WO2012033406A1 - Improved motor control for the control of a pulse controlled electric motor - Google Patents

Improved motor control for the control of a pulse controlled electric motor Download PDF

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Publication number
WO2012033406A1
WO2012033406A1 PCT/NL2011/050611 NL2011050611W WO2012033406A1 WO 2012033406 A1 WO2012033406 A1 WO 2012033406A1 NL 2011050611 W NL2011050611 W NL 2011050611W WO 2012033406 A1 WO2012033406 A1 WO 2012033406A1
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WO
WIPO (PCT)
Prior art keywords
control
motor control
switching
mosfets
motor
Prior art date
Application number
PCT/NL2011/050611
Other languages
French (fr)
Inventor
Harm Lok
Original Assignee
Harm Lok
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 Harm Lok filed Critical Harm Lok
Priority to EP11767813.6A priority Critical patent/EP2614587A1/en
Publication of WO2012033406A1 publication Critical patent/WO2012033406A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/16—Modifications for eliminating interference voltages or currents
    • H03K17/161—Modifications for eliminating interference voltages or currents in field-effect transistor switches
    • H03K17/165—Modifications for eliminating interference voltages or currents in field-effect transistor switches by feedback from the output circuit to the control circuit
    • 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
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
    • H03K5/01—Shaping pulses
    • H03K5/08—Shaping pulses by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding

Definitions

  • the invention relates to motor control for controlling a pulse-controlled electric motor for the purpose of rotating the electric motor at an adjustable rotation speed, wherein the motor control is provided with at least four MOSFETs which are arranged in at least two half-bridges, and a control unit for controlling the MOSFETs, wherein the motor control is provided with a device for suppressing periodic interference signals superimposed on a periodic control signal which comes from the control unit and which is intended for the purpose of controlling the MOSFETs.
  • Periodic interference signals occur at the control inputs of the MOSFETs and at the connections of the MOSFETs to the electric motor. These may be glitches, high-voltage peaks which contain a relatively large amount of energy and which form a risk for the electric motor and for a drive supplying the control signals, but also oscillation phenomena resulting from parasitic self-inductions and distributed capacities in the electric motor, in the wiring or in switch elements forming part of the drive. According to the prior art these interference signals are suppressed using snubber networks and zener diodes, which may produce good results but which inevitably causes energy loss.
  • the invention has for its object to provide a motor control according to the preamble which limits this energy loss.
  • the invention also has for its object to increase the efficiency of the motor control, this being particularly important when the motor control is powered by a battery.
  • the motor control according to the invention has for this purpose the feature that the device comprises a measuring member for measuring the control signal with the interference signals superimposed thereon, and a processor for deriving at least one switching signal from the measuring signal, in addition to at least one switch member for switching on and off a capacitive load for the control signal such that the interference signals are at least substantially wholly suppressed, and that the device also comprises at least one transformer for feedback of energy collected in the capacitive load to a power source for the control signal.
  • the MOSFETs will develop significantly less heat, which can result in a compact construction method and significantly increase the lifespan.
  • a further important additional advantage is that the electromagnetic interference level of the motor control is significantly reduced.
  • a highly favourable embodiment of the inventive motor control has the feature that the processor is adapted to derive from the measuring signal at least two switching signals for operating a first and a second pair of switches for the purpose of switching on and off the capacitive load for respectively positive interference signals and negative interference signals.
  • a further favourable embodiment has the feature that the measuring member comprises an analog/digital converter so that the further processing of the measured signals can take place in wholly digital manner.
  • a flash analog- digital converter known in the field is preferably used for this purpose so that the processor can generate a switching signal on time as soon as the measured voltage rises above a first threshold value or drops below a second threshold value.
  • a switch comprises at least one MOSFET.
  • a further favourable embodiment has the feature that the transformer comprises a self-inductance and is adapted to feed energy collected in the capacitive load to a self-inductance and to then feed energy stored in the self-inductance to the power source.
  • Fig. 1 shows schematically a possible embodiment of a prior art motor control
  • Fig. 2 shows a possible embodiment of a motor control according to the invention
  • Fig. 3A shows schematically a control signal with glitches together with switching peaks for the positive glitches and the negative glitches;
  • Fig. 3B shows a control signal with oscillation phenomena together with switching peaks for positive going and negative going oscillations on the control signal
  • Fig. 4A shows schematically a possible embodiment of a switching group for suppressing positive and negative interference signals at a gate of a
  • Fig. 4B shows schematically a possible embodiment of a transformer for feeding back energy to the power source.
  • Fig. 1 shows schematically a possible embodiment of a prior art motor control consisting of an H-bridge with MOSFETs 1a,..,1d, consisting of two half-bridges which are controlled from a control unit 2 with the purpose of rotating a relatively heavy electric motor 3, which provides the drive for instance for a boat or vehicle, at an adjustable rotation speed.
  • the H-bridge has the main purpose of applying a voltage to the electric motor, wherein the polarity of the voltage can be predetermined.
  • the rotation direction of the electric motor can hereby be determined.
  • Interference signals in the form of glitches and/or oscillation phenomena are almost inevitably superimposed on the control signals of control unit 2. In order to suppress these
  • Fig. 2 shows a possible embodiment of a motor control according to the invention, consisting of an H-bridge with MOSFETs 1a,..1d which are controlled from a control unit 2 with the purpose of rotating a relatively heavy electric motor 3, which provides the drive for instance for a boat or vehicle, at an adjustable rotation speed.
  • Interference signals in the form of glitches and/or oscillation phenomena are superimposed on the control signals of control unit 2.
  • These interference signals are fed to a measuring unit 4 comprising an analog-digital converter and provided with an analog multiplexer so that it can successively measure the control signals for the gates of MOSFETs 1a,..,1d.
  • Measuring unit 4 further comprises a processor 6 which derives switching signals from the output signal of analog-digital converter 5 at those moments when glitches or oscillation phenomena are detected. These switching signals are fed to a switch unit 7 comprising a number of switching groups 8 and a capacitor 9 with a + and a - terminal in which energy extracted from the glitches or oscillation phenomena is temporarily stored. This energy is then transformed by a transformer 10 such that it can be fed back to the power source.
  • Fig. 3A shows schematically a block-shaped control signal with glitches at a MOSFET gate. Below this can be seen switching peaks A generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the + pole of the power source, whereby capacitor 9 is charged. Below this can be seen switching peaks B generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the - pole of the power source, whereby capacitor 9 is recharged.
  • Fig. 3B shows a control signal with oscillation phenomena at a MOSFET gate. Below this can be seen switching peaks C generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the + pole of the power source, whereby capacitor 9 is charged. Below this can be seen switching peaks D generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the + pole of the power source, whereby capacitor 9 is recharged. Shown below this are switching peaks E generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the - pole of the power source, whereby capacitor 9 is recharged. Below this can be seen switching peaks F generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the - pole of the power source, whereby capacitor 9 is recharged.
  • Fig. 4A shows schematically a possible embodiment of a switching group 8 for suppressing positive and negative interference signals at a gate of a MOSFET 1.
  • the + terminal of capacitor 9 is connected via a MOSFET 12 to the gate of MOSFET 1 using a switch line 11 , while the - terminal is connected via a MOSFET 13 to the + terminal of the power source using switch line 11.
  • the - terminal of capacitor 9 is connected via a MOSFET 15 to the gate of MOSFET 1 using a switch line 14, while the + terminal is connected via a MOSFET 16 to the + terminal of the power source. It will be apparent that at least four of these switching groups are required for a full H- bridge. If desired, the switching groups can be accommodated in a MOSFET gate array known in the field.
  • Fig. 4B shows schematically a possible embodiment of a transformer for feeding back energy to the power source.
  • Capacitor 9 is connected via a MOSFET 17 to the + pole of the power source and via a further MOSFET 18 to a coil 19 which is connected to the + pole of the power source.
  • MOSFETs 17, 18 are then activated such that a charge can flow out of capacitor 9 and can build up a current in coil 19.
  • MOSFETs 17, 18 are then no longer activated and the energy present in coil 19 is fed back to the power source via a diode 20.
  • the inventive device is applied for the purpose of suppressing interference superimposed on the gate signals of four MOSFETs forming part of an H-bridge and reusing the energy present in these interference signals.
  • the gate signals of other types of motor control and the actual control signals for electric motor 3 can of course also be filtered in the same manner.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Control Of Direct Current Motors (AREA)
  • Inverter Devices (AREA)

Abstract

The invention relates to an improved motor control for controlling a pulse- controlled electric motor for the purpose of rotating the electric motor at an adjustable rotation speed, wherein the motor control is provided with at least four MOSFETs which are arranged in at least two half-bridges, and a control unit for controlling the MOSFETs, wherein the motor control is provided with a device for suppressing periodic interference signals superimposed on a periodic control signal which comes from the control unit and which is intended for the purpose of controlling the MOSFETs.

Description

IMPROVED MOTOR CONTROL FOR THE CONTROL OF A PULSE- CONTROLLED ELECTRIC MOTOR
The invention relates to motor control for controlling a pulse-controlled electric motor for the purpose of rotating the electric motor at an adjustable rotation speed, wherein the motor control is provided with at least four MOSFETs which are arranged in at least two half-bridges, and a control unit for controlling the MOSFETs, wherein the motor control is provided with a device for suppressing periodic interference signals superimposed on a periodic control signal which comes from the control unit and which is intended for the purpose of controlling the MOSFETs.
Periodic interference signals occur at the control inputs of the MOSFETs and at the connections of the MOSFETs to the electric motor. These may be glitches, high-voltage peaks which contain a relatively large amount of energy and which form a risk for the electric motor and for a drive supplying the control signals, but also oscillation phenomena resulting from parasitic self-inductions and distributed capacities in the electric motor, in the wiring or in switch elements forming part of the drive. According to the prior art these interference signals are suppressed using snubber networks and zener diodes, which may produce good results but which inevitably causes energy loss. The invention has for its object to provide a motor control according to the preamble which limits this energy loss. The invention also has for its object to increase the efficiency of the motor control, this being particularly important when the motor control is powered by a battery.
The motor control according to the invention has for this purpose the feature that the device comprises a measuring member for measuring the control signal with the interference signals superimposed thereon, and a processor for deriving at least one switching signal from the measuring signal, in addition to at least one switch member for switching on and off a capacitive load for the control signal such that the interference signals are at least substantially wholly suppressed, and that the device also comprises at least one transformer for feedback of energy collected in the capacitive load to a power source for the control signal. A significant additional advantage is that the MOSFETs will develop significantly less heat, which can result in a compact construction method and significantly increase the lifespan. A further important additional advantage is that the electromagnetic interference level of the motor control is significantly reduced.
A highly favourable embodiment of the inventive motor control has the feature that the processor is adapted to derive from the measuring signal at least two switching signals for operating a first and a second pair of switches for the purpose of switching on and off the capacitive load for respectively positive interference signals and negative interference signals.
A further favourable embodiment has the feature that the measuring member comprises an analog/digital converter so that the further processing of the measured signals can take place in wholly digital manner. A flash analog- digital converter known in the field is preferably used for this purpose so that the processor can generate a switching signal on time as soon as the measured voltage rises above a first threshold value or drops below a second threshold value. A further favourable embodiment has the feature that a switch comprises at least one MOSFET.
A further favourable embodiment has the feature that the transformer comprises a self-inductance and is adapted to feed energy collected in the capacitive load to a self-inductance and to then feed energy stored in the self-inductance to the power source.
The invention will now be further elucidated with reference to the following figures, in which: Fig. 1 shows schematically a possible embodiment of a prior art motor control;
Fig. 2 shows a possible embodiment of a motor control according to the invention;
Fig. 3A shows schematically a control signal with glitches together with switching peaks for the positive glitches and the negative glitches;
Fig. 3B shows a control signal with oscillation phenomena together with switching peaks for positive going and negative going oscillations on the control signal;
Fig. 4A shows schematically a possible embodiment of a switching group for suppressing positive and negative interference signals at a gate of a
MOSFET;
Fig. 4B shows schematically a possible embodiment of a transformer for feeding back energy to the power source.
Fig. 1 shows schematically a possible embodiment of a prior art motor control consisting of an H-bridge with MOSFETs 1a,..,1d, consisting of two half-bridges which are controlled from a control unit 2 with the purpose of rotating a relatively heavy electric motor 3, which provides the drive for instance for a boat or vehicle, at an adjustable rotation speed. The H-bridge has the main purpose of applying a voltage to the electric motor, wherein the polarity of the voltage can be predetermined. The rotation direction of the electric motor can hereby be determined. Interference signals in the form of glitches and/or oscillation phenomena are almost inevitably superimposed on the control signals of control unit 2. In order to suppress these
interference signals, resistors and zener diodes are incorporated in the connecting wires and the gates are protected with additional zener diodes. These measures are effective but dissipate energy, whereby the motor control develops a great deal of heat and less sailing or driving time is available with the charge of a battery which generally forms the power source.
Fig. 2 shows a possible embodiment of a motor control according to the invention, consisting of an H-bridge with MOSFETs 1a,..1d which are controlled from a control unit 2 with the purpose of rotating a relatively heavy electric motor 3, which provides the drive for instance for a boat or vehicle, at an adjustable rotation speed. Interference signals in the form of glitches and/or oscillation phenomena are superimposed on the control signals of control unit 2. These interference signals are fed to a measuring unit 4 comprising an analog-digital converter and provided with an analog multiplexer so that it can successively measure the control signals for the gates of MOSFETs 1a,..,1d. Measuring unit 4 further comprises a processor 6 which derives switching signals from the output signal of analog-digital converter 5 at those moments when glitches or oscillation phenomena are detected. These switching signals are fed to a switch unit 7 comprising a number of switching groups 8 and a capacitor 9 with a + and a - terminal in which energy extracted from the glitches or oscillation phenomena is temporarily stored. This energy is then transformed by a transformer 10 such that it can be fed back to the power source.
Fig. 3A shows schematically a block-shaped control signal with glitches at a MOSFET gate. Below this can be seen switching peaks A generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the + pole of the power source, whereby capacitor 9 is charged. Below this can be seen switching peaks B generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the - pole of the power source, whereby capacitor 9 is recharged.
Fig. 3B shows a control signal with oscillation phenomena at a MOSFET gate. Below this can be seen switching peaks C generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the + pole of the power source, whereby capacitor 9 is charged. Below this can be seen switching peaks D generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the + pole of the power source, whereby capacitor 9 is recharged. Shown below this are switching peaks E generated by processor 6, during which the - terminal of capacitor 9 is connected to the gate and the + terminal to the - pole of the power source, whereby capacitor 9 is recharged. Below this can be seen switching peaks F generated by processor 6, during which the + terminal of capacitor 9 is connected to the gate and the - terminal to the - pole of the power source, whereby capacitor 9 is recharged.
Fig. 4A shows schematically a possible embodiment of a switching group 8 for suppressing positive and negative interference signals at a gate of a MOSFET 1. In the case of a positive interference signal the + terminal of capacitor 9 is connected via a MOSFET 12 to the gate of MOSFET 1 using a switch line 11 , while the - terminal is connected via a MOSFET 13 to the + terminal of the power source using switch line 11. In the case of a negative interference signal the - terminal of capacitor 9 is connected via a MOSFET 15 to the gate of MOSFET 1 using a switch line 14, while the + terminal is connected via a MOSFET 16 to the + terminal of the power source. It will be apparent that at least four of these switching groups are required for a full H- bridge. If desired, the switching groups can be accommodated in a MOSFET gate array known in the field.
For a motor control which operates at a repetition frequency of for instance 15 kilohertz and can for instance produce 50 ampere from a 24 V battery, the interference signals will generally contain so much energy that capacitor 9 must have a value of at least 10 farad. The specifications of the MOSFETs forming part of the switching group must of course be adapted hereto. Fig. 4B shows schematically a possible embodiment of a transformer for feeding back energy to the power source. Capacitor 9 is connected via a MOSFET 17 to the + pole of the power source and via a further MOSFET 18 to a coil 19 which is connected to the + pole of the power source. If none of the switching groups is active, MOSFETs 17, 18 are then activated such that a charge can flow out of capacitor 9 and can build up a current in coil 19. When a switching group becomes active, MOSFETs 17, 18 are then no longer activated and the energy present in coil 19 is fed back to the power source via a diode 20. In the above described embodiment the inventive device is applied for the purpose of suppressing interference superimposed on the gate signals of four MOSFETs forming part of an H-bridge and reusing the energy present in these interference signals. The gate signals of other types of motor control and the actual control signals for electric motor 3 can of course also be filtered in the same manner.

Claims

1. Motor control for controlling a pulse-controlled electric motor (3) for the purpose of rotating the electric motor at an adjustable rotation speed, wherein the motor control is provided with at least four MOSFETs (1a, 1b, 1c, 1d) which are arranged in at least two half-bridges, and a control unit (2) for controlling the MOSFETs, wherein the motor control is provided with a device for suppressing periodic interference signals superimposed on a periodic control signal which comes from the control unit and which is intended for the purpose of controlling the MOSFETs, characterized in that the device comprises a measuring member (4) for measuring the control signal with the interference signals superimposed thereon, and a processor (6) for deriving at least one switching signal from the measuring signal, in addition to at least one switch member (7) for switching on and off a capacitive load (9) for the control signal such that the interference signals are at least substantially wholly suppressed, and that the device also comprises at least one transformer (10) for feedback of energy collected in the capacitive load to a power source for the control signal.
2. Motor control as claimed in claim , characterized in that the processor (6) is adapted to derive from the measuring signal at least two switching signals for operating a first and a second pair of switches for the purpose of switching on and off the capacitive load (9) for respectively positive interference signals and negative interference signals.
3. Motor control as claimed in any of the foregoing claims,
characterized in that the measuring member comprises an analog/digital converter (5).
4. Motor control as claimed in any of the foregoing claims,
characterized in that a switch member comprises at least one MOSFET (11, 12).
5. Motor control as claimed in any of the foregoing claims,
characterized in that the transformer (10) comprises a self-inductance (19) and is adapted to feed energy collected in the capacitive load (9) to a self- inductance and to then feed energy stored in the self-inductance to the power source.
PCT/NL2011/050611 2010-09-08 2011-09-08 Improved motor control for the control of a pulse controlled electric motor WO2012033406A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP11767813.6A EP2614587A1 (en) 2010-09-08 2011-09-08 Improved motor control for the control of a pulse controlled electric motor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1038228 2010-09-08
NL1038228A NL1038228C2 (en) 2010-09-08 2010-09-08 METHOD AND APPARATUS FOR SUPPRESSION OF INTERFERENCE SIGNALS SUPPRESSED ON A PERIODIC CONTROL SIGNAL.

Publications (1)

Publication Number Publication Date
WO2012033406A1 true WO2012033406A1 (en) 2012-03-15

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Application Number Title Priority Date Filing Date
PCT/NL2011/050611 WO2012033406A1 (en) 2010-09-08 2011-09-08 Improved motor control for the control of a pulse controlled electric motor

Country Status (3)

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EP (1) EP2614587A1 (en)
NL (1) NL1038228C2 (en)
WO (1) WO2012033406A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60148374A (en) * 1984-01-09 1985-08-05 Fuji Electric Co Ltd Dc/dc converter
US6111449A (en) * 1998-07-06 2000-08-29 Mitsubishi Denki Kabushiki Kaisha Clamping circuit for absorbing ringing of signal

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60148374A (en) * 1984-01-09 1985-08-05 Fuji Electric Co Ltd Dc/dc converter
US6111449A (en) * 1998-07-06 2000-08-29 Mitsubishi Denki Kabushiki Kaisha Clamping circuit for absorbing ringing of signal

Also Published As

Publication number Publication date
EP2614587A1 (en) 2013-07-17
NL1038228C2 (en) 2012-03-12

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