Three-level neutral point clamping type inverter circuit

• US 6,226,192 B1
• Filed: 04/14/2000
• Issued: 05/01/2001
• Est. Priority Date: 10/28/1997
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: Kumagae, Akira, Yamada, Kenji, Yamanaka, Katsutoshi, Terada, Takaaki
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): Laxton, Gary L.
• Application Number:
  US09/529,514
• Time in Patent Office: 382 Days
• Field of Search: 363/17, 363/52, 363/53, 363/58, 363/55, 363/56, 363/125, 363/127, 363/131, 363/132, 363/97, 363/98, 361/58, 361/111, 361/118
• US Class Current: 363/56.01
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/346 Passive non-dissipative snubbers
• CPC Class Codes: H02M 1/348 Passive dissipative snubbers
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

In a three-level neutral point clamping type inverter circuit which includes a positive bus line (4), a negative bus line (5) and a neutral line (6), wherein first and second IGBTs (11), (12) are connected in series between the positive bus line (4) and a phase voltage output terminal (10) and third and fourth IGBTs (13), (14) are connected in series between the negative bus line (5) and the phase voltage output terminal (10), the three-level neutral point clamping type inverter circuit further includes a first snubber capacitor (21) provided between the positive bus line (4) and the neutral line (6), a second snubber capacitor (22) provided between the negative bus line (5) and the neutral line (6), a first snubber diode (23) having a cathode coupled to the positive bus line (4) and an anode coupled to the phase voltage output terminal (10), and a second snubber diode (24) having an anode coupled to the negative bus line (5) and a cathode coupled to the phase voltage output terminal (10).

Claims

1. In a three-level neutral point clamping type inverter circuit which includes a positive bus line, a negative bus line and a neutral line, wherein a plurality of switching elements are connected in series between said positive bus line and a phase voltage output terminal and a plurality of switching elements are connected in series between said negative bus line and said phase voltage output terminal, said three-level neutral point clamping type inverter circuit is characterized by comprising:

a first snubber capacitor provided between said positive bus line and said neutral line;

a second snubber capacitor provided between said negative bus line and said neutral line;

a first snubber diode having a cathode coupled to said positive bus line and an anode coupled to said phase voltage output terminal; and

a second snubber diode having an anode coupled to said negative bus line and a cathode coupled to said phase voltage output terminal, wherein said first snubber capacitor has a first terminal directly connected to said neutral line and said second snubber capacitor has a first terminal directly connected to said neutral line.

2. In a three-level neutral point clamping type inverter circuit which includes a positive bus line, a negative bus line and a neutral line, wherein a plurality of switching elements are connected in series between said positive bus line and a phase voltage output terminal and a plurality of switching elements are connected in series between said negative bus line and said phase voltage output terminal, said three-level neutral point clamping type inverter circuit is characterized by comprising:

a first RCD snubber circuit having a first diode whose anode is coupled to said positive bus line, a first snubber capacitor coupled between a cathode of said first diode and said neutral line, and a first discharge resistor coupled in parallel to said first diode;

a second RCD snubber circuit having a second diode whose cathode is coupled to said negative bus line, a second snubber capacitor coupled between an anode of said second diode and said neutral line, and a second discharge resistor coupled in parallel to said second diode;

a first snubber diode having a cathode coupled to a connection point between said first diode of said first RCD snubber circuit and said first snubber capacitor and having an anode coupled to said phase voltage output terminal; and

a second snubber diode having an anode coupled to a connection point between said second diode of said second RCD snubber circuit and said second snubber capacitor and having a cathode coupled to said phase voltage output terminal.