Inverter type AC generator

• US 20060193158A1
• Filed: 02/07/2006
• Published: 08/31/2006
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: Yamaha Motor Power Products Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Motor Power Products Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Uchino, Takashi, Fukaya, Mitsuo
• Granted Patent: US 7,652,900 B2
• Time in Patent Office: Days
• US Class Current: 363/132
• CPC Class Codes: H02J 3/40 Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel

Abstract

An inverter type AC generator includes an inverter circuit converting a DC output into AC output of a predetermined frequency and supplying the AC output to a load via a load line in order to improve the quality of an AC output waveform at least in parallel operations. The inverter AC generator includes a zero-crossing detection circuit for detecting a timing of zero-crossings of an AC output voltage waveform on the output line. A controller generates a drive signal in synchronization with the timing of the detected zero-crossings, when a predetermined number of zero-crossings have been detected, and drives the inverter to perform a synchronized operation process.

Claims

1. An inverter type AC generator for converting DC output from a DC power source generating unit into AC output of a predetermined frequency and capable of supplying the AC output to a load via an output line, comprising:

a zero-crossing detection circuit configured to detect at least one zero-crossing of an AC output waveform on the output line; and

a controller configured to generate a drive signal in synchronization with a timing of the at least one zero-crossing detected by the zero-crossing detection circuit when the at least one detected zero-crossing meets a predetermined condition, the controller configured to drive the inverter via the drive signal to perform a synchronized operation process.

2. The AC generator according to claim 1, further comprising

a storage unit configured to store a plurality of control programs, the control programs configured to generate drive signals for a plurality of preset frequencies,

wherein the controller calculates a frequency of the AC output based on the timing of the at least one zero-crossing detected by the zero-crossing detection circuit, the controller executing one of the plurality control programs stored in the storage unit that corresponds to the calculated frequency to generate the drive signal.

3. The AC generator according to claim 2,

wherein the controller discontinues the synchronized operation process when a variation in the frequency of the AC output exceeds a predetermined threshold value, the controller configured to execute a normal operation process to drive the inverter via a drive signal generated based on an internally generated timing signal.

4. The AC generator according to claim 2, wherein the controller executes the normal operation process to drive the inverter based on the internally generated timing signal when the zero-crossing detection circuit does not detect at least one zero-crossing.

5. The AC generator according to claim 1, wherein the predetermined condition is the number of detected zero-crossings.

6. An inverter type AC generator for converting DC output from a DC power source generating unit into AC output of a predetermined frequency and capable of supplying the AC output to a load via an output line, comprising:

a zero-crossing detection circuit configured to detect at least one zero-crossing of an AC output waveform on the output line; and

means for generating a drive signal synchronized with a timing of the at least one zero-crossing detected by the zero-crossing detection circuit when the at least one detected zero-crossing meets a predetermined condition, said means driving the inverter via the drive signal to perform a synchronized operation process.

7. The inverter type AC generator according to claim 6, wherein said means for generating the drive signal includes means for calculating a frequency of the AC output based on the timing of the at least one detected zero-crossing, said means for generating the drive signal also executing one of a plurality control programs corresponding to the calculated frequency to generate the drive signal.

8. A method for synchronizing the operation of an inverter type AC generator, comprising:

monitoring a frequency of an AC output waveform;

generating a drive signal in synchronization with said frequency when a predetermined condition is met; and

driving an inverter with said drive signal to perform a synchronized operation process.

9. The method of claim 8, wherein monitoring includes detecting at least one zero-crossing in the AC output waveform, and wherein the drive signal is generated in synchronization with a timing of the at least one detected zero-crossing when the detection of the at least one zero-crossing meets the predetermined condition.

10. The method of claim 9, wherein the predetermined condition is the number of detected zero-crossings.

11. The method of claim 9, further comprising:

calculating a frequency of the AC output based on the timing of the at least one detected zero-crossing; and

executing a control program corresponding to the calculated frequency to generate the drive signal.

12. The method of claim 8, further comprising:

discontinuing the synchronized operation process when a variation in the frequency of the AC output exceeds a predetermined threshold value;

generating the drive signal based on an internally generated timing signal; and

driving an inverter.

13. The method of claim 9, further comprising:

discontinuing the synchronized operation process when a variation in the frequency of the AC output exceeds a predetermined threshold value;

generating the drive signal based on an internally generated timing signal; and

driving an inverter.

14. The method of claim 13, wherein the inverter is driven based on the internally generated timing signal when the number of detected zero-crossings is zero.