KR0123006B1 - Power conversion device - Google Patents

Abstract

The present invention relates to a power converting system which immediately cuts off power applied to all the circuits in case of short circuit, and provides a power control unit for keeping this state, and facilitates the confirmation of consumed power. This system includes an overload sensing part forming a current transformer detecting the level of power at the power input terminal of the power converting system and cutting off the power in case that any trouble occurs at the power input terminal and maintaining this state, and detecting an output state at an AC output terminal; an overload sensing part; a short-circuit sensing part operating at short circuit; and a level display part.

Description

Power converter

1 is a block diagram showing a known power converter.

2 is a block diagram showing a power conversion device incorporating the present invention.

3 is a detailed circuit diagram as an embodiment of FIG.

* Explanation of symbols for main parts of the drawings

10: power detection means 20: overload detection means

30: short circuit detecting means 40: level display means

50: set / reset means

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for converting a DC power source into an AC power source, and more particularly, to a power converter configured to detect a trouble on the power supply side and an abnormal state on the load side to simultaneously protect the power converter and the load.

In general, a power converter (inverter) is a device for converting a direct current into an AC power source has been variously used and widely used.

The power supply side of the power converter as described above is mainly formed of a capacitor, which is in a state of charge by a power generator (any type of generator) and discharges when necessary, and in some cases, power conversion from the power generator. The device and capacitor are supplied with power at the same time to perform the charging of the capacitor along with the power conversion.

On the other hand, in recent years, various AC loads are connected to and operated by a power converter, and precision electronic devices such as personal computers are all integrated therein.

Therefore, stable power conversion is essential, and it is desirable to screen it immediately in case of instability.

In view of the above-mentioned problems, the applicant of the present invention has proposed an invention including protection against overvoltage and undervoltage on the input power supply side and protection against overload condition on the output load side, such as Patent No. 67737.

Of course, prior to the selection of the present applicant according to the prior art, the protection against the power-side trouble and the load-side abnormal state was very insufficient.

In other words, when describing an automobile capacitor power as an example, a generator is operated by engine power to generate power, and the generated power is charged to a capacitor at a constant potential through a regulator, and when the capacitor charging potential reaches a peak, the charging is stopped and is very high. It becomes a stable state. However, when a fault occurs in the circuit (regulator) from the generator to the capacitor, the output terminal voltage of the generator is all caught by the capacitor, and the power converter connected to the capacitor is damaged by extreme overvoltage (tens of volts). There is a problem.

In the case of the AC output side, the primary push-pull power control element of the boosting transformer is turned off in case of overload, and it is configured to perform a repetitive operation of turning on again when the overload is released. There is a problem that causes thermal fatigue and destruction, or the load leads to destruction, and short circuits on the load side are not immediately and continuously interrupted, and as a whole, the safety on the power supply side, power converter, and load is deteriorated.

As prior arts of such a power conversion device, Korean Patent Publication Nos. 88-1151, 88-1836, 89-3394, 93-10607 and Utility Model Publication No. 89-9014, US Patent No. 4,706,177, and the like. have.

The present invention has been made to solve the problems of the conventional power converter has the following object.

First, the present invention provides a power conversion device capable of detecting a power level on an input power supply side to cut off the power supplied to all circuits in the event of an overvoltage and to maintain the cutoff state.

Second, the present invention forms a current transformer (CT) at the AC output stage to detect an overload condition on the load side, and provides an electric power converter that can cut off and hold the power supplied to all circuits in the overload state.

Thirdly, the present invention provides a power converter which is capable of immediately shutting off the power supplied to all circuits and holding this state at the load side short circuit through the current transformer.

Fourth, the present invention provides a power conversion device that can easily check the current load-side power used by the level drive the output state of the load side through the current transformer.

In another aspect, the present invention provides a power conversion device that can keep the power converter in a standby state until the power is supplied to all circuits by any of the above problems, until the trouble is eliminated and artificially reset. .

In order to achieve the above object, the present invention forms a power detecting means for detecting a power level on the power input side of the power conversion device, and switches the power supply to all the circuits in the rear stage via the power detecting means and troubles on the power input side. To cut off the power supply which is supplied at the time of occurrence and to keep this cut-off state, the current transformer to detect the output state at the AC output stage, the overload detection means operating at the overload breaking level, the short circuit detection means operating at the time of load short circuit, and the output It is made as a level display means for displaying the level by the power supply detection means is driven by the drive of the overload detection means or the short-circuit detection means to cut off the power supply to all circuits of the rear stage. As a result, the circuit can be protected from an extreme overvoltage on the power input side, and the circuit can be protected by an overload or a short circuit at the same time on the load side.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, a push-pull switching FET that saturates the boost transformer from the capacitor power input terminal DCIN to the pulse width modulation method (PWM) and a DC-DC converter (100) for converting the boosted transformer secondary side voltage into a direct current (DC). ) And a boosted DC power source of the DC-DC converter 100 are generated as an AC output through a load drive circuit composed of FETs that are point-symmetrically driven, and has an output regulation circuit for switching the load drive circuit to a commercial frequency. In the power conversion device including a DC-AC inverter 200 and the operation state display unit 300, the battery power supply (DC ⁺ ) is sensed to apply power to the circuit of the next stage when the normal, and abnormal to the rear circuit A power detecting means 10 is provided between the capacitor power input terminal DCIN and the DC-DC converter 100 to cut off the applied power and maintain the cutoff state of the power, and the AC output terminal of the DC-AC inverter 200. Output level at (ACOUT) An overload detecting means 20 which forms a current transformer CT for detecting a bell so as to switch the power detecting means 10 to a cutoff state in an overload state compared to the load side overload level, and the power detecting means at a load short circuit level. It consists of a short-circuit detecting means 30 to switch the state to the cut-off state and a level display means 40 of the LED to display the output level detected through the current transformer CT, the power detecting means 10 ), A set / reset section 50 for resetting.

Looking in more detail through the embodiment as shown in Figure 3 in the concrete implementation of the technical spirit of the present invention as described above are as follows.

Resistance (R ₁₎ to the input terminal (DCIN) of the capacitor power (DC ^+), Zener diodes (ZD), a forward diode (D ₁₎ and grounded with a resistance (R ₂₎ a voltage detector (1) and the battery power supply (DC ⁺⁾ A power switching unit 2 consisting of a relay RY and a reverse diode D ₂ connected to the transistor RY, a transistor Q ₁ for switching the relay RY, and a resistor C _{1 of} resistors R _{4 and} R ₅ . The switching unit 3, the gate of the thyristor (SCR) for limiting the transistor (Q ₁ ) base potential of the switching unit 3 is connected to the rear end of the diode (D ₁ ) of the voltage detector (1) and the anode is a resistor ( R ₃ ) is connected to the base resistance (R ₄ ) via a cathode and is a grounded state monitor (4) to form a voltage sensing unit (10 '), the current transformer (CT) is formed in the AC output terminal (ACOUT), The reference level is connected to the non-inverting input terminal of the level comparator 11 consisting of the resistors R ₆ to R ₁₀ capacitors C ₂ to C ₅ and the level comparator COM ₁ through the variable resistor VR. , reversal A half-wave rectifier circuit 12 formed of a diode (D ₃ ) resistor (R ₁₁ ) capacitor (C ₆ ) at an output terminal of the current transformer (CT) detection input, and at an output terminal of the level comparator (11); Buffer circuit 13 consisting of transistor (Q ₂ ), resistor (R ₁₂ ), and capacitor (C _7, C ₈ ), diode (D ₄ ) resistor (R ₁₃ ~ R ₁₉ ), capacitor (C ₉ , C ₁₀ ) And the overload output circuit 14 including the comparator COM ₂ connects the output of the buffer circuit 13 to a non-inverting input terminal, and connects the output of the overload detecting unit 20 'to the inverting input terminal with a reference voltage. It is connected to the thyristor (SCR) gate of the power detector 10 ', branched from the variable resistor (VR) to the resistors (R ₂₁ ~ R ₂₃ ), diodes (D ₅ ~ D ₆ ) and transistor (Q ₃ ). The output of the short-circuit detection unit 30 'is connected to the thyristor (SCR) gate of the power supply detection unit 10', branched out from the variable resistor VR, and the resistors R ₂₄ to R ₂₆ and the capacitor C ₁₁ to C ₁₃ ) And a level display section 40 'consisting of a level drive array IC ₁ and a level display LED, wherein a forward diode D ₁ is connected from the power supply DC ⁺ through a switch SW. The output of the diode D ₇ of the set / reset section 50 'is connected to the resistor R ₃ of the voltage sensing section 10'.

The manufacturing effect of the present invention constituting the above configuration will be described below.

The power converter including the present invention is connected to a normal capacitor to convert a DC power source into an AC power source. The capacitor power source DC ⁺ is connected to an input terminal DCIN to apply power to the present invention.

When the switch SW of the set / reset unit 50 'is closed after the power is applied, the power supply DC ⁺ via the diode D ₇ is relayed through the resistors R ₃ and R ₄ and the transistor Q ₁ . Causes excitation drive of (RY). Thus, the relay contact ry causes power to be supplied to the circuit at the rear end. In this case, when a trouble occurs in the power supply voltage, when the zener diode ZD of the voltage detector 10 ′ that detects the voltage of the power supply DC ⁺ becomes overvoltage greater than the breakover voltage, the input terminal DCIN is applied. All circuits are powered off immediately. That is, the brake reverse voltage of the zener diode ZD acts as a trigger signal to the gate of the thyristor SCR through the diode D ₁ , causing the thyristor SCR to switch the transistor Q ₁ to the turn-off state, and thus the relay. The protection of the circuit by the overvoltage input is implemented by the (RY) element and its contact (ry) interrupting the power supply (DC ⁺ ). Of course, the off state of the relay RY in response to the overvoltage detection is such that the state keeping section 4 made of the thyristor SCR maintains the state until the reset operation of the switch SW.

On the other hand, when the power is normally input and the power converter is driven, the output state of the AC output terminal (ACOUT) is monitored, which protects against overload and stops the apparatus of the present invention with respect to the load short (or output terminal short). By protection.

The state sensing on the load side is caused by the induced electric current exceeding that level due to the induced power detected from the current transformer CT formed at the AC output terminal (ACOUT) and the cutoff level for the set overload and the cutoff level for the short circuit. At this time, the power converter is in a stopped state.

First, the protection against overload is as follows.

The current transformer CT formed at the AC output terminal monitors the load-side output, and the induced power is generated and supplied through the variable resistance VR for sensitivity adjustment, and when the overload exceeds the reference output, the current transformer CT is connected to the resistance R. ₃ ) The capacitor is applied to the comparator COM ₁ of the level comparator 11 through the capacitors C ₂ and C ₃ , and the level is aligned and output based on the reference voltage of the non-inverting input terminal. The buffer circuit 13 operated as a surge-up server after being DC-driven through is applied to the non-inverting input terminal as a comparison voltage to the comparator COM ₂ of the overload output circuit unit 14 via the output and compared with the reference voltage of the inverting input terminal. The overload output generated at this time acts as a trigger signal to the gate of the thyristor (SCR) of the voltage sensing unit (10 ') described above via the resistor (R ₁₈ ) diode (D ₄ ) to relay (RY). To all circuits Turn off the Dunn. Of course, even if the overload condition is extinguished until the user artificially resets the switch (SW) of the set / reset unit 50 'acts to maintain the interrupted state by the overload continuously. At the same time, a known fault condition indicator (not shown) is turned on to alarm. The capacitor C ₇ of the buffer circuit 13 retains the overload detection output while delaying the voltage rise corresponding to the instantaneous overload.

In addition, in the cut-off operation by the short circuit detection, the output of the short circuit detection is generated when the organic power level of the current transformer CT turns on the transistor Q ₃ through the voltage divider R ₂₀ and R ₂₁ . R ₂₃ ), via diode D ₆ , also triggers the gate of the thyristor SCR to cause relay RY to shut off the power supply to all circuits.

On the other hand, the output level of the AC output terminal ACOUT by the current transformer CT is input to the level display unit 40 'in addition to the above-described overload cutoff level and the cutoff level due to a short circuit, and is applied to the level drive array IC. The level display LED connected through ₁ ) is displayed and driven according to the output level. Therefore, the saturation state of the output stage can be easily identified.

At the same time, the set / reset unit 50 'can be reset after the fault is eliminated when the power conversion device of the present invention is first set to a usable state or a problem occurs in any element on the power supply side or the load side and power supply to all circuits is interrupted. The diode D ₇ prevents the reverse polarity misconnection of the DC power supply DCIN and blocks the application of the power supply voltage in case of polarity mismatch. Here, the voltage detecting element of the voltage sensing unit 10 'is composed of a zener diode, but a separate element such as a resistor may be configured, and the thyristor (SCR) of the state monitoring unit may be replaced with other trigger elements, and the relay may also be used. It can be configured as a switching element and this modification is found to be identical to the technical idea of the present invention as a category of identity.

As described in detail above, the present invention can protect the device by not supplying power to the device during an extreme overvoltage input of the power supply side, and also detects when the load level is equal to or higher than a corresponding set level value against an overvoltage or a short circuit on the load side. As a current transformer, it can cut off the input power immediately and protect it without destroying the device and load.The interruption caused by this failure has the effect of increasing the stability by keeping the state as it is until the user resets it. By displaying the power usage level on the load side with the level display LED, it is possible to visually confirm whether the load is additionally accommodated or reduced, so that the power converter and the load can be protected in addition to simply converting the power. Very good inventor with convenient and concise configuration will be.

Lastly, in the embodiment of the present invention, the configuration of the overload detection unit 20 'for detecting the overload is possible to increase or decrease the detailed configuration blocks 11 to 14, and only according to the detection level of the current transformer CT. All can be implemented as long as the signal for driving 4) can be output, and this change is easy for those skilled in the art, and it is found that the equivalents belong to the claims of the present invention.

Claims (2)

A push-pull switching FET that saturates the boost transformer from the capacitor power input terminal DCIN to the pulse width modulation method (PWM), and a DC-DC converter 100 and a DC-DC converter 100 for converting the boosted transformer secondary side voltage into DC. DC-AC inverter (200) having an output control circuit for generating a boosted DC power supply to the AC output (ACOUT) through a load driving circuit of a point-symmetrically driven FET and switching the load driving circuit to a commercial frequency; In the power conversion device including the operation state display unit 300, the power supply to the circuit of the rear stage when the battery power (DC ⁺ ) is detected and normal, cut off the power applied to the rear circuit when abnormal. A power detecting means 10 capable of maintaining a blocking state is formed between the capacitor power input terminal DCIN and the DC-DC converter 100, and an output level is detected at the AC output terminal ACOUT of the DC-AC inverter 200. Current transformer (CT) And an overload detecting means 20 for switching the power detecting means 10 to a cut-off state in an overload state as compared to the load-side overload level, and switching the power detecting means 10 to a cut-off state at a load short-circuit level. A short-circuit detection means 30 and a level display means 40 of LEDs for displaying the output level detected through the current transformer CT, wherein the set / reset for resetting the power monitoring means 10 is performed. Power conversion device comprising a unit (50). The voltage detecting unit (1) of claim 1, wherein the voltage detecting unit (1) is grounded at the input terminal (DCIN) of the capacitor power supply (DC ⁺ ) with a resistor (R ₁ ), a zener diode (ZD) forward diode (D ₁ ), and a resistor (R ₂ ). Power switch ₂ consisting of a relay RY and a check diode D ₂ connected to a battery power source DC ⁺ , a transistor Q ₁ and a resistor R _{4 and} R ₅ for switching the relay RY The gate of the thyristor (SCR) for limiting the transistor (Q ₁ ) base potential of the switching unit 3 of (C ₁ ) and the switching unit 3 is located after the diode (D ₁ ) of the voltage detector (1). Connect the anode to the base resistor (R ₄ ) via the resistor (R ₃ ) and form a cathode grounded upper retainer (4) to form a voltage sensing (10 ′) and a current transformer (ACOUT). (CT) to form a non-inverting input terminal to the level comparator 11 consisting of resistors R ₆ to R ₁₀ capacitors C ₂ to C ₅ and level comparator COM ₁ through a variable resistor VR. Enter the reference level Results and half-wave a to the inverting input terminal has a current transformer (CT) forms by connecting the input to the detection level, the diode (D _3), the resistance (R _11), capacitor (C ₆₎ at the output end of the level comparison section (11) a rectifier circuit ( 12), a buffer circuit 13 comprising a transistor (Q ₂ ), a resistor (R ₁₂ ), and a capacitor (C ₇ , C ₈ ), a diode (D ₄ ), a resistor (R ₁₃ to R ₁₉ ), and a capacitor (C _9). , C ₁₀ ) and the overload output circuit 14 comprising the comparator COM ₂ connects the output of the buffer circuit 13 to the non-inverting input terminal, and connects the inverting input terminal with a reference voltage. Is connected to the thyristor (SCR) gate of the power sensing unit 10 'and branched from the variable resistor VR to resistors R ₂₁ to R ₂₃ , diodes D ₅ to D ₆ , and a transistor ( Q ₃ ) is connected to the thyristor (SCR) gate of the power supply detection unit 10 ', the output of the short-circuit detection unit 30', branched from the variable resistor (VR) resistors (R ₂₄ ~ R ₂₆ ) , A capacitor (C ₁₁ ~ C _13), and level drive array (IC ₁₎ and a level display connected to the level display section 40 'is formed as an LED for, and being made, the forward diode via a switch (SW) from the power supply (DC ⁺⁾ (D _1), the set / reset section 50 'by connecting a power conversion device for diode (D ₇₎ to output the voltage detecting unit (10, characterized in that formed by connecting the resistor (R ₃₎ a).