Patent EP0089150A1 successfully refreshed from Google Patents.
EP0089150A1
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EP
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Brushless D.C. motor drive
Assignee: Garrett Corp
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Filing: 1983-03-03
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Granted: —
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Expires: 2003-03-03
Abstract
Abstract A control circuit for a brushless d.c. motor (11) providing positive control whatever the polarities of motor voltage and motor current. The circuit provides control of motor current, thereby controlling motor torque, in response to an applied current command signal, relying solely on feedback signals of motor current (41) and rotor angle (36). The heart of the system is a level dependent logic stage (34) which selectively controls the states of the switches (40) applying power to the motor windings in accordance with a current error signal (le) developed by reference to the feedback current signal. The control circuit causes the motor current to correspond to an applied current command and works at any motor speed and torque for rotation in either direction. In a preferred embodiment, the basic control system is combined with additional feedback loops (22,14) developing servo information regarding rate and actuator position to provide an overall position control system, such as is particularly useful in place of the hydraulic actuator systems now employed in aircraft.
Inventors
- 👤 David A. Bailey
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 16:10
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/06
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
83 words
Apparatus for controlling a brushless d.c. motor comprising a plurality of solid state power switches (TS1-TS4, 56-66) connected to the motor windings (46,48,50) for selectively applying power to develop current therein; Logic means (34,38) for determining the states, and order of switching between states of the solid state switches in response to the level of a current error signal (Ie) derived from a combination of a current feedback signal dependent on the current in the motor winding, and an applied current command signal.
Claim 2
Dependent Claim
83 words
Apparatus for controlling a brushless d.c. motor comprising a plurality of solid state power switches (TS1-TS4, 56-66) connected to the motor windings (46,48,50) for selectively applying power to develop current therein; Logic means (34,38) for determining the states, and order of switching between states of the solid state switches in response to the level of a current error signal (Ie) derived from a combination of a current feedback signal dependent on the current in the motor winding, and an applied current command signal.
Claim 3
Dependent Claim
30 words
Apparatus as claimed in Claim 1 wherein the motor has at Least three windings and includes rotor- position-sensing means (36) for providing phase signals for application to the Logic means.
Claim 4
Dependent Claim
49 words
Apparatus as claimed in CLaim 1 or CLaim 2 wherein the Logic means comprise a plurality of LeveL dependent devices (U1A-U1D) coupled to be controlled by the current error signal, each of which exhibits a hysteresis effect relative to the directions of change of state of the power switches.
Claim 5
Dependent Claim
37 words
Apparatus as claimed in any preceding claim wherein the power switches are arranged by pairs, the switches of a pair being for controlling supply of motor current from the positive and negative sides of the supply respectively.
Claim 6
Dependent Claim
37 words
Apparatus as claimed in any preceding claim including a single LeveL dependent device biased to change state in the vicinity of zero control voltage to develop a signal for affecting the sign of the current feedback signaL.
Claim 7
Dependent Claim
42 words
Apparatus as claimed in any preceding claim wherein each of the power switches has a diode (56-66) connected in paraLLeL with it and poled to conduct current in a direction opposite to the normal direction of current thorugh the associated power switch.
Claim 8
Dependent Claim
48 words
Apparatus as claimed in any preceding claim including means for sensing the magnitude of current in the motor windings for use as the current feedback signal, and comprising a first resistor (RS1) connected with the power switches coupled between the windings and one side of the power supply.
Claim 9
Dependent Claim
70 words
Apparatus as claimed in CLaims 6 and 7 in which the first resistor (RS1) is connected in series with the power switches and a second resistor (RS2) is connected in series between said one side of the power supply and the diodes associated with said switches, and there are means for selecting the greater of the voltages developed across the first and second resistors to develop the current feedback signal.
Claim 10
Dependent Claim
30 words
Apparatus as claimed in any preceding claim including means (42) for controLLing the sign of said current feedback signal in accordance with the commanded direction of rotation of the motor.
Claim 11
Dependent Claim
90 words
Apparatus as claimed in any preceding claim including a dynamic compensation means for integrating and filtering the current error signal to develop the control signal for the LeveL dependent Logic means for example, including amplifying means having a gain which, together with the hysteresis characteristic of the LeveL dependent switches, is effective to develop pulse width modulation control of the power switches, and preferably including a current Limiting stage for Limiting the command signal within a selected range corresponding to the range of permissible current LeveLs in the motor windings.
Claim 12
Dependent Claim
49 words
11 Apparatus as claimed in any preceding claim, comprising an actuator (12) connected to be driven by the motor (11) and a feedback Loop including an actuator position sensor (14) for providing a position feedback signal to be compared with the command signal in developing a position error signal.
Claim 13
Dependent Claim
42 words
Apparatus as claimed in CLaim 11 further including a rate feedback Loop coupled to develop a rate feedback signal indicative of motor speed and means for comparing the position error signal and the rate feedback signal to develop the current command signal.
Claim 14
Independent Claim
129 words
A method of controlling the current and torque of a brushless d.c. motor (11) in response to a current command signal, which motor has associated power switches (56-66) for applying power to the windings (46-50) comprising the steps of: applying a current error signal (Ie) to a plurality of LeveL dependent switches (U1A-U1D) to selectively control the conduction states thereof, each of said switches being biased to develop a change of conduction state at a unique LeveL of control voltage; applying signals developed from the outputs of the LeveL dependent switches to control the states of the power switches; deriving (at 41) a current feedback signal indicative of motor current and combining (at 30) the current feedback signal with an applied current command signal to develop the error signaL.
Claim 15
Independent Claim
129 words
A method of controlling the current and torque of a brushless d.c. motor (11) in response to a current command signal, which motor has associated power switches (56-66) for applying power to the windings (46-50) comprising the steps of: applying a current error signal (Ie) to a plurality of LeveL dependent switches (U1A-U1D) to selectively control the conduction states thereof, each of said switches being biased to develop a change of conduction state at a unique LeveL of control voltage; applying signals developed from the outputs of the LeveL dependent switches to control the states of the power switches; deriving (at 41) a current feedback signal indicative of motor current and combining (at 30) the current feedback signal with an applied current command signal to develop the error signaL.
Claim 16
Dependent Claim
50 words
The method of CLaim 13 wherein the motor has at Least three windings, further including the step of combining the output signals of the LeveL dependent switches with signals indicative of motor phase in accordance with a predetermined commutation Logic arrangement, and applying the resulting signals to the power switches.
References Cited (Backward Citations)
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