Three-phase AC-to-AC series resonant power converter with reduced number of switches

• US 5,010,471 A
• Filed: 06/26/1989
• Issued: 04/23/1991
• Est. Priority Date: 06/26/1989
• Status: Expired due to Fees

• Current Assignee: Robert F. Frijouf, Electronic Power Conditioning Incorporated (Schneider Electric SE)
• Original Assignee: Robert F. Frijouf
• Inventors: Klaassens, J. Ben, de Beer, Freddy, Lauw, Hian K.
• Primary Examiner(s): Beha, Jr., William H.
• Application Number:
  US07/371,712
• Time in Patent Office: 666 Days
• Field of Search: 363/9, 363/10, 363/28, 363/157, 363/159-162, 363/164, 363/165
• US Class Current: 363/160
• CPC Class Codes: H02M 5/225 comprising two stages of AC-AC conversion, e.g. having a high frequency intermediate link
• CPC Class Codes: H02M 5/271 from a three phase input voltage
• CPC Class Codes: H02M 7/4826 operating from a resonant DC source, i.e. the DC input voltage varies periodically, e.g. resonant DC-link inverters

Abstract

An apparatus and method is disclosed for an improved AC--AC series-resonant converters incorporating power pulse modulation with internal frequencies of tens of kHz is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow and low distortion. The high pulse frequency allows the application of the principle of modulation and demodulation for fast system response. Switches are required which have bidirectional current conduction and voltage blocking ability. The conventional series-resonant AC--AC converter applies a total of 24 anti-parallel thyristors. The circuit configuration of the present invention is a series-resonant AC--AC converter with only 12 thyristors. Use of the converter results in a higher efficiency and lower costs. The alternative power circuit has three neutrals, related to the polyphase source, the load and the converter, which may be interconnected and the high-frequency component of the source and load currents will flow through the connection between the neutrals.

Claims

1. An improved resonant converter for transferring electrical power between a first, second and third input and a first, second and third output, comprising:

a series resonant circuit including a capacitor and an inductor connected in series;

first, second and third bidirectional input switch means connecting the first, second and third inputs to said series resonant circuit, respectively;

first, second and third bidirectional output switch means connecting the first, second and third outputs to said series resonant circuit, respectively;

first, second and third input capacitor means connected to the first, second and third inputs, respectively;

first, second and third output capacitor means connected to the first, second and third outputs, respectively; and

means connecting said first, second and third input capacitor means to said first, second and third output capacitor means for enabling only six bidirectional switches to interconnect the first, second and third inputs to the first, second and third outputs.

2. An improved resonant converter for transferring electrical power as set forth in claim 1, wherein each of said bidirectional input switch means and each of said bidirectional output switch means includes a pair of unidirectional switches connected in parallel with reverse polarity.

3. An improved resonant converter for transferring electrical power as set forth in claim 1, wherein said first bidirectional input switch means and said first bidirectional output switch means interconnect the first input with the first output with said series resonant circuit being interposed between the said first bidirectional input switch means and said first bidirectional output switch means;

said second bidirectional input switch means and said second bidirectional output switch means interconnect the second input with the second output with said series resonant circuit being interposed between the said second bidirectional input switch means and said second bidirectional output switch means; and

said third bidirectional input switch means and said third bidirectional output switch means interconnect the third input with the third output with said series resonant circuit being interposed between the said third bidirectional input switch means and said third bidirectional output switch means.

4. An improved resonant converter for transferring electrical power as set forth in claim 1, wherein said first, second and third input capacitor means are connected in series with said first, second and third output capacitor means between the first, second and third inputs and the first, second and third outputs, respectively.

5. An improved resonant converter for transferring electrical power as set forth in claim 1, wherein said first, second and third input capacitor means are connected in series with said first, second and third output capacitor means between the first, second and third inputs and the first, second and third outputs, respectively;

said series resonant circuit being connected in parallel with said first, second and third input and output capacitor means between the first, second and third inputs and the first, second and third outputs.

6. An improved three phase AC to AC series resonant converter for transferring electrical power between a first, second and third phase input and a first, second and third phase output, comprising:

a series resonant circuit including a capacitor and an inductor connected in series;

first, second and third bidirectional input switch means connecting the first, second and third phase inputs to said series resonant circuit, respectively;

first, second and third bidirectional output switch means connecting the first, second and third phase outputs to said series resonant circuit, respectively;

first, second and third input capacitor means connected to the first, second and third phase inputs, respectively;

first, second and third output capacitor means connected to the first, second and third phase outputs, respectively; and

means connecting said first, second and third input capacitor means in series with said first, second and third output capacitor means, respectively, for enabling only six bidirectional switches to interconnect the first, second and third phase inputs to the first, second and third phase outputs.

7. An improved three phase AC to AC series resonant converter for transferring electrical power between a first, second and third phase input and a first, second and third phase output, comprising:

a series resonant circuit including a capacitor and an inductor with said capacitor being connected in series with said inductor;

first, second and third bidirectional input switch means

first, second and third bidirectional output switch means;

said first bidirectional input switch means and said first bidirectional output switch means interconnecting the first phase input with the first phase output with said series resonant circuit being interposed between the said first bidirectional input switch means and said first bidirectional output switch means;

said second bidirectional input switch means and said second bidirectional output switch means interconnecting the second phase input with the second phase output with said series resonant circuit being interposed between the said second bidirectional input switch means and said second bidirectional output switch means;

said third bidirectional input switch means and said third bidirectional output switch means interconnecting the third phase input with the third phase output with said series resonant circuit being interposed between the said third bidirectional input switch means and said third bidirectional output switch means;

first, second and third input capacitor means;

first, second and third output capacitor means;

said first, second and third input capacitor means being connected in series with said first, second and third output capacitor means between the first, second and third inputs and the first, second and third outputs, respectively; and

said first, second and third input and output capacitor means being connected in parallel to said series resonant circuit between the first, second and third inputs and outputs for enabling for enabling only six bidirectional switches to interconnect the first, second and third phase inputs to the first, second and third phase outputs.