Control system for multiphase electric rotating machine

• US 8,395,338 B2
• Filed: 12/16/2008
• Issued: 03/12/2013
• Est. Priority Date: 01/09/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kuroda, Masahiro, Ueda, Nobumasa, Taki, Hiroshi
• Primary Examiner(s): Benson, Walter
• Assistant Examiner(s): GLASS, ERICK DAVID
• Application Number:
  US12/314,716
• Publication Number:
  US 20090174350A1
• Time in Patent Office: 1,547 Days
• Field of Search: 318/400.11, 318/400.32, 318/400.34, 318/459, 318/599, 318/811, 363/109, 363/98
• US Class Current: 318/400.11
• CPC Class Codes: H02M 7/53875 with analogue control of three-phase output
• CPC Class Codes: H02P 6/20 Arrangements for starting H02P6/08 takes precedence

Abstract

A control system controls a multiphase rotating machine by a 120° energization process and a PWM process. In the 120° energization process, respective ones of switching elements of a high side arm and switching elements of a low side arm of a power conversion circuit are turned on. In the PWM process, the switching elements of the power conversion circuit turn on/off so that two phases that are connected to the switching elements that are in the on-state are alternately rendered conductive to the high potential side input terminal and the low potential side input terminal of the power conversion circuit.

Claims

1. A control system for a multiphase rotating machine comprising:

a power conversion circuit including a plurality of switching elements, which is formed of high potential side switching elements connecting respective phases of the multiphase rotating machine to a high potential side input terminal of the power conversion circuit, and low potential side switching elements connecting the respective phases to a low potential input terminal of the power conversion circuit, the power conversion circuit rendering a first phase of the multiphase rotating machine conductive to the high potential side input terminal of the power conversion circuit, and rendering a second phase conductive to the low potential side input terminal of the power conversion circuit to apply a voltage of a rectangular waveform to the multiphase rotating machine; and

a control unit for operating the switching elements so as to alternately change over between a first state in which the first phase is rendered conductive to the high potential side input terminal through a high potential side switching element of the first phase and the second phase is rendered conductive to the low potential side input terminal through a low potential side switching element of the second phase, respectively, and a second state in which the first phase is rendered conductive to the low potential side input terminal through a low potential side switching element of the first phase and the second phase is rendered conductive to the high potential side input terminal through a high potential side switching element of the second phase, respectively, so as to modulate the voltage of the rectangular waveform in pulse width, wherein

the control unit is configured to control all switching elements of the plurality of switching elements forming the first state and the second state by pulse width modulation as the first state and the second state are alternately changed over.

2. The control system for multiphase rotating machine according to claim 1, further comprising:

a detector for detecting a rotation angle of the rotating machine by using an induced voltage, which appears in a terminal voltage of the rotating machine, the rotation angle being used to apply the voltage of the rectangular waveform based on detection of a zero-cross timing, at which the terminal voltage becomes a neutral-point voltage.

3. The control system for multiphase rotating machine according to claim 1, wherein:

the control unit conducts a pulse width modulation process when at least one of a rotating speed, a torque, and a current of the multiphase rotating machine is limited, and applies the voltage of the rectangular waveform directly to the multiphase rotating machine when no limitation is requested.

4. The control system for multiphase rotating machine according to claim 1, wherein:

the power conversion circuit further includes rectifying parts that are connected in parallel to the switching elements and define a direction to the high potential side switching element side as a forward direction; and

the switching elements allows a current to flow bi-directionally.

5. The control system for multiphase rotating machine according to claim 1, wherein:

the control unit is configured to perform the pulse width modulation during a predetermined period, in which the first phase is conductive to the high potential side input terminal and the second phase is conductive to the low potential side input terminal.

6. A control system for a multiphase rotating machine comprising:

a power conversion circuit including a plurality of switching elements, which is formed of high potential side switching elements connecting respective phases of the multiphase rotating machine to a high potential side input terminal of the power circuit, and low potential side switching elements connecting the respective phases to a low potential input terminal of the power conversion circuit, the power conversion circuit putting a specific phase of the multiphase rotating machine into a high impedance state in which neither of a high potential side input terminal nor a low potential side input terminal is rendered conductive, and sorting the remaining phases into two phases that are rendered conductive to the high potential side input terminal and rendered conductive to the low potential side input terminal; and

a control unit for operating the power conversion circuit so as to divide the two phases into a first phase and a second phase, and alternately rendering the first phase and the second phase conductive to the high potential side input terminal through a high potential side switching element thereof and the low potential side input terminal through a low potential side switch element thereof, respectively, wherein

the control unit is configured to control all switching elements forming the first phase and the second phase by pulse width modulation as the first phase and second phase are alternately rendered conductive to the high potential side input terminal and the low potential side input terminal.

7. The control system for multiphase rotating machine according to claim 6, wherein:

the power conversion circuit includes rectifying parts that are connected in parallel to the switching elements and define a direction to the high potential side switching element side as a forward direction; and

the switching elements allows a current to flow bi-directionally.

8. The control system for multiphase rotating machine according to claim 6, wherein:

the control unit is configured to perform the pulse width modulation during a predetermined period, in which the first phase is conductive to the high potential side input terminal and the second phase is conductive to the low potential side input terminal.

9. A control system for a multiphase rotating machine, comprising:

a power conversion circuit including a plurality of switching elements, the power conversion circuit rendering a first phase of the multiphase rotating machine conductive to a high potential side input terminal of the power conversion circuit, and rendering a second phase conductive to a low potential side input terminal of the conversion circuit to apply a voltage of a rectangular waveform to the multiphase rotating machine; and

a control unit for operating the switching elements so as alternately change over between a first state in which the first phase is rendered conductive to the high potential side input terminal and the second phase is rendered conductive to the low potential side input terminal, respectively, and a second state in which the first is rendered conductive to the low potential side input terminal and the second phase is rendered conductive to the high potential side input terminal, respectively, so as to modulate the voltage of the rectangular waveform in pulse width, wherein

each of the first phase and the second phase includes a high potential-side switching element and a low potential-side switching element connected in series between the high potential side input terminal and the low potential side input terminal,

the control unit is configured to control the high potential-side switching element and the low potential-side switching element of each phase to alternatively change between the first state and the second state and to obtain opposite states between an on-state and an off-state, and

the control unit is configured to control the high potential-side switching element and the low potential-side switching element of each phase by width modulation in each of the first state, the second state, the on-state, and the off-state.