CN116888872A

CN116888872A - Energy-saving induction motor

Info

Publication number: CN116888872A
Application number: CN202180094810.6A
Authority: CN
Inventors: 昆吉蒙·泰克·皮迪卡依尔
Original assignee: Parker Dynamics Private Ltd
Current assignee: Parker Dynamics Private Ltd
Priority date: 2021-01-09
Filing date: 2021-12-08
Publication date: 2023-10-13
Also published as: MX2023008203A; JP2024502380A; EP4275267A1; BR112023013793A2; ZA202307792B; CA3204631A1; AU2021418177A1; WO2022149155A1; KR20230137935A

Abstract

The invention relates to an energy-saving induction motor, comprising: a stator; a main winding (M) of the stator for generating a Rotating Magnetic Field (RMF); and a rotor arranged to rotate relative to the main winding (M) of the stator due to RMF. The stator comprises additional windings (a) for generating an alternating EMF induced in one or more of the additional windings (a) due to rotation of the rotor. The alternating EMF generated in the one or more additional windings (a) is synchronously fed back to the main winding (M) of the stator over a complete rotation period of the rotor by an electronic control unit coupled to the stator, thereby generating a composite AC output power that is continuously fed to the main winding (M) of the stator.

Description

Energy-saving induction motor

Technical Field

The present invention relates generally to an energy-efficient induction motor, and more particularly, to an induction motor that consumes less current than a conventional motor of the same capacity by collecting and manipulating EMF (electromotive force) generated in a stator winding to supplement a major portion of power required to drive the motor.

Background

With the dramatic increase in energy demand, various fields of industry or other fields are attempting to employ sustainable energy and fully utilize renewable energy. Concomitantly, there is a need to provide energy-efficient equipment and save the energy/power generated to meet the energy requirements and demands.

With the advancement of technology, motors have been applied as a main driving force to various industrial applications, which also causes excessive use of energy resources. In particular, induction motors (e.g., three-phase induction motors) are widely used in industry and agriculture, and the rate of energy consumption of these motors accounts for 65% of the total energy produced. Therefore, there is also a need to save a considerable amount of energy compared to the standard motors currently in use. In addition, there is a need to reduce the running costs of such motors by virtue of increased efficiency to design energy efficient motors.

Induction motors are basically classified into two types according to the type of input power to the motor and the type of rotor. Based on the type of input power, induction motors are classified into single-phase induction motors and three-phase induction motors. Based on the type of rotor, induction motors are classified into squirrel-cage motors (Squirre 1 cage motors) and slip-ring (or Wound type) motors (S1 ip ring motors).

The following describes the working principle of the induction motor. When the stator windings of an induction motor are fed with an AC input power, an alternating magnetic flux is generated around the stator windings due to the AC input power. The alternating magnetic flux rotates at a synchronous speed. The rotating magnetic flux is also referred to as a "Rotating Magnetic Field (RMF)".

The relative velocity between the stator RMF and the rotor conductor causes Induced electromotive force (Induced emf) in the rotor conductor according to faraday's law of electromagnetic induction. The rotor conductors are short-circuited, and thus a rotor current is generated due to the induced electromotive force. Because of its mechanism of operation, such motors are known as induction motors. This is similar to the action that occurs in a transformer, and thus an induction motor is also referred to as a resolver.

The induced current in the rotor also produces an alternating magnetic flux around the rotor. The rotor flux lags the stator flux. According to lenz's law, the direction of induced rotor current can be expressed as: the current tends to counteract the cause of its generation. Since the rotor current is generated due to the relative speed between the rotating stator flux and the rotor, the rotor will attempt to catch up with the stator RMF. Thus, the rotor rotates in the direction of the stator magnetic flux to minimize the relative speed. However, the rotor cannot always catch up with the synchronous speed of the rotating stator flux or RMF. This is the basic working principle of single-phase induction motors and three-phase induction motors.

In a three-phase induction motor, a three-phase power supply is used to balance high current consumption. Therefore, the three-phase power supply needs to operate the induction motor with 3 Horsepower (HP) or more.

The energy efficiency of electric machines, in particular induction machines, is a highly studied field. By increasing the efficiency of the induction motor, a significant amount of energy may be saved. However, it is difficult to achieve industry efficiency standards by using conventional designs for designing induction motors.

At present, the existing high-efficiency induction motor realizes design change by introducing a high-quality movement and winding materials so as to improve the operation efficiency of the motor. But this design variation is not cost effective. In the past, a great deal of work has been done in terms of energy saving and a great investment has been made in an effort to improve the current efficiency of the motor through various design changes rather than using high quality materials.

In most cases, squirrel cage induction motors are more suitable for applications where the speed is constant. However, current induction motors, although excellent in efficiency, are not commercially available due to significant winding losses. Other solutions that have been implemented to improve efficiency are the use of amorphous alloy cartridges and copper rotors, however, such solutions result in an overall increase in cost and may not be implemented within the industry.

CN201663527U relates to an electronic drive system design. The AC driving system of the electric forklift is a cage-type induction motor. The three-phase windings are placed in slots in the stator inner ring. A closed-loop rotor that generates rotating magnetic field induction generates a current. The three-phase winding space of the electric fork truck AC drive system is placed according to a 120 degree potential difference. The rotor type is a squirrel cage rotor formed by a cast aluminium strip with a rim groove at the outer edge of the rotor. After conversion using sinusoidal Pulse Width Modulation (PWM) and a DC/AC inverter, the voltage was 48V in the constant voltage frequency analog control. The fundamental frequency of the motor is the same as the frequency of the sine wave reference voltage. The required elements of the AC motor are greatly reduced, and the vulnerable parts do not need to be replaced conventionally and almost do not need maintenance. The motor is more efficient, stronger and more durable than a DC motor.

US4414499a discloses a motor protection retrofit economizer for an induction motor. The unmodified standard AC induction motor has its stator windings energized from a source of sine waves by a signal-responsive waveform modifier that is coupled from the source to the stator windings and is operable to control each portion of the period of the sine waves. An improved motor current demodulator responsive to energy efficiency related parameters and excessive stator winding inrush current each time the current increases from zero generates a signal for controlling a waveform modifier to maintain optimum motor efficiency through different motor loads and power source changes, and the signal synchronously controls a motor protection circuit that suppresses the waveform modifier to de-energize the stator winding in the event of excessive input current, excessive motor temperature, or both causing potential damage.

US4382223a relates to a voltage and frequency controlled AC waveform modifier. The unmodified standard AC induction motor has its stator windings energized from a source of sine waves by a signal-responsive waveform modifier operable to control the portion of each cycle of the sine wave that is coupled from the source to the stator windings. A load detection device comprising a relatively small AC generator coupled to the motor rotor generates a control signal that varies with changes in motor load for controlling the waveform modifier to increase the field density of the stator windings as motor load increases and to decrease the field density of the stator windings as motor load decreases.

US4864212a discloses an energy efficient AC power control system for powering an induction motor. A sine wave power supply connected to a control system with a gate electrode via a TRIAC is described herein, the sine wave power supply being energized by a signal string (sequence) of saw tooth type control signals having a Repetition rate (Repetition rate) twice the frequency of the sine wave power supply for providing short burst energy, thereby reducing the total power input due to lower power requirements for low speed operation variation frequencies at low fixed frequencies.

US4341984a discloses an electronic commutation for a DC motor. The DC motor includes a stator composed of a plurality of coils interconnected with each other, and a plurality of grid-controlled solid state rectifiers connected to interfaces of the coils for selectively conducting current into and out of the stator coil interface depending on which of the rectifiers is active in response to forced commutation below a certain rotational speed and self-commutation above the rotational speed. This creates Stator poles (Stator po1 e) that are angularly displaced from the poles of the motor rotor and are positionally offset as the rotor rotates. A plurality of trigger assemblies are provided for controlling the energization of the various gate electrodes, each of the above trigger assemblies including a Pick-up coil (Pick-up 1) forming part of a frequency selection circuit whose resonant frequency varies in dependence on the position of a magnetic element which moves relative to the Pick-up coil as the rotor rotates. A sine wave oscillator is coupled to the frequency selection circuit in the trigger assembly, the oscillator being operable to produce either of two different output frequencies, and an electronic switch selectively varies the output frequency of the oscillator in response to the rotational speed of the rotor. One of these frequencies causes the trigger assembly to operate at all rotor positions and causes the SCR trigger timing (SCR trigger timing) to be advanced for reliable start-up and very low speed operation. Other frequencies may delay SCR trigger timing for most efficient motors operating at medium and high speeds.

US4636702a discloses an economizer controlled current start and protection for an induction motor. A sampling transformer is described herein that is operable to generate voltage pulses related to an inrush current (inrush-current) parameter for controlling a portion of a sine wave of a power input to a stator winding for reducing current to a motor during low load. It is further limited to a "manually settable mode" for selecting the maximum value of the motor torque during the start-up mode of operation.

US6489742B2 discloses an efficiency maximising motor controller comprising a method of use with power delivery from a power source and mains voltage to an induction motor by a control element using a Digital Signal Processor (DSP) which calculates and optimises the supply of current for use with existing motor loads. The control elements may include standard TRIAC, field effect transistors, insulated gate bipolar transistors, three-quadrant TRIAC (Three quadrant TRIAC), or other selective control elements. Digital calculation of current demand for motor load and other motor parameters and motor control feed are calculated in parts per million seconds to provide motor current optimization for all motor usage conditions. The calculation of the motor load demand for the current and the supply of the current are actually synchronized.

Accordingly, there is a need for an energy efficient induction motor that will consume less current than any conventional motor of the same capacity and that efficiently collects the power generated by the motor to supplement a substantial portion of the power required to drive the motor.

Limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present invention with reference to the drawings.

Disclosure of Invention

Object of the invention

The main object of the present invention is to develop an energy efficient induction motor that consumes less current than a traditional motor of the same capacity to supplement the main part of the power required to run the motor, and that can be driven by a single phase main AC power source instead of a three phase main AC power source to meet any output requirements without compromising on the input power requirements.

Another object of the invention is to develop an energy efficient induction motor comprising specially designed electronic modules coupled with a tailored stator winding design, most suitable to ensure higher current efficiency.

It is a further object of the present invention to develop an energy efficient induction motor in which the stator windings of the induction motor are continuously supplied with composite power due to the alternating EMF generated within the stator windings during a complete rotation period of the rotor, the alternating EMF (generated EMF) thus being the primary source of supply power during continuous operation of the motor.

It is a further object of the present invention to devise a single phase induction motor having lower electrical, magnetic and thermal losses than a three phase motor of the same output requirement. In addition, the single-phase induction motor has lower magnetic loss and heat loss than a three-phase motor requiring the same input power.

Yet another object of the present invention is to devise an energy-efficient induction motor that can be industrially manufactured and is economical and efficient so that its price can be universally accepted by the industrial and agricultural fields, thereby achieving wide applicability.

Disclosure of Invention

An energy efficient induction motor as shown in and/or described in connection with at least one of the figures, as set forth more fully in the claims, is disclosed that consumes less current than a conventional motor of the same capacity.

The energy efficient induction motor includes a stator including a main winding for generating a Rotating Magnetic Field (RMF) when a main AC power is supplied to the main winding of the stator, and a rotor arranged to rotate relative to the main winding of the stator due to the presence of the RMF. The stator further comprises one or more additional windings for generating an alternating EMF in the additional windings due to the rotation of the rotor. The alternating EMF generated in the one or more additional windings is then synchronously collected, manipulated and fed to the main winding of the stator by an Electronic Control Unit (ECU) coupled to the stator during a complete rotation cycle of the rotor. Thus, since the motor partially functions as a generator, the energy generated during rotation of the rotor satisfies a major portion of the energy requirements of the induction motor.

The alternating EMF generated in the one or more additional windings is fed to the ECU. The ECU includes a rectifying circuit for converting the AC voltage of the main AC power source and the alternating EMF generated in the one or more additional windings into corresponding DC power. The composite DC power is obtained by adding the corresponding DC power.

The composite DC power is then converted to composite AC output power by an inverter circuit in the ECU. The ECU includes a frequency converter (VFD) control module configured to vary the voltage and frequency of the composite AC output power.

The ECU further includes a frequency synchronization circuit configured to synchronize the frequency of the composite AC output power with the frequency of the main AC power source. At this stage, the ECU may disconnect the connection of the main AC power source directly to the stator via the disconnect switch, and the composite AC output power is continuously supplied only to the stator by the ECU.

These and other features and advantages of the present invention will be understood from the following detailed description of the invention and the accompanying drawings, in which like reference numerals refer to like parts throughout.

Drawings

Fig. 1 is a diagram illustrating various components and operations of an energy-saving induction motor according to an exemplary embodiment of the present invention.

Fig. 2 is a schematic view of a stator of an energy-efficient induction motor according to an exemplary embodiment of the present invention.

Fig. 3 is a schematic view of a rotor of an energy efficient induction motor according to an exemplary embodiment of the present invention.

Fig. 4 is a schematic diagram of a stator winding of an energy efficient induction motor depicting terminals according to an exemplary embodiment of the present invention.

Fig. 5 is a graphical representation of power generated in a stator winding according to an exemplary embodiment of the present invention.

Fig. 6 is a graph depicting the magnetic flux distribution in a set of stator windings according to an exemplary embodiment of the present invention.

Fig. 7 is a diagram describing a power line distribution of an energy-saving induction motor according to an exemplary embodiment of the present invention.

Fig. 8A is a diagram of an Electronic Control Unit (ECU) for collecting power/energy generated in an additional winding of a stator of an energy-saving induction motor according to an exemplary embodiment of the present invention.

Fig. 8B is a simplified diagram of an ECU for collecting power/energy generated in multiple windings of a stator of an energy efficient induction motor according to an exemplary embodiment of the present invention.

Fig. 9 is a diagram of an ECU for controlling power/energy supply for generating torque for a load of an energy-saving induction motor according to an exemplary embodiment of the present invention.

Detailed Description

The embodiments described below can be found in the disclosed energy efficient induction motor, which includes: a stator including a main winding for generating a Rotating Magnetic Field (RMF) when a main AC power is supplied to the main winding of the stator; and a rotor arranged to rotate relative to the main winding of the stator due to the presence of the RMF. The stator further comprises one or more additional windings for generating an alternating EMF in the one or more additional windings due to rotation of the rotor. The alternating EMF generated in the one or more additional windings is then synchronously collected, steered and fed to the main winding of the stator through an Electronic Control Unit (ECU) coupled to the stator during a complete rotation cycle of the rotor. Therefore, because the motor partially acts as a generator, the energy generated during rotation of the rotor meets a major portion of the energy requirements of the induction motor.

The ECU also includes a frequency synchronization circuit configured to synchronize the frequency of the composite AC output power with the primary AC power source frequency. At this stage, the ECU may turn off the connection of the main AC power source directly to the stator via the disconnection switch, and the composite AC output power is continuously supplied only to the stator by the ECU.

According to one embodiment, the ECU comprises a microprocessor configured to calculate the phase difference of the voltage and current by measuring the time difference between the voltage peak and the current peak when the induction motor is loaded.

The ECU includes a capacitor bank including a plurality of capacitors, each of the plurality of capacitors having its own capacitance value. The capacitor bank balances the load of the induction motor and stabilizes to the power input of the induction motor and the Power Factor (PF) of the main power line. The capacitor bank includes a plurality of capacitors whose capacitances vary based on the total amount of load the induction motor is subjected to. The total amount of load is reflected in the amperage measured by the Current Transformer (CT) coil in the ECU.

The ECU further includes a TRIAC for enabling a switch (ON/OFF) function to select a capacitor of the plurality of capacitors from the capacitor bank for providing power to the induction motor based ON a load demand of the induction motor. The ECU adds the required capacitance value from the capacitor bank by switching on the TRIAC in the ECU. As the load increases, the value of the capacitance will increase. When the load changes, the ECU will change the capacitance value in the capacitor bank by switching the TRIAC.

According to an embodiment, the switching function of the TRIAC is controlled by the control device. The control device is located inside the ECU or outside the ECU. The control device may include, but is not limited to: a microcontroller, digital Signal Processor (DSP), microprocessor, or network-operated computing device.

Fig. 1 is a diagram illustrating various components and operations of an energy-efficient induction motor according to an exemplary embodiment of the present invention. Referring to fig. 1, there is shown an induction motor 100 comprising: the stator 102, the rotor 104, the main AC power source 106, the main winding (M) of the stator 102, one or more additional windings (a) of the stator 102, the RMF 108 generated in the main winding (M), the alternating EMF 110 generated in the one or more additional windings (a), the Electronic Control Unit (ECU) 112, the control device 114, the composite AC output power 116, and the load 118 of the induction motor 100.

The stator 102 includes a main winding (M) and one or more additional windings (a). Respective terminal ends of the main winding (M) and the additional winding (a) are connected to the ECU 112.

The main winding (M) of the stator 102 generates RMF 108 to provide an electrical power input when the main AC power source 106 is connected to the main winding (M).

The rotor 104 is arranged to rotate relative to the main winding (M) of the stator 102 due to the RMF 108 generated in the main winding (M). One or more additional windings (a) of the stator 102 generate an alternating EMF 110 in the additional windings (a) due to rotation of the rotor. The main winding (M) and the one or more additional windings (a) may comprise a single core wire or a multi-core wire.

The alternating EMF 110 generated in the one or more additional windings (a) is then synchronously collected, steered and fed to the main winding (M) of the stator 102 over a complete rotation period of the rotor 104 by an ECU 112 coupled to the stator 102. Because induction machine 100 functions, in part, as a generator, the energy generated during rotation of rotor 104 (alternating EMF 110) meets a substantial portion of the energy requirements of induction machine 100.

Details of the construction and operation of Guan Dingzi (102) and rotor (104) are further described in conjunction with fig. 2, 3, 4, 5, 6 and 7.

The alternating EMF 110 generated in the one or more additional windings (a) is fed to the ECU 112. The ECU 112 converts the AC voltage of the main AC power source 106 and the alternating EMF 110 generated in the one or more additional windings (a) into corresponding DC power. The composite DC power is obtained by adding the corresponding DC power.

The composite DC power is then converted to composite AC output power 116 by the inverter circuitry of ECU 112. The ECU 112 then feeds the composite AC output power 116 to the main winding (M) of the stator 102. Accordingly, only the composite AC output power 116 is continuously supplied to the stator 102.

The control device 114 is critical to the functioning of the ECU 112. The control device 114 controls the supply power/energy (RMF 108) required to rotate the rotor 104 and drive the load 118 by providing the required torque, frequency, and power (alternating EMF 110) generated by the rotor 104 as it rotates. The control device 114 is located inside the ECU 112 or outside the ECU 112. The control device 114 may include, but is not limited to: a microcontroller, a Digital Signal Processor (DSP), a microprocessor, or a network operated computing device external to ECU 112.

The main AC power source 106 provides power to the ECU 112, which in turn, functions and provides the induction motor 100 with the power or torque required to drive the load 118. The energy required to generate torque is provided cooperatively by the main power line of the main AC power source 106 and the alternating EMF 110 generated in the one or more additional windings (a) of the stator 102 due to the rotation of the rotor 104.

Various embodiments of the ECU 112 are further described in conjunction with fig. 8 and 9. As described in further detail below, the ECU 112 may include a number of functional features and components. Alternatively or additionally, induction motor 100 may use multiple ECUs.

Fig. 2 is a schematic view of a stator of an energy-efficient induction motor according to an exemplary embodiment of the present invention. Referring to fig. 2, a stator 102 is shown, comprising: a Frame or Yoke (Yoke) 202, a stator core 204, stator slots 206, and stator windings 208.

The frame or yoke 202 is made of fine grain cast iron or aluminum alloy and forms an integral part of the stator 102. The primary function of the frame or yoke 202 is to provide a protective cover for other complex assemblies or components in the induction motor 100.

The stator core 204 is formed from laminations that include stator slots 206 perforated from laminations of silicon steel. The stator slots 206 provide sufficient space to accommodate stator windings 208 that include one or more sets of winding wires. In a related aspect, the stator slots 206 may provide more space than conventional slots. The winding wire is an insulated wire as used in conventional motors. The size of the stator slots 206 may be adjusted and maintained for even distribution of the stator windings 208.

The space provided in the stator slot 206 is configured to accommodate one or more sets of winding wires, including: a main winding (M) carrying the supply power/energy (RMF 108) required to rotate the rotor 104; and one or more additional windings for transmitting electrical power (alternating EMF 110) induced in the one or more additional windings (a) as the rotor 104 rotates. Because induction machine 100 functions, in part, as a generator, the energy generated during rotation of rotor 104 (alternating EMF 110) meets a substantial portion of the energy requirements of induction machine 100.

In addition, the stator 102 includes slots (Rabbet) and bores (Bore) that are tightly machined to ensure air gap uniformity. The stator 102 in the induction motor 100 uses the same shaft and bearings as other conventional motors. Ball bearings of suitable dimensions are used to reduce rotational friction and support radial and axial loads. A fan is provided to circulate air sufficiently to cool the stator windings 208. The amount of heat generated in induction machine 100 is relatively small due to the low current consumption and due to the operation of stator winding 208 (i.e., main winding (M) corresponding to the supply power/energy (RMF 108) required to rotate rotor 104) and one or more additional windings (a) corresponding to the transmission of power (alternating EMF 110) generated in the one or more additional windings as rotor 104 rotates. Accordingly, the size of the cooling fan is also reduced, thereby saving some of the energy used thereby. Bearings are mounted to the crankshaft end and are fixed to a frame or yoke 202.

The stator 102 determines the number of poles and windings needed based on the speed of the induction motor 100 because according to the equation: ns=120 f/P, the synchronization speed is proportional to the frequency and inversely proportional to the number of poles, where Ns is the synchronization speed, f is the frequency, and P is the number of poles.

According to an exemplary embodiment of the present invention, the stator 102 is provided with 24 slots required for 6 poles, each having 4 slots, as shown in fig. 1. Each slot is provided with a set of two winding wires, the main winding (M) corresponding to the supply power/energy (RMF 108) required for the rotation of the rotor 104, and the one or more additional windings (a) corresponding to the transmission of power (alternating EMF 110) generated in the one or more additional windings (a) upon rotation of the rotor 104. The respective terminal ends of these windings are connected to the ECU 112.

Fig. 3 is a schematic view of a rotor of an energy efficient induction motor according to one exemplary embodiment of the present invention. Referring to fig. 3, a rotor 104 is shown that includes a steel lamination 302, an aluminum fence 304, a rotor shaft 306, and an end ring 308.

In this particular embodiment, the rotor 104 is a squirrel cage rotor. The rotor 104 includes a cylinder of steel laminations 302, the steel laminations 302 having an aluminum fence 304 for separating the steel laminations 302 of the rotor 104. In some embodiments, the rotor 104 may include a highly conductive metal (typically aluminum or copper) embedded in the rotor surface, parallel or substantially parallel to the rotor shaft 306 and proximate to the surface of the rotor 104. At both ends of the rotor 104, continuous end rings 308 of similar material to the rotor conductors short circuit the rotor conductors. The rotor conductors and end rings 308 self complete closed loop circuits.

RMF 108 is generated as AC current moves through stator windings 208. This induces a current in the rotor windings and creates its own magnetic field. The magnetic fields generated by the stator and rotor windings interact to produce torque on the rotor 104.

RMF 108 causes a voltage in the rotor rail, causing a short circuit current to begin to flow into the rotor rail. These rotor currents generate self-magnetic fields that interact with the RMF 108 of the stator 102. The rotor magnetic field will attempt to counteract the cause of its generation (i.e., RMF 108). Thus, the rotor 104 begins to catch up with the RMF 108. At the moment the rotor 104 catches up with the RMF 108, the rotor current will drop to zero since no relative motion between the RMF 108 and the rotor 104 occurs. Thus, when the rotor 104 experiences zero tangential force, the rotor 104 decelerates at this time. After the rotor 104 is decelerated, the relative motion between the rotor 104 and the RMF 108 is reestablished, thereby again inducing rotor current. In this way, the tangential force for rotation of the rotor 104 reappears and the rotor 104 begins to rotate again following the RMF 108. In this way, the rotor 104 maintains a constant speed that is less than the speed of the RMF 108 or the synchronous speed (Ns).

Fig. 4 is a schematic diagram of a stator winding of an energy efficient induction motor depicting terminals according to one exemplary embodiment of the present invention. Referring to fig. 4, a stator winding 208 is shown that includes motor winding terminals (supply power input) of phase I of the first set of windings (M1, M2), motor winding terminals (supply power input) of phase II of the second set of windings (MM 1, MM 2), motor winding terminals (supply power input) of phase III of the third set of windings (MMM 1, MMM 2), motor winding terminals (alternating EMF output) of phase I of the first set of windings (A1, A2), motor winding terminals (alternating EMF output) of phase II of the second set of windings (AA 1, AA 2), and motor winding terminals (alternating EMF output) of phase III of the third set of windings (AAA 1, AAA 2).

M1& M2, MM1& MM2, and MMM1& MMM2 refer to both ends of each winding coil of the stator 102 corresponding to the supply power/energy (RMF 108) required to rotate the rotor 104. A1& A2, AA1& AA2, and AAA1& AAA2 refer to both ends of the respective winding coils of stator 102 in the same group corresponding to the transmission of alternating EMF 110, alternating EMF 110 being the power generated in one or more additional windings (a) of stator 102 as rotor 104 rotates.

According to an exemplary embodiment of the present invention, the winding connection inside the induction motor 100 is as follows.

Each of M1, MM1, and MMM1, each carrying a main AC power supply 106, is connected to ECU 112. M2, MM2 and MMM2 are joined together to form a star connection as shown in fig. 4.

A1, AA1, and AAA1, each carrying an alternating EMF 110, are each connected to ECU 112. A2, AA2 and AAA2 are joined together to form a star-shaped connection as shown in fig. 4.

Fig. 5 is a graphical representation of power generated in a stator winding according to an exemplary embodiment of the present invention. Referring to FIG. 5, a graphical representation of a sine wave is shown, where M _s A sine wave corresponding to the supply power/energy (RMF 108) carried by the main winding (M) of the stator 102 for rotating the rotor 104 is depicted, while a _s A sine wave corresponding to the alternating EMF110 generated by the one or more additional windings (a) of the stator 102 due to rotation of the rotor 104 is depicted.

Fig. 6 is a graph depicting the magnetic flux distribution in a set of stator windings according to an exemplary embodiment of the present invention. Referring to fig. 6, a rotating magnetic flux M1 generated in the main winding (M) of the stator 102 and an alternating magnetic flux A1 generated in one or more additional windings (a) of the stator 102 are shown.

The rotating magnetic flux M1 is generated in the main winding (M) of the stator 102 for generating torque that drives the rotor shaft 306 of the induction motor 100. The alternating magnetic flux A1 generates/generates an alternating EMF110 in one or more additional windings (a) of the stator 102. The rotating magnetic flux M1 is in phase with the alternating magnetic flux A1 and in opposite directions to each other. These magnetic fluxes are distributed at 120 degree intervals.

Fig. 7 is a diagram describing a power line distribution of an energy-saving motor according to an exemplary embodiment of the present invention. Referring to fig. 7, there is shown a main AC power source 106 as an electrical power input, an ECU 112 as a generated electrical power output, and an alternating EMF 110.

As shown in fig. 7, it is assumed that one revolution is divided into two equal segments/regions, which represent one complete revolution of induction motor 100. When the rotor 104 starts rotating, the rotor 104 takes power from the main AC power source 106 (input power), and synchronously generates/generates an alternating EMF110 as a power output.

Fig. 8A is a diagram of an ECU for collecting power/energy generated in an additional winding of an energy-saving motor according to an exemplary embodiment of the present invention. Referring to fig. 8A, an ECU 112 is shown that includes: a rectifier circuit 802, an inverter circuit 804, a frequency converter (VFD) control module 806, a frequency synchronization circuit 808, an off-link switch 810, and a microprocessor 812.

The rectifier circuit 802 includes one or more rectifiers for converting the AC voltage of the main AC power source 106 and the alternating EMF 110 generated in the one or more additional windings (a) into corresponding DC power. The composite DC power 814 is obtained by adding the corresponding DC power, which is then fed to the inverter circuit 804.

The inverter circuit 804 includes one or more inverters for converting the composite DC power 814 to the composite AC output power 116.

The VFD control module 806 is configured to vary the voltage and frequency of the composite AC output power 116.

The frequency synchronization circuit 808 is configured to synchronize the frequency of the composite AC output power 116 with the frequency of the primary AC power source 106. The composite AC output power 116 is then fed from the ECU 112 to the main winding (M) of the stator 102.

At this stage, the disconnect switch 810 is configured to disconnect the disconnect main AC power source 106 from the main winding (M) of the stator 102, and thus, continuously supply only the main winding (M) of the stator 102 with the composite AC output power 116.

The microprocessor 812 is configured to calculate a phase difference of the voltage and the current by measuring a time difference between a voltage peak and a current peak when the induction motor 100 is loaded.

Fig. 8B is a simplified diagram of an ECU for harvesting power/energy generated in multiple windings of an energy efficient motor according to an exemplary embodiment of the present invention. Referring to fig. 8B, ECU 112 is shown to include a drive circuit 816, a frequency control circuit 818, and a switch 820.

The drive circuit 816 includes rectifiers 1-n for converting the AC voltage of the main AC power supply 106 and the alternating EMF 110 generated in the plurality of additional windings (a) 1-n of the stator 102 into corresponding DC power. The alternating EMF 110 generated in each of the plurality of additional windings (a) is fed to a corresponding rectifier of the drive circuit 816 for conversion to a respective DC power. For example, rectifier 1 converts the alternating EMF 110 generated in additional winding 1 into corresponding DC power, rectifier 2 converts the alternating EMF 110 generated in additional winding 2 into corresponding DC power, rectifier n converts the alternating EMF 110 generated in additional winding n into corresponding DC power, and so on.

Composite DC power 814 is obtained by adding the corresponding DC power and then fed to frequency control circuit 818 to produce composite AC output power 116.

The frequency control circuit 818 is configured to synchronize the frequency of the composite AC output power 116 with the frequency of the primary AC power source 106. The composite AC output power 116 is then fed from the ECU 112 to the main winding (M) of the stator 102. At this stage, the switch 820 is configured to disconnect the connection between the main AC power source 106 and the main winding (M) of the stator 102, and thus, continuously supply only the main winding (M) of the stator 102 with the composite AC output power 116.

Fig. 9 is a diagram of an ECU for controlling power/energy to generate torque to drive an energy efficient motor load according to an exemplary embodiment of the present invention. Referring to fig. 9, there is shown an ECU 112, which includes: a microcontroller 902, a step-down transformer 904, a Current Transformer (CT) coil 906, a capacitor bank (C3, C4, C5) 908, TRIACs (TR 1, TR2, TR3, TR4, TR5, TR 6) 910, a digital-to-analog converter 912, and a display 914.

The microcontroller 902 is critical to the functioning of the ECU 112. The microcontroller 902 controls the power/energy supply (RMF 110) required to rotate the rotor 104 and controls the torque, frequency, and power (alternating EMF 110) produced by the rotor 104 as it rotates for driving the load 118. A bridge rectifier (not shown) is used to convert the AC supply voltage to the microcontroller 902 to a DC voltage for operation of the microcontroller 902.

Step-down transformer 904 provides power only for operating ECU 112. The main power line (phase) to the main AC power source 106 of the induction motor 100 is connected to the step-down transformer 904 of the ECU112 and the stator windings 208, and the neutral line of the main AC power source 106 is connected to the ECU112 and the terminal box of the induction motor 100.

The CT coil 906 of the current sense transformer measures the input current and stabilizes the current. The output of the CT coil 906 is connected to the microcontroller 902. The input of the current sense transformer is connected to the line/input voltage for sensing current and the output of the current sense transformer is connected to the microprocessor 902.

The capacitor bank 908 includes a plurality of capacitors (C3, C4, C5), each of the plurality of capacitors (C3, C4, C5) having its own capacitance value. Capacitor bank 908 is used to balance load 118 of induction motor 100 and stabilize the power input to induction motor 100 and the Power Factor (PF) of the main power line.

TRIAC 910 enables a switch (ON/OFF) function to select a capacitor of the plurality of capacitors (C3, C4, C5) from capacitor bank 908 for providing power to induction motor 100 based ON a load demand of induction motor 100. The switching function of the TRIAC is controlled by the control device 114, in this case the control device 114 is a microcontroller 902. When induction motor 100 is operating under different loads, TRIAC 910 selects a desired capacitance from capacitor bank 908 based on the load requirements. The switching of TRIAC 910 controls the load 118 and the input current to induction motor 100.

As the rotor 104 begins to rotate, the rotor 104 draws power from the main AC power source 106 and synchronously causes an alternating EMF 110 in one or more additional windings (a) of the stator 102. The current consumption is measured by the CT coil 906 and the current is provided to the ECU 112. This current is then transferred to the microcontroller 902, the microcontroller 902 being programmed to activate the TRIAC 910 based on the load 118, the load 118 in turn activating the TRIAC 910 to select and connect a particular capacitor from a plurality of capacitors (C3, C4, C5) in the capacitor bank 908, the capacitor bank 908 having different levels provided herein to meet the torque requirements. For example, for a 1 Horsepower (HP) motor, the capacitance value selected would be 15 to 20 μf.

Digital-to-analog converter 912 is provided herein as an Integrated Circuit (IC) that is connected to the output of microcontroller 902. The digital-to-analog converter 912 converts the digital output signal of the microcontroller 902 into an analog signal, which is then passed to the TRIAC 910. Thus, TRIAC 910 controls load 118 of induction motor 100.

According to one exemplary scenario, TRIAC 910 selects a capacitor (say capacitor C3) from capacitor bank 908, capacitor bank 908 having a capacitor that changes capacitance based on the total amount of load 118 experienced by induction motor 100, as reflected in the amperage measured by CT coil 906.

According to this scenario, upon powering up the induction motor 100, it is connected to the capacitor C3 by means of the switch TRIAC 1 provided in the ECU 112, and the induction motor 100 starts to rotate and generates an alternating EMF 110 in one or more additional windings (a) provided in the stator 102 in synchronization. As load 118 increases, TRIAC 2 activates capacitor C4. As the load increases further, TRIAC 3 will activate capacitor C5, and so on. In this way, the load 118 on the induction motor 100 is balanced.

A display 914 provided in ECU 112 displays the voltage, current, frequency, and power consumption of induction motor 100 under different loads.

In various other embodiments, the ECU 112 is also provided with overload protection, short circuit protection, and overheat tripping devices.

The invention has the advantages that: the present invention provides an energy efficient induction motor that has a wider industrial applicability than other conventional AC motors due to its reliable performance. The energy-saving induction motor greatly reduces the consumption of current and provides economic benefits for the industries of agriculture, locomotive and other widely applied induction motors.

The energy-saving induction motor consumes less current by realizing the special design of the electronic module and the special design of the stator winding, thereby ensuring higher current efficiency.

The present invention provides an energy efficient induction motor that consumes less current than a conventional motor of the same capacity due to the implementation of windings disposed in the stator that are capable of generating a certain EMF (alternating EMF) when the motor is rotating, thereby meeting a portion of the energy requirements needed to drive the motor when the motor is running. The disclosed invention also makes it possible to replace a three-phase induction motor with a single-phase induction motor without compromising on the input power requirements.

In addition, single phase induction motors constructed using the disclosed invention have lower electrical, magnetic and thermal losses than three phase induction motors having the same output requirements. In addition, the single phase induction motor has lower magnetic and thermal losses than a three phase induction motor having the same output power requirements.

Those skilled in the art will appreciate that the above-identified and other advantages described herein are merely exemplary and are not meant to fully represent all of the advantages of the various embodiments of the present invention.

The present invention may be realized in hardware or a combination of hardware and software. The invention may be implemented in a centralized fashion in at least one computer system or in a distributed fashion where different elements are spread across several interconnected computer systems. Computer systems or other apparatus/devices suitable for performing the methods described herein may also be suitable. The combination of hardware and software may be a general purpose computer system with a computer program that, when loaded and executed on the computer system, controls the computer system such that it carries out the methods described herein. The invention may be implemented in hardware comprising part of an integrated circuit that also performs other functions. The invention may also be implemented as firmware forming part of a media presentation device.

The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which, when loaded in and/or executed on a computer system, is configured to carry out these methods. In the context of this document, a computer program refers to a set of instructions, expressed in any language, code or notation, that is intended to cause a system having an information processing capability to perform a particular function either directly or by either or both of the following: a) Conversion to another language, code or notation; b) Reproduced in different material forms.

While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An induction motor (100), comprising:

a stator (102) comprising a main winding (M) for generating a Rotating Magnetic Field (RMF) (108) when a main AC power source (106) is provided to the main winding (M) of the stator (102);

-a rotor (104) arranged to rotate with respect to the main winding (M) of the stator (102) due to the RMF (108), characterized in that:

the stator (108) further comprises one or more additional windings (a), wherein rotation of the rotor (104) causes an alternating EMF (110) in the one or more additional windings (a) of the stator (102), wherein the alternating EMF (110) generated in the one or more additional windings (a) is fed back to the main winding (M) of the stator (102) over a complete rotation period of the rotor (104) by an Electronic Control Unit (ECU) (112) coupled to the stator (102), wherein the ECU (112) comprises:

-a rectifying circuit (802) for converting an AC voltage of the main AC power supply (106) and the alternating EMF (110) generated in the one or more additional windings (a) into a respective DC power, wherein a composite DC power (814) is obtained by adding the respective DC power; and

an inverter circuit (804) for converting the composite DC power (814) to composite AC output power (116),

Wherein the ECU (112) is configured to feed the composite AC output power (116) to the main winding (M) of the stator (102).

2. The induction machine (100) of claim 1, wherein the stator (102) is comprised of a lamination stack comprising a plurality of stator slots (206), each stator slot of the plurality of stator slots (206) comprising one or more sets of winding wires, each set of winding wires comprising a main winding (M) and one or more additional windings (a), wherein the main winding (M) is supplied with power required for rotation of the rotor and the one or more additional windings (a) enable transmission of an alternating EMF (110) generated in the one or more additional windings (a) as a result of rotation of the rotor (104).

3. The induction machine (100) of claim 2, wherein a size of a stator slot in the stator is configured to accommodate the one or more additional windings (a), wherein the size is configured to facilitate uniform distribution of the winding wires.

4. The induction machine (100) of claim 2, wherein respective terminal ends of the main winding (M) and the one or more additional windings (a) are connected to the ECU (112).

5. The induction motor (100) of claim 1, wherein the ECU (112) includes a step-down transformer (904) for providing power for operation of the ECU (112).

6. The induction motor (100) of claim 5, wherein a main power line to the main AC power source (106) of the induction motor (100) is connected to the step-down transformer (904) of the ECU (112) and the main winding (M) of the stator (102), and wherein a neutral line of the main AC power source (106) is connected to the ECU (112) and a terminal box of the induction motor (100).

7. The induction motor (100) of claim 1, wherein the ECU (112) includes a frequency converter (VFD) control module (806), the VFD control module (806) configured to vary the voltage and frequency of the composite AC output power (116).

8. The induction motor (100) of claim 1, wherein the ECU (112) includes a frequency synchronization circuit (808), the frequency synchronization circuit (808) configured to synchronize the frequency of the composite AC output power (116) with the frequency of the main AC power source (106) and feed the composite AC output power (116) to the main winding (M) of the stator (102).

9. The induction motor (100) of claim 8, wherein the ECU (112) is configured to disconnect the primary AC power source (106) to the primary winding (M) of the stator (102) via an disconnect switch (810), wherein the primary winding (M) of the stator (102) is continuously supplied with the composite AC output power (116) only.

10. The induction motor (100) of claim 1, wherein the ECU (112) comprises a microprocessor (812), the microprocessor (812) configured to calculate a phase difference of voltage and current by measuring a time difference between a voltage peak and a current peak when the induction motor (100) is loaded.

11. The induction machine (100) of claim 1, wherein the ECU (112) further comprises:

a capacitor bank (908) comprising a plurality of capacitors, each of the plurality of capacitors having its own capacitance value, wherein the capacitor bank (908) balances a load (118) of the induction motor (100) and stabilizes to a power input of the induction motor (100) and a Power Factor (PF) of a main power line; and

a TRIAC (910) for enabling an ON/OFF switching function to select a capacitor of the plurality of capacitors from the capacitor bank (908) for providing power to the induction motor (100) based ON a load demand of the induction motor (100).

12. The induction machine (100) of claim 11, wherein a control device (114) is configured to control the ON/OFF switching function of the TRIAC (910).

13. The induction motor (100) of claim 12, wherein the control device (114) is located inside the ECU (112) or outside the ECU (112), wherein the control device (114) is at least one of a microcontroller (902), a Digital Signal Processor (DSP), a microprocessor, or a network operated computing device.

14. The induction motor (100) of claim 12, wherein the ECU (112) comprises a Current Transformer (CT) coil (906), the CT coil (906) for controlling and measuring an input current to the induction motor (100) and stabilizing the input current, wherein an output of the CT coil (906) is connected to the control device (114).

15. The induction motor of claim 14, wherein the capacitor bank (908) comprises a plurality of capacitors that change capacitance based on a total amount of load (118) experienced by the induction motor (100), wherein the total amount of load (118) is reflected in an amperage measured by the CT coil (906).

16. The induction motor (100) of claim 12, wherein the ECU (112) comprises a digital-to-analog converter (912), the digital-to-analog converter (912) being connected to an output of the control device (114) for converting a digital output signal of the control device (114) into an analog signal, which is then fed to the TRIAC (910).