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MarketScreener Homepage  >  Equities  >  Tokyo  >  Denso Corp    6902   JP3551500006

DENSO CORP

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Researchers Submit Patent Application, “Control Apparatus And Control Method For Rotating Electrical Machine”, for Approval (USPTO 20190229667): Denso Corporation

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08/14/2019 | 05:00pm EDT

2019 AUG 14 (NewsRx) -- By a News Reporter-Staff News Editor at Technology Business Daily -- From Washington, D.C., NewsRx journalists report that a patent application by the inventors NAKAOKA, Takuro (Kariya-city, Japan); FUJII, Kiyoshi (Kariya-city, Japan), filed on July 10, 2017, was made available online on July 25, 2019.

The patent’s assignee is Denso Corporation (Kariya-city, Aichi-pref., Japan).

News editors obtained the following quote from the background information supplied by the inventors: “Conventionally, idling stop is known which automatically stops an engine when a vehicle stops at an intersection, or the like.

“After idling stop is implemented, even during speed reduced rotation until the engine is stopped, there is, for example, a case where a driver performs operation for starting the vehicle in reaction to change of a traffic light from red to green. In this case, the vehicle requires quick restart of the engine in response to operation for starting the vehicle by the driver. To address this requirement, for example, there is a case where the engine is restarted using a motor generator (which will be also referred to as an ISG) in which a motor function and a power generation function are integrated. A revolving field type synchronous motor generator is sometimes used as the motor generator mounted on a vehicle. The revolving field type synchronous motor generator includes a field winding as a rotor, and includes an armature winding as a stator.

“However, when an engine is restarted using a synchronous motor generator, a field winding has large inductance. Therefore, a synchronous motor generator requires time to cause a field current to rise. That is, a time period from when a field current starts to be applied to a field winding until when the field current reaches a target value becomes long. As a result, it takes time to restart the engine.

“In contrast to this, PTL 1 discloses the following technique. In the technique disclosed in PTL 1, after a time period during which a rate of rise of a field current is relatively high has elapsed since the field current started to be applied to a field winding, a d-axis component of an armature current is applied to an armature winding in a direction in which a field magnetic flux caused by the field current is cancelled out. According to this technique, it is possible to cancel out voltage drop due to the self-inductance component of the field winding with a mutual inductance component of the field winding and the armature winding. By this means, it is possible to cause the field current to rise early. As a result, it is possible to shorten a time period until when the field current reaches a target value, so that it is possible to restart the engine quickly.”

As a supplement to the background information on this patent application, NewsRx correspondents also obtained the inventors’ summary information for this patent application: “Technical Problem

“With the technique disclosed in PTL 1, a rotation angle sensor which detects an angular position of a rotor is required to specify a d-axis of the rotor (a central axis of the field winding). That is, with the technique disclosed in PTL 1, a rotation angle sensor is essential, and the technique cannot be performed without a rotation angle sensor.

“The present disclosure provides a technique of controlling rotating electrical machine which is capable of detecting an angular position of a rotor without using a rotation angle sensor.

“Solution to Problem

“A control apparatus of rotating electrical machine which is one aspect of the technique of the present disclosure includes a rotor including a field winding and a stator including a polyphase armature winding. The control apparatus of the rotating electrical machine includes a field current control unit, a rotor position detecting unit and an armature current control unit. The field current control unit controls a field current applied to the field winding. The rotor position detecting unit detects an angular position of the rotor. The armature current control unit controls an armature current applied to the armature winding on the basis of the angular position of the rotor detected by the rotor position detecting unit. The rotor position detecting unit includes an induced voltage detecting unit and a rotor position judging unit. The induced voltage detecting unit detects induced voltages generated at respective phases of the armature winding while the field current applied to the field winding by the field current control unit rises toward a target value. The rotor position judging unit detects the angular position of the rotor on the basis of the induced voltages detected by the induced voltage detecting unit.

“The rotor position detecting unit of the present disclosure can detect the angular position of the rotor even while the rotor is stopped. During a period while the field current flowing through the field winding rises toward the target value, induced voltages are generated at the respective phases of the armature winding by temporal differentiation of a magnetic flux which interlinks with the armature winding. Therefore, the rotor position detecting unit of the present disclosure detects the induced voltages using the induced voltage detecting unit, and detects the angular position of the rotor using the rotor position judging unit on the basis of the detected induced voltages. By this means, with the technique of the present disclosure, it is not necessary to use an expensive rotation angle sensor to detect an angular position of a rotor. It is therefore possible to reduce cost.”

The claims supplied by the inventors are:

“1. A control apparatus of rotating electrical machine including a rotor including a field winding and a stator including a polyphase armature winding, the control apparatus comprising: a field current control unit configured to control a field current applied to the field winding; a rotor position detecting unit configured to detect an angular position of the rotor; and an armature current control unit configured to control an armature current applied to the armature winding on a basis of the angular position of the rotor detected by the rotor position detecting unit, wherein the rotor position detecting unit comprises: an induced voltage detecting unit configured to detect induced voltages generated at respective phases of the armature winding while the field current applied to the field winding by the field current control unit rises toward a target value; and a rotor position judging unit configured to detect the angular position of the rotor on a basis of the induced voltages detected by the induced voltage detecting unit.

“2. The control apparatus of rotating electrical machine according to claim 1, wherein the rotor position judging unit detects the angular position of the rotor on a basis of amplitude ratios and polarities of the induced voltages generated at the respective phases of the armature winding.

“3. The control apparatus of rotating electrical machine according to claim 1, wherein the rotor position judging unit detects the angular position of the rotor on a basis of magnitude relationship and polarities of the induced voltages generated at the respective phases of the armature winding.

“4. The control apparatus of rotating electrical machine according to claim 3, wherein the armature winding has six or more phases, and the rotor position judging unit has two or more thresholds for judging the magnitude relationship and the polarities of the induced voltages generated at the respective phases of the armature winding.

“5. The control apparatus of rotating electrical machine according to claim 3, wherein the armature current control unit advances or delays a phase of the armature current in a direction reducing an induced voltage of an intermediate phase among the magnitude relationship of the induced voltages generated at the respective phases of the armature winding.

“6. The control apparatus of rotating electrical machine according to claim 1, wherein, when a direction of a magnetic flux generated by a field pole of the rotor is defined as a d-axis, and a direction electrically orthogonal to the d-axis is defined as a q-axis, the armature current control unit divides the armature current to be applied to the armature winding into a current component in a direction of the d-axis and a current component in a direction of the q-axis, and applies the current component in the direction of the d-axis to the armature winding in a direction in which a field magnetic flux generated by the field current is cancelled out while the field current to be applied to the field winding by the field current control unit rises toward the target value.

“7. A control method of rotating electrical machine including a rotor including a field winding and a stator including a polyphase armature winding, the control method comprising: a field current control step of controlling a field current applied to the field winding; a rotor position detection step of detecting an angular position of the rotor; and an armature current control step of controlling an armature current applied to the armature winding on a basis of the detected angular position of the rotor, wherein the rotor position detection step comprising: an induced voltage detection step of detecting induced voltages generated at respective phases of the armature winding while the field current applied to the field winding by the field current control step rises toward a target value; and a rotor position judging step of detecting the angular position of the rotor on a basis of the detected induced voltages.”

For additional information on this patent application, see: NAKAOKA, Takuro; FUJII, Kiyoshi. Control Apparatus And Control Method For Rotating Electrical Machine. Filed July 10, 2017 and posted July 25, 2019. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220190229667%22.PGNR.&OS=DN/20190229667&RS=DN/20190229667

(Our reports deliver fact-based news of research and discoveries from around the world.)

Copyright © 2019 NewsRx LLC, Technology Business Daily, source Technology Newsletters

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