INTERCONNECTION INVERTER DEVICE

• US 20120075899A1
• Filed: 07/30/2009
• Published: 03/29/2012
• Est. Priority Date: 07/30/2009
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Nishio, Naoki
• Granted Patent: US 8,593,844 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode

Abstract

The interconnection point of capacitors C1, C2 is connected with one end of an electric power system and one end of a reactor L. First switch section (S1, D1) is connected, at its respective ends, to the positive electrode of the direct-current DC power source, and to the other end of the reactor L. One end of a second switch section (S2, D2) is connected to the negative electrode of the DC power source, while the other end is connected to the other end of the reactor L. One end of a third switch section (S3, D3) is connected to the other end of the reactor L, while the other end is connected to the other end of the electric power system. One end of a fourth switch section (S4, D4) is connected to the other end of the reactor L, while the other end is connected to the other end of the electric power system.

Claims

1. An interconnection inverter device for converting direct-current power fed from a direct-current power source to alternating-current power to interconnect to an electric power system, the interconnection inverter device comprising:

first and second capacitors which are connected in series to both ends of the direct-current power source and an interconnection point of which is connected to one end of the electric power system;

a reactor with one end connected to the connection point between the first capacitor and the second capacitor;

a first switch section with one end connected to a positive electrode of the direct-current power source and the other end connected to the other end of the reactor;

a second switch section with one end connected to a negative electrode of the direct-current power source and the other end connected to the other end of the reactor;

a third switch section with one end connected to the other end of the reactor and the other end connected to the other end of the electric power system;

a fourth switch section with one end connected to the other end of the reactor and the other end connected to the other end of the electric power system; and

a third capacitor connected to both ends of the electric power system in parallel thereto.

6. The interconnection inverter device according to claim 1, wherein

the first switch section is controlled to be OFF during a positive half cycle of a system voltage and PWM-controlled during a negative half cycle,

the second switch section is PWM-controlled during the positive half cycle of the system voltage and controlled to be OFF during the negative half cycle,

the third switch section is controlled to be OFF during the positive half cycle of the system voltage and controlled to be ON during the negative half cycle, and

the fourth switch section is controlled to be ON during the positive half cycle of the system voltage and controlled to be OFF during the negative half cycle.

7. The interconnection inverter device according to claim 6, further comprising a system voltage detection section for detecting an output voltage from the electric power system as the system voltage.

8. The interconnection inverter device according to claim 1, further comprising:

a system voltage detection section for detecting an output voltage from the electric power system as the system voltage; and

a system current detection section for detecting a current flowing into and out of the electric power system as a system current, and wherein

when the system voltage has a positive polarity and the system current has a negative polarity, the second and fourth switch sections are controlled to be OFF, the first switch section is controlled to be ON, and the third switch section is PWM controlled,

when the system voltage has a positive polarity and the system current has a positive polarity, the first and third switch sections are controlled to be OFF, the fourth switch section is controlled to be ON, and the second switch section is PWM controlled,

when the system voltage has a negative polarity and the system current has a positive polarity, the first and third switch sections are controlled to be OFF, the second switch section is controlled to be ON, and the fourth switch section is PWM controlled, and

when the system voltage has a negative polarity and the system current has a negative polarity, the second and fourth switch sections are controlled to be OFF, the third switch section is controlled to be ON, and the first switch section is PWM controlled.

2. An interconnection inverter device for converting direct-current power fed from a direct-current power source to alternating-current power to interconnect to an electric power system, the interconnection inverter device comprising:

first and second capacitors which are connected in series to both ends of the direct-current power source and an interconnection point of which is connected to one end of the electric power system;

a reactor with one end connected to the connection point between the first capacitor and the second capacitor;

a first switch section actuated when energy from the first capacitor is stored in the reactor;

a second switch section actuated when energy from the second capacitor is stored in the reactor;

a third switch section actuated when the energy stored in the reactor is supplied by the actuation of the first switch section to the electric power system;

a fourth switch section actuated when the energy stored in the reactor is supplied by the actuation of the second switch section to the electric power system; and

a third capacitor connected to both ends of the electric power system in parallel thereto.

3. The interconnection inverter device according to claim 2, wherein

the first switch section is controlled to be OFF during a positive half cycle of a system voltage and PWM-controlled during a negative half cycle,

the second switch section is PWM-controlled during the positive half cycle of the system voltage and controlled to be OFF during the negative half cycle,

the third switch section is controlled to be OFF during the positive half cycle of the system voltage and controlled to be ON during the negative half cycle, and

the fourth switch section is controlled to be ON during the positive half cycle of the system voltage and controlled to be OFF during the negative half cycle.

4. The interconnection inverter device according to claim 3, further comprising a system voltage detection section for detecting an output voltage from the electric power system as the system voltage.

5. The interconnection inverter device according to claim 2, further comprising:

a system voltage detection section for detecting an output voltage from the electric power system as the system voltage; and

a system current detection section for detecting a current flowing into and out of the electric power system as a system current, and wherein

when the system voltage has a positive polarity and the system current has a negative polarity, the second and fourth switch sections are controlled to be OFF, the first switch section is controlled to be ON, and the third switch section is PWM controlled,

when the system voltage has a positive polarity and the system current has a positive polarity, the first and third switch sections are controlled to be OFF, the fourth switch section is controlled to be ON, and the second switch section is PWM controlled,

when the system voltage has a negative polarity and the system current has a positive polarity, the first and third switch sections are controlled to be OFF, the second switch section is controlled to be ON, and the fourth switch section is PWM controlled, and

when the system voltage has a negative polarity and the system current has a negative polarity, the second and fourth switch sections are controlled to be OFF, the third switch section is controlled to be ON, and the first switch section is PWM controlled.