EP1389362A1 - Machine tournante electrique a connexion en polygone a portee variable - Google Patents

Machine tournante electrique a connexion en polygone a portee variable

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Publication number
EP1389362A1
EP1389362A1 EP02744124A EP02744124A EP1389362A1 EP 1389362 A1 EP1389362 A1 EP 1389362A1 EP 02744124 A EP02744124 A EP 02744124A EP 02744124 A EP02744124 A EP 02744124A EP 1389362 A1 EP1389362 A1 EP 1389362A1
Authority
EP
European Patent Office
Prior art keywords
terminals
mesh
circuit element
terminal
inverter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02744124A
Other languages
German (de)
English (en)
Other versions
EP1389362A4 (fr
Inventor
Jonathan Sidney Edelson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Borealis Technical Ltd
Original Assignee
Borealis Technical Ltd
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Filing date
Publication date
Application filed by Borealis Technical Ltd filed Critical Borealis Technical Ltd
Publication of EP1389362A1 publication Critical patent/EP1389362A1/fr
Publication of EP1389362A4 publication Critical patent/EP1389362A4/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
    • H02P25/22—Multiple windings; Windings for more than three phases
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/28—Layout of windings or of connections between windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
    • H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/50—Reduction of harmonics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/22—Auxiliary parts of casings not covered by groups H02K5/06-H02K5/20, e.g. shaped to form connection boxes or terminal boxes
    • H02K5/225—Terminal boxes or connection arrangements

Definitions

  • the present invention relates to motors and their inverter drives . In particular it related to methods and apparatus for connecting polyphase devices .
  • An alternating current motor is commonly driven by an inverter.
  • An inverter is a device capable of supplying alternating current of variable voltage and variable frequency to the alternating current motor, allowing for control of machine synchronous speed and thus of machine speed.
  • the inverter may also be used with alternating current generators, and can cause an alternating current motor to act as a generator for braking applications.
  • An alternating current motor may be an induction motor, a synchronous motor with either a wound rotor or permanent magnet rotor, or a brushless DC motor.
  • the cost of the inverter is considerably greater than the cost of the motor being supplied. It is thus necessary to minimize the size of the inverter power electronics in order to control system cost .
  • the alternating current machine itself may have substantial overload capability, and may carry currents of the order of five to ten times full rated current for periods measured in minutes, the overload capability of the inverter electronics is severely limited. Exceeding the voltage or current ratings of the inverter electronics will swiftly cause device failure.
  • inverter electronics is specified such that it can tolerate 150% of nominal full load current for 1 minute, and for any given motor, and inverter will be selected which has the same nominal current capability as that of the motor.
  • Voltage is set internally by the inverter system or by the rectified supply voltage. Voltage overload is normally not specified, and will cause near instantaneous destruction of semiconductor elements.
  • the voltage ratings of the semiconductors instead set the maximum output voltage of the inverter system, and an inverter will be selected which has a maximum output voltage that matches the operating voltage of the motor at full speed. With any reasonably sized inverter, substantial motor overload capabilities remain untapped.
  • Electrical rotating machinery presents impedance that changes with mechanical load and rotational velocity.
  • the voltage produced by a generator, or the voltage required by a motor will tend to increase proportionally.
  • a constant ratio of applied voltage to frequency is maintained.
  • the back-emf produced by the motor will increase as rotor speed increases, again requiring increased voltage in order to drive the machine.
  • Even direct current machines (not covered by the present invention) require increased voltage as speed is increased, if magnetic field strength is maintained as a constant.
  • alternating current machine For a simple three phase alternating current machine system, such a system would require at least two single-pole three-phase contactors, and would only offer a factor of 1.7 increase in low speed overload capability. With three contactors, a factor of two change is possible.
  • the change in series turns may be considered a change in alternating current machine impedance, or current versus voltage relation.
  • an alternating current machine will have a fixed relationship between synchronous speed and impedance, characterized by the Volts/Hertz ratio.
  • a machine wound with a higher Volts/Hertz ratio will have a lower maximum speed, but higher peak low speed torque .
  • an electrical rotating apparatus comprising two polyphase circuit elements, each having N phases.
  • the first polyphase circuit element which may be, for example, an inverter, has N outputs
  • the second polyphase circuit element comprises N single-phase sub-elements.
  • Each sub-element comprises an even- and an odd-numbered terminal .
  • the odd-numbered terminals are individually connected electrically to the N outputs of the first circuit element in a first sequence. The sequence is in either ascending or descending order of phase angle .
  • the even-numbered terminals are individually connected electrically to the odd-numbered terminals in a mesh connection in a second sequence, which has been shifted in relation to the first sequence according to a spanning value, L.
  • an electrical rotating apparatus comprising two polyphase circuit elements, each having N phases, and an N-pole, N-way switch having 2N terminals.
  • the first polyphase circuit element which may be, for example, an inverter, has N outputs
  • the second polyphase circuit element comprises N single-phase sub-elements. Each sub-element comprises an even- and an odd- numbered terminal.
  • the odd-numbered terminals are individually connected electrically to the N outputs of the first circuit element in a first sequence.
  • the sequence is in either ascending or descending order of phase angle.
  • the N-poles of the switch are also individually connected electrically to the N outputs of the first circuit element in a first sequence.
  • the N ways of the switch are individually connected electrically to the even- numbered terminals in a mesh connection in a second sequence, which has been shifted in relation to the first sequence according to a spanning value, , which may be selected according to the operation of the switch.
  • a drive system for driving the N single phase sub-elements of a first polyphase circuit element in which each sub-element having an odd-numbered and an even numbered terminal that comprises a second polyphase circuit element, an N-pole, N-way switch having 2N terminals, and a terminal block.
  • the second polyphase circuit element which may be, for example, an inverter, has N outputs.
  • the terminal block has 2N terminals comprising a first set of N terminals for connection to each odd-numbered terminal and a second set of N terminals for connection to each even-numbered terminal.
  • the first set of N terminals is individually connected electrically to the N outputs of the second circuit element in a first sequence.
  • the sequence is in either ascending or descending order of phase angle.
  • the N-poles of the switch are also individually connected electrically to the N outputs of the second circuit element in a first sequence.
  • the N ways of the switch are individually connected electrically to the second set of N terminals in a second sequence, which has been shifted in relation to the first sequence according to a spanning value, L, which may be selected according to the operation of the switch.
  • a mesh- connected electrical rotating apparatus having a variable spanning number, L, which comprises a terminal block for connection to a first polyphase circuit element, a second polyphase element and an N-pole, N-way switch.
  • the first polyphase circuit element which may be, for example, an inverter, has N outputs.
  • the terminal block has N terminals for connection to the N outputs of the first polyphase circuit element in a first sequence based on the phase angle order of the first polyphase element .
  • the second polyphase circuit element comprises N single-phase sub-elements. Each sub- element comprises an even- and an odd-numbered terminal .
  • the odd-numbered terminals are individually connected electrically to the N terminals of the terminal block in a first sequence.
  • the N-poles of the switch are also individually connected electrically to the N terminals of the terminal block in a first sequence.
  • the N ways of the switch are individually connected electrically to the even-numbered terminals in a second sequence, which has been shifted in relation to the first sequence according to a spanning value, L, which may be selected according to the operation of the switch.
  • a technical advantage of the present invention is that high torque overload may be provided at low speeds whilst sufficient voltage is also provided for high-speed applications.
  • a further technical advantage of the present invention is that the spanning value L may be altered in a particularly simple switching arrangement to obtain a change in operational Volts/Hz ratio.
  • a further technical advantage of the present invention is that altering the spanning value L by changing the harmonic applied by the inverter to the mesh connection provides a change in Volts/Hz ratio through a logical change of the output synthesized by the inverter.
  • a yet further technical advantage is that the change in harmonic content may be obtained in a smooth fashion, successively passing through various admixtures of harmonic components .
  • a further technical advantage of the present invention is that by changing the spanning value L, the same machine pole count is maintained.
  • Figure 1 is a diagrammatic representation of a motor stator and windings
  • Figure 2 is a diagrammatic representation of connections possible with a 9- phase polyphase device.
  • Figure 3 is a diagrammatic representation of the connections and mesh diagrams for a 7-phase polyphase device.
  • Figure 4 is a diagrammatic representation of how polyphase devices and a switch may be interconnected.
  • Figure 5 is a diagrammatic representation of a rotary switch.
  • Figure 6 is a diagrammatic representation of a slider switch.
  • Figure 7 - 12 are diagrammatic representations of the mesh connections possible for various phase values. Best Mode for Carrying Out the Invention
  • a high phase order induction machine is used with each phase terminal separately connected to an inverter output .
  • the windings of the induction machine are wound as full span connected windings, and the motor terminals are connected with a mesh connection to produce a low impedance output .
  • the inverter is capable of operating with a variable phase sequence that changes the effective impedance of the motor.
  • the following equations relate the voltage placed across the windings of a mesh connected machine to the voltages applied to the machine terminals as measured between the terminal and neutral. These are the equations which relate the output voltages of a star connected supply to the winding voltages of a mesh connected motor, and can be inverted to relate a mesh connected supply to a star connected motor. The equations could be used twice to describe a mesh connected supply connected to a mesh connected motor.
  • Equation 1 describes the line to neutral voltage of the supply, where m is the number of phases in a balanced supply, K is the particular phase of interest, and may range from 0 to m-1 , CO is the frequency of the alternating current in radians per unit time, t is time, h is the harmonic order being generated, and VM A X is the peak voltage of the output waveform.
  • the equation is written using standard complex exponentiation form, in which the constant e is raised to a complex number. In this case, the exponent is a purely imaginary value, thus the result of the exponentiation has constant periodicity over time. Only the real portion of this periodic function is used.
  • the terms in the exponent include a function of time, which results in the periodic nature of the voltage with time, and a constant rotation term, which results in the phase difference between the various phases.
  • each phase differs from the other phases only by the constant rotation term, and that the periodic term does not depend in any way upon the particular phase.
  • Equation 3 The voltage across the particular winding K as a function of the voltage applied to its two ends is given by Equation 3.
  • Equation 3 The voltages applied to winding K are simply that of phase K and phase K+L, where L is the spanning value for the particular mesh connection, which represents the number of inverter output phases between the first and second terminal of each single phase winding. The greater the spanning value, the greater the voltage placed upon a winding for a given inverter output voltage. Expanding Equation 3 using the terms in Equation 2 gives:
  • Equation 4 may be rearranged as follows
  • Equation 7 is the desired result, separating the exponential term into constant and periodic portions of the various variables .
  • the term VM X , the periodic term, and the constant rotation term all remain as in the original equation, but an additional term is added. This term depends upon the applied harmonic h, the spanning value L, the number of phases m, but is independent of the particular phase K and is also independent of frequency ⁇ or time t.
  • Equation 7 shows that the voltage applied to a winding depends upon the voltage output of the supply, but it also depends upon the harmonic order h and the spanning value L .
  • the advantage of changing the harmonic applied by the inverter to the mesh connection is that the change in Volts/Hz ratio may be obtained through a logical change of the output synthesized by the inverter.
  • the motor may have a fixed electrical connection to the inverter.
  • This technique is disclosed in my co-pending application 09/713,654, filed November 15, 2000, entitled “High Phase Order Induction Machine with Mesh Connection” .
  • the change in harmonic content may be obtained in a smooth fashion, successively passing through various admixtures of harmonic components.
  • there is no sudden discontinuity in drive when switching between harmonic operating states Disadvantages of this technique are that it requires a machine capable of operation with harmonic drive; e.g.
  • pole count changing alternating current machine or a synchronous machine with variable pole count rotor, or a permanent magnet machine with a rotor which reacts both to the fundamental and the harmonic components of the drive waveform.
  • An additional disadvantage with a pole count changing alternating current machine is that the basic efficiency of such a machine will go down as the pole area is reduced.
  • the advantage of changing the spanning value L is that the same machine pole count is maintained.
  • methods that change the spanning value are applicable to machines with fixed pole counts . This includes some wound rotor alternating current machines, as well as most synchronous machines, permanent magnet machines, and brushless DC machines.
  • pole area is maintained, which increases machine efficiency.
  • changing the spanning value L generally permits a greater number of possible Volts/Hz ratios to be obtained from the same machine.
  • Disadvantages of changing the spanning value L are that a mechanical contactor arrangement must be used to physically change the electrical connectivity of the mesh connection, and that power to the motor must be interrupted in order to change the mesh connection.
  • each phase winding set can be described by two terminals. There may be a larger number of terminals, but these are always grouped in series or parallel groups, and the entire set can be characterized by two terminals.
  • one of these terminals is driven by the inverter or power supply, while the other terminal is connected to the machine neutral point. All current flows through one terminal, through the neutral point into other windings, and though the driven terminals of the other phases.
  • these two terminals are connected directly to two different supply points .
  • Each of these points represents an inverter terminal 2, to which one of the terminals of each of one or more motor windings 1 may be connected.
  • Permissible connections of the N phase windings are either from the center point, to each of the N points on the circle ⁇ this being the star connection shown as Figure 2a) or from each of the N points to another point distant in the clockwise direction.
  • the voltage across the connected windings is exactly equal to the inverter output voltage.
  • the voltage across a winding is given by the vector difference in voltage of the two inverter output terminals to which the winding is connected. When this phase difference is large, then the voltage across the winding will be large, and when this phase difference is small, then the voltage across the winding will be small. It should be noted that the inverter output voltage stays exactly the same in all these cases, just that the voltage difference across a given winding will change with different connection spans.
  • the equation for the voltage across a winding is given by:
  • ⁇ is the phase angle difference of the inverter output terminals driving the winding
  • V out is the output to neutral voltage of the inverter.
  • L l
  • the phase angle difference is 40 degrees
  • the voltage across a winding is 0.684Vout.
  • the phase angle difference is 80 degrees
  • the voltage across the winding is 1.29Vout.
  • the voltage across the winding is 1.73Vout.
  • different connections place different voltage across the windings, and will cause different currents to flow in the windings .
  • the different mesh connections cause the motor to present different impedance to the inverter.
  • the different mesh connections allow the motor to use the power supplied by the inverter in different rations of voltage and current, some ratios being beneficial to maximize the torque output (at the expense of available speed) , and some ratios to maximize the speed output (at the expense of maximum available torque) .
  • the inverter outputs may be represented as points on a unit circle, with the relative positions of the points representing the phase angle of this inverter output .
  • the winding of the motor is composed of individual single phase windings, each of which as two terminals.
  • the single phase windings are represented by line segments, and are the single phase sub-elements described above.
  • the end points of these line segments represent the terminals of the windings.
  • a star connection may be represented.
  • line segments are connected between points on the unit circle, then a mesh connection is represented.
  • An M phase symmetrical mesh connection will be represented by a diagram which has M fold rotational symmetry.
  • Each of the mesh connections may be represented by the spanning value L' , which represents the number of inverter output phases between the first and second terminal of each single phase winding.
  • L' represents the number of inverter output phases between the first and second terminal of each single phase winding.
  • the greater the spanning value the greater the voltage placed upon a winding for a given inverter output voltage.
  • Changes in spanning value may be considered a rotation of the connection between second terminals of each single phase winding and the inverter output terminals .
  • Figure 3A shows how these connections are made in a 7-phase polyphase circuit element.
  • the corresponding mesh diagrams are shown in Figures 3D, 3E and 3F.
  • a polyphase circuit element 402 is connected to another polyphase circuit element 406.
  • Polyphase circuit element 406 is mesh connected via switch 414.
  • polyphase circuit elements 402 and 406 are each shown as having seven phases; this is not intended to limit the scope of the present invention, and polyphase circuit elements having values for phase number of other than seven are contemplated.
  • the seven-phase circuit element 406 may be considered to consist of seven individual single-phase sub-elements.
  • Each such sub-element has two terminals, represented in Figure 4 by the terminal set 408 labeled 1 - 7 and the terminal set 410 labeled 8 - 14, and so there is a single phase circuit element between terminals 1 and 8, 2 and 9, etc (for the sake of clarity, the individual circuit elements are not shown in Figure 4) .
  • These labels correspond to those used in Figure 3.
  • Describing the sub-elements as having even-numbered (410) and odd-numbered (408) terminals is not intended to limit the scope of the present invention, but instead to illustrate how connections are made . It is to be understood that the terms “even-numbered” and “odd-numbered” are interchangeable, and that "odd-numbered” may be used instead of "even-numbered” and vice versa.
  • Each terminal of the single-phase sub-element is connected to another terminal of another single-phase sub- element via a switch 414 to form a mesh connection.
  • Switch 414 has two sets of terminals 416, labeled A - G, and 418, labeled a - g.
  • the switch alters how the sub-elements of polyphase circuit element 406 are connected to each other, and thereby sets the spanning value, L .
  • the connections between polyphase circuit element 404 and the mesh connected polyphase circuit element 406 are shown in Table 1. Referring to the first row of Table 1, the first three columns of the table indicate that terminal 1 of terminal set
  • terminal 1 of polyphase circuit element 406 and terminal A of terminal set 416 are directly connected to each other, and the last two columns indicate that terminal a of terminal set 418 and terminal 8 of polyphase circuit element 406 are also directly connected to each other, as shown in Figure 4.
  • the remaining columns indicate how switch 414 changes the connectivity between terminal sets 416 and 418, thereby altering the value for L . Note that for the column headed "*", each sub-element of polyphase circuit element 406 is "short-circuited"; that is, terminal 1 on 406 is connected to terminal 8 on 406, and so on. Under most normal operating conditions, this position of the switch will not be used, and its selection will be prevented.
  • connections are made to terminal set 416 in a sequence, and the sequence is phase angle order.
  • the order is ascending order, but descending order is also within the scope of the present invention.
  • Table 1 the operation of the switch shifts the sequence, but does not change the relative order of the connections.
  • Many switch types are available which are able to 'shift' the connectivity described above.
  • the switch may be a rotary switch or a slider switch; it may be mechanical or electronic.
  • the switch may be described as an N-pole N-way switch, in which all of the N poles share the same set of ways, and that each pole goes to one way at a time, and that by rotation or sliding different poles are connected to different ways, always keeping the same relative order.
  • the switch may have an interlock to prevent selection of the A to a option.
  • 402 is an inverter and 406 is a motor.
  • Table 1 show that 7 possible connections are possible, one is undesirable (marked with a "*") and the remaining six have a two-fold symmetry. Thus the minimum number of positions for the switch is just 3.
  • Table 1 shows that a plurality of ordered phases is connected to terminal set 404, the plurality of ordered phases consisting of the phase outputs from 402 in ascending or descending order of phase angle.
  • Switch 414 of Figure 4 may be any type of switch that is capable of altering the mesh connection in the manner disclosed.
  • a stop 119 is used.
  • Such a segmented cylinder in which there is a plurality of segments insulated from one another, is akin to the commutator of a brush DC motor, the details of which are well known in the art.
  • the contact points or brushes are well known in the art .
  • This contactor arrangement is capable of coupling each second terminal of each single phase winding in turn to the various output terminals of the inverter, with each rotational position of the segmented cylinder giving a different mesh connection.
  • a set of ordered winding terminals can be arranged in a first circle, and the terminals of the ordered phases of a second device arranged in a second circle; the two circles are concentric to one another and the terminals of the first device are positioned to contact the terminals of the second device.
  • Means to rotate one of the circles to selectively connect the second set of ordered winding terminals of the first device with the ordered terminals of the second device are provided.
  • FIG. 6 An example of a slider switch embodiment of switch 414 is shown in Figure 6, which shows a slider switch having a fixed set of terminals 122, and a movable set of terminals 124.
  • the fixed set of terminals is electrically connected to contact areas 128.
  • Terminal set 124 connects to contact areas 128 via wipers or brushes 126.
  • terminal A is connected to terminal b.
  • the switch 414 enables the Volts/Hertz ratio of the mesh connected machine to be simply changed by rotating the segmented cylinder or sliding the slider to the appropriate position.
  • a device comprising 402 and a switch 414; 406 in Figure 4 is then replaced by a terminal block.
  • a unit comprising an inverter and switch is contemplated. This may be used to connect directly to any polyphase motor or other polyphase device.
  • a device comprising switch 414 and 406; 404 is then replaced by a terminal block.
  • a unit comprising a motor and a switch is contemplated, which may be powered by a polyphase inverter. Examples
  • Tables 2 to 7 and Figures 7 to 12 indicate the possible mesh connections and voltages for 5 to 15 phase devices.
  • the value for V is the voltage across the windings when 1.0 volt is applied by a star connected source.
  • inverter fed induction motor In the classic arrangement, a conventional three-phase induction motor is supplied with alternating current by an inverter. The inverter synthesizes alternating current of the proper voltage and frequency to operate the motor in a desired mechanical output state, adjusting frequency, voltage, or current as necessary to control motor torque or speed.
  • an inverter may still feed an induction motor, however additional performance and flexibility of operation may be obtained.
  • a 13-phase inverter is used to supply a 13 -phase induction motor.
  • the 13 phase inverter is composed of components well known in the art, including a rectifier to supply DC power to other components, a DC link filter to maintain constant DC voltage, precharge and control circuitry, and output half bridges. All of these components are well known in the art. Less well known in the art are the specifics of high phase order operation; these are disclosed in U.S. Patent No. 6,054,837. In brief, additional output half bridges are used, 13 in the case of the present example.
  • the inverter output has 13 separate phases, each with a phase angle displacement of 1/13 full cycle, as contrasted to the output of a conventional inverter, with 3 separate phases and a phase angle displacement of 1/3 full cycle.
  • the example 13 -phase motor is a 4 pole, 26 slot machine, with 6.5 slots per pole.
  • Conventional lap windings are used, with a 1 to 7 span.
  • the 1 to 7 and the 14 to 20 windings are in the same phase, and placed electrically in series, as are the 12 other series pairs of the same relative slot displacement .
  • the net result is a winding with 13 individual series circuits, each of which is at an electrical angle of 1/13 full cycle apart, each with two available terminals, numbered 1 to 26 in order to correspond to the slots associated with the termination.
  • the two-coil, two-terminal winding sets are as follows, along with the relative electrical angles of the windings:
  • These coil sets may be connected in the 6 possible different symmetric mesh connections that may be used with this motor, each presenting a different impedance to the inverter.
  • As the highest impedance mesh connection current requirements from the inverter are reduced, however the voltage requirements are increased. This connection is thus suitable for low speed operation.
  • the machine may be adjusted between these mesh connections through the use of a 13 pole, 13 way, shared way switch.
  • a switch has 13 pole terminals and 13 way terminals, and in one position connects, for example, pole 1 to way 2, pole 2 to way 3, pole 13 to way 1, etc.
  • the switch is electrically connected to the motor such that the 0° winding terminal 1 is connected to pole 1, 21 . 1 ° winding terminal 2 is connected to pole 2, etc.
  • the switch is further connected such that 21 . 1 ° winding terminal 21 is connected to way 1, 55.4° winding terminal 22 is connected to way 2, etc.
  • switch position 1 where pole 1 connects to way 1, pole 2 to way 2, etc.
  • a 13 -phase inverter and motor winding are used, as above.
  • the rotor is not a shorted cage as would be used in an induction motor, but instead a permanent magnet rotor, possibly with a shorting cage for starting.
  • Standard synchronous motor control techniques are used, however for different operating speed regimes, different mesh connections are selected in order to best utilize the inverter.
  • a set of 7 resistance heaters each rated 10 Ohms, is supplied with electrical power by a 7 phase generator rated at 100 volts per phase line to neutral.
  • a 13 phase brushless DC drive is used. This is topologically a 13 phase inverter, however full DC link voltage is placed across each winding in turn as appropriate, and commutation signals are supplied by a rotor position detector.
  • a 13 stator as described in 1) above is used, and the rotor is a permanent magnet rotor .
  • a suitable mesh connection is selected at the time of machine installation and commission.
  • this mesh connection technique is applicable to alternating current machines, to wound rotor synchronous machines, as well as to permanent magnet machines and brushless DC motors. It can be used both for motors and for generators, maintaining, for example, a relatively constant output voltage over a large range of generator operating speeds .
  • This mesh connection technique may even be used for polyphase resistive loads, essentially altering the impedance of the resistive load by changing its connectivity.
  • the change in Volts/Hz ratio essentially permits a dynamic tradeoff between machine voltage and current requirements.
  • a low span mesh connection may be beneficially used. This low span mesh connection presents a high voltage to the inverter, and lowers the current requirements placed upon the inverter by a corresponding amount. Examined from the other side of the connection, the low span mesh connection draws low current at high voltage from the inverter, and causes high current at low voltage to flow through the windings of the machine .
  • two polyphase devices may be interconnected using a mesh connection.
  • the impedance that each device presents to the other may be altered, providing various benefits.
  • This change in mesh connection may be described in a different yet functionally equivalent fashion.
  • N phase polyphase device being connected with 2*N sets of connections to the 2*N terminals of a second N phase polyphase device
  • the impedance of this N phase device with its N terminal nodes will vary as the mesh connection utilized varies.
  • An N phase device may be considered as being composed of N two terminal single-phase circuit elements.
  • these circuit elements are connected together, in, for example, an N phase star connection or an N phase mesh connection. Once these circuit elements are connected together, then only N connections need be made to an external circuit.
  • a 10-phase motor will have 10 separate coil sets. Each coil set will have two ends, for a total of 20 coil ends which must all be connected in order to provide a current path through each of these coils.
  • a source of electrical power eg. an inverter output terminal, requiring 20 inverter output terminals .
  • the first option is to select one terminal from each of the coil sets, an connect these 10 terminals together, leaving 10 terminals which must be connected to inverter output terminals.
  • This is the classic star connection. Current will flow from an inverter output terminal, through the corresponding winding, to the neutral or star point. The current will then flow through other phases and back to the inverter system. With a properly balanced star connection, the total of the current through all of the phases is zero, with current flowing into some phases and out of others, and the star point will remain neutral .
  • the second option is the mesh connection. With the mesh connection, these 20 coil ends are connected in pairs, forming 10 terminal nodes. These 10 terminal nodes are then connected to inverter output terminals .
  • the current through each winding flows from one of its terminals, through the winding, to the other terminal.
  • the current flowing out of each of the inverter terminals is equal to the sum of the current flowing into the two connected motor windings. If current happens to be flowing out of one motor winding, and into the other motor winding, then the net current through the inverter terminal may be substantially smaller than that through the connected windings.
  • the voltage placed across the N two terminal circuit elements of an N phase device internally connected using a mesh connection is given by the equations above, and depends upon the number of phases, the harmonic order, and the spanning value.
  • the switching element described above may be considered a device used to change the spanning value of a mesh connected N phase device, without reference to any connected high phase order elements .
  • the spanning value of a motor may be changed without reference to an inverter or generator.
  • the switching element acts to connect the N first terminals of the N two terminal circuits of an N phase device to the N second terminals of said two terminal circuits.
  • the variable position of the switching element corresponds to different second terminal connections for each first terminal.
  • Each switching element position corresponds to a different spanning value, and thus a different N phase composite impedance. It may be seen that these two descriptions are equivalent.
  • N phase polyphase device may be considered as having N terminal nodes, it is entirely possible to interconnect two N phase polyphase devices, each with a variable mesh connection.
  • This mesh connection technique is applicable to alternating current machines, to wound rotor synchronous machines, as well as to permanent magnet machines. It can be used both for motors and for generators, maintaining, for example, a relatively constant output voltage over a large range of generator operating speeds. This mesh connection technique may even be used for polyphase resistive loads, essentially altering the impedance of the resistive load by changing its connectivity.
  • the possible range is quite large, for example, with a 17 phase machine, the Volts/Hertz ratio may be changed by a factor of 5.4:1, in 8 steps. With higher phase counts, even larger changes in Volts/Hertz ratio are possible. Useful capabilities are available even from small phase count machines. For example, in a 5 phase machine, there are two possible
  • the concept is a mechanical switch which may be used to change the impedance which a mesh connected high phase order device presents to another high phase order device.
  • the mesh connected device is the motor, and it is connected to an inverter.
  • the mesh-connected device could be an array of resistors, or a magnetic induction heater.
  • the power supply could be an inverter, a high phase order generator, or mains power properly phase shifted with transformers.
  • the mesh-connected device could be a generator, and the other device could be an array of resistors. You could even have two mesh connected devices, each with its own mesh changing switching device, connected together.
  • a high phase order device is any device which is composed of similar sub- units, each of which is a single phase alternating current device, all of which are operated with different phases of alternating current.
  • a particularly important use of this invention is to connect a star connected inverter to a mesh connected motor, using the switching device to change the particular mesh connection that the motor uses, to change the impedance that the motor presents " to the inverter.
  • the load could be star connected, for example a rectifier being used to charge batteries, or it could be a mesh connected load.
  • an inverter for a generator, unless that generator requires a source of quadrature current.
  • An induction generator would require some source of quadrature current, which could be an inverter, a synchronous motor, or a suitable capacitor bank.
  • the inverter has substantial control of the generator power output .
  • the winding or circuits described herein do not limit other circuit elements which may be used or attached to the present system. Multiples of the present invention may be utilized in a single device, for example a motor with an 18 phase winding may be operated using the method of the present invention as two 9 phase windings with suitable mesh connections, both wound upon the same stator.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

La présente invention concerne une machine tournante électrique qui possède une impédance variable. On obtient ce résultat en connectant un des éléments (406) polyphasé de cet appareil dans une connexion en polygone. On peut varier la valeur de portée L de cette connexion polygonale en changeant le contenu harmonique fourni par un élément convertisseur continu-alternatif. Cette invention concerne aussi un procédé permettant de connecter un convertisseur continu-alternatif à un moteur, dans lequel un agencement (414) de commutation permet la simple modification entre diverses connexions en polygones de différentes valeurs de portée, modifiant ainsi le rapport volts/hertz de ce moteur.
EP02744124A 2001-04-26 2002-04-26 Machine tournante electrique a connexion en polygone a portee variable Withdrawn EP1389362A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US28686201P 2001-04-26 2001-04-26
US286862P 2001-04-26
PCT/US2002/013268 WO2002089306A1 (fr) 2001-04-26 2002-04-26 Machine tournante electrique a connexion en polygone a portee variable

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EP1389362A1 true EP1389362A1 (fr) 2004-02-18
EP1389362A4 EP1389362A4 (fr) 2007-03-07

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Publication number Priority date Publication date Assignee Title
EP1550203A4 (fr) * 2002-04-24 2005-11-30 Borealis Tech Ltd Systeme de freinage connecte en polygone pour machines tournantes electriques
DE102006052111A1 (de) * 2006-11-06 2008-05-08 Robert Bosch Gmbh Elektrische Maschine
CN107453658B (zh) * 2016-06-01 2023-05-09 哈尔滨工业大学（威海） 一种基于多频率调制输出的多台电机串联装置
US11183960B1 (en) 2020-08-27 2021-11-23 Honeywell International Inc. Fail-safe motor control architecture for open-end winding motors

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US1536077A (en) * 1920-08-05 1925-05-05 Creedy Frederick Dynamo-electric machine
US4218646A (en) * 1976-12-21 1980-08-19 Mitsubishi Denki Kabushiki Kaisha AC Feeding apparatus and rotating field apparatus having AC feeding apparatus
DE2908484A1 (de) * 1979-03-05 1980-09-11 Siemens Ag Polumschaltbare mehrphasenwicklung
US4751448A (en) * 1983-12-14 1988-06-14 Siemens Aktiengesellschaft Armature winding for a static converter-fed electrical induction machine
US4890049A (en) * 1987-07-23 1989-12-26 Siemens Aktiengesellschaft Circuit and winding arrangement for a multiphase electric rotating field machine
US5614799A (en) * 1994-07-14 1997-03-25 Mts Systems Corporation Brushless direct current motor having adjustable motor characteristics

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US6101109A (en) * 1998-03-23 2000-08-08 Duba; Greg A. Static power converter multilevel phase driver containing power semiconductors and additional power semiconductor to attenuate ripple voltage

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1536077A (en) * 1920-08-05 1925-05-05 Creedy Frederick Dynamo-electric machine
US4218646A (en) * 1976-12-21 1980-08-19 Mitsubishi Denki Kabushiki Kaisha AC Feeding apparatus and rotating field apparatus having AC feeding apparatus
DE2908484A1 (de) * 1979-03-05 1980-09-11 Siemens Ag Polumschaltbare mehrphasenwicklung
US4751448A (en) * 1983-12-14 1988-06-14 Siemens Aktiengesellschaft Armature winding for a static converter-fed electrical induction machine
US4890049A (en) * 1987-07-23 1989-12-26 Siemens Aktiengesellschaft Circuit and winding arrangement for a multiphase electric rotating field machine
US5614799A (en) * 1994-07-14 1997-03-25 Mts Systems Corporation Brushless direct current motor having adjustable motor characteristics

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO02089306A1 *

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WO2002089306A1 (fr) 2002-11-07
BR0209188A (pt) 2004-08-03
EP1389362A4 (fr) 2007-03-07

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