EP0483894A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Motor control system
Assignee: Motors Liquidation Co
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Filing: 1991-10-05
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Granted: —
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Expires: 2011-10-05
Abstract
Abstract A pulse-width modulated inverter controller (20) for a brushless DC motor in which the controller (20) sets the carrier frequency at one of at least two discrete values, depending on the inverter load. At light and medium loading where the output power and device losses are moderate and the inverter heat sink is adequately large, the carrier frequency is set to a relatively high value. At heavy loading where the inverter losses are relatively high, the carrier frequency is reduced to reduce the switching losses. The controller (20) can be used to reduce the rate of temperature increase in a given inverter design, or alternately, to permit the use of a smaller heat sink for the same rate of temperature increase.
Inventors
- 👤 Michael George Reynolds
- 👤 Chandra Sekhar Namuduri
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 12:17
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/08; H02P6/085; B; B60; B60L; B60L50/00; B60L50/50; B60L50/60; H02P29/00; H02P29/60; H02P29/68; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64; Y02T10/70
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
205 words
Apparatus for controlling the operation of a switching device which is adapted to be alternately rendered conductive and non-conductive so as to supply alternating current to a load (10) from a source of direct current (18), comprising command means (22) for generating a current command (I cmd ) representative of a desired current to be supplied to the load; feedback means (32) for sensing the actual current supplied to the load; a reference signal generator (70,74) adapted to generate a reference signal (I err ) related to the difference between the current command (I cmd ) and the actual current; and carrier means (62,66) adapted to develop a substantially fixed magnitude triangular wave (c) for comparison with the reference signal; characterised by a modulator (78,40) adapted to modulate the operation of the switching device (50-60) on the basis of a comparison of the reference signal with the triangular carrier wave; and in that the carrier means (62,66) is adapted to generate a triangular wave (c) having a relatively high frequency when the current command is less than a reference current (I REF ), and a triangular wave (c) having relatively low frequency when the current command is at least as great as the reference current.
Claim 2
Dependent Claim
32 words
Apparatus according to Claim 1, wherein the load is a vehicle traction motor and the current command is determined in relation to a demand signal generated by an operator of the vehicle.
Claim 3
Dependent Claim
153 words
A motor control system including a source of direct current (18), an electrical load (10), a transistor inverter (16) connected to supply alternating current to the load from the source of direct current, and a controller (20) for pulse-width-modulating a transistor (50-60) of the inverter between conductive and non-conductive states on the basis of a comparison between a carrier waveform (c) and a modulation waveform (M) determined in relation to a load current command (I cmd ); characterised in that the controller (20) is adapted to set the frequency of the carrier waveform (c) to a relatively high frequency value when the load current command (I cmd ) is relatively low, thereby to reduce losses and noise related to ripple in the supplied current, and to a relatively low frequency value when the load current command (I cmd ) is relatively high, thereby to reduce losses related to the modulation of the transistor.
Claim 4
Dependent Claim
33 words
Apparatus according to Claim 3, wherein the load is a vehicle traction motor and the load current command is determined in relation to a demand signal generated by an operator of the vehicle.
References Cited (Backward Citations)
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