Output voltage controller for AC vehicle generator

• US 7,944,183 B2
• Filed: 03/07/2006
• Issued: 05/17/2011
• Est. Priority Date: 03/07/2006
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nishimura, Shinji
• Primary Examiner(s): Patel; T. C.
• Assistant Examiner(s): Cuevas; Pedro J
• Application Number:
  US12/094,536
• Publication Number:
  US 20090212625A1
• Time in Patent Office: 1,897 Days
• Field of Search: 322/25, 322/28, 322/73, 290/3, 123/198.R
• US Class Current: 322/28
• CPC Class Codes: H02J 7/243 with on/off action
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage
• CPC Class Codes: H02P 9/305 controlling voltage H02P9/302 takes precedence
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

An output voltage controller for an AC vehicle generator is proposed. The output voltage controller can easily suppress variation in rectified output voltage due to a switching surge without using a slope generation circuit in a voltage adjustment circuit. An excitation circuit that excites a field coil 13 includes a circulation element 31, a semiconductor switch element 33, an inductor 35, and transient voltage absorption means 40. The circulation element 31 is connected in parallel to the field coil 13. The semiconductor switch element 33 is connected in series with the field coil 13 and turned on and off by a voltage adjustment circuit 60. The inductor 35 is connected in series with the field coil 13 and the semiconductor switch element 33. The transient voltage absorption means 40 absorbs a transient voltage generated in the inductor 35 in association with the switching of the semiconductor switch element 33 between ON and OFF.

Claims

1. An output voltage controller for an AC vehicle generator including an armature coil and a field coil and driven by a motor equipped in the vehicle so that an AC output voltage is generated in the armature coil, the output voltage controller comprising:

a rectifier that rectifies the AC output voltage to produce a rectified output voltage;

an excitation circuit that excites the field coil by using the rectified output voltage;

a circulation element provided in the excitation circuit and connected in parallel to the field coil;

a semiconductor switch element provided in the excitation circuit and connected in series with the field coil;

a voltage adjustment circuit that turns the semiconductor switch element on and off based on the rectified output voltage and adjusts the rectified output voltage to a level within a predetermined range;

an inductor provided in the excitation circuit and connected in series with the field coil and the semiconductor switch element; and

transient voltage absorption means provided in the excitation circuit, the transient voltage absorption means absorbing a transient voltage generated in the inductor in association with the switching of the semiconductor switch element between ON and OFF.

2. The output voltage controller for an AC vehicle generator according to claim 1,

wherein the transient voltage absorption means is a capacitor.

3. The output voltage controller for an AC vehicle generator according to claim 2,

wherein the circulation element is a Schottky diode.

4. The output voltage controller for an AC vehicle generator according to claim 2,

wherein the capacitor is connected to a branch circuit that is disposed in parallel to the field coil and the semiconductor switch element, and

when the semiconductor switch element is switched from ON to OFF, the transient voltage generated in the inductor charges the capacitor.

5. The output voltage controller for an AC vehicle generator according to claim 2,

wherein the capacitor is connected to a branch circuit that is disposed in parallel to the semiconductor switch element, and

when the semiconductor switch element is switched from ON to OFF, the transient voltage generated in the inductor charges the capacitor.

6. The output voltage controller for an AC vehicle generator according to claim 5,

wherein the output voltage controller further comprises a first diode connected to the branch circuit in series with the capacitor, and

the first diode is connected in such a way that the polarity thereof allows the capacitor to be charged by the transient voltage when the semiconductor switch element is switched from ON to OFF.

7. The output voltage controller for an AC vehicle generator according to claim 6, further comprising a first resistor connected to the branch circuit in series with the capacitor and the first diode.

8. The output voltage controller for an AC vehicle generator according to claim 7, further comprising a second resistor connected to a branch circuit that is disposed in parallel to the first diode and the first resistor.

9. The output voltage controller for an AC vehicle generator according to claim 5,

wherein that the output voltage controller further comprises a second diode disposed in the excitation circuit, and

the second diode is connected in such a way that the polarity thereof allows the capacitor to discharge through the field coil and the semiconductor switch element when the semiconductor switch element is switched from OFF to ON.