Method and system for starting a motor-commutated SCR inverter
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H02P-005/40
출원번호
US-0509625
(1983-06-30)
발명자
/ 주소
Gary James R. (Elk Grove Village IL) Geis Everett R. (Orange CA) King Todd L. (Buffalo Grove IL) Singh Daljit (Elk Grove Village IL)
출원인 / 주소
Borg-Warner Corporation (Chicago IL 02)
인용정보
피인용 횟수 :
29인용 특허 :
5
초록▼
Highly reliable and consistent starting is achieved by first initializing the rotor position, namely establishing the rotor in a known starting position. This is accomplished by gating on two pairs of SCRs in sequence and supplying current pulses through the gated SCRs to the stator of the motor to
Highly reliable and consistent starting is achieved by first initializing the rotor position, namely establishing the rotor in a known starting position. This is accomplished by gating on two pairs of SCRs in sequence and supplying current pulses through the gated SCRs to the stator of the motor to rotate the rotor to a first position and then to a second position, the rotor coming to a complete stop in each of those positions. The rotor aligns itself with the magnetic field created by the stator in each position and any ambiguity in the rotor position is eliminated. Thereafter, the inverter is operated asynchronously in a second mode with predetermined pairs of the inverter SCRs being sequentially gated into conduction at an increasing frequency to current pulse energize the motor to effect step-by-step rotation of the rotor at a faster and faster rate, the motor current being reduced to zero at the termination of each energizing pulse to force commutate the conducting pair of SCRs. After the motor has reached a preset speed, operation in a third mode occurs and the inverter is synchronized with the motor, gating of the SCRs being controlled by the motor voltage in order that the rotor position will be synchronized to the revolving magnetic field created by the stator. During this third operating mode the motor speed continues to increase and the SCRs are forced commutated, as a result of which the rotor follows the stator magnetic field very closely and synchronization will be perfected. When the motor subsequently reaches a given speed sufficiently high to permit motor commutation exclusively, the starting system switches to a fourth and normal running mode wherein the gating of the inverter SCRs continues to be synchronized with the motor and controlled by the motor voltage, but the SCRs will now be commutated only by the motor voltage. Operation in the third mode provides a buffer and ensures a very smooth, reliable, consistent and a relatively short transition from asynchronous, forced-commutation operation to synchronous, motor-commutated operation.
대표청구항▼
A starting system for an interter-motor system wherein a synchronous motor, having a stator and a rotor, is normally driven by the output a-c voltage developed by an inverter, which has a series of motor-commutated SCRs that are gated into conduction in predetermined pairs and in a prescribed sequen
A starting system for an interter-motor system wherein a synchronous motor, having a stator and a rotor, is normally driven by the output a-c voltage developed by an inverter, which has a series of motor-commutated SCRs that are gated into conduction in predetermined pairs and in a prescribed sequence to conduct current to the motor, from an applied d-c bus voltage, and in response to received bus current, translated to the inverter over a d-c bus and a series-connected filter inductance from a controlled rectifier bridge to which is applied a-c line voltage, said starting system comprising: means for sequentially gating the pairs of inverter SCRs at an increasing frequency to current pulse energize the motor to effect step-by-step rotation thereof at a faster and faster rate, the motor current being reduced to zero at the termination of each energizing pulse by controlling the rectifier bridge to force commutate the conducting pair of SCRs, the bus current being decreased to zero, to force commutate the conducting SCRs, by controlling the rectifier bridge so that it will rapidly dissipate the energy that builds up and becomes stored in the filter and motor inductances when the bus current flows therethrough, thereby minimizi:ng the decay time of the bus current to zero to facilitate faster gating on of the next pair of SCRs in the sequence; a synchronizing circuit, operative after the motor has reached a preset speed, for sensing only the motor voltage and for developing synchronizing pulses in response to that sensed motor voltage, said synchronizing circuit including a rectifier for rectifying the motor voltage, an integrator for integrating the rectified motor voltage, a comparator for comparing the integrated voltage with a reference voltage representing a preset threshold level, a synchronizing pulse being produced each time the integrated voltage integrates up to the reference voltage and reaches the threshold level, and a reset circuit for feeding each synchronizing pulse back to the integrator to effect reset thereof to zero in order to start a new integration cycle, a constant volt-time integral thereby being obtained between successive synchronizing pulses as determined by the value of the reference voltage; and means for utilizing each synchronizing pulse to control the rectifier bridge to reduce the bus current to zero to force commutate the conducting pair of inverter SCRs and to then gate on the next pair of SCRs in the prescribed sequence and supply current to the motor through that next pair of SCRs, thereby effectively synchronizing the gating of the inverter SCRs to the rotor position while at the same time force commutating the SCRs, a constant ratio of the inverter output voltage relative to the inverter frequency being obtained as a result of the constant volt-time integral.
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이 특허에 인용된 특허 (5)
Tsuboi Takashi (Katsuta JA) Tanamachi Tokunosuke (Katsuta JA), AC motor control system.
Schray Hans-Dieter (Markgrningen DEX) Taubitz Bernd (Schwieberdingen DEX) Wirtz Rainer (Markgrningen DEX), Circuit for operating a synchronous motor from a dc supply.
Fulton Donald E. (Stoneham MA) Curtiss William P. (Winthrop MA) Fejes ; Jr. William T. (Needham MA), Self-starting transducerless, brushless D.C. motor controller.
Chausse B. Paul (Roanoke VA) Espelage Paul M. (Salem VA) Lippitt David L. (Scotia NY) Tupper Leland C. (Schenectady NY), Transitioning between multiple modes of inverter control in a load commutated inverter motor drive.
Kaufmann, Tom; Stauder, Peter; Bitsch, Christian; Budianu, Bogdan; Leideck, Jochen, Method and circuit arrangement for checking the rotor position of a synchronous machine.
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