EP0402367B1 - Active filter - Google Patents

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Publication number
EP0402367B1
EP0402367B1 EP89902253A EP89902253A EP0402367B1 EP 0402367 B1 EP0402367 B1 EP 0402367B1 EP 89902253 A EP89902253 A EP 89902253A EP 89902253 A EP89902253 A EP 89902253A EP 0402367 B1 EP0402367 B1 EP 0402367B1
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EP
European Patent Office
Prior art keywords
voltage
current
protective device
regulating circuit
input
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EP89902253A
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German (de)
French (fr)
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EP0402367A1 (en
Inventor
Reinhard Kalfhaus
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Individual
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Individual
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Priority to AT89902253T priority Critical patent/ATE89439T1/en
Publication of EP0402367A1 publication Critical patent/EP0402367A1/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
    • G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
    • G05F1/569—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for protection

Definitions

  • the invention relates to a protective device for a power converter such as a power supply unit, inverter or DC / DC converter with a voltage control circuit and a current control circuit which forms a current limiting device and is arranged in parallel or subordinate to the latter, and an actuator in the voltage and current control circuit which has a variable resistance value , the resistance value of which is changed as a function of the difference between the voltage present at the input of the protective device and the voltage present at the output of the protective device, the voltage control loop including a comparison device connected to a voltage setpoint generator and a voltage actual value transmitter, which is followed by a control amplifier, the Resistance value of the actuator can also be changed as a function of the input current derived from a shunt and supplied to the current control loop as an actual value.
  • a power converter such as a power supply unit, inverter or DC / DC converter with a voltage control circuit and a current control circuit which forms a current limiting device and is arranged in parallel or subordinate to the latter
  • a control device with the features described above is known from DE-A-36 26 088. This control device is intended to accelerate the build-up of the input voltage to its final value.
  • a power supply unit with a transformer-fed bridge rectifier, to the outputs of which a capacitor is connected.
  • the series connection of a Darlington transistor and a shunt is arranged between the rectifier and the power supply unit output.
  • the transistor is an actuator in a voltage control loop, which regulates the output voltage to a constant value.
  • the power supply contains a current limiting device which has a transistor which is connected in parallel with the base-emitter path to the shunt and whose collector is connected to the control input of the Darlington transistor.
  • the control input is also connected to an output of a differential amplifier, which works as a voltage setpoint and actual voltage comparator, and to an operating voltage source. Due to the non-linear characteristic of the transistor connected to the shunt, the current limitation starts at a certain limit, whereby the Darlington transistor receives less base current, so that its resistance value increases (US-A-3,671,852).
  • a protective device with a current limiting device which contains a fixed ohmic resistor and a transistor connected in parallel with it, which works as an adjustable resistor.
  • the emitter-collector path of a bipolar transistor is connected in parallel to two resistors arranged in series.
  • a further resistor is arranged in the emitter circuit of the transistor, through which the entire current fed into a power converter flows.
  • the further resistor is connected at its connection not connected to the emitter to the base of the transistor via two diodes arranged in series, which are further connected to an operating voltage source fed by the power converter, which is supplied with voltage by an auxiliary winding of the transformer of the power converter .
  • the capacitive input of the power converter is charged with a current limited by the resistance value via the fixed resistor until the transistor is controlled by a base current.
  • the transistor gradually saturates so that the majority of the current flows through the transistor. If undesired high voltages occur at the input of the protective device when the transistor is saturated, the increasing current increases the negative feedback voltage in the emitter circuit of the transistor.
  • the associated reduction in the base-emitter potential increases the resistance of the emitter-collector path, so that the emitter current in turn decreases (EP-A-0250 158).
  • the invention is based on the object of further developing a protective device of the type described at the outset in such a way that the power converter is protected against undesirably high voltages occurring at the input of the protective device.
  • the charging of an energy-storing and capacitive input of the power converter should also take place more quickly at the protective device even when the input voltages are below the nominal voltage.
  • the protective circuit is arranged in front of a power converter which is connected to an energy source via the series connection of the shunt and the actuator, and has a capacitive input with at least one capacitive element at which the actual value the voltage of the voltage control loop is tapped, the setpoint of the voltage control loop being set so high that the setpoint does not appear at the capacitive element of the power converter, even with minimum resistance of the actuator and maximum nominal input voltage, and the current setpoint of the current control loop the maximum permissible input current is set.
  • the resistance value preferably corresponds to the quotient of maximum permissible static nominal input voltage and the no - load current drawn by the power converter at this nominal input voltage, so that the charging current can be limited to a desired small value when the energy source is switched on.
  • the current control circuit - subordinate or connected in parallel - causes a current corresponding to the current setpoint to flow in the adjustable resistor.
  • the capacitor is therefore not only charged with the current flowing through the charging current limiting resistor, as a result of which the charging is accelerated.
  • a desired current profile can be achieved by coordinating the charging current limiting resistor and the current setpoint.
  • the setpoint of the voltage control loop is set so high that even with a minimum resistance of the transistor the maximum nominal input voltage is not sufficient so that the voltage setpoint is reached at the capacitive element of the power converter.
  • the adjustable resistance then has its lowest value at the nominal input voltage, which results in the lowest current heat losses. This has a favorable effect on the efficiency of the power converter such as the power supply. If the input voltage rises above the limit specified by the voltage setpoint, the control loop prevents the occurrence of high undesired voltages on the capacitive elements or the downstream circuits.
  • the input voltage can therefore e.g. accept the peak voltages permitted according to VDE or VG guidelines for the defined time, without inadmissibly high voltages occurring at the capacitor itself or the downstream circuits, especially the semiconductors.
  • An additional comparison device connected to the shunt is preferably connected to the control amplifier, which is followed by a further control amplifier, the output of which feeds the control electrode of the actuator designed as a transistor.
  • the protective device in which the protective device is supplied, in particular during autonomous operation, by its own voltage supply, which in turn is obtained from the nominal input voltage, it is provided that the protective device is switched to inactive in order to nonetheless prevent idling currents from the energy source to prevent existing operational readiness.
  • a switching regulator for generating a regulated direct voltage is connected to the capacitive load and contains a transformer which is provided with an auxiliary winding for generating the operating voltage for the regulating amplifiers in the regulating circuit of the protective device.
  • the switching regulator which can have a customary structure, only comes into operation at a certain minimum voltage at the capacitive load. This means that the protective device or its control circuit are only supplied with operating voltage when the switching regulator is working.
  • the charging current limiting resistor In the first time immediately after the nominal input voltage is applied, e.g. AC mains voltage or battery voltage, the charging current limiting resistor therefore determines the charging current of the capacitive element such as the capacitor alone.
  • the adjustable resistance only occurs when the control amplifiers have received their operating voltage, i.e. the transistor in operation.
  • the protective device can be supplied, in particular in the case of autonomous operation, by its own voltage supply, which in turn is obtained from the nominal input voltage.
  • an auxiliary voltage supplied to a chopper stage is fed from the supply voltage via the chopper stage and a transformer to the voltage current control circuit.
  • the current limiting resistor can be omitted and e.g. With a remote - controlled switch - off signal, the protective device can be switched inactive in order to prevent no - load currents from the energy source while the device is still ready for operation.
  • a remote control signal can be used to immediately switch both the supply voltage for the voltage current control circuit and the downstream power stage or power stages to inactive.
  • one proposal is characterized in that the chopper stage is switched on immediately via a remote control signal, and the power stage or power stages are switched on with a delay with a link to the minimum limit voltage.
  • the current control loop can be replaced by a plurality of current control loops connected in parallel and each having the actuator.
  • the invention is described with the aid of a power converter in the form of a power supply unit, without this being intended to impose a restriction.
  • a power supply unit for generating a DC voltage contains a rectifier (1), e.g. a full-wave rectifier, which is fed with its AC voltage inputs (2), (3) from the mains AC voltage.
  • the rectifier (1) is connected to the DC voltage outputs (4), (5) in each case to a charging current limiting resistor (6) and to the drain electrode of a field effect transistor (13), which has a drain-source path in series with a capacitive element (10), which is connected to the DC voltage output (5) of the rectifier (1).
  • a switching stage consisting of the switching transistor (7) designed as a field-effect transistor and the transformer (9) is connected in parallel with the capacitive element (10), the capacitive element (10) being used in particular for smoothing and energy storage of the rectified AC mains voltage.
  • a further rectifier (not shown in more detail) and smoothing devices are connected to the secondary winding (11) of the transformer (9) and feed a load.
  • the gate electrode of the field effect transistor (7) is connected to a control and regulating circuit (12) which actuates the field effect transistor (7) with pulse duration modulation in order to generate a regulated DC voltage at the output of the power supply.
  • the control and regulating circuit (12) forms a switching regulator with the transformer (9), the rectifier on the secondary side of the transformer (9) as well as with the smoothing means and a voltage actual value transmitter.
  • a transistor (13), preferably a field effect transistor, is arranged in series with a current sensor (a shunt) (14) as the adjustable resistor.
  • the control electrode of the transistor (13) is connected to a comparison device (16) which is connected to the current sensor (14) and via a resistor (17) to the output of another control amplifier (18).
  • a voltage limiting device (19) e.g. Zener diode (19) connected.
  • the control amplifier (18) is connected at its input to a comparison device (26) to which a voltage setpoint device (20), e.g. a Zener diode, and a resistor (21) which connects one electrode (reference point (32)) of the capacitive element (10).
  • the transformer (9) contains an auxiliary winding (22) which is arranged in series with a diode (23) which feeds a capacitor (24), from which the operating voltage for the control amplifiers (15), (18) is tapped .
  • the capacitor (24) is arranged parallel to the series connection of the auxiliary winding (22) and the diode (23), and has an electrode with the shunt (14) (reference number (30)) and the capacitive element (10) (reference number (31 )) in connection (potential in points (30) and (31) is the same).
  • the charging current limiting resistor (6) is of high impedance. It limits the inrush or inrush current of the AC line voltage when the maximum overvoltage value is applied. It is at a value which is as large as the current flowing into the capacitor when the power supply is idling. Charging the capacitive element (10) builds up a voltage that reaches a limit above which the control and regulating circuit (12) begins to function, the switching regulator starting to work by means of the field effect transistor (7). As a result, the control amplifiers (15), (18) are also supplied with operating voltage via the auxiliary winding (22), the diode (23) and the capacitor (24).
  • the nominal value of the voltage at the comparison device (26) corresponds to the maximum nominal input voltage.
  • the control amplifier (18) receives operating voltage, a high output DC voltage occurs at the control amplifier (18), which is set, for example, by means of the resistor (17) and the Zener diode (19) in such a way that it becomes a reference variable Current value corresponds.
  • This voltage which corresponds to the maximum permissible current value, has the effect via the comparison device (16) and the control amplifier (15) that the transistor (13) is turned on and regulates the maximum permissible current setpoint in the capacitive element (10) and the downstream circuits feeds in.
  • the transistor (13) has a resistance corresponding to the current setpoint.
  • the resistor (21), the voltage setpoint transmitter (20), the comparison device (26), the control amplifier (18), the resistor (17), the Zener diode (19), the comparison device (16) and the control amplifier (15 ) are components of the control circuit described above, which contains the transistor (13) as an actuator and, as a control variable, influences the voltage drop across the capacitor (10) or the current flowing through the shunt (14).
  • This control loop (Reference symbol (28)) contains a current control circuit (33) with the transistor (13) as an actuator, the current sensor (14) as a current actual value transmitter, the control amplifier (15) and the comparison device (16), and a voltage control circuit (34) with the voltage sensor ( 21) as a voltage actual value transmitter, the voltage setpoint transmitter (20), the control amplifier (18) and the comparison device (26).
  • the current and voltage control circuit (33) or (34) can also act directly (in parallel) on the actuator (13) with their respective output and not as shown.
  • the current flowing into the capacitive element (10) and the downstream circuits would increase indefinitely without the current control circuit (33).
  • the transistor (13) receives less control current or control voltage when the input voltage rises, as a result of which its resistance is increased, i. the current setpoint is retained because the actual voltage value remains lower than the voltage setpoint. This means that the voltage - If the voltage at the input rises even further, above the set voltage setpoint, the voltage falling across the capacitive element (10) is regulated, i.e. the downstream circuits do not receive a DC voltage that rises in the same way over the input voltage.
  • the voltage control loop (34) therefore limits the voltage at the capacitive element (10) to a value that is compatible with the system. High input voltages therefore cause voltage drops at the current limiting resistor (6) and at the adjustable resistor (13) connected in parallel with it. Therefore, the power supply can generate a regulated output voltage with secured functionality even with dynamic overvoltage.
  • a voltage limiting circuit (27) is expediently arranged parallel to the capacitive element (10), the response threshold of which is higher than the voltage setpoint (20) present at the comparison device (26).
  • This voltage limiting circuit (27) can protect the capacitive element at very high input voltages and the resulting current via the resistor (6) when the input voltage is too high and especially when the device is idling. It is advantageous if the value of the charging current limiting resistor corresponds to the quotient of the difference between the maximum permissible static overvoltage and the voltage setpoint at the capacitive element (10) and the no-load current of the power converter.
  • Fig. 2 the protective device described with reference to Fig. 1 is modified so that an autonomous mode of operation is possible. Apart from the charge current limiting resistor (6), the circuit elements and the structure of the circuit are otherwise preserved. To enable self-sufficient operation, an auxiliary voltage (36) is taken from the DC voltage outputs (4) and (5), which is fed to a chopper stage (37) and then via a transformer with the primary winding (35) in the Secondary winding (22) is fed. The function of the circuit according to FIG. 2 otherwise corresponds to that of FIG. 1.
  • FIG. 2 shows the possibility of switching the power supply inactive or inhibit with an extremely low quiescent current.
  • a remote control signal (39) is fed to the chopper stage (37) and a logic stage (40) with a switch-on delay stage (41) which may be connected downstream.
  • the chopper stage (37) and thus the current voltage control loop (28) are activated immediately and the power stage (12) or several power stages connected in parallel are delayed (circuit (41)) via the AND link (40 ) activated.
  • the lower switch-on threshold (31), (32) of the power level is detected.

Abstract

A power transformer, such as a mains appliance, generates a d.c. voltage by means of a rectifier (1) connected to a capacitative element (10) via a charging current limiting resistor (6) which has a high value. A variable resistor arranged parallel to the charging current limiting resistor (6) serves as a control element in a control circuit whose control value is the voltage at the capacitative element (10). A current-regulating circuit (33) for regulating the current flowing through the control element is connected in cascade or in parallel with the voltage-regulating circuit (34).

Description

Die Erfindung bezieht sich auf eine Schutz - einrichtung für einen Leistungswandler wie Netzgerät, Wechselrichter oder Gleichspannungs - wandler mit einem Spannungsregelkreis und einem diesem parallel oder unterlagert angeordneten, eine Strombegrenzungseinrichtung bildenden Stromre - gelkreis sowie einem einen veränderlichen Widerstandwert aufweisenden Stellglied in dem Spannungs - und Stromregelkreis, dessen Widerstandswert in Abhängigkeit von der Differenz der am Eingang der Schutzeinrichtung anliegenden Spannung und der am Ausgang der Schutzein - richtung anliegenden Spannung verändert wird, wobei der Spannungsregelkreis eine an einen Spannungssollwertgeber und einen Spannungsistwertgeber angeschlossene Vergleichseinrichtung enthält, der ein Regelverstärker nachgeschaltet ist, wobei der Widerstandswert des Stellgliedes auch in Abhängigkeit des von einem Shunt abgeleiteten und dem Stromregelkreis als Istwert zugeführten Eingangsstromes veränderbar ist.The invention relates to a protective device for a power converter such as a power supply unit, inverter or DC / DC converter with a voltage control circuit and a current control circuit which forms a current limiting device and is arranged in parallel or subordinate to the latter, and an actuator in the voltage and current control circuit which has a variable resistance value , the resistance value of which is changed as a function of the difference between the voltage present at the input of the protective device and the voltage present at the output of the protective device, the voltage control loop including a comparison device connected to a voltage setpoint generator and a voltage actual value transmitter, which is followed by a control amplifier, the Resistance value of the actuator can also be changed as a function of the input current derived from a shunt and supplied to the current control loop as an actual value.

Eine Regeleinrichtung mit den vorstehend be - schriebenen Merkmalen ist aus der DE-A-36 26 088 bekannt. Mit dieser Regeleinrichtung soll ein beschleunigter Aufbau der Eingangsspannung auf ihren Endwert erfolgen.A control device with the features described above is known from DE-A-36 26 088. This control device is intended to accelerate the build-up of the input voltage to its final value.

Bekannt ist auch ein Netzgerät, mit einem transformatorgespeisten Brückengleichrichter, an dessen Ausgänge ein Kondensator angeschlossen ist. Zwischen dem Gleichrichter und dem Netzge - räteausgang ist die Reihenschaltung eines Darlington - Transistors und eines Shunts angeordnet. Der Transistor ist Stellglied in einem Spannungsregelkreis, durch den die Ausgangsspannung auf einen gleichbleibenden Wert geregelt wird.Also known is a power supply unit with a transformer-fed bridge rectifier, to the outputs of which a capacitor is connected. The series connection of a Darlington transistor and a shunt is arranged between the rectifier and the power supply unit output. The transistor is an actuator in a voltage control loop, which regulates the output voltage to a constant value.

Das Netzgerät enthält eine Strombegren - zungseinrichtung, die einen mit der Basis-Emitter-Strecke zum Shunt parallel gelegten Transistor aufweist, dessen Kollektor mit dem Steuereingang des Darlington-Transistors verbunden ist. Der Steuereingang ist weiterhin an ei - nen Ausgang eines als Spannungssoll - und Spannungsistwertvergleicher arbeitenden Diffe - renzverstärkers und an eine Betriebsspannungs - quelle angeschlossen. Aufgrund der nichtlinearen Kennlinie des an den Shunt angeschlossenen Transistors, setzt die Strombegrenzung ab einem bestimmten Grenzwert ein, wobei der Darlington - Transistor weniger Basisstrom erhält, so daß sein Widerstandswert zunimmt (US-A-3,671,852).The power supply contains a current limiting device which has a transistor which is connected in parallel with the base-emitter path to the shunt and whose collector is connected to the control input of the Darlington transistor. The control input is also connected to an output of a differential amplifier, which works as a voltage setpoint and actual voltage comparator, and to an operating voltage source. Due to the non-linear characteristic of the transistor connected to the shunt, the current limitation starts at a certain limit, whereby the Darlington transistor receives less base current, so that its resistance value increases (US-A-3,671,852).

Schließlich ist eine Schutzeinrichtung mit einer Strombegrenzungseinrichtung bekannt, die einen festen ohmschen Widerstand und einen zu diesem parallel geschalteten Transistor enthält, der als einstellbarer Widerstand arbeitet. Die Emitter - Kollektor-Strecke eines bipolaren Transistors ist zu zwei in Serie angeordneten Widerständen parallel gelegt. Im Emitterkreis des Transistors ist ein weiterer Widerstand angeordnet, der vom gesam - ten, in einen Leistungswandler eingespeisten Strom durchflossen wird. Der weitere Widerstand ist an seinem nicht an den Emitter gelegten Anschluß über zwei in Serie angeordnete Dioden mit der Basis des Transistors verbunden, die weiterhin an eine vom Leistungswandler gespeiste Betriebsspannungsquelle angeschlossen ist, die von einer Hilfswicklung des Transformators des Leistungs - wandlers mit Spannung versorgt wird. Der kapazi - tive Eingang des Leistungswandlers wird über den festen Widerstand mit einem durch den Widerstandswert in der Höhe begrenzten Strom aufgeladen, bis der Transistor durch einen Basisstrom leitend gesteuert wird. Der Transistor gelangt all - mählich in die Sättigung, so daß der überwiegende Teil des Stroms über den Transistor fließt. Wenn bei gesättigtem Transistor am Eingang der Schutzeinrichtung unerwünscht hohe Spannungen auftreten, erhöht der ansteigende Strom die Gegenkopplungsspannung im Emitterkreis des Tran - sistors. Durch die hiermit verbundene Verkleine - rung des Basis-Emitter-Potential erhöht sich der Widerstand der Emitter - Kollektor - Strecke, so daß der Emitterstrom wiederum abnimmt (EP-A-0250 158).Finally, a protective device with a current limiting device is known which contains a fixed ohmic resistor and a transistor connected in parallel with it, which works as an adjustable resistor. The emitter-collector path of a bipolar transistor is connected in parallel to two resistors arranged in series. A further resistor is arranged in the emitter circuit of the transistor, through which the entire current fed into a power converter flows. The further resistor is connected at its connection not connected to the emitter to the base of the transistor via two diodes arranged in series, which are further connected to an operating voltage source fed by the power converter, which is supplied with voltage by an auxiliary winding of the transformer of the power converter . The capacitive input of the power converter is charged with a current limited by the resistance value via the fixed resistor until the transistor is controlled by a base current. The transistor gradually saturates so that the majority of the current flows through the transistor. If undesired high voltages occur at the input of the protective device when the transistor is saturated, the increasing current increases the negative feedback voltage in the emitter circuit of the transistor. The associated reduction in the base-emitter potential increases the resistance of the emitter-collector path, so that the emitter current in turn decreases (EP-A-0250 158).

Der Erfindung liegt die Aufgabe zugrunde, eine Schutzeinrichtung der eingangs beschriebenen Gattung so weiterzuentwickeln, daß der Leistungs - wandler vor unerwünscht hohen, am Eingang der Schutzeinrichtung auftretenden Spannungen geschützt wird. Auch soll die Aufladung eines energiespeichernden wie kapazitiven Eingangs des Leistungswandlers schneller auch bei unterhalb der Nennspannung liegenden Eingangsspannungen an der Schutzeinrichtung ablaufen.The invention is based on the object of further developing a protective device of the type described at the outset in such a way that the power converter is protected against undesirably high voltages occurring at the input of the protective device. The charging of an energy-storing and capacitive input of the power converter should also take place more quickly at the protective device even when the input voltages are below the nominal voltage.

Die Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Schutzschaltung vor einem Lei - stungswandler angeordnet ist, der mit einer Energiequelle über die Reihenschaltung des Shunts und des Stellgliedes verbunden ist, und einen kapaziti - ven Eingang mit mindestens einem kapazitiven Element aufweist, an dem der Istwert der Span - nung des Spannungsregelkreises abgegriffen wird, wobei der Sollwert des Spannungsregelkreises so hoch eingestellt ist, daß auch bei minimalem Wi - derstand des Stellgliedes und maximaler Nenn - eingangsspannung der Sollwert am kapazitiven Element des Leistungswandlers nicht auftritt, und wobei der Stromsollwert des Stromregelkreises auf den maximal zulässigen Eingangsstrom eingestellt wird.The object is achieved according to the invention in that the protective circuit is arranged in front of a power converter which is connected to an energy source via the series connection of the shunt and the actuator, and has a capacitive input with at least one capacitive element at which the actual value the voltage of the voltage control loop is tapped, the setpoint of the voltage control loop being set so high that the setpoint does not appear at the capacitive element of the power converter, even with minimum resistance of the actuator and maximum nominal input voltage, and the current setpoint of the current control loop the maximum permissible input current is set.

Bei Vorhandensein eines festen Strombegren - zungswiderstands entspricht dessen Widerstands - wert vorzugsweise dem Quotienten aus maximal zulässiger, statischer Nenneingangsspannung und dem bei dieser Nenneingangsspannung vom Leistungswandler aufgenommenen Leerlaufstrom, so daß der Ladestrom beim Aufschalten der Energie - quelle auf einen gewünschten kleinen Wert begrenzt werden kann. Solange die Spannung am jeweiligen energiespeichernden kapazitiven Element wie Kondensator unterhalb des eingestellten Spannungssollwerts liegt, bewirkt der - unterlagerte oder parallel geschaltete - Stromregelkreis das Fließen eines dem Stromsollwert entsprechenden Stroms im einstellbaren Widerstand. Der Kondensator wird deshalb nicht nur mit dem über den Ladestrombegrenzungswiderstand fließenden Strom aufgeladen, wodurch die Aufladung beschleunigt wird. Durch die Abstimmung zwischen dem Ladestrombegrenzungswiderstand und dem Stromsollwert kann ein gewünschter Stromverlauf erreicht werden.If there is a fixed current limiting resistor, its resistance value preferably corresponds to the quotient of maximum permissible static nominal input voltage and the no - load current drawn by the power converter at this nominal input voltage, so that the charging current can be limited to a desired small value when the energy source is switched on. As long as the voltage at the respective energy-storing capacitive element, such as the capacitor, is below the set voltage setpoint, the current control circuit - subordinate or connected in parallel - causes a current corresponding to the current setpoint to flow in the adjustable resistor. The capacitor is therefore not only charged with the current flowing through the charging current limiting resistor, as a result of which the charging is accelerated. A desired current profile can be achieved by coordinating the charging current limiting resistor and the current setpoint.

Der Sollwert des Spannungsregelkreises wird so hoch eingestellt, daß auch bei minimalem Wi - derstand des Transistors die maximale Nennein - gangsspannung nicht ausreicht, damit am kapazi - tiven Element des Leistungswandlers der Span - nungssollwert erreicht wird. Dann hat der einstell - bare Widerstand bei der Nenneingangsspannung seinen geringsten Wert, wodurch die geringsten Stromwärmeverluste auftreten. Dies wirkt sich günstig auf den Wirkungsgrad des Leistungswandlers wie Netzgerät aus. Steigt die Eingangs - spannung über die durch den Spannungssollwert vorgegebene Grenze an, dann verhindert der Regelkreis das Auftreten hoher unerwünschter Span - nungen an den kapazitiven Elementen bzw. den nachgeschalteten Stromkreisen. Die Eingangsspannung kann daher z.B. die nach VDE bzw. VG - Richtlinien zulässigen Spitzenspannungen für die definierte Zeit annehmen, ohne daß an den dem Kondensator selbst bzw. den nachgeschalte - ten Stromkreisen, insbesondere den Halbleitern, unzulässig hohe Spannungen entstehen.The setpoint of the voltage control loop is set so high that even with a minimum resistance of the transistor the maximum nominal input voltage is not sufficient so that the voltage setpoint is reached at the capacitive element of the power converter. The adjustable resistance then has its lowest value at the nominal input voltage, which results in the lowest current heat losses. This has a favorable effect on the efficiency of the power converter such as the power supply. If the input voltage rises above the limit specified by the voltage setpoint, the control loop prevents the occurrence of high undesired voltages on the capacitive elements or the downstream circuits. The input voltage can therefore e.g. accept the peak voltages permitted according to VDE or VG guidelines for the defined time, without inadmissibly high voltages occurring at the capacitor itself or the downstream circuits, especially the semiconductors.

Vorzugsweise ist an den Regelverstärker eine zusätzliche, mit dem Shunt verbundene Vergleichseinrichtung angeschlossen, der ein weiterer Regelverstärker nachgeschaltet ist, dessen Ausgang die Steuerelektrode des als Transistor ausgebildeten Stellglieds speist.An additional comparison device connected to the shunt is preferably connected to the control amplifier, which is followed by a further control amplifier, the output of which feeds the control electrode of the actuator designed as a transistor.

In einer weiteren besonders hervorzuhebenden Ausführungsform, bei der die Schutzeinrichtung insbesondere bei autarkem Betrieb durch eine ei - gene Spannungsversorgung, die ihrerseits aus der Nenneingangsspannung gewonnen wird, versorgt wird, ist vorgesehen, daß die Schutzeinrichtung inaktiv geschaltet wird, um Leerlaufströme aus der Energiequelle bei dennoch bestehender Betriebs - bereitschaft zu unterbinden.In a further particularly noteworthy embodiment, in which the protective device is supplied, in particular during autonomous operation, by its own voltage supply, which in turn is obtained from the nominal input voltage, it is provided that the protective device is switched to inactive in order to nonetheless prevent idling currents from the energy source to prevent existing operational readiness.

Bei einer bevorzugten Ausführungsform ist mit der kapazitiven Last ein Schaltregler für die Erzeugung einer geregelten Gleichspannung verbunden, der einen Transformator enthält, der mit einer Hilfswicklung zur Erzeugung der Betriebsspannung für die Regelverstärker im Regelkreis der Schutzeinrichtung versehen ist. Der Schaltregler, der einen üblichen Aufbau haben kann, tritt erst bei einer gewissen Mindestspannung an der kapazitiven Last in Funktion. Dies bedeutet, daß die Schutzeinrichtung bzw. deren Regelkreis erst beim Arbeiten des Schaltreglers mit Betriebsspannung versorgt werden. In der ersten Zeit unmittelbar nach dem Anlegen der Nenneingangsspannung wie z.B. einer Netzwechselspannung bzw. Batteriespannung, bestimmt daher der Ladestrombegren - zungswiderstand den Aufladestrom des kapazitiven Elements wie Kondensator alleine. Erst wenn die Regelverstärker ihre Betriebsspannung erhalten haben, tritt der einstellbare Widerstand, d.h. der Transistor in Funktion.In a preferred embodiment, a switching regulator for generating a regulated direct voltage is connected to the capacitive load and contains a transformer which is provided with an auxiliary winding for generating the operating voltage for the regulating amplifiers in the regulating circuit of the protective device. The switching regulator, which can have a customary structure, only comes into operation at a certain minimum voltage at the capacitive load. This means that the protective device or its control circuit are only supplied with operating voltage when the switching regulator is working. In the first time immediately after the nominal input voltage is applied, e.g. AC mains voltage or battery voltage, the charging current limiting resistor therefore determines the charging current of the capacitive element such as the capacitor alone. The adjustable resistance only occurs when the control amplifiers have received their operating voltage, i.e. the transistor in operation.

In einer weiteren besonders hervorzuhebenden Ausführungsform kann die Schutzeinrichtung insbesondere bei autarkem Betrieb durch eine eigene Spannungsversorgung, die ihrerseits aus der Nenneingangsspannung gewonnen wird, versorgt werden. Insbesondere ist vorgesehen, daß von der Versorgungsspannung eine einer Chopper-Stufe zugeführte Hilfsspannung über die Chopper-Stufe und einen Transformator dem Spannungsstromre - gelkreis zugeführt wird.In a further particularly noteworthy embodiment, the protective device can be supplied, in particular in the case of autonomous operation, by its own voltage supply, which in turn is obtained from the nominal input voltage. In particular, it is provided that an auxiliary voltage supplied to a chopper stage is fed from the supply voltage via the chopper stage and a transformer to the voltage current control circuit.

Bei autarkem Betrieb kann der Strombegren - zungswiderstand entfallen und mittels z.B. eines ferngesteuerten Ausschaltsignals kann die Schutz - einrichtung inaktiv geschaltet werden, um Leerlaufströme aus der Energiequelle bei dennoch bestehender Betriebsbereitschaft zu unterbinden.In the case of autonomous operation, the current limiting resistor can be omitted and e.g. With a remote - controlled switch - off signal, the protective device can be switched inactive in order to prevent no - load currents from the energy source while the device is still ready for operation.

So kann über ein Fernsteuersignal sowohl die Versorgungsspannung für den Spannungsstrom - regelkreis als auch die nachgeschaltete Leistungsstufe bzw. nachgeschalteten Leistungsstufen unverzüglich inaktiv geschaltet werden. Insbeson - dere zeichnet sich ein Vorschlag dadurch aus, daß über ein Fernsteuersignal die Chopper-Stufe unverzüglich, die Leistungsstufe bzw. Leistungsstufen über eine Verknüpfung mit der minimalen Grenzspannung zeitverzögert aktiv geschaltet werden.A remote control signal can be used to immediately switch both the supply voltage for the voltage current control circuit and the downstream power stage or power stages to inactive. In particular, one proposal is characterized in that the chopper stage is switched on immediately via a remote control signal, and the power stage or power stages are switched on with a delay with a link to the minimum limit voltage.

Schließlich ist hervorzuheben, daß der Strom - regelkreis durch mehrere parallel geschaltete, jeweils das Stellglied aufweisende Stromregelkreise ersetzbar ist.Finally, it should be emphasized that the current control loop can be replaced by a plurality of current control loops connected in parallel and each having the actuator.

Weitere Einzelheiten, Vorteile und Merkmale der Erfindung ergeben sich nicht nur aus den An - sprüchen, den diesen zu entnehmenden Merkmalen -für sich und/oder in Kombination-, sondern auch aus der nachfolgenden Beschreibung von in der Zeichnung dargestellten bevorzugten Ausfüh - rungsbeispielen.Further details, advantages and features of the invention result not only from the claims, the features to be extracted from them - by themselves and / or in combination - but also from the following description of preferred exemplary embodiments shown in the drawing.

Es zeigen:

  • Fig. 1 ein Blockschaltbild einer Schutzeinrich - tung und
  • Fig. 2 die Schutzeinrichtung nach Fig. 1 in au - tarker Betriebsweise.
Show it:
  • 1 is a block diagram of a protective device and
  • 2 shows the protective device according to FIG. 1 in an autonomous mode of operation.

Die Erfindung wird an Hand eines Leistungs - wandlers in Form eines Netzgerätes beschrieben, ohne daß hierdurch eine Einschränkung erfolgen soll.The invention is described with the aid of a power converter in the form of a power supply unit, without this being intended to impose a restriction.

Ein Netzgerät zur Erzeugung einer Gleichspannung enthält einen Gleichrichter (1), z.B. einen Doppelweggleichrichter, der mit seinen Wechsel - spannungseingängen (2), (3) von der Netzwech - selspannung gespeist wird. Der Gleichrichter (1) ist mit den Gleichspannungsausgängen (4), (5) jeweils an einen Ladestrombegrenzungswiderstand (6) und an die Drain - Elektrode eines Feldeffekttransistors (13) angeschlossen, der mit seiner Drain-Source - Strecke in Reihe zu einem kapazitiven Element (10) gelegt ist, das mit dem Gleichspan - nungsausgang (5) des Gleichrichters (1) verbunden ist. Parallel zu dem kapazitiven Element (10) ist eine Schaltstufe bestehend aus dem als Feldeffekttransistor ausgebildeten Schalttransistor (7) und dem Transformator (9) geschaltet, wobei das kapazitive Element (10) insbesondere zur Glättung und Energiespeicherung der gleichgerichteten Netzwechselspannung verwendet wird. An die Sekundärwicklung (11) des Transformators (9) ist ein weiterer, nicht näher dargestellter Gleichrichter nebst Glättungseinrichtungen angeschlossen, der eine Last speist. Die Gate - Elektrode des Feldeffekttransistors (7) ist mit einer Steuer- und Regelschaltung (12) verbunden, die den Feldeffekttransistor (7) impulsdauermoduliert betätigt, um am Ausgang des Netzgerätes eine geregelte Gleich - spannung zu erzeugen. Die Steuer- und Regelschaltung (12) bildet mit dem Transformator (9), dem Gleichrichter auf der Sekundärseite des Transformators (9) sowie mit den Glättungsmitteln und einem Spannungsistwertgeber einen Schaltregler.A power supply unit for generating a DC voltage contains a rectifier (1), e.g. a full-wave rectifier, which is fed with its AC voltage inputs (2), (3) from the mains AC voltage. The rectifier (1) is connected to the DC voltage outputs (4), (5) in each case to a charging current limiting resistor (6) and to the drain electrode of a field effect transistor (13), which has a drain-source path in series with a capacitive element (10), which is connected to the DC voltage output (5) of the rectifier (1). A switching stage consisting of the switching transistor (7) designed as a field-effect transistor and the transformer (9) is connected in parallel with the capacitive element (10), the capacitive element (10) being used in particular for smoothing and energy storage of the rectified AC mains voltage. A further rectifier (not shown in more detail) and smoothing devices are connected to the secondary winding (11) of the transformer (9) and feed a load. The gate electrode of the field effect transistor (7) is connected to a control and regulating circuit (12) which actuates the field effect transistor (7) with pulse duration modulation in order to generate a regulated DC voltage at the output of the power supply. The control and regulating circuit (12) forms a switching regulator with the transformer (9), the rectifier on the secondary side of the transformer (9) as well as with the smoothing means and a voltage actual value transmitter.

Parallel zum Ladestrombegrenzungswiderstand (6) ist als einstellbarer Widerstand ein Transistor (13), vorzugsweise ein Feldeffekttransistor, in Reihe mit einem Stromfühler (einem Shunt) (14) angeordnet. Die Steuerelektrode des Transistors (13) ist mit dem eine Vergleichseinrichtung (16) angeschlossen ist, die mit dem Stromfühler (14) und über einen Widerstand (17) mit dem Ausgang eines anderen Regelverstärkers (18) verbunden ist.Parallel to the charging current limiting resistor (6), a transistor (13), preferably a field effect transistor, is arranged in series with a current sensor (a shunt) (14) as the adjustable resistor. The control electrode of the transistor (13) is connected to a comparison device (16) which is connected to the current sensor (14) and via a resistor (17) to the output of another control amplifier (18).

Weiterhin ist an die Vergleichseinrichtung (16) eine Spannungsbegrenzungseinrichtung (19), z.B. Zener-Diode (19) angeschlossen. Der Regelver - stärker (18) ist an seinem Eingang mit einer Vergleichseinrichtung (26) verbunden, an die ein Spannungssollwertgeber (20), z.B. eine Zener- Diode, und über einen Widerstand (21) die eine Elektrode (Bezugspunkt (32)) des kapazitiven Elements (10) angeschlossen ist.Furthermore, a voltage limiting device (19), e.g. Zener diode (19) connected. The control amplifier (18) is connected at its input to a comparison device (26) to which a voltage setpoint device (20), e.g. a Zener diode, and a resistor (21) which connects one electrode (reference point (32)) of the capacitive element (10).

Der Transformator (9) enthält eine Hilfswicklung (22), die in Reihe mit einer Diode (23) ange - ordnet ist, die einen Kondensator (24) speist, an dem die Betriebsspannung für die Regelverstärker (15), (18) abgegriffen wird. Der Kondensator (24) ist parallel zur Reihenschaltung der Hilfswicklung (22) und der Diode (23) angeordnet, und steht mit einer Elektrode mit dem Shunt (14) (Bezugszeichen (30)) und dem kapazitiven Element (10) (Bezugszeichen(31)) in Verbindung (Potential in dem Punkten (30) und (31) ist gleich).The transformer (9) contains an auxiliary winding (22) which is arranged in series with a diode (23) which feeds a capacitor (24), from which the operating voltage for the control amplifiers (15), (18) is tapped . The capacitor (24) is arranged parallel to the series connection of the auxiliary winding (22) and the diode (23), and has an electrode with the shunt (14) (reference number (30)) and the capacitive element (10) (reference number (31 )) in connection (potential in points (30) and (31) is the same).

Der Ladestrombegrenzungswiderstand (6) ist hochohmig ausgebildet. Er begrenzt den Einschalt- bzw. Aufschaltstrom der beim Anlegen der ihren maximal zulässigen Überspannungswert aufweisenden Netzwechselspannung. Er steht auf einem Wert, der so groß wie der im Leerlauf des Netzgerätes in den Kondensator fließenden Stromes ist. Durch die Aufladung des kapazitiven Ele - ments (10) baut sich eine Spannung auf, die eine Grenze erreicht, ab der die Steuer- und Regelschaltung (12) jeweils in Funktion tritt, wobei der Schaltregler mittels des Feldeffekttransistors (7) zu arbeiten beginnt. Hierdurch werden auch die Regelverstärker (15), (18) über die Hilfswicklung (22), die Diode (23) und der Kondensator (24) mit Betriebsspannung versorgt.The charging current limiting resistor (6) is of high impedance. It limits the inrush or inrush current of the AC line voltage when the maximum overvoltage value is applied. It is at a value which is as large as the current flowing into the capacitor when the power supply is idling. Charging the capacitive element (10) builds up a voltage that reaches a limit above which the control and regulating circuit (12) begins to function, the switching regulator starting to work by means of the field effect transistor (7). As a result, the control amplifiers (15), (18) are also supplied with operating voltage via the auxiliary winding (22), the diode (23) and the capacitor (24).

Der Sollwert der Spannung an der Vergleichs - einrichtung (26) entspricht der maximalen Nenn - eingangsspannung. Wenn der Regelverstärker (18) Betriebsspannung erhält, tritt an der durch die der Regelverstärker (18) eine hohe Ausgangsgleich - spannung erzeugt, die beispielsweise mittels des Widerstandes (17) und der Zenerdiode (19) so eingestellt wird, daß sie als Führungsgröße einem zulässigen Stromwert entspricht. Diese dem maxi - mal zulässigen Stromwert entsprechende Span - nung bewirkt über die Vergleichseinrichtung (16) und den Regelverstärker (15), daß der Transistor (13) aufgesteuert wird und den maximal zulässigen Stromsollwert in das kapazitive Element (10) und die nachgeschalteten Stromkreise geregelt ein - speist. Dabei hat der Transistor (13) einen dem Stromsollwert entsprechenden Widerstand. Über den hochohmigen Ladestrombegrenzungswiderstand (6) fließt bei arbeitendem Transistor (13) ein vernachlässigbar kleiner Strom.The nominal value of the voltage at the comparison device (26) corresponds to the maximum nominal input voltage. When the control amplifier (18) receives operating voltage, a high output DC voltage occurs at the control amplifier (18), which is set, for example, by means of the resistor (17) and the Zener diode (19) in such a way that it becomes a reference variable Current value corresponds. This voltage, which corresponds to the maximum permissible current value, has the effect via the comparison device (16) and the control amplifier (15) that the transistor (13) is turned on and regulates the maximum permissible current setpoint in the capacitive element (10) and the downstream circuits feeds in. The transistor (13) has a resistance corresponding to the current setpoint. When the transistor (13) is operating, a negligibly small current flows through the high-resistance charging current limiting resistor (6).

Der Widerstand (21), der Spannungssollvertgeber (20), die Vergleichseinrichtung (26), der Re - gelverstärker (18), der Widerstand (17), die Zener-Diode (19), die Vergleichseinrichtung (16) und der Regelverstärker (15) sind Bestandteile des zuvor beschriebenen Regelkreises, der als Stell - glied den Transistor (13) enthält und als Regel - größe die am Kondensator (10) abfallende Spannung bzw. den über den Shunt (14) fließenden Strom beeinflußt. Dieser Regelkreis (Bezugszeichen (28)) enthält einen Stromregelkreis (33) mit dem Transistor (13) als Stellglied, dem Stromfühler (14) als Stromistwertgeber, dem Regelverstärker (15) und der Vergleichseinrichtung (16) sowie einen Spannungsregelkreis (34) mit dem Spannungsfühler (21) als Spannungsistwertgeber, dem Spannungssollwertgeber (20), dem Regelver - stärker (18) und der Vergleichseinrichtung (26). Der Strom - und Spannungsregelkreis (33) bzw. (34) können mit ihrem jeweiligen Ausgang auch direkt (parallel) auf das Stellglied (13) einwirken und nicht wie dargestellt.The resistor (21), the voltage setpoint transmitter (20), the comparison device (26), the control amplifier (18), the resistor (17), the Zener diode (19), the comparison device (16) and the control amplifier (15 ) are components of the control circuit described above, which contains the transistor (13) as an actuator and, as a control variable, influences the voltage drop across the capacitor (10) or the current flowing through the shunt (14). This control loop (Reference symbol (28)) contains a current control circuit (33) with the transistor (13) as an actuator, the current sensor (14) as a current actual value transmitter, the control amplifier (15) and the comparison device (16), and a voltage control circuit (34) with the voltage sensor ( 21) as a voltage actual value transmitter, the voltage setpoint transmitter (20), the control amplifier (18) and the comparison device (26). The current and voltage control circuit (33) or (34) can also act directly (in parallel) on the actuator (13) with their respective output and not as shown.

Bei einer dynamischen Eingangsspannungserhöhung würde der in das kapazitive Element (10) und die nachgeschalteten Stromkreise fließende Strom ohne den Stromregelkreis (33) unbegrenzt ansteigen. Infolge des Stromregelkreises (33) erhält jedoch der Transistor (13) bei ansteigender Ein - gangsspannung weniger Steuerstrom bzw. Steu - erspannung, wodurch sein Widerstand erhöht wird, d.h. der Stromsollwert bleibt erhalten, da der Spannungsistwert niedriger als der Spannungssollwert bleibt. Das heißt, daß der Spannungs - Bei noch weiter, noch über den eingestellten Span - nungssollwert steigender Spannung am Eingang wird die am kapazitiven Element (10) abfallende Spannung geregelt, d.h. die nachgeschalteten Stromkreise erhalten keine in gleicher Weise über die Eingangsspannung ansteigende Gleichspan - nung. Der Spannungsregelkreis (34) begrenzt die Spannung am kapazitiven Element (10) daher auf einen systemverträglichen Wert. Hohe Eingangs - spannungen bewirken deshalb Spannungsabfälle am Strombegrenzungswiderstand (6) und an dem diesem parallel geschalteten einstellbaren Widerstand (13). Daher kann das Netzgerät auch bei dynamischer Überspannung eine geregelte Ausgangsspannung durch gesicherte Funktionalität erzeugen.In the event of a dynamic input voltage increase, the current flowing into the capacitive element (10) and the downstream circuits would increase indefinitely without the current control circuit (33). As a result of the current control circuit (33), however, the transistor (13) receives less control current or control voltage when the input voltage rises, as a result of which its resistance is increased, i. the current setpoint is retained because the actual voltage value remains lower than the voltage setpoint. This means that the voltage - If the voltage at the input rises even further, above the set voltage setpoint, the voltage falling across the capacitive element (10) is regulated, i.e. the downstream circuits do not receive a DC voltage that rises in the same way over the input voltage. The voltage control loop (34) therefore limits the voltage at the capacitive element (10) to a value that is compatible with the system. High input voltages therefore cause voltage drops at the current limiting resistor (6) and at the adjustable resistor (13) connected in parallel with it. Therefore, the power supply can generate a regulated output voltage with secured functionality even with dynamic overvoltage.

Parallel zum kapazitiven Element (10) ist zweckmäßigerweise eine Spannungsbegren - zungsschaltung (27) angeordnet, deren Ansprech - schwelle höher als der an der Vergleichseinrich - tung (26) anstehende Spannungssollwert (20) ist. Diese Spannungsbegrenzungsschaltung (27) kann bei sehr hohen Eingangsspannungen und dem daraus resultierenden Strom über den Widerstand (6) bei statisch anliegender zu hoher Eingangsspannung und speziell im Leerlauf des Gerätes das kapazitive Element schützen. Es ist günstig, wenn der Wert des Ladestrombegrenzungswiderstandes dem Quotienten aus der Differenz der maximal zulässigen statischen Überspannung und dem Spannungssollwert am kapazitiven Element (10) und dem Leerlaufstrom des Leistungswandlers entspricht.A voltage limiting circuit (27) is expediently arranged parallel to the capacitive element (10), the response threshold of which is higher than the voltage setpoint (20) present at the comparison device (26). This voltage limiting circuit (27) can protect the capacitive element at very high input voltages and the resulting current via the resistor (6) when the input voltage is too high and especially when the device is idling. It is advantageous if the value of the charging current limiting resistor corresponds to the quotient of the difference between the maximum permissible static overvoltage and the voltage setpoint at the capacitive element (10) and the no-load current of the power converter.

In Fig. 2 ist die an Hand der Fig. 1 beschriebene Schutzeinrichtung dahingehend modifiziert, daß eine autarke Betriebsweise möglich ist. An - sonsten sind mit Ausnahme des Ladestrombe - grenzungswiderstands (6) die Schaltungselemente und der Aufbau der Schaltung erhalten. Um einen autarken Betrieb zu ermöglichen, wird von den Gleichspannungsausgängen (4) und (5) eine Hilfs - spannung (36) abgenommen, die einer Chopper-Stufe (37) zugeführt wird und sodann über einen Transformator mit der Primärwicklung (35) in die Sekundärwicklung (22) eingespeist wird. Die Funktion der Schaltung nach Fig. 2 entspricht an - sonsten der der Fig. 1.In Fig. 2, the protective device described with reference to Fig. 1 is modified so that an autonomous mode of operation is possible. Apart from the charge current limiting resistor (6), the circuit elements and the structure of the circuit are otherwise preserved. To enable self-sufficient operation, an auxiliary voltage (36) is taken from the DC voltage outputs (4) and (5), which is fed to a chopper stage (37) and then via a transformer with the primary winding (35) in the Secondary winding (22) is fed. The function of the circuit according to FIG. 2 otherwise corresponds to that of FIG. 1.

Ferner ist in Fig. 2 die Möglichkeit dargestellt, das Netzgerät mit extrem niedrigem Ruhestrom inaktiv oder inhibit zu schalten.Furthermore, FIG. 2 shows the possibility of switching the power supply inactive or inhibit with an extremely low quiescent current.

Ein Fernsteuersignal (39) wird der Chopper-Stufe (37) und einer Verknüpfungsstufe (40) mit gegebenenfalls nachgeschalteter Einschaltverzö - gerungsstufe (41) zugeführt.A remote control signal (39) is fed to the chopper stage (37) and a logic stage (40) with a switch-on delay stage (41) which may be connected downstream.

Beim Inaktivschalten werden unverzüglich die aktiven Schaltkreise stromlos geschaltet.When inactive, the active circuits are immediately de-energized.

Beim Aktivieren wird zunächst unverzüglich die Chopper-Stufe (37) und somit der Stromspan - nungsregelkreis (28) aktiviert und die Leistungs - stufe (12) bzw. mehrere parallel geschaltete Leistungsstufen zeitverzögert (Schaltung (41)) über die UND-Verknüpfung (40) aktiv geschaltet. Hierzu wird die untere Einschaltschwelle (31), (32) der Leistungsstufe erfaßt.When activated, the chopper stage (37) and thus the current voltage control loop (28) are activated immediately and the power stage (12) or several power stages connected in parallel are delayed (circuit (41)) via the AND link (40 ) activated. For this purpose, the lower switch-on threshold (31), (32) of the power level is detected.

Ferner soll nachdrücklich auf eine weitere hervorzuhebende Ausgestaltung hingewiesen werden. So besteht die Möglichkeit, an Stelle eines Stromregelkreises (33) mit dem Stellglied (13) mehrere Stromregelkreise mit aufgeteilter Strom - verteilung parallel zu schalten. Das heißt, daß das dem Spannungsregelkreis (34) entnommene verstärkte Differenzsignal mehreren Stromregelkrei - sen, die den Aufbau des Stromregelkreises (33) zeigen, parallel angeboten werden.Furthermore, a further design to be emphasized should be emphasized. Instead of a current control loop (33), it is possible to use the actuator (13) to connect several current control loops with split power distribution in parallel. This means that the amplified difference signal taken from the voltage control loop (34) is offered in parallel to several current control loops which show the structure of the current control loop (33).

Claims (9)

1. A protective device for a power converter such as a power supply unit, a d.c. - a.c. converter or a d.c. - d.c. converter comprising a voltage regulating circuit (34) and a current regulating circuit (33) which is arranged in parallel to or below said voltage regulating circuit (34) and forms a current limiting device, and comprising a control element (13), which possesses a variable resistance value, in the voltage - and current regulating circuit, the resistance value of which control element (13) is changed in dependence upon the difference between the voltage present at the input of the protective device and the voltage present at the output of the protective device, wherein the voltage regulating circuit (34) contains a comparator device (26) which is connected to a voltage theoretical value sensor (20) and a voltage actual value sensor and which at its output end is connected to a variable amplifier (18), where the resistance value of the control element can also be changed in dependence upon the input current derived from a shunt (14) and supplied to the current regulating circuit as actual value, characterised in that the protective circuit is arranged before a power converter which is connected to an energy source via the series arrangement of the shunt (14) and the control element (13) and possesses a capacitive input with at least one capacitive element (10) from which the actual value of the voltage of the voltage regulating circuit (34) is tapped, where the theoretical value of the voltage regulating circuit is set such that even in the case of the minimum resistance of the control element (13) and the maximum nominal input voltage, the theoretical value does not occur across the capacitive element of the power converter, and where the current theoretical value of the current regulating circuit is set at the maximum permissible input current.
2. A protective device as claimed in Claim 1 comprising a fixed current limiting resistor (6) which is connected in parallel to the adjustable control element (13), characterised in that the resistance value of the fixed current limiting resistor (6) corresponds to the quotient of the maximum permissible, static nominal input voltage and the no load current consumed by the power converter at this nominal input volt - age.
3. A protective device as claimed in one or more of the preceding claims, characterised in that an additional comparator device (16), connected to the shunt (14), is connected to the variable amplifier (18), where said comparator device (16) is connected at its output end to a further variable amplifier (15) whose output feeds the control electrode of the control ele - ment (13) which has the form of a transistor.
4. A protective device as claimed in one or more of the preceding claims, characterised in that the difference between the voltage theoretical value (20) and the voltage actual value (21), amplified via the variable amplifier (18), can be fed directly to the transistor (13).
5. A protective device as claimed in one or more of the preceding claims, characterised in that the protective device, which possesses its own voltage supply obtained from the input voltage of the protective device, can be deactivated by means of a preferably remote - controlled switching signal (39).
6. A protective device as claimed in one or more of the preceding claims, characterised in that from the supply voltage (4, 5), an auxiliary voltage (36) supplied to a chopper stage (37) is fed via the chopper stage (37) and a trans - former (35) to the voltage - and current regu - lating circuit (28).
7. A protective device as claimed in Claim 5, characterised in that both the supply voltage for the voltage - and current regulating circuit (28) and the following power stage or stages (12) are deactivated immediately via the switching signal (39).
8. A protective device as claimed in one or more of the preceding claims, characterised in that via a remote control signal (39) the chopper stage (37) is activated immediately while the power stage or stages (12) are activated with a time delay (41) via a logic - linking stage (40) with the minimum limit voltage (31, 32).
9. A protective device as claimed in one or more of the preceding claims, characterised in that the supply voltage for the protective device is tapped via an auxiliary winding (22) of a transformer (9).
EP89902253A 1988-02-10 1989-02-09 Active filter Expired - Lifetime EP0402367B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89902253T ATE89439T1 (en) 1988-02-10 1989-02-09 ACTIVE FILTER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3804074 1988-02-10
DE3804074A DE3804074A1 (en) 1988-02-10 1988-02-10 ACTIVE FILTER

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EP0402367A1 EP0402367A1 (en) 1990-12-19
EP0402367B1 true EP0402367B1 (en) 1993-05-12

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EP89902253A Expired - Lifetime EP0402367B1 (en) 1988-02-10 1989-02-09 Active filter

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EP (1) EP0402367B1 (en)
DE (2) DE3804074A1 (en)
WO (1) WO1989007853A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19546132C2 (en) * 1995-12-11 2000-10-12 Berthold Fuld Circuit arrangement for protection against overcurrent on the input side for voltage intermediate circuit converters
US7032051B2 (en) 2000-12-11 2006-04-18 Linear Technology Corp. Methods and circuitry for interconnecting data and clock busses of live backplane circuitry and input/output card circuitry, and methods and circuitry for isolating capacitanes of a live backplane from the capacitanes of at least one input/output card

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Publication number Priority date Publication date Assignee Title
JP2634306B2 (en) * 1990-08-08 1997-07-23 三菱電機株式会社 Inverter drive circuit
DE4031505C2 (en) * 1990-10-05 1998-08-20 Telefunken Sendertechnik DC power supply with inrush current limitation
US6465909B1 (en) 2000-07-31 2002-10-15 Linear Technology Corporation Circuits and methods for controlling load sharing by multiple power supplies
US7489120B2 (en) * 2006-07-12 2009-02-10 Power Integrations, Inc. Method and apparatus for a high voltage power supply circuit

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DE1763885A1 (en) * 1968-08-30 1972-01-13 Fritz Walther Circuit arrangement for limiting the current in a series control circuit
DE2020034A1 (en) * 1970-04-24 1971-12-02 Zentro Elektrik Gmbh Current limiting circuit for a voltage stabilized power supply device
US3671852A (en) * 1971-09-01 1972-06-20 Hewlett Packard Co Series transistor power supply regulator
DE2359845C3 (en) * 1973-11-30 1979-06-07 Standard Elektrik Lorenz Ag, 7000 Stuttgart Circuit arrangement for keeping a direct voltage constant
GB8615010D0 (en) * 1986-06-19 1986-07-23 Powertron Ltd Power supplies
DE3626088A1 (en) * 1986-07-31 1988-02-04 Philips Patentverwaltung Controlling system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19546132C2 (en) * 1995-12-11 2000-10-12 Berthold Fuld Circuit arrangement for protection against overcurrent on the input side for voltage intermediate circuit converters
US7032051B2 (en) 2000-12-11 2006-04-18 Linear Technology Corp. Methods and circuitry for interconnecting data and clock busses of live backplane circuitry and input/output card circuitry, and methods and circuitry for isolating capacitanes of a live backplane from the capacitanes of at least one input/output card

Also Published As

Publication number Publication date
DE3804074C2 (en) 1990-04-19
WO1989007853A1 (en) 1989-08-24
EP0402367A1 (en) 1990-12-19
DE58904360D1 (en) 1993-06-17
DE3804074A1 (en) 1989-08-24

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