WO1992008276A1 - Moteur a courant alternatif protege par reactance capacitive - Google Patents

Moteur a courant alternatif protege par reactance capacitive Download PDF

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Publication number
WO1992008276A1
WO1992008276A1 PCT/US1991/008052 US9108052W WO9208276A1 WO 1992008276 A1 WO1992008276 A1 WO 1992008276A1 US 9108052 W US9108052 W US 9108052W WO 9208276 A1 WO9208276 A1 WO 9208276A1
Authority
WO
WIPO (PCT)
Prior art keywords
capacitor
motor
voltage
direct current
power supply
Prior art date
Application number
PCT/US1991/008052
Other languages
English (en)
Inventor
Fred A. Brown
Original Assignee
Comair Rotron, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Comair Rotron, Inc. filed Critical Comair Rotron, Inc.
Publication of WO1992008276A1 publication Critical patent/WO1992008276A1/fr

Links

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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/34—Modelling or simulation for control purposes

Definitions

  • the present invention relates generally to motors, including fan motors, that may be powered by an alternating current power supply.
  • AC motors have several problems, which prevent AC motors from being used over a broad range of voltages and frequencies. With AC synchronous motors, for example, it is virtually impossible to obtain speeds other than those for which the motor was designed. DC motors do not have these problems. However, where only AC voltages are available, the added cost of providing an AC to DC converter, so that a DC fan motor may run off of an AC power supply, is frequently prohibitive. Furthermore, unless the AC-to-DC converter is properly designed, damage may occur to the DC circuitry or the performance of the DC motor may be degraded.
  • capacitors may be used to create an AC voltage drop in an alternating current circuit.
  • transformers are typically preferred in AC-to-DC converters in order to lower the AC voltage, because they provide isolation of the load from the AC power source, and because the output voltage is relatively independent of the load.
  • circuits are necessary to protect critical components from failure when the motor is under load or when windings may become shorted.
  • the present invention provides an improved motor that includes a stator having an electromagnetic coil mounted thereon and a rotor having a permanent magnet mounted thereon.
  • the rotor being so mounted with respect to the stator that the permanent magnet may rotate past the electromagnetic coil.
  • Switching circuitry alternately permits direct current to flow through the electromagnetic coil depending on the position of the rotor.
  • the foregoing components of the motor are typically found in standard DC brushless motors.
  • the improvement permits the motor to run off of an AC power supply.
  • the improvement includes terminals for connecting to an AC power supply, a capacitor in serial connection with one of the terminals, and a rectifying circuit. The capacitor, because of its inherent reactance, causes a voltage drop of the AC proportional to the motor load.
  • a larger load causes the motor to pull a larger current; the larger current causes a greater voltage drop across the capacitor.
  • the rectifying circuit rectifies the AC to produce DC, which the switching circuitry alternately permits to flow through the electromagnetic coil.
  • capacitive reactance between the AC power supply and the rectifying circuitry what is essentially a DC motor can be simply adapted to run over a broad range of AC voltage and frequency, thereby providing the flexibility of a DC motor.
  • a fan that has all the performance flexibility of a DC fan and that is capable of running an AC power supply is provided.
  • the capacitor provides load protection to the motor at the same time it achieves a voltage drop to the rectifier circuit.
  • the invention reduces overall product cost, and provides a new and reliable motor safety protection scheme.
  • Fig. 1 shows a block diagram of one embodiment of the invention
  • Fig. 2 shows a schematic of a specific embodiment of the invention.
  • Fig. 1 shows a block diagram of a preferred embodiment of the invention.
  • a varying AC power supply VAC is shown connected by means of capacitor Cl to a rectifier.
  • the rectifier rectifies the AC and provides direct current to the rest of the circuitry.
  • the rectifier is a full-wave rectifier, although a half-wave rectifier may also be used.
  • a shunt regulator is used to maintain the proper impedance over a range of motor load.
  • the detection device requires a DC potential, and provides an output, based on the position of the rotor, to the switching circuit.
  • the switching circuit switches direct current through two coils LA and LB based on the output from the from detection device.
  • capacitor Cl serves as the capacitive component for creating the voltage drop.
  • Resistor Rl is a safety feature; it permits discharging of the capacitor Cl when the motor is not in use.
  • Diodes Dl, D2, D3 and D4 form a full-wave rectifier, which rectifies the AC to supply DC to the DC circuitry, i.e., the circuitry to the right of the full-wave rectifier D1-D4 in the schematic.
  • Zener diode Zl and transistor Tl serve as a shunt regulator to maintain a constant impedance.
  • Hall effect device H which senses the position of the rotor, is connected to the base terminals of transistors T2 and T3. The Hall effect device H provides output to transistors T2 and T3, so that transistors can switch the current through electromagnetic coils LA and LB respectively at the proper times. These coils are, of course, mounted on the stator. The following is a list of the components used in the specific embodiment shown in Fig. 2:
  • Resistors Rl 500 K ⁇
  • This embodiment is based on a DC fan motor with a low running current and that is operable at 48 volts DC.
  • DC fans with other suitable voltages may be used. Since the current drawn by the DC circuitry will effectively dictate the impedance the DC circuitry will impose on the capacitor Cl, it is preferable that capacitor Cl have a capacitance such that 48 volts is supplied to the DC circuitry within a suitable range of AC voltage from the AC power supply. During the normal running conditions of the motor, the input voltage may exceed the normal operating range of the motor. To prevent over-voltage damage, the shunt voltage regulator clamp modifies the basic impedance of the DC circuitry to maintain the proper voltage drop across the capacitor. In the case of motor failure, the circuit prevents over-voltage conditions. The capacitive reactance circuit maintains a relatively constant AC load and provides effective motor protection, similar to impedance protection.
  • the motor impedance may vary by a factor of 2 or 3 to 1.
  • the shunt voltage regulator is programmed to clamp incoming voltage to a safe level. As the voltage attempts to increase, the shunt regulator maintains a counter-acting impedance.which serves to achieve an effective constant current to the motor control circuitry.
  • This circuit also allows relatively constant performance over a broad range of input voltages and line frequencies, so that performance of the fan does not deteriorate when operating at 50 Hz.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)

Abstract

L'invention concerne un circuit destiné à faire fonctionner un moteur classique sans balai à courant continu coupé sur une alimentation en courant alternatif (VAC). Un condensateur (C1) est connecté en série entre l'alimentation en courant alternatif (VAC) et un redresseur (D1, D2, D3, D4). Le condensateur (C1) assure au moteur une protection contre les chutes et les charges de tension. Un régulateur en dérivation (Z1, T1) peut être utilisé afin de maintenir une impédance constante. Un circuit de commutation (H, T2, T3) est utilisé afin de commuter le courant dans les bobines électromagnétiques du moteur (LA, LB).
PCT/US1991/008052 1990-10-30 1991-10-30 Moteur a courant alternatif protege par reactance capacitive WO1992008276A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US60580090A 1990-10-30 1990-10-30
US605,800 1990-10-30

Publications (1)

Publication Number Publication Date
WO1992008276A1 true WO1992008276A1 (fr) 1992-05-14

Family

ID=24425272

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/008052 WO1992008276A1 (fr) 1990-10-30 1991-10-30 Moteur a courant alternatif protege par reactance capacitive

Country Status (1)

Country Link
WO (1) WO1992008276A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0688091A1 (fr) * 1994-05-04 1995-12-20 Emerson Electric Co. Alimentation en courant électrique à grande puissance pour un moteur à aimants permanents sans balai
GB2401496A (en) * 1999-12-17 2004-11-10 Sunonwealth Electr Mach Ind Co Conversion circuit for a DC brushless motor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6095619A (ja) * 1983-10-28 1985-05-29 Yokogawa Medical Syst Ltd 定電圧電源回路
JPH01308141A (ja) * 1988-06-01 1989-12-12 Furonteia Fuiirudo Prod:Kk サーモモジュール駆動用トランスレス直流電源回路
JPH0241686A (ja) * 1988-07-28 1990-02-09 Tokyo Electron Ltd 直流モータ制御装置
FR2636182A1 (fr) * 1988-09-05 1990-03-09 Technologique Sarl Comp Circuit de commande pour moteur a courant continu sans collecteur, notamment d'un ventilateur

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6095619A (ja) * 1983-10-28 1985-05-29 Yokogawa Medical Syst Ltd 定電圧電源回路
JPH01308141A (ja) * 1988-06-01 1989-12-12 Furonteia Fuiirudo Prod:Kk サーモモジュール駆動用トランスレス直流電源回路
JPH0241686A (ja) * 1988-07-28 1990-02-09 Tokyo Electron Ltd 直流モータ制御装置
FR2636182A1 (fr) * 1988-09-05 1990-03-09 Technologique Sarl Comp Circuit de commande pour moteur a courant continu sans collecteur, notamment d'un ventilateur

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 14, no. 108 (E-89)27 February 1990 & JP,A,1 308 141 ( FURONTEIA FUIIRUDO PROD K.K. ) 12 December 1989 *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 200 (E-92)24 April 1990 & JP,A,2 041 686 ( TOKYO ELECTRON LTD ) 9 February 1990 *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 243 (P-392)30 September 1985 & JP,A,60 095 619 ( YOKOKAWA MEDICAL SYSTEM KK ) 29 May 1985 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0688091A1 (fr) * 1994-05-04 1995-12-20 Emerson Electric Co. Alimentation en courant électrique à grande puissance pour un moteur à aimants permanents sans balai
GB2401496A (en) * 1999-12-17 2004-11-10 Sunonwealth Electr Mach Ind Co Conversion circuit for a DC brushless motor
GB2401496B (en) * 1999-12-17 2005-02-09 Sunonwealth Electr Mach Ind Co Brushless DC motor fan driven by an AC power source

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