Field of the Invention

[0001 ] This invention relates generally to electric motors, and more particularly, this invention relates to an electric motor having a timing circuit which energises electromagnets to counteract magnetic field interaction between rotor and stator magnets depending on the rotational position of the rotor assembly to thereby create rotational force.

Background of the Invention

[0002] Conventional electric motors typically have a rotor having electromagnets which are switched according to the rotational position of the rotor to attract stator magnet, thereby inducing rotation.

[0003] The present invention seeks to provide an alternative form of electric motor, which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[0004] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

Summary of the Disclosure

[0005] There is provided herein an electric motor comprising a stator assembly having a stator magnet, a rotor assembly having a rotor magnet magnetically interacting with the stator magnet and a timing circuit which energises an electromagnet to counteract magnetic field interaction between the magnets depending on the rotational position of the rotor assembly.

[0006] The rotor and stator magnets may be arranged to repel each other. As such, the timing circuit energises the electromagnet as the rotor magnet approaches the stator magnet, thereby diminishing the repulsive force.

[0007] When the rotor magnet and the stator magnet are substantially adjacent, the electromagnet may be de-energised to thereby no longer inhibit the magnetic interaction, thereby reinstating the repulsive force to repel the rotor magnet away from the stator magnet, thereby inducing rotational force of the rotor assembly.

[0008] Other aspects of the invention are also disclosed.

Brief Description of the Drawings

[0009] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0010] Figure 1 shows an electric motor in accordance with an embodiment;

[001 1 ] Figure 2 shows an electric circuit of the electric motor in accordance with an embodiment;

[0012] Figure 3 shows timing discs of the motor in accordance with an embodiment; and

[0013] Figure 4 shows rotors of the motor in accordance with an embodiment.

Description of Embodiments

[0014] An electric motor 100 comprises a stator assembly having a stator magnet 101 and a rotor assembly having at least one rotor magnet 102 magnetically interacting with the stator magnet 101.

[0015] The motor 100 further comprises a timing circuit which energises at least one electromagnet 103 to counteract magnetic field interaction between the magnets 101 , 102 depending on the rotational position of the rotor assembly.

[0016] The magnets 101 , 102 may be arranged so as to repel each other. In this regard, the magnets 101 , 102 may be monopolar and of the same polarity or dipolar having their same poles facing to thereby create a repulsive force.

[0017] As such, the timing circuit may energise the electromagnet 103 as a rotor magnet 102 approaches a stator magnet 101 , thereby diminishing the repulsive force. [0018] When the rotor magnet 102 and the stator magnet 101 are substantially adjacent, the electromagnet 103 may be de-energised to thereby no longer inhibit the magnetic interaction between the magnets 101 and 102, thereby reinstating the repulsive force to repel the rotor magnet 102 away from the stator magnet 101 , thereby inducing rotational force of the rotor assembly.

[0019] The electromagnet may comprise a solenoid.

[0020] The timing circuit may be configured according to a width of the rotor magnet. [0021 ] The rotor assembly may comprise a rotor disk 104 having the rotor magnet 102 thereon. In the embodiment shown, the rotor disc 104 comprises at least one pair of oppositely located rotor magnets 102A and 102B. The rotor disc 104 is preferably non-magnetic, such as comprising aluminium, or acrylic in a preferred embodiment to reduce the overall weight of the motor 100.

[0022] In a preferred embodiment, each electromagnet 103 may have a nanocrystalline annealed Metglas™ amorphous metal cylindrical core of approximately 25 mm in diameter and approximately 65 mm in length. Furthermore, the electromagnets 103 may have a wire diameter of 0.60mm and have 1400 turns of enamelled copper wire on a bobbin with an internal diameter of approximately 25mm and a length of approximately 60mm. Furthermore, a heat sink may interface each electromagnet 103.

[0023] Figure 4 shows an embodiment wherein the rotor magnet 102 uses a series of dipolar magnets 105. As alluded to above, the dipolar magnets 105 may be orientated oppositely to dipolar magnets of the stator magnet 101 so that like poles thereof interface, thereby creating repulsive force. As is shown in Figure 2, the dipolar magnets 105 may be angled with respect to a radial axis of the rotor assembly, thereby generating a magnetic field angled with respect to the radial axis which creates a tangential force vector to assist rotation of the rotor assembly. As is further shown in Figure 2, a first dipolar magnet 105 may be aligned with the radial axis whereas the other dipolar magnets 105 may be successively arranged at an increasing angles with respect to the radial axis to gradually increase the tangential force vector.

[0024] As shown in Figure 4 rotor discs 104 comprise 12 magnets in total, in four groups of three. As such, in the embodiment shown, each rotor magnet 102 comprises three adjacent dipolar magnets 105. [0025] Each dipolar magnet 105 may have a cross-section which increases in width radially. In other words, each dipolar magnet 105 may be substantially trapezoidal as shown.

[0026] The distance between the rotor magnet 102 and the stator magnet 101 may be sufficient so that repulsive force therebetween is greater than an attractive force between the rotor magnet 102 and an iron core of the electromagnet 103.

[0027] With reference to Figure 1 , the rotor assembly may comprise a first set of rotor magnets 102A and a second set of rotor magnets 102B out of phase with respect to the first set of rotor magnets 102A with respect to a rotational axis of the rotor assembly. In the embodiment shown, the second set of rotor magnets 102B is 90° out of phase with respect to the first set of rotor magnets 102 A.

[0028] Each set of rotor magnets 102 may comprise at least one pair of oppositely located rotor magnets 102.

[0029] In the embodiment shown, the rotor assembly may comprise a first rotor disc 104A having the first set of rotor magnets 102A and a respective first electromagnet 103A and a second rotor disc 104B having the second set of rotor magnets 102B and a respective second electromagnet 103B. The rotor discs 104 may share a common rotor shaft 106. As such, the motor 100 may comprise a pair of electromagnets 103A and 103B each of which are switched four times per rotation (i.e., twice for each rotor magnet 102 of the respective rotor disc 104).

[0030] The rotor discs 104 may be spaced apart to reduce magnetic interaction between the first set of rotor magnets 102A and the second electromagnet 103B and the second set of rotor magnets 102B and the first electromagnet 103A.

[0031 ] The motor 100 may further comprise a timing disc 107 operably coupled to the timing circuit. The timing disc 106 may comprise timing magnets 108 switching timing switches 109 of the timing circuit of the stator assembly.

[0032] The timing magnets 108 may have a width configured to control the duration of switching of the magnetic switches 109. For example, the timing magnets 109 may have a width configured according to a width of the respective rotor magnet 102.

[0033] The timing switches 109 may be reed switches. [0034] In embodiment shown, the motor 100 may comprise first and second timing discs 107A and 107B each controlling timing for a respective electromagnet 103.

[0035] The timing disc 107 is preferably also non-magnetic, such as comprising aluminium.

[0036] Figure 2 shows an electrical circuit 1 15 of the motor 100 which comprises a regenerative circuit 1 1 1 comprising at least one electric generator 1 12. In the embodiment shown, the circuit 1 15 comprises an electric generator 1 12 either side of the rotor shaft 106.

[0037] The electric generator 1 12 may be a three-phase electric generator wherein the circuit 100 further comprises rectification 1 13 and power storage voltage conditioning 1 14 to recharge power storage 1 10, which may comprise a (super) capacitor bank. In alternative embodiments, the storage 1 10 may comprise battery storage.

[0038] The power storage 1 10 may be pre-charged prior operation and the storage 1 10 may be charged using excess wattage from the generator 1 12. For example, the electric generator 1 12 may be able to generate over 120 W and approximately 50 W of power from the generator 1 12 may be used to recharge the power storage 1 10, more than is required to power the electromagnets 103.

[0039] Where the power storage 1 10 comprises a battery, a charging controller may control charging of the battery according to the charge state of the battery. For example, the charging controller may control the switches 109 to draw power from the generator 1 10 inversely proportional to the charge state of the battery.

[0040] In the embodiment shown, the power storage voltage conditioning 1 14 is a 150 V DC to 24 V DC buck converter. An isolation relay 1 16 may interface the voltage conditioning 1 14 and the power storage 1 10.

[0041 ] In the embodiment shown, a first electric generator 1 12A is used to recharge the power storage 1 10 whereas a second electric generator 1 12B is used to provide power to a load 1 17. In embodiment shown, load voltage conditioning 1 18 interfaces the second electric generator 1 12B and the load 1 17. [0042] In the embodiment shown, the load voltage conditioning 118 may comprise a 150V DC to 14V DC buck converter followed by a 12 V DC to 240 V AC converter 120.

[0043] The circuit 115 shows the magnetic switches 109 being single pole double throw switches which, in a first position close a charging circuit to allow the generator 112A to recharge the power storage 110 and, in a second position, close a stator electromagnet circuit 121 to assist the electromagnets 103.

[0044] A 3 A 24 V DC regulator 122 may interface the power storage 110 and the electromagnets 103.

[0045] At least one of the magnets 101 , 102 and 108 may comprise rare earth magnets.

[0046] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.