Unlock instant, AI-driven research and patent intelligence for your innovation.

Power conversion device and power conversion system

a technology of power conversion device and power conversion system, which is applied in the direction of dc-ac conversion without reversal, ac network to reduce harmonics/ripples, emergency protective arrangements for limiting excess voltage/current, etc., and can solve the problem of increasing the size of the power conversion device and the increase of the leakage curren

Active Publication Date: 2018-09-27
KK TOSHIBA
View PDF6 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a power conversion device and system that can suppress leakage current while avoiding upsizing of the device. The invention includes a function that can extract a common mode current and a DC link filter circuit with a Y-shaped capacitor to approximate the leakage current to 0 A. The invention also includes a first power conversion circuit and a second power conversion circuit connected via a DC link part, which can be parallelized for increased efficiency. The invention can be applied to a power conditioner and can be used in a power conversion device. The technical effects of the invention include reducing the size of the power conversion device and suppressing electromagnetic noises.

Problems solved by technology

However, any of the measures has a problem leading to upsizing of a power conversion device.
In this case, if a large-capacity capacitor is selected for producing a noise suppressing effect near a low frequency, increase in the leakage current is provoked.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Power conversion device and power conversion system
  • Power conversion device and power conversion system
  • Power conversion device and power conversion system

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0017]Hereinafter, the first embodiment will be described with reference to FIG. 1. FIG. 1 shows a power conversion device having a three-phase AC input / three-phase AC output configuration. A power conversion device 1 includes a converter 2 disposed on an input side and corresponding to a first power conversion circuit. Three-phase input terminals of the converter are connected to respective phase terminals of a three-phase AC power supply 3 via an external impedance adjustment circuit 4. The external impedance adjustment circuit 4 includes coils 4u, 4v and 4w corresponding to the respective phases.

[0018]Moreover, to the three-phase input terminals of the converter 2, a first common mode extraction circuit 5 is connected. The first common mode extraction circuit includes, for example, not-shown capacitors corresponding to the respective phases; one ends of the three capacitors are connected to the respective corresponding phases, and the other ends are connected in common to a virtu...

second embodiment

[0023]Hereinafter, same parts as those in the first embodiment are assigned with the same reference signs and descriptions thereof are omitted, while different parts will be described. FIG. 2 partially shows a configuration of a DC link filter circuit 21 of the second embodiment alternative to the DC link filter circuit 9. In the DC link filter circuit 21, a coil 22 is inserted between the common connection point of the Y-shaped capacitor 12 and the virtual neutral potential line 6. By use of such a DC link filter circuit is possible to increase selectivity of frequency to suppress the leakage current.

third embodiment

[0024]A power conversion device 23 of the third embodiment shown in FIG. 3 shows each component of the power conversion device 1 of the first embodiment more specifically and changes a part of the configuration. The first common mode extraction circuit 5 includes, as described in the first embodiment, capacitors 5u, 5v and 5w corresponding to the respective phases. A second common mode extraction circuit 16 includes capacitors 16u, 16v and 16w corresponding to the respective phases, and common mode choke coils 16A, 16E and 16C connected between these capacitors and the virtual neutral potential line 6.

[0025]Each of the converter 2 and the inverter 9 is configured by connecting six switching elements in a three-phase bridge configuration. To each switching element, a return diode is connected in anti-parallel, and between arms of the respective phases, capacitors are connected in parallel. Note that, as to a motor 15, together with stator coils 15u, 15v and 15w of the respective phas...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A power conversion device includes: a first power conversion circuit that converts power inputted from outside and outputs the converted power to a second power conversion circuit connected to the first power conversion circuit via a DC link, which outputs the converted power to a load; smoothing capacitors provided in an output part of the first power conversion circuit and an input part of the second power conversion circuit; a first and second common mode current extraction circuits provided in an input part of the first power conversion and second power conversion circuits; and a virtual neutral potential line that connects the first and second common mode current extraction circuits; a DC link filter circuit that includes a Y-shaped capacitor connected between the DC link part and the virtual neutral potential line.

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]Embodiments of the present invention relate to a device and a system that convert power inputted from the outside and output the converted power to a load.Description of the Related Art[0002]For example, when a metal material included in a power conversion device, such as an inverter or a load device, such as a motor, is disposed to face a ground potential, a parasitic capacitance is formed therebetween, and a leakage current is generated via the parasitic capacitance. Since the leakage current leads to deterioration of machines or unexpected electrical shock, there is a need to approximate the leakage current to 0 A as much as possible. Moreover, due to advanced performance of a semiconductor switching element, an operating frequency of a power conversion device is increased. Since an impedance of the parasitic capacitance is reduced with increase in frequency, it becomes more significant to take measures against the leakage cu...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): H02M1/12H02J3/01H02H9/08H02M7/537
CPCH02M1/12H02J3/01H02H9/08H02M7/537H02M7/48H02M7/493H02M1/0038H02M1/123H02M5/458
Inventor HASEGAWA, KOHEIMAEKAWA, SARIYASUZUMI, TAKENORIKUZUMAKI, ATSUHIKO
Owner KK TOSHIBA