JPH01286780A - Power transistor module - Google Patents

Abstract

PURPOSE:To accurately monitor the reset timing of a main transformer by incorporating an element for detecting a regenerative current in a power transistor module itself, and monitoring the timing of the transformer. CONSTITUTION:A power transistor module 1-1 is composed of a power transistor 1a, etc., of Darlington connection contained therein. The module 1-1 forms a photocoupler of a light emitting diode 1i and a phototransistor 1f, and performs a function as a current detector for detecting a regenerative current. The diode 1i is simultaneously operated as a function of a circulating diode. Thus, output terminals 1g, 1h are connected to a controlling circuit to be monitored, thereby easily detecting the reset timing of a main transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transistor module used as a power switching element in the field of power electronics typified by inverters and the like.

[Conventional technology]

FIG. 2 shows an internal circuit configuration of a conventional power transistor module used, for example, in an inverter power source, and FIG. 3 shows an example of an inverter circuit in which this module is actually used. In the figure, 1 is a power transistor module, and la is a power transistor module! The built-in power transistor with Darlington connection, 1b is the power transistor module! Freewheeling diode built in, 1c is collector terminal, 1d is base terminal, 1e is emitter terminal, 2 is control circuit, 3 is main transformer, 3a is primary winding, 3b is secondary winding, 3
c is a reset detection winding, and 4 is a resonance capacitor.

Next, the operation of the inverter circuit shown in FIG. 3 will be explained.

The power transistor 1a in the power transistor module 1 is turned on for a certain period of time in response to the ON signal from the control circuit section 2, and during this period, an exciting current flows through the primary winding 3a of the main transformer 3, and at the same time, an exciting current flows through the secondary winding 3b. Power is sent to the connected circuit.

Next, when the switching transistor 1a is turned off by the off signal from the control circuit 2, the primary winding 3 of the main transformer 3
The electromagnetic energy stored in a is first used to charge the resonance capacitor 4.

When the charging of the resonant capacitor 4 is completed, the direction of the current in the negative winding 3a is reversed, and the resonant capacitor 4 begins to be charged with the opposite polarity. When the voltage of the resonant capacitor reaches approximately the power supply voltage, the freewheeling diode turns on. , -The electromagnetic energy of the secondary winding 3a is returned to the power supply side in the form of a current.

This current is called a regenerative current, and when this regenerative current becomes zero, that is, when the main transformer 3 is reset, the power transistor la is turned on again and the above-described operation is repeated. In this way, DC power is converted to AC power.

(Problem to be Solved by the Invention) Conventional power transistor modules have a built-in freewheeling diode for flowing regenerative current as described above, but since the module cannot detect the regenerative current, the main transformer @1 for reset detection is installed in main transformer 3 to detect the reset timing of
A3c was wound, and the voltage generated in this winding was fed back to the control circuit to determine control timing. However, with this method, electrical insulation must be considered between the reset winding and other windings, resulting in a complicated shape of the main transformer.

Another method for detecting the reset timing of the main transformer is to add a current transformer to the circuit and detect the regenerative current, but the components themselves are expensive and require a considerable amount of mounting area when mounted on the board. There are problems such as 7.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a power transformer module that can detect regenerative current and output the reset timing of the main transformer as an electrical signal.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a power transistor module is configured as follows.

That is, it includes a power transistor, a freewheeling diode connected in antiparallel to the power transistor, a current detection element that detects the current of the freewheeling diode, and an output terminal that extracts a detection signal from the current detection element.

[Effect]

With this configuration, the regenerative current can be detected in the power transistor module and the reset timing of the main transformer can be output.

〔Example〕

This invention will be explained below with reference to Examples.

FIG. 1 is an internal circuit configuration diagram of a "power transistor module" which is an embodiment of the present invention. In the figure 1
8 to 1e indicate the same or equivalent parts as the same reference numerals in FIG. 2, and 1-1 indicates a power transistor module. 1
1 is a light emitting diode, lf is a phototransistor, and both constitute a photocoupler and function as a current detection element for detecting regenerative current. The light emitting diode 11 also functions as a freewheeling diode.

Since this embodiment is configured as described above, when it is incorporated into a circuit as shown in FIG. 3, the switching operation by the power transistor 1a and the light emitting diode (recirculating A regenerative operation is performed using the diode (diode) 11.

When the regenerative current further starts to flow, the light emitting diode 11 emits light, the phototransistor 1f turns on, and the output terminal 1g,
The impedance is poor between ih and ih.

When the main transformer is completely reset and the regenerative current becomes zero, the light emitting diode 11 stops emitting light, the phototransistor 1f is turned off, and the state between the output terminals Ig and ih becomes high impedance again.

Therefore, by connecting and monitoring the output terminals 1 and 2 to the control circuit 2, the reset timing of the main transformer 3 can be easily detected, and the control signal for switching the power transistor 1a can be accurately detected. It can be released at the right time.

In the above embodiment, the regenerative current is detected by a photocoupler, but by connecting a resistor in series with the freewheeling diode, and connecting this series connection in antiparallel to the power transistor,
The voltage across the resistor may be detected by means of detecting the voltage across the resistor, or by connecting a parallel-connected resistor in series with a freewheeling diode to shunt the regenerative current, and then inserting a current transformer into the side with a smaller current value. Any means may be used, and the same functions and effects as those of the above-mentioned embodiments can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the power transistor module itself has a built-in element for detecting regenerative current and is configured to monitor the reset timing of the main transformer. There is no longer a need to take other measures such as winding or adding a current transformer. Additionally, since the regenerative current itself is detected, the reset timing of the main transformer can be accurately monitored.

[Brief explanation of the drawing]

FIG. 1 is an internal circuit diagram of a "power transistor module" which is an embodiment of the present invention, FIG. 2 is an internal circuit diagram of a conventional power transistor module, and FIG.
The figure is a circuit diagram showing an example of a circuit using a conventional power transistor module. In the figure, 1-1 is a power transistor module, 1a is a power transistor, 11 is a light emitting diode, 1f is a phototransistor, and Ig and lh are output terminals. Note that the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] The device is characterized by comprising a power transistor, a freewheeling diode connected in antiparallel to the power transistor, a current detection element for detecting the current of the freewheeling diode, and an output terminal for extracting a detection signal from the current detection element. power transistor module.