JPS61128765A - Gate control semiconductor power converter - Google Patents

Abstract

PURPOSE:To readily and effectively protect and discover a plurality of semiconductor elements against overheat by providing one overheat protecting means in a heat sink, and stopping the operation of a gate control semiconductor element on the heat sink by its detection signal. CONSTITUTION:Parallel semiconductor element units 2 are connected in parallel to form one arm 1 of a power converter, and cooled at the heat sink, for example, by cooling air 3 of air cooling type. In this case, A semiconductor element 10 is turned ON by the temperature detection of a temperature detecting sensor 12 to shortcircuit between the gate G and the cathode K of the element 10, a gate input signal 23 is turned OFF to stop the operation of the element 10. Thus, the heating of the element 10 due to the case that the unbalance of the current share increases can be protected, and the heat can be readily discovered by a heat indicator.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a semiconductor power conversion device for gate control, and particularly to a semiconductor power conversion device for gate control suitable for providing overheat protection for each semiconductor element with gate control connected in parallel. The present invention relates to a semiconductor power conversion device.

[Background of the invention]

As a prior art related to the protection of gate control semiconductor elements (Japanese Utility Model Publication No. 58-59379), there is a method of detecting a failure as a result of failure of the semiconductor element itself or failure of the gate control circuit.

This technique has a problem in that it cannot protect the semiconductor element before it breaks down.

Generally, overheating protection for semiconductor elements in conventional semiconductor power conversion equipment involves installing a temperature sensor that detects overheating only on representative elements within the power conversion equipment. This is to protect against overheating by reducing or stopping the medium.

Moreover, this protection method is mainly designed to protect the entire device, and when the load current is the rated current, current imbalance between multiple semiconductor elements that share the current during normal operation can cause changes in the characteristics of circuit components and connections. If the contact resistance or impedance of the semiconductor element changes too much, the loss caused by the forward voltage drop will be large, and if overheating occurs, the semiconductor element may be damaged or discovered. There is a drawback that it cannot be done.

Furthermore, even if the cooling device is sound, an imbalance may occur in the cooling medium flowing in the cooling heat sink for each parallel semiconductor element. In this case as well, the cooling effect of the heat sink decreases due to the decrease in the amount of cooling medium, resulting in overheating, and the disadvantage is that the overheated semiconductor element cannot be detected and protected.

[Purpose of the invention]

An object of the present invention is to provide a highly reliable gate-controlled semiconductor conversion device that can effectively and reliably perform overheat protection and detection for each of a plurality of parallel-connected semiconductor elements.

[Summary of the invention]

To achieve such an object, the present invention provides a gated semiconductor power converter device comprising gated semiconductor devices current shared and mounted on at least one heatsink, in which at least one superheated semiconductor device is provided for each heatsink. A protection means is provided, and means is further provided for stopping the operation of a gate control semiconductor element on a heat sink corresponding to the overheat protection means in response to a detection signal from the overheat protection means.

[Embodiments of the invention]

FIG. 2 shows a part of the arm 1 of a gate-controlled semiconductor power conversion device according to an embodiment of the present invention.

In the figure, parallel semiconductor element units 2 (hereinafter referred to as units) are Umtti, Ust2, and Umtti, respectively.
... Umtt -n % are connected in parallel to constitute one arm 1t of the power converter.

In this example, the number of parallel units 2 of arm 1 is Umt
t −1, Uatt −2++jl@4U1t −n
As a result, a bus current It of arm 1 - l1 pI as a shared current of each parallel unit flows, but this naturally increases or decreases depending on the capacity of the device.

For example, each unit is cooled by an air cooling method, where the cooling air 3 cools the heat sink of the parallel unit 2, and the cooling air volume of each unit is Qs, Qs, etc.
・It is designed to be cooled by Qs.

1, (a), (b), and (C) each show the configuration of this embodiment of the parallel unit 2 shown in FIG. 2. FIG.

In the figure, the method (a) shows the most basic implementation circuit configuration of the present invention.

This method relies on temperature detection by the temperature detection sensor 12.
(N operation) of the semiconductor element 10, G-cathode is shorted (ON), the gate input signal is set to 0FFL, and the operation of the semiconductor element 10 is stopped.

In addition, the method shown in FIG. 3(b) is based on temperature detection by the temperature detection sensor 12, contrary to the method described in Ca). DOFF works,
This is an embodiment in which the cathode Kit[ of the semiconductor element 10 is opened (OFF) and the gate input signal is turned OFF to stop the operation of the semiconductor element 10. In this embodiment, the OFF (open) contact of the temperature detection sensor 12 is provided on the cathode side, but it can also be provided on the gate G side.

The method shown in FIG. 2(c) shows an example of a circuit configuration in which the gate input signal cutoff method is a non-contact method. In the same figure (C), a semiconductor element overheat protection device 11 includes a sensor 12 for detecting the temperature of the semiconductor element, a forward voltage V of the semiconductor element, a light emitting diode 13-1 for driving a phototransistor 13-2, and a phototransistor 13-2 driving light emitting diode 13-1. A light emitting diode 16 for indicating overheating, and a series resistor 15 for optimizing the current of the light emitting diode.
are connected in series and connected in parallel between the anode and the cathode of the semiconductor element 10. The diode 14 is connected in parallel to protect the light emitting diode 13 from reverse voltage. Further, a phototransistor 13-2 for the purpose of blocking the gate input of the gate input signal 23 of the semiconductor element 10 is connected between the gate G-cando.

FIG. 1(d) shows a heat sink 3 for cooling the semiconductor element 10.
This is an example of how the temperature detection sensor 12 and temperature detection sensor 12 are attached. Note that there is also a method of detecting the temperature detection sensor 12 by indirectly detecting the temperature of the heat sink cooling medium without directly attaching it to the cooling heat sink 30.

What should be noted here is that the forward voltage of the semiconductor element itself is used to detect overheating of the element itself, and the gate G-cando is short-circuited, and the gate signal t-o is used to protect the element from operating. and the ability to individually display overheating detection.

In general, the busbar electrical work shown in Figure 2 is connected to parallel unit 2.
T-I! ...... However, when the semiconductor device is a thyristor, variations in turn-off time, variations in forward voltage drop (FVD 1, variations in circuit impedance and contact resistance of connections) etc. becomes large, it is conceivable that the shared current will become excessive only to a specific unit.

If such a malfunction occurs, this embodiment can provide protection and display an overheat indication.

As an example, assume that the initial value of the shared current of U-+t-1 in FIG. 2 is It'v'' (A).

Here, I s : initial shared current of U-+t-1 (
A) Engineering: Bus line voltage K of the power converter (A)n: Number of parallel semiconductor units of the power converter In this case, U-1t Junction temperature T of the 1 semiconductor element
1 and the temperature detection sensor part temperature T26tt are expressed as follows.

Tr = Ta+r+P tx (R+-*+Rs-*s
s+Ru5-a+r) (C)T2m g=
T a□+P1×几was−atr (C) Here, T
, : Cooling air temperature 40 (C) PK = shared current, loss due to element forward current 2
20(W) RJ-*: Thermal resistance between element junction and element case 0, os
(C/W) Ram-, 6, Thermal resistance between the element case and the temperature sensor mounting part 0.04 (C/W) Rsss-air: Thermal resistance between the temperature sensor mounting part and the cooling air (heat sink) 0 .13(C'/W), the temperature of each T J I THs is T
i=40C+220WX(0.05+0.04+0.1
3) C/W = 84C T2g11 = 40C + 220W x 0.13 = 66G is not normal operation, and if the temperature sensor setting temperature in this case is 800, there will be no protective operation or overheat detection display.

Next, if we assume that the current of the above-mentioned process 1 increases to about 130% of the shared current and a problem occurs, the loss Pi caused by the forward current of the element increases to more than 1501, which is about 33
Assuming that it increases to 0 (W), TJ, T! al
l is as follows, T+=400+330WX(0,0
5+0.04+0.13) C/W=11L6G Txag= 40C+330WX0.13 C/W=
82. ．． 9C, and the temperature sensor's set value is 80C.
With the above, Figure 1 (C) and (ψ temperature sensor 1
2 is activated by detecting overheating, and a voltage shared by the series resistor 15 of the element voltage (VA-K) is applied to the phototransistor light emitting diode 13-1 and the overheating indicating light emitting diode 16, and the ON operation of the phototransistor applies the voltage shared by the series resistor 15. This means that the input signal is stopped and the light emitting heating display is performed.

At this time, the temperature Tj of the element junction is 11Z6C, and in the case of a thyristor, the junction temperature is within the allowable temperature of 125C.
The thyristor must be protected from heating.

The above describes in detail the case where the unbalance rate of current sharing becomes large, but also when the cooling air volume decreases or the cooling air volume of the heat sink part of each element becomes unbalanced, the thermal resistance R of the heat sink part *If 5s-air is large, the protection operation and overheat detection indicator will operate in exactly the same way as described above.

According to the embodiments of the present invention, it is possible to display the heating of a malfunctioning heating element, protect the semiconductor element, and facilitate the discovery of a heated portion by means of the heating display device.

In FIG. 1(C) of an embodiment of the present invention, a neon lamp or the like can also be used for the light emitting diode in the 160s.
It is also possible to easily obtain a protection alarm signal by providing a control section that obtains a common alarm output using the optical signals of these light-emitting displays.

In addition, although a temperature switch was used as the temperature detection sensor, a heat-sensitive resistor (positive characteristic or negative characteristic) was used instead.
It is also possible to perform protection and heating detection display by detecting the heat temperature and changing the impedance due to heating to turn on the p1 heating display (in the case of normally off display) or off (in the case of normally on display).

In addition, in the circuit configuration examples of embodiments (a) and (c), as a method for turning off the gate input signal, the gate G and cathode of the semiconductor element 10 are short-circuited by an ON operation signal. Input series resistor 22 and gate series diode 2
There is also a method of short-circuiting the gate input signal 'e' and the cathode with an ON operation signal to turn off the gate input signal 'e'.

〔Effect of the invention〕

According to the present invention, even if heating occurs in an example of a power conversion device using a gate-controlled semiconductor element, it is possible to easily protect and detect the heating portion.

[Brief explanation of the drawing]

FIGS. 1(a) to d) are a circuit configuration diagram and a front view showing an embodiment of a gate-controlled semiconductor power converter according to the present invention, respectively, and FIG. 2 shows semiconductors in one arm of the gate-controlled semiconductor power converter. FIG. 3 is a diagram illustrating an example of a circuit in which elements are connected in parallel. l...Semiconductor element unit, 10...Gate control semiconductor element, 11...Element overheat protection device, 12...Temperature detection sensor, 13...Photocoupler (13-1)
...Light emitting diode, 13-2...Phototransistor), 14...Diode, 15...Resistor, 16.
...Light emitting diode, 21...Diode, 22...
・Resistor, 23... Gate trigger "Signal, 30...
Heat sink for element cooling.

Claims (1)

[Scope of Claims] 1. In a gate-controlled semiconductor power conversion device comprising a gate-controlled semiconductor element that is current-shared and mounted on at least one heat sink, each heat sink is provided with at least one overheat protection means, A gate-controlled semiconductor power conversion device further comprising means for stopping the operation of a gate-controlled semiconductor element on a heat sink corresponding to the overheat protection means in response to a detection signal from the overheat protection means. 2. The gate-controlled semiconductor power conversion device according to claim 1, wherein the overheat protection means is provided for each gate-controlled semiconductor element. 3. Claims 1 and 2, wherein the display device is driven by the detection signal of the overheat protection means.
The gate-controlled semiconductor power conversion device described in 1.