Manually operable apparatus for converting kinetic energy to electrical energy

Abstract

Manually operable apparatus for converting kinetic energy to electrical energy, comprising: a rotor 1005 coupled to a rotor axle 1007 for rotation therewith; a stator 1001, 1003 provided in close prox

Description

Field 5 This disclosure relates, in one aspect, to manually operable apparatus for converting kinetic energy to electrical energy. Another aspect of the disclosure relates to a storage system for electrical energy, particularly - but not exclusively - to a storage system for electrical energy that comprises manually operable apparatus for converting kinetic energy to electrical energy, for example apparatus of the type aforementioned. 10 In one envisaged implementation, the storage system may be modular in nature. In yet another implementation, the manually operable apparatus for converting kinetic energy to electrical energy may be configured as a module of the modular electrical energy storage system. The manually operable apparatus for converting kinetic energy to electrical 15 energy is described below in the context of a storage system for electrical energy, but it should be remembered that this implementation of the teachings of this disclosure is merely illustrative and that the manually operable apparatus herein disclosed may have other applications. 20 Background Smartphones, tablets and other portable data processing devices (for example, smartwatches like the Samsung Galaxy range, or electronic gaming consoles like the Nintendo Switch) are becoming ever more commonplace, and whilst modern battery technology is much improved it is not unusual for users to have to charge their device(s) 25 at least daily - and sometime multiple times in a day if they are using power-hungry applications (such as mapping apps that make use of GPS transceivers) or downloading large amounts of data. When users have access to mains electrical outlets, the necessity to put a device "on charge" is less of an issue, although the time taken to fully charge a device may 30 mean that users are only able to partly charge their battery-powered devices in the time available to them. To address power issues when users are not able to access mains electricity or it is inconvenient for them to do so, it has previously been proposed to provide so-called "powerbanks" that typically comprise a number of Lithium-ion batteries that store charge 35 and can be called upon to recharge a device in the event that access cannot immediately be had to mains electricity. Such "powerbanks" work well, but they do require the user to remember to charge them before use To address such issues it has previously been proposed to provide crank-driven charging devices that can be operated by hand by a user to generate an electric charge (which charge can be used to charge an electronic device). Whilst such devices have 5 the advantage, as compared with a powerbank for example, that they do not need to be charged before use, they have a number of drawbacks. One of these is that as electricity is generated instantaneously, generation of electricity immediately stops when the user stops turning the crank, and little or no electric charge storage is provided. As a result, these charging devices can take hours of winding to create a useful, practical 10 charge for an electronic device such as a phone or tablet. To address such issues, we have previously proposed, in our international PCT patent application number WO2022 / 043642, to provide a power supply system which incorporates storage for electric charge, manually operable apparatus for converting kinetic energy to electrical energy, and electronic regulator circuits which manage 15 charging and discharging of the storage. Whilst our previously proposed device functions adequately and provides numerous advantages over other previously proposed arrangements, it has highlighted that it is advantageous if the effort expended by a user in operation of the manually-operable converter is reasonable for the charge generated. If too much effort is required to operate the convertor, either in terms of the 20 force required to operate the converter or the time for which it must be operated to store a useful level of charge, then users may be reluctant to use the device. A key consideration, therefore, is the efficiency of the manually operable apparatus for converting kinetic energy to electrical energy, and aspects of this disclosure have been devised with this in mind. 25 Summary In one presently preferred implementation of the teachings of this disclosure there is provided manually operable apparatus for converting kinetic energy to electrical energy, the apparatus comprising: a rotor coupled to a rotor axle for rotation therewith; a 30 stator provided in close proximity to the rotor; a crank assembly rotatable by hand to rotate the rotor axle; and a gear assembly coupled between the crank assembly and the rotor axle, the gear assembly being operable to increase the rotational speed of the axle and rotor in use as compared with the rotational speed of the crank assembly; wherein: one of the rotor and the stator comprises an array of magnets arranged about the rotor 35 axle in a first circle, and the other of the rotor and the stator comprises an array of cores arranged around the rotor axle in a second circle having substantially the same diameter as the first circle; said cores each comprise a rectangular strip of electrically conducting material that has been rolled up to form a coiled core and arranged so that a short side of said strip is substantially parallel with said rotor axis, and the apparatus further comprises an electrical conductor wound round the cores so that an electrical current 5 can be generated as the magnet array and core array are rotated relative to one another about said rotor axis. One advantage of this arrangement is that the coiled cores formed by rolling up strips of electrically conducting material significantly reduce eddy current losses, and hence improve the efficiency of the apparatus as a whole. 10 In a preferred implementation of the teachings of this disclosure, the gear assembly may be operable to increase the rotational speed of the axle, as compared with the rotational speed of the crank assembly, by a factor of at least 10. In another arrangement, the gear assembly may be operable to increase the rotational speed of the axle, as compared with the rotational speed of the crank assembly, by a factor of at least 15 15. The gear assembly may comprise an epicyclic gear assembly. The array of cores may be coupled to the stator. This is advantageous as it simplifies collection of electric charge from the electrical conductor. The apparatus may comprise multiple stators arranged in close proximity to said rotor, each said stator having an array of cores coupled thereto. The rotor may comprise 20 a rotor plate fixedly coupled to said rotor axle for rotation therewith, and the apparatus may further comprise a first stator arranged on one side of said rotor plate and a second stator arranged on a second side of said rotor plate. The first and second stators may be coupled to each other so that the cores of each array are maintained in close proximity to, and equally spaced from, the rotor. In one embodiment each array of cores 25 is spaced from the rotor by a spacing that is in the order of a few millimetres, typically less than one centimetre, and more typically in the order of 1 to 5 millimetres. A first array of cores coupled to said first stator may be angularly offset relative to a second array of cores coupled to said second stator. Cores of said first array may be offset by an angle of 30 degrees relative to the cores of said second array. Preferably 30 each array of cores comprises six cores arranged to extend in a direction parallel to said rotor axle. The array of magnets may be coupled to the rotor. The rotor may comprise a rotor plate having a first major face and a second major face, a first array of magnets being coupled to said first face, and a second array of magnets being couped to said 35 second face. Each array of magnets may comprise six magnets. Each said magnet may be disc-shaped. Each said magnet may be approximately 2 cm in diameter and a few millimetres thick, typically around 1 mm thick; and each said core may be approximately 2 cm in diameter. Preferably said cores are of sheet steel, preferably laminated steel sheet. Another aspect of the present disclosure relates to a power supply system 5 comprising a power store and apparatus of the type disclosed herein, wherein said apparatus is manually operable to generate an electric charge for storage in said power store. The system may be modular in nature and said apparatus may comprise a module that is detachable from other modules of said system. The power store may include a plurality of supercapacitors. 10 A further aspect of the present disclosure provides manually operable apparatus for converting kinetic energy to electrical energy that comprises a detachable module of a portable power storage system, the apparatus comprising: a rotor plate coupled to a rotor axle for rotation therewith, the rotor plate having first and second major faces; a first stator provided in close proximity to the first major face of the rotor; a second stator 15 provided in close proximity to the second major face of the rotor; a crank assembly rotatable by hand to rotate the rotor axle; and an epicyclic gear assembly coupled between the crank assembly and the rotor axle, the gear assembly being operable to increase the rotational speed of the axle and rotor in use as compared with the rotational speed of the crank assembly; wherein: the rotor plate comprises a first array of magnets 20 fixed to said first major face of the rotor plate and a second array of magnets fixed to said second major face of said rotor plate, said first and second arrays of magnets being arranged about the rotor axle in a first and second circles respectively, said first and second circles having substantially the same diameter; the first stator comprises a first array of cores arranged around the rotor axle in a third circle having substantially the 25 same diameter as the first circle; the second stator comprises a second array of cores arranged around the rotor axle in a fourth circle having substantially the same diameter as the second circle; said cores each comprise a rectangular strip of electrically conducting material that has been rolled up to form a coiled core and arranged so that a short side of said strip is substantially parallel with said rotor axis, and the apparatus 30 further comprises a first electrical conductor wound round the cores coupled to the first stator and a second electrical conductor wound round the cores of the second stator, the arrangement being such that an electrical current can be generated as the magnet arrays and core arrays are rotated relative to one another about said rotor axis. Other advantages and aspects of the apparatus and storage system disclosed 35 herein will be apparent from the detailed description provided below. Brief Description of the Drawings The teachings of this disclosure, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which: 5 Fig. 1 is a schematic diagrammatic representation of an electrical energy storage system that embodies the teachings of this disclosure; Fig. 2 is an isometric view of a component of the system depicted in Fig. 1; Fig. 3 is an isometric exploded view of the component shown in Fig. 2; Fig. 4 is an isometric view of the system of Fig. 1; 10 Fig. 5 depicts the system of Fig. 1 in conjunction with an optional mains power adaptor; Fig. 6 illustrates the working principle of the system; Figs. 7a and 7b are charts depicting typical charge and discharge characteristics, Fig. 8 depicts capacitors in series and associated charge storage components; 15 Fig. 9 depicts a supercapacitor bank and integral controlling elements; Fig. 10 depicts the supercapacitor bank and its' integration with a microcontroller; Fig. 11 is a schematic perspective view of part of a stator and rotor assembly that form part of apparatus for converting kinetic energy to electrical energy; Fig. 12 is a perspective view of the rotor depicted in Fig. 11; 20 Fig. 13 is a schematic perspective view of part of the stator and rotor assembly depicting an illustrative electrical conductor wound round cores of the stator; Fig. 14 is a schematic sectional view of the stator and rotor assembly of Fig. 11 coupled to a gear assembly and crank assembly; and Fig. 15 is a schematic perspective view of a rolled-up spiral core. 25 Detailed Description Referring firstly to Fig. 11 of the drawings, there is depicted part of a stator and rotor assembly 1000 of a preferred implementation of the teachings of this disclosure. As shown, in this particular arrangement the stator and rotor assembly 1000 comprises 30 first and second stators 1001, 1003 that are arranged on either side of a rotor 1005. The rotor 1005 is mounted on a rotor axle 1007 for rotation therewith. In this implementation each stator 1001, 1003 consists of an array of cores 1009, 1011 that are arranged around the circumference of respective notional circles that are each of the same diameter and centred on the rotor axle 1007. The cores 1009 of the 35 first stator 1001 are each coupled, for example bolted, to a first support plate 1013; and the cores 1011 of the second stator 1003 are each coupled, for example bolted, to a second support plate 1015. As shown, the cores are arranged so that they extend from a support plate in a direction parallel to the axis of the rotor axle 1007. The first and second support plates 1011, 1013 each include a respective bearing 1017, 1019 that supports the rotor axle for rotation relative to the plates 1011, 5 1013. As shown in Fig. 11, the support plates 1011, 1013 are coupled to each other, in this instance by a series of rods and bolts, so that the cores of each array are maintained in close proximity to, and equally spaced from, the rotor 1005. Typically, the spacing between each array of cores and the rotor is in the order of a few millimetres, typically less than one centimetre, and more typically in the order of 1 to 5 millimetres. 10 In this particular implementation of the teachings of the invention, the array of cores 1009 that make up the first stator 1001 are offset in a circumferential direction relative to the array of cores 1011 that make up the second stator 1003. In this arrangement, each stator comprises an array of six cores, and the cores of the first stator are each offset by 30 degrees relative to the cores of the second stator. 15 Referring now to Fig. 12, there is depicted a schematic perspective view of the rotor 1005. The rotor 1005 comprises a circular plate 1018 that is fixedly coupled, in this instance by means of bolts, to the rotor axle 1007 so that the rotor plate 1018 rotates with the rotor axle 1007. Opposite major faces 1019, 1021 of the rotor plate 1018 have an array of magnets 1023, 1025 coupled thereto. The magnets on each major face of 20 the plate 1018 are each arranged in a notional circle centred on the rotor axle 1007. The diameter of the notional circles in which the magnets are arranged are, at least approximately, the same diameter as the notional circles in which the cores of each of the core arrays are arranged - the arrangement being such that rotation of the axle and rotor plate causes the magnets of each array to closely pass the cores of each array. In 25 this arrangement the cores are generally circular in lateral cross-section, the magnets each comprise a disc, and the diameter of a free end of each core (the end of the core nearest the rotor) is at least approximately the same as the diameter of each disc. In one envisaged arrangement, each magnet is approximately 2 cm in diameter and approximately 1 mm thick, and each core is approximately 2 cm in diameter. As will 30 later be described, in a preferred arrangement each core is formed by rolling up a rectangular sheet of electrically conducting material (preferably a metal sheet, such as a steel sheet, more preferably a laminated steel sheet) in a direction parallel to a long side of the sheet to form a cylindrical spiral or coil of metal as illustrated schematically in Fig. 15. In one arrangement, the sheet is approximately 0.3 mm thick, and is rolled up 35 around 33 times to form a cylinder that is approximately 2 cm in diameter. Once rolled-up the sheet may be spot welded, or otherwise coupled together, to stop it from unrolling. As shown in Fig 13, a first electrical conductor 1027 is wound around the cores of the first stator, and a second electrical conductor 1029 is wound around the cores of the second stator. The first and second electrical conductors are wound repeatedly around 5 a first core, and then around the next adjacent core, and so on until all the cores have a desired number of turns of electrical conductor wound around them. As will be appreciated by persons skilled in the art, when the rotor is rotated, an electric current is induced in the electrical conductors. In this particular arrangement, the offset between the cores of the first and second stators gives rise to a phase difference in the current 10 flowing through the first and second electrical conductors. In an envisaged implementation, the electrical conductors each comprise wires having a diameter of 0.5 to 1.0 mm, preferably around 0.75 mm. The first electrical conductor is wound round the cores of the first stator array, and the second electrical conductor is wound round the cores of the second stator array. In each case the 15 conductors typically have in the region of 80 to 120 turns per core (preferably around 90 to 95 turns), which equates to over 500 turns per stator and over a thousand total turns for the first and second stators. Conductors of a diameter in the region of 0.75 mm are suitable for a current of up to 9A, which is adequate for this particular application. Fig. 14 shows - in cross-section - the rotor and stator assembly of Fig. 11 20 coupled to a gear assembly 1031 that is, in turn, coupled to a crank assembly 1033 to provide manually operable apparatus for converting kinetic energy to electrical energy. The gear assembly 1031, in this particular arrangement, is a planetary gear assembly that is coupled to the rotor axle 1007. Although skilled persons will recognise that other types of gear assembly may be employed if desired, a planetary gear assembly is 25 preferred as it provides the necessary step-up in angular rotation in a particularly compact form. The crank assembly 1033 comprises a crank arm 1035 that is coupled at one end to the gear assembly 1031, and a handle 1037 coupled to the crank arm 1035 in the vicinity of an end of the arm that is distal from the gear assembly 1031. The crank arm 30 1035 may be configured so that it can be reduced in size (for example, folded in half) to reduce the size of the apparatus as a whole. As will be appreciated, the function of the gear assembly is to step-up the angular velocity, i.e rotational speed, of the rotor axle as compared to that which could be attained by coupling the crank arm directly to the rotor axle. In a preferred 35 arrangement, the planetary gear assembly 1031 is configured to provide a gear ratio of at least 10:1, preferably in the region of 13.6:1, and up to 15:1. With the preferred implementation described above, the “spiral” coiled cores depicted schematically in Fig. 15 exhibit significantly reduced eddy current losses as compared with the eddy current losses that would result from stators with an array of solid cores. Indeed, in comparative tests of a solid core of length 25mm, diameter 5 20mm, carrying a current of 1000A at 60Hz, we calculated that the Ohmic loss would be in the region of 0.03999W. However, with a spiral core of the same size and shape and also carrying a current of 1000A at 60Hz, we calculated that the Ohmic loss would be in the region of 0.00218 W - i.e. a factor of 18 times lower eddy current losses. It is this substantial reduction in eddy current losses that has enabled us to raise the efficiency of 10 the apparatus for converting kinetic energy to electrical energy to such a point that the apparatus can readily be operated to quickly generate a charge that is sufficient for charging an electronic device, such as a mobile telephone or tablet. As has been explained above in detail, in the preferred arrangement - for simplicity - the stators comprise the cores, and the rotor comprises the magnets. It will 15 be appreciated, however, that in an alternative arrangement, the magnets could be provided on the stators and the cores could be provided on the rotor (with a suitable arrangement, such as commutators for example, for providing an electrical connection to the windings around the cores). Similarly, whilst in the preferred arrangement there are two stators each with six cores and one rotor with six magnets on one major face and six 20 on the other major face, it will be appreciated that other arrangements are contemplated - although the above-described arrangement is advantageous as the apparatus is relatively small and compact. As will now be described, in a preferred implementation of the teachings of this disclosure, the apparatus described above in detail may be a component part of a power 25 storage system. In a particularly preferred arrangement, the power storage system may be modular in nature, and the apparatus for converting kinetic energy to electrical energy may comprise a module of the power storage system. One advantage of a modular system is that it may not always be necessary to have the apparatus for converting kinetic energy to electrical energy immediately to hand, and with a modular system that 30 apparatus can be left behind. It is appropriate at this juncture to devote a few paragraphs to a discussion, using proven and recognised engineering formulae, of the operating principle of the power storage system disclosed herein. In Figure 6, each of C1, C2, C3 and C4 may be either a single supercapacitor or 35 several supercapacitors connected in parallel. The resultant capacitance of values of C1 to C4 are connected in series to form a capacitance network in the preferred 10 15 25 arrangement. Other implementations of the teachings of this disclosure are not limited to the number of supercapacitors used, or their parallel-series configuration, or their capacitance value, or their working voltage. Supercapacitors C1 to C4 form the core Charge Storage Element (604). In Figure 6, when SW1 (602) is in position A and an appropriate source of electrical power (601) is applied, an Input Regulator (102) charges the Charge Storage Element (604) to the maximum allowed voltage, Vc. When the Charge Storage Element (604) is fully charged and SW1 (602) is changed to position B, the maximum energy held as electrical charge in the Charge Storage Element (604) then becomes available to the constant power Output Regulator (106). This is designed to deliver a stable output voltage into Rload (108). Stored energy in the Charge Storage Element (604) is proportional to (voltage)2 hence in this case using four series capacitors to increase the overall working voltage to a higher level as opposed to using just one larger supercapacitor rated at its maximum working voltage, typically 2.7 volts. While four supercapacitors of the same value connected in parallel will store the same energy at 2.7 volts, limited voltage swing to drive an Output Regulator and inefficiencies imposed by the electronic components used as regulators can significantly reduce the discharge time in practical low voltage configurations. The preferred implementation therefore uses supercapacitors connected in series. Excluding component tolerances, the following equations are used in this analysis:- Equation1.1 Total capacitance value of the Charge Storage Element (604) = C Where C Cl C2 C3 C4 Equation 1.2 Operating voltage of the Charge Storage Element (604) Vc = VC1 + VC2 + VC3 + VC4 Where VC1 = VC2 = VC3 = VC4 = the maximum permissible working voltage of 30 each capacitor Equation 1.3 The time ‘h’ to charge the capacitor ‘C’ from a minimum voltage ‘Vmin‘ to maximum voltage ‘Vmax’ using a constant current source delivering ‘i’ Amps is: (Fmax — X C ti = -----------------:----- In the preferred arrangement, a constant current CICV Input Regulator (102) is used to charge the supercapacitor network from Vmin to the maximum operating voltage Vmax when SW1 (602) is in the ‘A’ position. It then maintains that voltage level using constant voltage control until SW1 (602) changes to the ‘B’ position at which point, the 5 discharge cycle occurs through the Output Regulator (106). Equation 1.4 The stored energy in capacitor ‘C’ when charged to a voltage ‘V’ is: ½CV2 Joules (Note: 1 Joule = 0.00027778 Watt hours (to 8 decimal places). Equation 1.5 10 The theoretical discharge time k of a capacitor decaying at constant power is defined by the following equation: — vy 12 “ 2P Where C is the supercapacitor value in Farads, Vs is the fully charged voltage; Vf is the voltage at which the Output Regulator (106) or Microcontroller (113) ends the 15 discharge cycle, and P is the output power in Watts demanded by the resistive load, Rload (108). Scenario 1 Where C1 to C4 each equal 1,250F at 2.7V maximum working voltage. The 20 series supercapacitor combination is charged from 3.2 volts to 10.8 volts via the Input Regulator (102) at a constant current of 3 Amps. It is then discharged at constant power via the Output Regulator (106) into a 2.5 Watt load, Rload (108) back down to 3.2 volts. The minimum voltage of 3.2 volts is the lowest voltage at which the Output Regulator (106) can sustain its output power into the load before turning off. 25 Using the above equations 1.1 to 1.5: 1.1.1 Total capacitance value (604) = 312.5 Farads 1.2.1 Maximum working voltage - 2.7 Volts x 4 = 10.8 volts Note minimum operating voltage = 0.8 volts x 4 = 3.2 volts 7.6X312.5 1.3.1 Charge time 1 3 30 ti = 791 sec (13.2 mins) 1.4.1 Stored Energy: Maximum stored energy = 1>4(312.5 x 10.82) = 18,225 Joules Minimum stored energy = 1>4(312.5 x 3.22) = 1,600 Joules Available energy = 16,625 Joules, or 4.6 Watt hours 1.5.1 Maximum discharge time t2 at constant power load of 2.5 Watts: cf 10.82-3.22) I — Discharge time “ 2x2.5 t2 = 6,650 sec (110 mins) 5         Scenario 2 Where C1 to C4 each equal 1,250F at 3.8V maximum working voltage. This series supercapacitor combination in this case is charged from 10 volts to 15.2 volts at a constant current of 3 Amps via the Input Regulator (102). It is then discharged via the Output Regulator (106) at constant power into a 2.5 Watt load, Rload (108) back down to 10 10 volts. The minimum voltage of 10 volts is the lowest voltage at which this particular series combination of C1 to C4 will operate without degradation. The minimum operating voltage of each supercapacitor in this case is 2.5 volts and their maximum working voltage is 3.8 volts. Using the above equations 1.1. to 1.5: 15 1.1.2 Total capacitance value (604) = 312.5 Farads 1.2.2 Maximum working voltage - 3.8 Volts x 4 = 15.2 volts Note minimum operating voltage = 2.5 volts x 4 = 10 volts 5.2X312.5 t1 =-------- 1.3.2 Charge time 1 3 ti = 541 sec (9 mins) 20 1.4.2 Stored Energy: Maximum stored energy = 1>4(312.5 x 15.22) = 36,100 Joules Minimum stored energy = 1>4(312.5 x 102) = 15,625 Joules Available energy = 20,475 Joules, or 5.69 Watt hours 1.5.2 Maximum discharge time t2 at constant power load of 2.5Watts: c(15.22—102) t. = —------- 25 Discharge time 2x2.5 t2 = 8,190 sec (136 mins) This analysis shows that Scenario 2 is a preferred option for providing improved energy density and better charge and discharge time performance. Figure 7a therefore 30 shows the charge time characteristic under constant current for Scenario 2. Linear charging occurs through region (702) until the maximum voltage is achieved at which point, charging method changes to constant fixed voltage charging. Figure 7b is the discharge characteristic for Scenario 2. The product of voltage decay (703) and increasing current (704) is constant when operating the Output Regulator (106) in constant power output mode. In practice, when the voltage drops to approximately 10 volts, the current is at its maximum (705). At this point, charging is no longer viable. The supercapacitors are sufficiently discharged but have theoretically 5 delivered a regulated output for Rload (108) for over 8,000 seconds without any further application of source energy. In an implementation of the teachings of this disclosure, SW1 is replaced by two Electronic Switches (903 &905) located in the Supercapacitor Module (104) which contains the Supercapacitor Bank (105). These Electronic Switches are controlled by a 10 Microcontroller (113) and have negligible impedance when switched on. As aforementioned, in one aspect the present disclosure relates to a handheld device designed to store electrical energy and make it available for charging an externally Connected Device (108), by way of non-limiting illustrative example a device that typically consumes 2.5 Watts of power supplied at 5 volts over a period of time. Fig 15 1 shows a high-level electrical and electronic system diagram of a power storage system in accordance with the teachings of this disclosure - for example a modular power storage system. In one implementation the system comprises an Energy Cartridge (202) that is detachable from the Main Body (201) and contains the electrical storage components of 20 the device. Housed in the Energy Cartridge is a Supercapacitor Module (104) that contains a Supercapacitor Bank (105) and the charge management components to sense, monitor and switch charge within the electronic system. The Supercapacitor Module (104) is controlled by a Microcontroller (113) via a Charge Control Interface (111) and connects to an Input Regulator (102) and an Output Regulator (106) that 25 manage transfer of system power. Energy Cartridges (202) of different capacities can be fitted to the energy storage system. This creates the ability to store more or less energy depending on how the user wishes to use the system. Embodiments of the Energy Cartridge capacities include (83.3 Farads), medium (150 Farads), and large (312.5 Farads) but capacities are not limited to 30 these three embodiments. The Energy Cartridge can be unclipped from the Main Body (201) and in other embodiments, replaced by an upgraded unit containing different supercapacitor values or configurations to suit the system’s performance specification. Although Fig 1 shows only one for simplicity, there may without limitation be more than one Supercapacitor Bank (105) existent inside the Supercapacitor Module 35 (104). For example, in one embodiment the Supercapacitor Module (104) may contain two low capacity supercapacitor banks forming a supercapacitor network that operates in a back-to-back 'dual bank mode' fashion. In this mode of operation, one bank can be charged while the other is discharging into the Output Regulator (106) that supplies the Connected Device (108). When the discharge cycle becomes exhausted in one bank, the Microcontroller (113) 5 reverses the switching, and the other charged bank is made available to the Output Regulator (106). The discharged bank will start replenishment at that point. The cycle toggles between banks and so on with the power output to the Connected Device (108) being uninterrupted throughout. Allowing the Microcontroller (113) to monitor and alternate charge control 10 between two supercapacitor banks will result in charge being made more rapidly available for the Connected Device (108) and with potentially less applied cranking effort and longer availability of charge time. An illustrative physical enclosure design for the system is illustrated in Fig 2. Other embodiments of the physical enclosure design can exist but the electronic system 15 (Fig 1) is unchanged. Fig 3 illustrates how the detachable Energy Cartridge (202) is fitted to the Main Body (201). Connection to electronics located in the main body (201) is made with Electrical Contacts (302). The Energy Cartridge (202) is latched into place with a mechanical locking arrangement (301). 20 The system uses an attachable Generator Unit (401) - otherwise known as the aforementioned apparatus for converting kinetic energy to electrical energy - that connects to the Main Body via an Electromechanical Arrangement (203). In one embodiment, a permanent magnet brushless DC generator (BLDC Generator) (117) is fitted inside the Generator Unit (401). This is the primary source of energy to power the 25 system and is capable of supplying appropriate charge current at a maximum voltage of 24 volts. The user cranks the Lever (403) with the Handle (402) and their rotational kinetic energy is converted to electrical power by the BLDC Generator (117). Power generated by this action is rectified by a 3-phase Bridge Rectifier (118) into a suitable DC voltage and fed through the Input Manager (101) into the Input Regulator (102) 30 which charges the supercapacitors. The Input Manager circuitry arbitrates between energy sources and enables the most appropriate source to supply the system with power. As is described above in connection with Figs. 11 to 14, a lever arrangement (402 and 403) is mechanically connected to a gearbox inside the Generator Unit (401) 35 and coupled through gears to increase the angular velocity of the rotor in the BLDC Generator (117). Gearbox ratio is chosen to optimise the output power of the BLDC generator when cranking the handle at 150 revolutions per minute. To assist the user during cranking, the system may incorporate a variable length arm for the crank. This can be adjusted (404) by the user to match their anthropometries and applied cranking torque. 5 Further ease of use is achieved by the Microcontroller (113) electronically limiting input current in discrete steps and hence controlled limiting of the torque a user applies to the Generator Unit (401). This programmable torque control of the hand cranked Generator (117) is one embodiment of the system. The Microcontroller (113) switches in pre-set levels of current limit in the Input Regulator (102) to restrict current drawn from 10 the BLDG Generator, hence torque control. Levels are set by firmware during a set up mode and stored in non-volatile memory within the microcontroller (113). An integrated Solar Array (103) may be located in the upper surface of the Main Body (201) to provide supplementary low-level electrical power to charge the power supply system when placed under sufficient light. At any time in good sunlight 15 conditions, the system should be capable of generating power to fully charge an energy cartridge of 83 Farads in as little as 3 hours without any user intervention. The system may also receive power from an ancillary AC-DC Adaptor (119) that can be optionally plugged into a Socket (502) located on the Generator Unit (401) using Plug (501). A LED Indicator (503) acknowledges a connection to local mains power 20 which enables rapid charging when available. The trickle charge from the Solar Array (103) will be available to add supplementary charge to the Supercapacitor Bank (105) at a small rate compared to the much higher power generated by either hand cranking the BLDG Generator (117) or supplied by the mains powered AC-DC Adaptor (119). 25 The Main Body (201) of the invention is a plastics enclosure designed to be water and dust resistant to the recognised IP65 ingress specification. With the exception of the detachable Energy Cartridge (202); the Generator Unit (401) and the Connected Device (108), the entire electronic system depicted in Figure 1 is housed in the Main Body (201) of the system. 30 Fig 8 shows how the supercapacitors are connected to create a Supercapacitor Bank (105). This is formed by connecting 'n' supercapacitors (802) in series (Cl + C2 + Cn). Several supercapacitors may further be connected in a parallel-series configuration to create sufficient capacitance and increase the working voltage of the Supercapacitor Bank. The combined capacitance (803) is used to store charge in the system. When 35 charged to within a workable voltage range (Vcap), electrical energy is switched to the Output Regulator (106) via switch (905). In a typical embodiment, n = 4 for four supercapacitors connected in series where each series supercapacitor may comprise of one or more additional supercapacitors connected in parallel. To overcome the imbalance of tolerance and leakage variations between series connected supercapacitors, active electronic 5 Balancing Circuits (801) are introduced. Balancing keeps the voltage (V1, V2 Vn) across each Supercapacitor (802) within specification and avoids premature component failure caused by ageing and out of specification voltage excursions throughout the operating temperature range. The Supercapacitor Bank (105) also contains circuitry (804) to monitor and 10 protect against under-voltage and over-voltage conditions that might degrade the supercapacitors in the event of a system failure. Status and control of this circuitry (804) can be overridden by the Microcontroller (113) via the Charge Control Interface (111). Temperature monitoring (807) and Supercapacitor Bank size and type (806) sensors provide decision information to the firmware of the Microcontroller (113). 15 Fig 9 is a schematic of the Supercapacitor Module (104). Input charge flowing into the supercapacitor bank (105) is controlled by the electronic Switch A (903). The discharge cycle is enabled by electronic Switch B (905). Control of Switch A (903) and Switch B (905) is normally mutually exclusive such that both switches cannot be on at the same time although in other embodiments, this may be overridden in enhanced 20 operating modes. With Switch A (903) closed, the charge cycle takes place when input energy is applied to the system and Switch B (905) is set to open. Conversely, when the microcontroller senses that sufficient charge exists, it will open Switch A (903) and close Switch B (905). The Output Regulator (106) then operates to provide a stabilised voltage 25 supply to the Connected Device (108) throughout significant voltage excursions of the discharge cycle of the supercapacitors. The resulting discharge time is illustrated throughout the operating voltage region shown in Fig 7b. Included within the Supercapacitor Module (104) are circuits to enable the microcontroller to manage the functionality of the system. Circuit D (907) causes the 30 Supercapacitor Bank (105) to gracefully discharge (DisCAP) under storage, disconnection or fault conditions. An analogue Sensor Circuit C (906) measures the voltage level (CAPgood) of the supercapacitor bank and is used to control Switch B (905). With the aim of keeping the voltage on the supercapacitors within working limits, 35 under-voltage and over-voltage monitoring hardware (804) will automatically isolate the Supercapacitor Bank (105) by turning the isolation switch (805) off until charge is reapplied. The Microcontroller (113) tracks this via the 'CTRL' signal and can override the hardware putting the system into a 'hibernate' mode until charge is applied by the user. A circuit in the Supercapacitor Bank (105) senses what size and type (CAP type) 5 of detachable Energy Cartridge (202) is connected to the Main Body (201). The firmware in the Microcontroller (113) recognises the Energy Cartridge (206) type and uses these signals to make charge control decisions. The system incorporates two electronic circuits configured as regulators. The regulator circuits are used to set the voltage and current levels of the charging and 10 discharging cycles of the Supercapacitor Module (104). The Input Regulator (102) circuit contains 'step-down' functionality and converts power from the energy source providing controlled charge to the Supercapacitor Bank (105) during the charging cycle. It is operated in a “constant current - constant voltage” mode to charge the supercapacitors in the most efficient manner as long as sufficient 15 power is applied to the system. Constant current charging technique used by the Input Regulator (102) reduces capacitor charging time compared to exponentially charging the supercapacitors, so the system has adopted a constant-current, constant-voltage (CICV) method of charging the Supercapacitor Bank (105). Schottky Diode (902) protects the Input Regulator (102) from reverse voltage damage while Schottky Diode (904) provides 20 an OR function for charging with the solar array (103). When the Supercapacitor Bank (105) is fully charged, the Input Regulator (102) automatically switches to a constant voltage mode to maintain the maximum working peak voltage on the Supercapacitor Bank (105) under no-load conditions. This characteristic is illustrated in Figure 7a. In this condition, the Supercapacitor Bank (105) 25 is fully charged (ref 702). During the charge cycle, the Microcontroller (113) monitors supercapacitor charge and decides at which level the output can be switched on or if charging is still required. Status and Control (114) of the Input Regulator is handled by the Microcontroller. 30 The Output Regulator (106) circuit with “step-up / step-down” functionality converts charge stored in the Supercapacitor Bank (105) to a stable voltage during the discharge cycle. The Output Regulator (106) is configured in a constant power mode to deliver power into a Connected Device (108) with a regulated output voltage of 5 volts. In one embodiment, the power output is, but not limited to, 2.5 Watts. The Output Regulator 35 (106) is configured to maintain a stable output throughout the entire window of the decay cycle of the Supercapacitor Bank (105) whether or not the Supercapacitor Bank is being charged or not. This is illustrated across the “step-up” and “step-down” regions on Figure 7b. The point at which the Output Regulator (106) ceases to regulate electronically is determined by the electronic design and at that point, the output will switch off and await further charging of the system from the power source (103, 117 or 119). Status and 5 Control (114) of the Output Regulator is handled by the Microcontroller (113). An Input Manager circuit (101) acts as an OR function such that the power source can come from either the Generator Unit (401) or an AC mains powered AC-DC Adaptor (502). The resulting power is then made available to the Input Regulator (102). In practice, switching losses and component power dissipation will reduce the efficiency 10 of the system with maximum losses of around 8% being anticipated. The user may choose to apply effort to crank the BLDC Generator (117) (i.e. the apparatus for converting kinetic energy to electrical energy described above in connection with Figs. 11 to 14) at any point during the discharge cycle. This will immediately start to top-up the charge because it is constantly being managed by the 15 Microcontroller (113). Fig 10 illustrates that a microcontroller (113) is an advantageous component of the system because it monitors the charge status of the supercapacitor bank (105), manages both regulators (102 and 106) and controls the supercapacitor module (104). A decision is made by firmware when to charge the supercapacitor module (104), 20 or maintain the power output to the charge device (108). It will occur when sufficient accumulated charge in the Supercapacitor Bank (105) can provide output power for a period of several minutes and still have the ability to be topped up. This period of time facilitates charge accumulation and enables a useful amount of power to the Connected Device (108). The point to start charging the connected device (108) is set by the 25 firmware in the microcontroller (113). A Control Bus (111) acts as a 'Charge Control Interface' and is provided to both connect the detachable Energy Cartridge (206) to the Main Body (207) and be an expansion bus for future enhancements or implementing the 'dual bank' functionality. Ambient and supercapacitor temperature sensing to protect the system in extreme 30 environments is transmitted over this Control Bus (111). Integral within the Main Body (201) is a liquid crystal display (LCD Screen) (109) that alerts the user of the charge condition of the Supercapacitor Module (104) and other status messages. An on / off Button (204) on the Control Switches interface panel (115) activates the system and issues an audio alert. It also duplicates to invoke a self-35 diagnostic function. Power output from the system to the Connected Device (108) is made via a USB Interface (107) (or any other type of interface) that also enables diagnostic control of firmware in the invention from an associated software App. In another envisaged arrangement, the system may be configured to wirelessly charge the connected device 108 by means of a suitable inductive charger. An internal Auxiliary Power Supply (116) provides standby power for the 5 electronics in the system and needs minimal charge from any one of the energy sources to initiate the Microcontroller (113) when an energy source is present and the system requires to be controlled. That power is held in a separate circuit to the Supercapacitor Bank (105) and can be maintained for a considerable period of time. It is topped up by any of the three energy sources of the system. 10 The Microcontroller (113) is a very low power device and is capable of wake-up calls from energy applied to the system. The microcontroller (113) and its associated electronics are booted up immediately when power is applied to the system and presents the system's current status on the LCD Display (109). A reset facility is included for the microcontroller (113) enabling a cold-start of the controlling firmware from a zero-15 charge condition. A Flash Interface (112) is provided for firmware updates and can be programmed via the USB Charging Connector (107) using special commands from a software App. Diagnostic status and setup of the system is also available via this USB Charging Connector (107). Spare non-volatile memory in the Microcontroller (113) is used to store 20 charge cycle data and customisation, and firmware algorithms can make use of this information to shape charging profiles of the user. It will be understood from the foregoing that the apparatus for converting kinetic energy into electrical energy described above in connection with Figs. 11 to 14 of the drawings provides a way of inputting electrical energy into the power supply system that 25 enables the energy storage system to be effectively recharged using only the energy conversion system described above. It will be appreciated that whilst various aspects and embodiments of the present disclosure have heretofore been described, the scope of the present disclosure is not limited to the particular arrangements set out herein and instead extends to encompass 30 all arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims.

Claims

1. Manually operable apparatus for converting kinetic energy to electrical energy, the apparatus comprising:5 a rotor coupled to a rotor axle for rotation therewith;a stator provided in close proximity to the rotor;a crank assembly rotatable by hand to rotate the rotor axle; anda gear assembly coupled between the crank assembly and the rotor axle, the gear assembly being operable to increase the rotational speed of the axle and rotor in 10 use as compared with the rotational speed of the crank assembly; wherein:one of the rotor and the stator comprises an array of magnets arranged about the rotor axle in a first circle, and the other of the rotor and the stator comprises an array of cores arranged around the rotor axle in a second circle having substantially the same diameter as the first circle;15 said cores each comprise a rectangular strip of electrically conducting materialLO that has been rolled up to form a coiled core and arranged so that a short side of saidstrip is substantially parallel with said rotor axis, andthe apparatus further comprises an electrical conductor wound round the cores so that an electrical current can be generated as the magnet array and core array are 20 rotated relative to one another about said rotor axis.CXI2. Apparatus according to Claim 1, wherein the gear assembly is operable to increase the rotational speed of the axle, as compared with the rotational speed of the crank assembly, by a factor of at least 10.

253. Apparatus according to Claim 1 or 2, wherein the gear assembly is operable to increase the rotational speed of the axle, as compared with the rotational speed of the crank assembly, by a factor of up to 15.30 4. Apparatus according to any preceding claim, wherein the gear assemblycomprises an epicyclic gear assembly.

5. Apparatus according to any preceding claim, wherein the array of cores is coupled to the stator.

6. Apparatus according to any preceding claim, comprising multiple statorsarranged in close proximity to said rotor, each said stator having an array of cores coupled thereto.

7. Apparatus according to Claim 6, wherein the rotor comprises a rotor plate fixedly 5 coupled to said rotor axle for rotation therewith, the apparatus further comprising a first stator arranged on one side of said rotor plate and a second stator arranged on a second side of said rotor plate.

8. Apparatus according to Claim 7, wherein said first and second stators are10 coupled to each other so that the cores of each array are maintained in close proximity to, and equally spaced from, the rotor.

9. Apparatus according to Claim 8, wherein each array of cores is spaced from the rotor by a spacing that is in the order of a few millimetres, typically less than one 15 centimetre, and more typically in the order of 1 to 5 millimetres.LO10. Apparatus according to any of Claims 6 to 9, wherein a first array of cores coupled to said first stator is angularly offset relative to a second array of cores coupled to said second stator.2011. Apparatus according to Claim 10, wherein cores of said first array are offset by an angle of 30 degrees relative to the cores of said second array.

12. Apparatus according to Claim 11, wherein each array of cores comprises six 25 cores arranged to extend in a direction parallel to said rotor axle.

13. Apparatus according to any preceding claim, wherein said array of magnets are coupled to said rotor.30 14. Apparatus according to Claim 13, wherein said rotor comprises a rotor platehaving a first major face and a second major face, a first array of magnets being coupled to said first face, and a second array of magnets being couped to said second face.

15. Apparatus according to Claim 14, wherein each array of magnets comprises six35 magnets.

16. Apparatus according Claim 15, wherein each said magnet is disc-shaped.

17. Apparatus according to Claim 16, wherein each said magnet is approximately 2 cm in diameter and a few millimetres thick, typically around 1 mm thick; and each said 5 core is approximately 2 cm in diameter.

18. Apparatus according to any preceding claim, wherein said cores are of sheet steel, preferably laminated steel sheet.10 19. A power supply system comprising a power store and apparatus according toany preceding claim, wherein said apparatus is manually operable to generate an electric charge for storage in said power store.

20. A power supply system according to Claim 19, wherein said system is modular in 15 nature and said apparatus comprises a module that is detachable from other modules of LO said system.CXI21. A power supply system according to Claim 19 or 20, wherein said power store includes a plurality of supercapacitors.2022. Manually operable apparatus for converting kinetic energy to electrical energy that comprises a detachable module of a portable power storage system, the apparatus comprising:a rotor plate coupled to a rotor axle for rotation therewith, the rotor plate having 25 first and second major faces;a first stator provided in close proximity to the first major face of the rotor;a second stator provided in close proximity to the second major face of the rotor;a crank assembly rotatable by hand to rotate the rotor axle; andan epicyclic gear assembly coupled between the crank assembly and the rotor30 axle, the gear assembly being operable to increase the rotational speed of the axle and rotor in use as compared with the rotational speed of the crank assembly; wherein:the rotor plate comprises a first array of magnets fixed to said first major face of the rotor plate and a second array of magnets fixed to said second major face of said rotor plate, said first and second arrays of magnets being arranged about the rotor axle35 in a first and second circles respectively, said first and second circles having substantially the same diameter;the first stator comprises a first array of cores arranged around the rotor axle in a third circle having substantially the same diameter as the first circle;the second stator comprises a second array of cores arranged around the rotor axle in a fourth circle having substantially the same diameter as the second circle;5 said cores each comprise a rectangular strip of electrically conducting materialthat has been rolled up to form a coiled core and arranged so that a short side of said strip is substantially parallel with said rotor axis, andthe apparatus further comprises a first electrical conductor wound round the cores coupled to the first stator and a second electrical conductor wound round the10 cores of the second stator, the arrangement being such that an electrical current can be generated as the magnet arrays and core arrays are rotated relative to one another about said rotor axis.27 11 25

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