RU2375802C1 - Intellectual filter of pulse switching overvoltages - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention refers to the field of electric engineering. Device contains protective diode, power switch, current sensor, discharge diode, reactor coil, condenser, uninterrupted power supply with built-in accumulator battery, input voltage sensor, voltage control and load voltage first-order time derivative signal generation sensor, microcontroller, non-volatile memory, random-access memory, real-time clock, power switch control driver, analog-digital converter, data bus adapter, communication bus, external control system and load.

EFFECT: performing operational readjustment of technical characteristics (reprogramming) of intellectual filter both for recording parameters of pulse switching overvoltages intrinsic to various electrical networks and to meet requirements of various loads (crucial and particularly sensitive to pulse switching overvoltages and interference).

5 cl, 1 dwg

Description

The invention relates to the field of electrical engineering and power industrial electronics and, in particular, to filters for the active suppression of pulsed switching overvoltages and interference, providing effective protection of critical and especially sensitive to overvoltage and interference equipment from adverse effects from power supply systems. The invention can be used to protect consumers of direct current electricity from the effects of pulsed switching overvoltages that occur in the supply network when switching its loads: turning on consumers of electricity, turning off inductive circuits (high-power motors, transformers, etc.), in emergency conditions (emergency short circuits in the network, followed by shutdown by protective devices), during lightning discharges, as well as to limit the transient currents of input circuits phase loads (static voltage converters, autonomous inverters, etc.).

A device for protection against surge surges is known (RF Patent for Utility Model No. 42921 DEVICE FOR PROTECTION AGAINST PULSE OVERVOLTAGE of 02.08.2004, IPC 7 Н02Н 9/04, GOU VPO "South Russian State Technical University (Novocherkassk Polytechnic Institute)").

Device for surge protection consists of a parallel connected first varistor and a symmetrical protective diode separated by inductance, and series-connected diode and a second varistor connected in parallel with the load.

A device for protection against surge switching surges is also known (RF Patent for Utility Model No. 43108 DEVICE FOR PROTECTION AGAINST PULSE COMMUTATION OVERVOLTAGE of 08.08.2004, IPC 7 Н02Н 9/04, State Educational Institution of Higher Professional Education “South Russian State Technical University (Novocherkassky Polytechnic) ").

A device for protection against surge switching surges consists of a varistor, a proximity key and a control system, the proximity key and varistor being connected in series with each other.

The common disadvantages of these two protection devices are as follows:

The principle of operation of these protection devices is based on shunting the load with a varistor (a semiconductor resistor with a non-linear dependence of conductivity on the value of the applied voltage) upon receipt of switching switching overvoltages from the supply network. The devices under consideration provide effective protection only for certain values and certain slew rate of interference voltage, since each particular type of varistor is designed for a specific operating voltage and maximum operating frequency. In addition, varistors change their parameters with time and with temperature.

In addition, these protection devices relate to semiconductor surge suppressors of an absorbing type. The devices contain elements (a varistor, a varistor with a diode connected in series, a varistor with a contactless key connected in series), which, to suppress interference (when the protection is triggered), absorb and convert the electrical energy of the pulse switching overvoltage. Therefore, to ensure the operability of highly heated elements in the design of devices, effective measures must be taken to dissipate the released heat energy (radiators, fans, etc.).

A device is known for protecting the load from overvoltage (RF Patent No. 2069436 DEVICE FOR PROTECTING LOADS FROM OVERVOLTAGES of 11/20/1996, IPC 6 Н02Н 9/04, Galaktionova TI, Galaktionov LG).

A device for protecting the load from overvoltage consists of a delay unit, a threshold element, a control pulse shaper, regulating and controlling transistors, a threshold zener diode resistor circuit, current-setting and limiting resistors, and a diode array.

The disadvantage of this device is that it allows you to limit the amplitude of the arising pulse-switching overvoltages of the transient process only within specific limits, rigidly determined by the device elements used in the device (determined by the type of zener diode, the ratio of resistor resistors, etc.).

The closest to execution analogue adopted as a prototype of the invention is (RF Patent No. 2264015 METHOD OF PROTECTION AGAINST PULSE OVERVOLTAGE of 02.08.2004, IPC 7 Н02Н 3/20, GOU VPO South Russian State Technical University (Novocherkassk Polytechnic Institute) ").

To implement a method of surge protection, the invention provides a device consisting of a proximity key, a discharge diode, a choke, a capacitor, an integral and differential device, an adder and a threshold element.

The essence of the proposed method of protection against surge surges is to limit the increase in output voltage when exposed to surge surges in the power circuit by periodically switching the load with a proximity switch at a sufficiently high frequency, followed by smoothing out the voltage surges using an inductive-capacitive filter. Moreover, the control signals of the proximity key are proportional to the integral of the voltage across the inductor winding and the first time derivative of the voltage across the load.

The disadvantages of the device that implements the method of protection against surge, according to the prototype is the following.

The main disadvantage of this device is that it allows you to limit the amplitude of the arising pulse switching overvoltages only within specific limits, rigidly determined by the elements used in the device. That is, to ensure reliable protection of the load, exposing specific technical requirements for the quality of the supply network, it is necessary to select a choke and capacitor with certain parameters and the corresponding integral and differential devices, as well as the threshold element, to be set up corresponding to these elements.

In addition, the device does not provide:

- protection of the device from short circuits and polarity reversal of power buses in the supply network;

- control of the input voltage of the supply network;

- recording parameters of transient (including emergency) processes occurring in the supply network;

- the ability to transfer control information about the technical condition of the device and the supply network to an external control system.

The objectives of the invention is:

- the creation of a flexible (reprogrammable) automatic control system for power circuits of the device for protecting the load from switching switching overvoltages and interference;

- protection of the device itself from short circuits and polarity reversal of power buses in the supply network;

- control of the supply voltage (overvoltage, voltage dip / sag);

- providing the ability to accurately maintain (stabilize) the specified parameters of the device (threshold voltage values, the limit value of the rate of rise of voltage at the load, etc.);

- protection of the device itself from overload currents and short circuit currents in the load;

- limitation in transient currents of input circuits of critical equipment (static voltage converters, autonomous inverters, etc.);

- registration (recording in non-volatile memory of the automatic control system) of transient parameters, including after an emergency power off;

- providing remote monitoring of the operation of the protection device and the parameters of the supply network;

- ensuring the uninterrupted power supply of the automatic control system of the protection device for the time necessary for recording transient parameters, including after an emergency shutdown of the supply network, as well as for transmitting control information about the technical state of the protection device and the supply network to an external control system.

The tasks are achieved by the fact that in an intelligent filter of pulse switching overvoltage, consisting of a power switch, a discharge diode, an inductor, a capacitor, a voltage monitoring sensor and the formation of a signal of the first time derivative of the voltage across the load, the input of the power switch is connected to the positive bus of the power supply network, output the power switch through the inductor is connected to the first input of the load, the second input of the load is connected to the negative bus of the power supply network, between the connection point of the power with a choke and a negative power supply bus, a discharge diode is turned on with respect to the power supply buses, a capacitor and a sensor for monitoring the voltage and generating a signal of the first time derivative of the voltage across the load are connected, an input voltage sensor, a protective diode, a current sensor, a microcontroller are introduced, non-volatile storage device, random access memory, real-time clock, power key control driver, analog-to-digital converter, and Apter data bus, the information exchange bus, the external control system and an uninterruptible power supply with a built-in rechargeable battery; the inputs of the uninterruptible power supply with a built-in battery and the inputs of the input voltage sensor are connected to the positive and negative bus of the power supply network, between the positive bus of the power supply network and the input of the power switch, according to the power supply, a protective diode is connected, a current sensor is connected between the output of the power switch and the inductor; non-volatile memory, random access memory, real-time clock and information bus adapter are connected to the first, second, third and fourth microcontroller I / O, the microcontroller output is connected to the power key control input through the power key control driver, and the analog- digital converter, the output of the input voltage sensor is connected respectively to the first, second and third input of the analog-to-digital converter voltage, output of the current sensor and the output of the voltage monitoring sensor and generating the signal of the first time derivative of the voltage at the load, the data bus adapter is connected via an information exchange bus to an external control system; the output of an uninterruptible power supply with a built-in battery is connected to the power inputs of the microcontroller, random access memory, power key driver, analog-to-digital converter and data bus adapter.

The essence of the invention is to limit the increase in output voltage by an intelligent filter when exposed to pulsed switching overvoltages and interference coming from the supply network due to periodic switching of the input voltage by a power switch (usually this is a powerful IGBT transistor switch) and subsequent voltage smoothing by an inductive-capacitive filter. The switching of the power switch necessary for the effective operation of the smart filter is provided by a high-speed automatic control system created on the basis of a microcontroller that analyzes the state of the supply network, the load current passed by the filter and the rate of change of voltage across the load. The use of a microcontroller in the control system allows you to quickly reconfigure the technical characteristics (reprogramming) of the smart filter both to take into account the parameters of the pulse switching overvoltages characteristic of various power supply networks, and to fulfill the requirements of various loads (responsible and especially sensitive to pulse switching overvoltages and interference) to the quality of their power supply.

The inclusion of a non-volatile memory and an uninterruptible power supply with a built-in rechargeable battery in the smart filter allows you to register transient parameters, including a chronogram of emergency loss of power supply load and transfer relevant control information to an external control system.

The drawing shows a structural diagram of an intelligent filter pulse switching overvoltage (IFIKP).

According to the drawing, an intelligent surge filter connected to the power supply 1 includes a protective diode 13, a power switch 14, a current sensor 15, a discharge diode 16, a choke 17, a capacitor 18, an uninterruptible power supply with a built-in battery 2, an input voltage sensor 12, a sensor voltage control and signal generation of the first time derivative of voltage at load 19, microcontroller 6, non-volatile memory 3, random access memory 4, clock nogo time 5, the power control key driver 10, an analog-digital converter 11, the data bus adapter 7, the information exchange bus 8, an external control system 9 and the load 20.

Moreover, the input of the power switch 14 is connected to the positive bus of the power supply network 1, the output of the power switch 14 through the inductor 17 is connected to the first input of the load 20, the second input of the load 20 is connected to the negative bus of the power supply 1, between the connection point of the power switch 14 with the inductor 17 and the negative by the bus of the power supply network 1, the discharge diode 16 is turned on with respect to the buses of the power supply network 1, a capacitor 18 and a sensor for monitoring the voltage and generating the signal of the first time derivative are connected in parallel with the load 20 voltage at load 19, the inputs of the uninterruptible power supply with a built-in battery 2 and the inputs of the input voltage sensor 12 are connected to the positive and negative bus of the power supply network 1, a protective diode 13 is connected between the positive bus of the power supply network 1 and the input of the power switch 14 according to the power supply , between the output of the power switch 14 and the inductor 17 includes a current sensor 15; non-volatile memory 3, random access memory 4, real-time clock 5 and information bus adapter 7 are connected to the first, second, third and fourth input-output of the microcontroller 6, the output of the microcontroller 6 is connected to the control input of the power key through the driver of the power key 10 14, an analog-to-digital converter 11 is connected to the input of the microcontroller 6, and a sensor output is connected to the first, second, and third input of the analog-to-digital converter 11 the input voltage 12, the output of the current sensor 15 and the output of the voltage monitoring sensor and generating a signal of the first time derivative of the voltage across the load 19, the information bus adapter 7 is connected via an information exchange bus 8 to an external control system 9; the output of an uninterruptible power supply with a built-in rechargeable battery 2 is connected to the power inputs of the microcontroller 6, random access memory 4, power key driver 10, analog-to-digital converter 11 and information bus adapter 7.

In IFICP, as an information exchange bus 8 of microcontroller 6 with an external control system 9, an RS-232 interface or an RS-485 interface, or a CAN-bus interface of distributed real-time systems, or an Ethernet interface of local area networks can be used.

The proposed IFICP operates in the following three main modes:

- operating mode with a normal power supply network (there are practically no pulse switching overvoltages and noise in the network);

- the mode of active suppression of periodically arising and arriving at the input of the filter from the power supply network pulse switching overvoltage and interference;

- operation mode during an accident in the power supply network.

Normal Power Mode

When voltage is applied to the input, the IFICP receives uninterruptible power supply with a built-in rechargeable battery 2, which generates the voltages necessary to provide power to the microcontroller 6, random access memory 4, power key control driver 10, analog-to-digital converter 11, and information bus adapter 7. After that, from the non-volatile storage device 3, the working program of the smart filter is loaded into the random access memory 4, then the microcontroller 6, using the input voltage sensor 12 and the analog-to-digital converter 11, analyzes the state of the power supply network 1. Next, using the current sensor 15, determines the value of the current passing through the filter to the load 20, and using the voltage monitoring and formation sensor of the signal of the first time derivative of the voltage across the load 19; the rate of increase of voltage across the load 20 (which is especially important for eliminating overcurrents that are unacceptable for insulation of electrical circuits at load 20, which has and predominantly capacitive character), microcontroller 6, the force acting on the control key driver 10 produces PWM generation of control signals to the power switch 14, thereby ensuring a smooth application of the voltage to the load 20 (the so-called soft start). In addition, with the help of a current sensor 15, the IFPCI itself is protected against overload currents and short circuit currents in the load.

If in the power supply network 1 there is practically no pulse switching overvoltage and interference, the microcontroller 6 completely opens the power switch 14, which passes the entire load current 20 through itself without restrictions.

Active surge suppression mode

In real electrical installations of most power supply networks 1 periodically occur and go to the input of the filter and then to the load 20 pulse switching overvoltage and interference.

In this case, analyzing the input voltage sensor 12, the current sensor 15, the voltage monitoring sensor and generating the signal of the first time derivative of the voltage at the load 19, the analog-to-digital converter 11 and the real-time clock 5, the parameters of the pulse switching overvoltage and interference (level, power, duration, etc.), the microcontroller 6 generates PWM control signals to a power switch 14, which restrict (suppress) their passage through the filter to a load of 20. In addition, the IFPC performs S THE subsequent smoothing voltage inductive capacitive filter (choke 17 and capacitor 18). In addition, the microcontroller 6, using information from a current sensor 15 and a voltage monitoring sensor and generating a signal of the first time derivative of the voltage across the load 19, provides a limitation in transient currents of input circuits of critical equipment (static voltage converters, autonomous inverters, etc.) .

To ensure the continuity of current in the inductor 17 and to prevent unacceptable overvoltages on the power switch 14 when it is opened (as well as during operation of the FKPP with a load of 20, which has powerful inductive circuits: electric motors, transformers, etc.), a discharge diode 16 is provided in the filter.

Operating mode in case of an accident in the power supply network

To protect the IFICP from short circuits in the supply network 1 (disconnect the IFPCI from the positive bus of the damaged power supply network 1 until the supply voltage is restored) and from the polarity reversal of the power supply bus lines of the power supply network 1, a protective diode 13 is designed.

In the event of an emergency in the power supply network 1 (raising or lowering the supply voltage to an unacceptable level, short circuit, etc.), determined using the input voltage sensor 12, the microcontroller 6 records the parameters of the transient processes in the power supply 1 taking into account the current time , determined using the real-time clock 5, in non-volatile memory 3.

After the filter has completely lost power from the power supply network 1 (and, accordingly, the complete loss of power supply by the load 20), the uninterruptible power supply with built-in battery 2, using the energy stored in the battery, provides power to the microcontroller 6, random access memory 4, information bus adapter 7 v the flow of time necessary to complete the registration and initial processing of transient parameters, as well as to transmit control information about the technical the state of the filter itself and the network supplying it to the external control system 9. Having formed the corresponding control information for the external control system 9, the microcontroller 6 uses the information bus adapter 7 to transmit it via the information exchange bus 8. Analysis of this information (chronograms of the development and completion of an accident in power supply network 1) operators of the external control system 9 allows you to take the necessary measures for the timely restoration of power supply to the load 20.

Industrial applicability of the invention is determined by the fact that the proposed intelligent filter surge switching voltage can be made in accordance with the above description and diagram (see figure 1) on the basis of known components and technological equipment.

Thus, the proposed smart filter can be used to protect a variety of equipment (responsible and especially sensitive to surge switching overvoltages and noise) from adverse effects from power supply systems in various fields: military equipment, industry, housing and communal services, etc.

Based on the foregoing and based on the results of our patent information search, we believe that the proposed intelligent filter of pulse switching surges meets the criteria of “Novelty”, “Inventive step” and can be protected by a patent of the Russian Federation for an invention.

Claims (5)

1. Intelligent surge switching filter, consisting of a power switch, a discharge diode, an inductor, a capacitor, a voltage monitoring sensor and generating the first time derivative of the voltage across the load, the input of the power switch is connected to the positive bus of the power supply network, the output of the power switch through the inductor is connected to the first input of the load, the second input of the load is connected to the negative bus of the power supply network, between the connection point of the power switch with the inductor and the negative bus set and power supply, a discharge diode is turned on with respect to the busbars of the power supply network, a capacitor and a sensor for monitoring the voltage and generating a signal of the first time derivative of the voltage across the load are connected in parallel with the load, characterized in that an input voltage sensor, a protective diode, a current sensor, a microcontroller are inserted into it non-volatile storage device, random access memory, real-time clock, power switch control driver, analog-to-digital converter, inform adapter communication bus, data exchange bus, external control system and uninterruptible power supply with built-in rechargeable battery; the inputs of the uninterruptible power supply with a built-in battery and the inputs of the input voltage sensor are connected to the positive and negative bus of the power supply network, between the positive bus of the power supply network and the input of the power switch, according to the power supply, a protective diode is connected, a current sensor is connected between the output of the power switch and the inductor; non-volatile storage device, random access memory, real-time clock and information bus adapter are connected to the first, second, third and fourth microcontroller input-output, the microcontroller output is connected to the power key control input through the power key control driver, and the analog- digital converter, the output of the input sensor to the first, second and third inputs of the analog-to-digital converter voltage, the output of the current sensor and the output of the voltage monitoring sensor and generating a signal of the first time derivative of the voltage across the load, the information bus adapter is connected via an information exchange bus to an external control system; the output of the uninterruptible power supply with a built-in battery is connected to the power inputs of the microcontroller, random access memory, power key driver, analog-to-digital converter and information bus adapter. 2. The intelligent filter of pulse switching surges according to claim 1, characterized in that the RS-232 interface is used as the bus of information exchange of the microcontroller with an external control system. 3. The intelligent surge switching filter according to claim 1, characterized in that the RS-485 interface is used as the bus for the information exchange of the microcontroller with an external control system. 4. The intelligent surge switching filter according to claim 1, characterized in that the CAN-bus interface is an interface of distributed real-time systems as an information exchange bus of a microcontroller with an external control system. 5. The intelligent surge switching filter according to claim 1, characterized in that the interface of local area networks based on "Ethernet" is used as the bus of information exchange of the microcontroller with an external control system.