Overcurrent detection device

Abstract

This invention provides an overcurrent detection device for use in inverters. [Solution] The inverter comprises a series connection of upper arm switches and lower arm switches for each phase, and a detection circuit provided individually corresponding to the upper arm switch of each phase for detecting overcurrent flowing through the upper arm switch. The overcurrent detection device applied to the inverter includes a common terminal KC. Each detection circuit includes a first electrical path for detecting overcurrent, the first electrical path is connected to the common terminal KC, and the common terminal KC is connected to a high-potential path, thereby detecting the overcurrent of the upper arm switch corresponding to the detection circuit 40.

Claims

1. A series connection of the upper arm switch (SWH) and lower arm switch (SWL) for each phase, It has a first electrical path (31) and a second electrical path (32), and a detection circuit (40) provided individually for each phase corresponding to the upper arm switch, which detects the overcurrent flowing through the upper arm switch, The high-potential path (21H) to which the high-potential terminal of the upper arm switch is electrically connected, The low-potential path (21L) to which the low-potential terminal of the lower arm switch is electrically connected, In an overcurrent detection device applied to an inverter (20) equipped with, Each of the above detection circuits is, Diodes (42, 42A, 42B) provided in the first electrical path, A detection unit (43) for detecting the potential difference between the first electrical path and the second electrical path, Equipped with, The first end of the first electrical path is electrically connected to the detection unit. The first end of the second electrical path is electrically connected to the detection unit. The second end of the second electrical path is electrically connected to the low-potential terminal of the upper arm switch. The anode of the diode is electrically connected to the detection unit. Each of the detection circuits is equipped with common terminals (KC, KH1, KI1, KJ) that are electrically connected to at least two of the second ends of the first electrical path, The aforementioned common terminal is an overcurrent detection device electrically connected to the high-potential path.

2. The control board (50) has a board surface on which each of the aforementioned detection circuits is provided, In each phase, the upper arm switch and the detection unit corresponding to the upper arm switch constitute the upper arm section (51U, 51V, 51W), In the plate surface, insulating patterns (53A, 53B) are provided so that the upper arm portions are insulated from each other. The overcurrent detection device according to claim 1, wherein the diode electrically connected to the common terminal is positioned in a location that overlaps with the insulating pattern in a plan view of the board surface.

3. The upper arm portions of each phase are arranged side by side on the plate surface. The insulating pattern is provided on the plate surface between adjacent upper arm portions. Of the adjacent upper arm sections, the common terminal is located on one terminal-arranged arm section (51V), while the common terminal is not located on the other non-arranged arm section (52U, 52W). The diode electrically connected to the detection unit of the unplaced arm unit has a main body (142B), an anode terminal (142A) provided on the main body unit, and a cathode terminal (142K) provided on the main body unit. The overcurrent detection device according to claim 2, wherein the main body straddles the insulating pattern provided between the unplaced arm portion and the terminal-placed arm portion, the anode terminal is placed on the unplaced arm portion and the cathode terminal is placed on the terminal-placed arm portion.

4. In each phase, the upper arm switch constitutes a switch module (PWC1, PWC2), Of the switch modules for each phase, the terminal arrangement module (PWC1) corresponding to the terminal arrangement arm portion is: The case portion (60, 61) housing the upper arm switch, The common terminal, which is electrically connected to the high-potential side terminal of the upper arm switch and protrudes from the case, A ground terminal (KE) is electrically connected to the low-potential side terminal of the upper arm switch and protrudes from the case portion, It has, In the terminal arrangement module, the common terminal is electrically connected to the second end of the first electrical path, and the ground terminal is electrically connected to the second end of the second electrical path. Of the switch modules for each phase, the unassigned module (PWC2) corresponding to the unassigned arm portion has the case portion and the ground terminal electrically connected to the second end of the second electrical path. The overcurrent detection device according to claim 3, which is electrically connected to the high-potential side terminal of the upper arm switch and does not have a terminal protruding from the case portion.

5. The overcurrent detection device according to claim 4, wherein the second end of the first electrical path provided in each of the detection circuits is electrically connected to the common terminal.

6. Each of the above detection circuits is, A capacitor (44) electrically connects the anode of the diode and the second electrical path, Determination unit (41), It has, The detection unit detects the voltage across the terminals of the capacitor, The overcurrent detection device according to any one of claims 1 to 5, wherein the determination unit determines that an overcurrent is flowing through the upper arm switch if the terminal voltage detected when the upper arm switch is controlled to the ON position is greater than an overcurrent threshold.

7. The inverter includes a smoothing capacitor (11) or discharge resistor (12) having a first terminal (KH1, KI1) electrically connected to the high-potential path and a second terminal (KH2, KI2) electrically connected to the low-potential path. The overcurrent detection device according to claim 1, wherein the common terminal is the first terminal.

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