Rotary electric machine capable of detecting malfunction in switch

Patent metadata

Field	Value
Publication number	US-9716456-B2
Application number	US-201514694257-A
Country	US
Kind code	B2
Filing date	Apr 23, 2015
Priority date	Apr 23, 2014
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

In a rotary electric machine, a modulation signal generator generates a modulation signal including information indicative of rotation of a rotor based on change of a voltage at an output end of a stator winding, and outputs the modulation signal. A rectifying unit alternately turns on and off the switch to rectify the voltage at an output end of the stator winding, thus generating a rectified voltage. An excitation current supplying circuit is communicably connected to the modulation signal generator via a communication line, and starts a supply of an excitation current to the excitation winding of the rotor to induce a rotating magnetic field in the stator winding when the modulation signal output from the modulation signal generator is input thereto via the communication line.

First claim

What is claimed is:

1. A rotary electric machine comprising:
a stator winding having an output end;
a rotor including an excitation winding;
a switch connected to the output end of the stator winding;
a modulation signal generator configured to:
generate a modulation signal including information indicative of rotation of the rotor based on change of a voltage at the output end of the stator winding; and
output the modulation signal; and

a rectifying unit configured to alternately turn on and off the switch to rectify the voltage at the output end of the stator winding, thus generating a rectified voltage; and
an excitation current supplying circuit communicably connected to the modulation signal generator via a communication line and configured to start a supply of an excitation current to the excitation winding of the rotor to induce a rotating magnetic field in the stator winding when the modulation signal output from the modulation signal generator is input thereto via the communication line,
wherein:
the modulation signal generator is configured to:
output a first modulation signal that is the modulation signal, the first modulation signal having a duty factor and a signal variation range;
monitor the output end of the stator winding;
generate a second modulation signal when a result of the monitor represents one of: the voltage at the output end of the stator winding becoming equal to or higher than a predetermined value; and detection of a current flowing through the output end of the stator winding; and
output the second modulation signal to the communication line;
the second modulation signal being a pulse signal having a duty factor and a signal variation range, at least one of the duty factor and the signal variation range of the second modulation signal differing from a corresponding at least one of the duty factor and the signal variation range of the first modulation signal, and
the excitation current supplying circuit is configured to:
start the supply of the excitation current to the excitation winding of the rotor when instructed externally; and
control the supply of the excitation current to the excitation winding of the rotor to stabilize the rectified voltage when the second modulation signal output from the modulation signal generator is input thereto,
the stator winding includes multiphase stator windings, each of the multiphase stator windings having an output end;
the switch includes a plurality of switches connected to the respective multiphase stator windings;
the modulation signal generator includes a plurality of modulation signal generators provided for the respective multiphase stator windings;
the plurality of modulation signal generators and the excitation current supplying circuit are communicably connected to each other via the communication line; and
only one of the plurality of modulation signal generators is configured to generate the first and second modulation signals, and output the first and second modulation signal to the communication line.

2. The rotary electric machine according to claim 1 , wherein each of the plurality of modulation signal generators is configured to generate a third modulation signal, and output the third modulation signal to the excitation current supplying circuit and the other modulation signal generators when there is a malfunction in a corresponding one of the plurality of switches,
the third modulation signal differing from the first and second modulation signals, and including information indicative of at least an occurrence of the malfunction in a corresponding one of the plurality of switches.

3. The rotary electric machine according to claim 2 , wherein:
each of the plurality of switches includes a first switching element and a second switching element; and
each of the plurality of modulation signal generators is configured to generate the third modulation signal when there is a malfunction in one of the first and second switching elements of a corresponding one of the plurality of switches,
the third modulation signal including second information indicative of whether the malfunction has occurred in the first switching element or the second switching element of a corresponding one of the plurality of switches.

4. The rotary electric machine according to claim 3 , wherein:
each of the plurality of modulation signal generators is configured to:
determine that there is a short-circuit malfunction, as the malfunction, across the first switching element of a corresponding one of the plurality of switches when the second modulation signal is input thereto from an alternative one of the plurality of modulation signal generators, and the voltage at the output terminal of a corresponding one of the plurality of stator windings is equal to or higher than a first reference value for a first predetermined period; and
determine that there is a short-circuit malfunction, as the malfunction, across the second switching element of a corresponding one of the plurality of switches when the second modulation signal is input thereto from an alternative one of the plurality of modulation signal generators, and the voltage at the output terminal of a corresponding one of the plurality of stator windings is equal to or lower than a second reference value for a second predetermined period.

5. The rotary electric machine according to claim 3 , wherein
each of the plurality of modulation signal generators is configured to:
generate the third modulation signal when there is a short-circuit malfunction that is the malfunction across one of the first and second switching elements of a corresponding one of the plurality of switches; and
generate the third modulation signal when there is a temperature malfunction that is the malfunction in one of the first and second switching elements of a corresponding one of the plurality of switches.

6. The rotary electric machine according to claim 3 , wherein, when the third modulation signal is input to the excitation current supplying circuit is configured to:
notify an external circuit of information indicative of an occurrence of a malfunction; and
reduce a value of the excitation current supplied to the excitation winding of the rotor; and
the rectifying unit includes a plurality of rectifying units each configured to alternately turn on or off the first switching element and the second switching element of a corresponding one of the plurality of switches,
each of the plurality of rectifying units being configured to turn on a selected one of the first switching element and the second switching element of a corresponding one of the plurality of switches while turning off the other thereof, the malfunction having occurred in the selected one of the first switching element and the second switching element.

7. The rotary electric machine according to claim 6 , wherein:
the excitation current supplying circuit includes an excitation system for supplying the excitation current, and is configured to cause the excitation system to control the supply of the excitation current to the excitation winding of the rotor to thereby adjust the rectified voltage to a target regulated voltage, and is configured to:
generate a fourth modulation signal when the rectified voltage becomes higher than a predetermined threshold voltage due to a malfunction in the excitation system, the predetermined threshold voltage being set to be higher than the target regulated voltage; and
output the fourth modulation signal to the communication line; and
each of the plurality of rectifying units is configured to turn on a selected one of the first switching element and the second switching element of a corresponding one of the plurality of switches while turning off the o

Assignees

• Denso Corp

Inventors

• Maruyama Toshinori
• Inokuchi Takatoshi
• Nakanishi Masaya

Classifications

• H02J7/16

  Regulation of the charging current or voltage by variation of field · CPC title

• H02J7/163 Primary

  with special means for initiating or limiting the excitation current · CPC title

• H02P9/48

  Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle (H02P9/04 - H02P9/46 take precedence) · CPC title

• H02P23/00 Primary

  Arrangements or methods for the control of AC motors characterised by a control method other than vector control · CPC title

• H02P9/08

  Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation · CPC title