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Electric power converter

A power converter and voltage technology, applied in the direction of electrical components, output power conversion devices, etc., can solve problems such as difficulty in response speed

Inactive Publication Date: 2009-09-23
KK TOSHIBA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if the gate resistance is lowered, a surge voltage will be generated during the shutdown operation, so it is difficult to improve the response speed by using a gate resistance with a small resistance value.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] figure 1 It is a configuration diagram of the power converter according to Embodiment 1 of the present invention.

[0032] The switching circuits 10 and 20 represent, for example, one of the lower arms and one of the upper arms of the three-phase inverter, and are connected in series to the DC power supply DC1. The switching circuits 10 and 20 have the same structure, and the switching element 1 ( 21 ) and the freewheeling diode 2 ( 22 ) are connected in antiparallel to each other. exist figure 1 Although only the control circuit for controlling the switch circuit 10 is shown in the figure, the same control circuit may be configured for the switch circuit 20 .

[0033] The switching element 1 is driven by the gate circuit 3, and the element current Ic of the switching element 1 is controlled. The gate current Ig applied to the gate of the switching element 1 from the gate circuit 3 is detected by the gate current detection unit 4, and the detected value is input to t...

Embodiment 2

[0048] Figure 4 It is a configuration diagram of a power converter according to Embodiment 2 of the present invention. The same reference numerals are assigned to the same constituent elements as those in Embodiment 1, and detailed description thereof will be omitted. Compared with the first embodiment, the second embodiment is provided with a gate voltage detection unit 8 and a Miller period determination unit 9 . When the Miller period judging section 9 is in normal operation of the switching element 1, it will be as follows: figure 2 The period in which the gate current flows into the gate circuit 3 as shown and the gate voltage maintains a constant value is determined as the Miller period, and the surge voltage during the turn-off operation of the switching element 1 is prevented.

[0049] The Miller period judging section 9 refers to the output value of the comparing section 7b, and when the gate current value detected by the gate current detecting section 4 becomes t...

Embodiment 3

[0055] Figure 5 It is a configuration diagram of a power converter according to Embodiment 3 of the present invention. for with Figure 4 The same reference numerals are given to the same elements, and repeated descriptions are omitted.

[0056] In the third embodiment, a differentiating circuit 10 for differentiating the gate voltage detected by the gate voltage detecting unit 8 is provided. The Miller period determination unit 9 detects a period in which the differential value of the gate voltage obtained by the differentiating circuit 10 is zero as the Miller period.

[0057] In Example 2, the Miller period is determined when the gate current flows in the negative direction and the gate voltage is constant during normal operation. However, since this constant voltage varies depending on element characteristics, element current Ic, etc., reliability may not be maintained if it is judged to be a Miller period simply by comparing with a certain set voltage value. In order...

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PUM

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Abstract

The invention provides an electric power converter, comprising a grid current detection part, a first comparison part, a second comparison part and a short circuit judging part. The grid current detection part (4) detects grid current of a first switch element (1) in the first and the second switch elements connected mutually in parallel on a power source. The first and the second comparison parts (7a, 7b) respectively compare voltage corresponding to the grid current detected by the grid current detection part (4) with the reference positive voltage (V1) and the reference negative voltage (V2). The short circuit judging part (5) judges that the switch element makes short circuit on the power source when the voltage corresponding to the grid current becomes less than the reference negative voltage in a scheduled time from the time when the voltage corresponding to the grid current becomes more than the reference positive voltage (V1).

Description

technical field [0001] The present invention relates to a power converter using a switching element for electric power. Background technique [0002] The range of use of power converters using switching elements for electric power is steadily expanding along with the increase in capacity and speed of switching elements. Among such switching elements for electric power, particularly recently, the fields of application have been expanded to IGBTs and MOSFETs which are MOS gate switching elements. [0003] IGBTs and MOSFETs are non-latching switching elements that do not keep on / off by themselves. Compared with latching switching elements such as thyristors, it is possible to realize high controllability by gate drive. Big plus. In the event of a short circuit, the short circuit current can also be reduced by controlling the gate voltage of the switching element. Therefore, a power converter employing a short-circuit protection system controlled by the gate voltage of the IG...

Claims

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Application Information

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IPC IPC(8): H02M1/00H02M1/08
Inventor 松下晃久田井裕通
Owner KK TOSHIBA