instances , where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together and/or A, B and C together etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings,

should be understood to contemplate the possibilities of including one of the terms, either of the terms or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known related art or later developed deigns and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
The technology used herein is for the expose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternative thereof, may be combined into other systems or application. Various presently unforeseen or unanticipated alternatives, modification, variation, or improvements therein.

KEY FEATURES
1. The dual input solar platform truck that is charged overnight using a direct current supply unit and charged by solar photovoltaic module while in movement under the sun and when parked under the sun.
2. The dual input solar platform truck with a MOSFET based solar charge controller operated by a microcontroller that compares the voltage from solar photovoltaic modules and voltage of the battery to ensure proper charging.
3. The dual input solar platform truck with solar photovoltaic modules installed on top of the driver seat of the platform trucking ensuring proper exposure to sun and providing extra comfort to the driver from weathers.
4. The dual input solar platform truck having plurality of solar photovoltaic modules having electrical connection between one solar photovoltaic module to one battery each to increase the charging efficiency.

WE CLAIM

1. A dual power input powered moving vehicle that includes means of power
supply;
- atleast a Photovoltaic (1) coupled to a solar charge control (3);
- atleast a power storage (2);
- a supply unit (4) coupled to the power storage (2) by a double pole single throw switch (5);
- a DC motor drive unit (6) for driving series motors (7);
- said motor (7) comprising magnetic field control (8) coupled to a motor (6) by a double pole single throw switch (9); and
- a mechanical interlock between double pole single throw switch (5) and double pole single throw switch (9).

2. The dual power input powered moving vehicle as claimed in claim 1, comprising a semiconductor diode (10) coupled to the PV (1) for conversion of energy.
3. The dual power input powered moving vehicle as claimed in claim 1, wherein the associated electronic includes MOSFET (11), gate terminal (12), microcontroller (13), voltage divider (14 and 15), input capacitive filter (16), output capacitive filter (17), positive terminal (18) and negative terminal (19).
4. A dual power input powered moving vehicle that includes means of power supply, as substantially described and illustrated herein with reference to the accompanying drawings.