CN111064172A

CN111064172A - Protection circuit and variable pitch system

Info

Publication number: CN111064172A
Application number: CN201811210506.XA
Authority: CN
Inventors: 张智勇
Original assignee: Beijing Etechwin Electric Co Ltd
Current assignee: Beijing Etechwin Electric Co Ltd
Priority date: 2018-10-17
Filing date: 2018-10-17
Publication date: 2020-04-24

Abstract

The embodiment of the application provides a protection circuit and a become oar system for wind generating set, this protection circuit's input interface and the power that becomes the oar controller are connected, and output interface and the oar controller of becoming are connected, and this protection circuit includes: the anti-surge protection circuit, the main protection circuit, the switching circuit and the current sensor are connected between the input interface and the output interface; the main protection circuit is used for clamping the voltage at the control end of the switching circuit when detecting that the input voltage of the switching circuit surges, so that the output voltage of the switching circuit is limited within a specified voltage range; when the instantaneous overcurrent of the output current of the switch circuit is detected by the current sensor, the output current of the switch circuit is limited, or the switch circuit is controlled to be in a closed state; and controlling the switch circuit to be in a closed state when detecting that the input voltage of the switch circuit is continuously over-voltage and/or the input current of the switch circuit is continuously over-current in a set period.

Description

Protection circuit and variable pitch system

Technical Field

The application relates to the technical field of wind power generation, in particular to a protection circuit and a variable pitch system.

Background

The control core in the pitch system of the wind generating set is a Programmable Logic Controller (PLC), and any problem of the PLC will cause a catastrophic result to the pitch system, even the whole wind generating set, and a problem of a weak current system supplying power to the PLC will cause the PLC to work abnormally.

The power supply of + 24V is generally used for supplying power to the PLC, the reliability requirement on the power supply is high when the PLC works, the power supply requirement is far beyond the power supply requirement in the general industrial control field, and an important factor influencing the reliability is the anti-interference and anti-lightning surge capacity of the PLC.

The wind generating set is usually built in places with rare people and severe environment, is particularly influenced by lightning weather, is easily interfered by surge during working, and often causes problems of a weak current power supply system due to direct lightning strike, inductive lightning, switching surge and other influences.

The inventor of the application discovers to the prior art research that in order to improve the reliability of a power supply, the prior art adds a lightning protection surge protection module at the power input end of the PLC, and the lightning protection surge protection module can solve a part of problems, but has the problem that the output power residual voltage is high, so that key components such as the PLC still have a large amount of damage in thunderstorm seasons, and the lightning protection surge protection module has short service life and needs to be regularly checked and replaced.

Disclosure of Invention

In view of this, this application provides a protection circuit and becomes oar system for solve overvoltage, overcurrent and the surge problem of PLC power supply circuit, improve PLC power supply circuit's reliability.

In order to achieve the above object, the present application provides the following technical solutions:

the embodiment of the application provides a protection circuit for wind generating set, this protection circuit's input interface and the power that becomes the oar controller are connected, and output interface and the oar controller of changing are connected, and this protection circuit includes: the anti-surge protection circuit, the main protection circuit, the switching circuit and the current sensor are connected between the input interface and the output interface;

the input end of the anti-surge protection circuit is connected with the input interface;

the control end of the switching circuit is connected with the main protection circuit, the input end of the switching circuit is connected with the output end of the anti-surge protection circuit and the main protection circuit, and the output end of the switching circuit is connected with one end of the current sensor and the main protection circuit;

the other end of the current sensor is connected with the output interface and the main protection circuit;

the main protection circuit is used for clamping the voltage at the control end of the switching circuit when detecting that the input voltage of the switching circuit surges, so that the output voltage of the switching circuit is limited within a specified voltage range; when the instantaneous overcurrent of the output current of the switch circuit is detected by the current sensor, the output current of the switch circuit is limited, or the switch circuit is controlled to be in a closed state; and controlling the switch circuit to be in a closed state when detecting that the input voltage of the switch circuit is continuously over-voltage and/or the input current of the switch circuit is continuously over-current in a set period.

Optionally, the main protection circuit comprises an integrated circuit and a configuration circuit, the configuration circuit being disposed outside the integrated circuit;

the configuration circuit comprises a current limiting circuit and a switch threshold value setting circuit;

one end of the current limiting circuit is connected with the input end of the switch circuit, and the other end of the current limiting circuit is connected with the integrated circuit and is used for matching with the integrated circuit to limit the current generated when the switch circuit is detected;

the first end of the switch threshold value setting circuit is connected with the control end of the switch circuit, the second end of the switch threshold value setting circuit is connected with the integrated circuit, and the third end of the switch threshold value setting circuit is connected with the grounding end and is used for being matched with the integrated circuit to set the threshold value of the switch circuit;

the integrated circuit is used for controlling the switching circuit to be in a closed state through the switching threshold value setting circuit when detecting that the input voltage of the switching circuit is continuously over-voltage and/or the input current of the switching circuit is continuously over-current in a set period; and the control end voltage of the switching circuit is clamped through the switching threshold value setting circuit when the input voltage of the switching circuit is detected to generate surge, so that the output voltage of the switching circuit is limited in a specified voltage range.

Optionally, the configuration circuit further comprises a fault setting circuit and a device protection circuit;

one end of the fault setting circuit is connected with the integrated circuit, and the other end of the fault setting circuit is connected with the grounding end, and is used for setting the turn-off time of the switch circuit and the cooling period of the integrated circuit when in fault;

the first end of the device protection circuit is connected with the input end of the switch circuit, the second end of the device protection circuit is connected with the integrated circuit, the third end of the device protection circuit is connected with the grounding end, and the device protection circuit is matched with the integrated circuit to protect the switch circuit and the current sensor when the integrated circuit detects that the input voltage of the switch circuit is continuously over-voltage and/or the input current of the switch circuit is continuously over-current in a set time period.

Optionally, the integrated circuit is configured with an automatic retry function.

Optionally, the current limiting circuit comprises a first resistor; the switch threshold setting circuit comprises a second resistor, a third resistor and a first capacitor; the fault setting circuit comprises a second capacitor; the device protection circuit comprises a fourth resistor, a third capacitor and a first one-way transient diode;

one end of the first resistor is connected with the integrated circuit, and the other end of the first resistor is connected with the input end of the switch circuit;

one end of the second resistor is connected with the control end of the switch circuit, and the other end of the second resistor is connected with the integrated circuit;

the third resistor and the first capacitor are connected in series between the other end of the second resistor and the grounding end;

one end of the second capacitor is connected with the integrated circuit, and the other end of the second capacitor is connected with the grounding end;

one end of the fourth resistor is connected with the input end of the switch circuit, and the other end of the fourth resistor is connected with the integrated circuit, one end of the third capacitor and one end of the first unidirectional transient diode;

the other end of the third capacitor is connected with the grounding end, and the other end of the first unidirectional transient diode is connected with the grounding end.

Optionally, the configuration circuit further includes a second unidirectional transient diode, one end of the second unidirectional transient diode is connected to the other end of the second resistor, the other end of the second unidirectional transient diode is connected to the other end of the current sensor, and the other end of the current sensor is connected to the integrated circuit.

Optionally, the switch circuit is an N-type metal oxide semiconductor type field effect transistor, and a gate of the N-type metal oxide semiconductor type field effect transistor is connected with a gate signal output terminal in the integrated circuit.

Optionally, the protection circuit further includes an energy storage circuit, and the energy storage circuit is connected between the current sensor and the output interface, and is used for providing electric energy for the pitch controller when the switch circuit is in the off state.

Optionally, the energy storage circuit includes a plurality of super capacitors connected in series in sequence, for two super capacitors located at two ends, one end of one super capacitor is connected between the current sensor and the output interface, one end of the other super capacitor is connected with the ground terminal, and each super capacitor is provided with a resistor in parallel;

or, the tank circuit comprises a battery;

or, the energy storage circuit comprises an emergency power supply.

Optionally, the anti-surge protection circuit comprises a first-stage protection circuit, a delay overcurrent protection circuit and a second-stage protection circuit which are connected in series in sequence;

the first-stage protection circuit is used for absorbing energy generated by surge so as to reduce the voltage value input to the delay overcurrent protection circuit;

the delay overcurrent protection circuit is used for prolonging the transmission time of surge energy to a circuit connected behind the delay overcurrent protection circuit when the surge comes;

and the second-stage protection circuit is used for absorbing energy generated by the common-mode surge and the differential-mode surge input by the time-delay overcurrent protection circuit.

Optionally, the first-stage protection circuit includes a gas discharge diode, a first end of the gas discharge diode is connected to the input interface, a second end of the gas discharge diode is connected to the ground terminal, and a third end of the gas discharge diode is connected to the protection ground terminal; or the like, or, alternatively,

the first-stage protection circuit comprises a voltage dependent resistor, one end of the voltage dependent resistor is connected with the input interface, and the other end of the voltage dependent resistor is connected with the grounding terminal.

Optionally, the delay overcurrent protection circuit includes a fifth resistor, a sixth resistor, a first self-recovery fuse, and a second self-recovery fuse;

the fifth resistor and the first self-recovery fuse are sequentially connected in series between the first end of the gas discharge diode and the second-stage protection circuit;

the sixth resistor and the second self-recovery fuse are sequentially connected in series between the second end of the gas discharge diode and the grounding end;

or, the delay overcurrent protection circuit comprises a first inductor, a second inductor, a first self-recovery fuse and a second self-recovery fuse;

the first inductor and the first self-recovery fuse are sequentially connected in series between the first end of the gas discharge diode and the second-stage protection circuit;

the second inductor and the second self-recovery fuse are sequentially connected in series between the second end of the gas discharge diode and the ground terminal.

Optionally, the second stage protection circuit comprises a first bi-directional transient diode, a second bi-directional transient diode and a third bi-directional transient diode;

the first bidirectional transient diode and the second bidirectional transient diode are connected in series, one end of the first bidirectional transient diode is connected with the first self-recovery fuse, one end of the second bidirectional transient diode is connected with the ground terminal, and a node between the first bidirectional transient diode and the second bidirectional transient diode is connected with the protective ground terminal;

the first bidirectional transient diode and the second bidirectional transient diode are connected in series and then connected in parallel with the third bidirectional transient diode.

Optionally, the input interface comprises a first lead, a second lead, a third lead, and a fourth lead;

the first lead is connected with the first-stage protection circuit and outputs a voltage value required by the variable pitch controller;

the second lead and the third lead are both connected with the shielding layer of the cable;

the fourth lead is connected with the grounding end;

the output interface comprises a fifth lead, a sixth lead, a seventh lead and an eighth lead;

the fifth lead and the sixth lead are both connected with the current sensor;

the seventh lead and the eighth lead are both connected with the ground terminal.

The embodiment of the application also provides a variable pitch system, which comprises a variable pitch controller, a power supply of the variable pitch controller and the protection circuit.

The beneficial effects that technical scheme that this application embodiment provided brought include:

therefore, the protection circuit provided by the embodiment of the application can solve the problems of overvoltage, overcurrent and surge of the power circuit of the variable pitch controller, and the reliability of the power circuit is improved; and the protection circuit can ensure that the residual voltage is low enough, plays a good role in protecting a weak current system which is easy to be interfered, and greatly improves the reliability of the wind generating set.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments of the present application will be briefly described below.

Fig. 1 is a block diagram of a protection circuit according to an embodiment of the present disclosure;

fig. 2 is a block diagram of another protection circuit provided in the embodiment of the present application;

fig. 3 is a block diagram of a protection circuit according to an embodiment of the present disclosure;

fig. 4 is a circuit structure diagram of a protection circuit according to an embodiment of the present application.

The meaning of the reference symbols of the embodiments of the present application is explained below:

10-power supply of pitch controller; 11-an input interface; 12-an output interface; 13-a pitch controller; 14-anti-surge protection circuit; 15-a main protection circuit; 16-a switching circuit; 17-a current sensor; 18-a tank circuit;

151-integrated circuit; 152-configuration circuitry; 1521-current limiting circuit; 1522-switch threshold setting circuit; 1523-fault setting circuit; 1524-device protection circuit; 141-first stage protection circuit; 142-a delay overcurrent protection circuit; 143-second stage protection circuit.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Further, "connected" as used herein may include wirelessly connected. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

First, several terms referred to in the present application will be introduced and explained.

TVS: transient Voltage super, a high performance protection device in the form of a diode, has extremely fast response time (sub-nanosecond) and relatively high surge absorption capability. When the two ends of the TVS are subjected to transient high-energy impact, the TVS can change the impedance value between the two ends from high impedance to low impedance at a very high speed so as to absorb a transient large current and clamp the voltage between the two ends of the TVS at a preset value, thereby protecting the following circuit elements from the impact of transient high-voltage spike pulse.

GDT: a Gas Discharge Tube (Gas Discharge Tube) is a Discharge gap sealed in a ceramic chamber filled with an inert Gas to stabilize the Discharge voltage of the Discharge Tube. The high-voltage and high-voltage power supply has the main characteristics of large through-current energy which can reach dozens to hundreds of Kiloamperes (KA), extremely high insulation resistance, no leakage current, no aging failure, no polarity bidirectional protection and extremely small static capacitance, and is particularly suitable for the coarse protection of high-speed network communication equipment. The lightning protection device can be widely applied to first-stage lightning surge protection of various power supplies and signal lines.

Super capacitor: supercapacitors, also known as electrochemical capacitors, electric double layer capacitors, gold capacitors, farad capacitors, are electrochemical devices that have been developed in the seventh and eighties of the last century and store energy by means of polarized electrolytes. It is different from traditional chemical power source, and is a power source with special performance between traditional capacitor and battery, and mainly depends on electric double layer and redox pseudo-capacitance charge to store electric energy. But no chemical reaction occurs in the process of energy storage, the energy storage process is reversible, and the super capacitor can be repeatedly charged and discharged for tens of thousands of times.

Self-recovery insurance: an overcurrent electronic protection element is made up by using high-molecular organic polymer, under the conditions of high pressure, high temp. and sulfurization reaction, and adding conductive particle material, and making it pass through a special technological process. The traditional fuse overcurrent protection can only protect once and is blown to be replaced, and the self-recovery fuse has the dual functions of overcurrent and overheat protection and automatic recovery.

Residual pressure: residual voltage is the peak voltage at a given terminal of the protector when a discharge current flows, and may also be referred to as the voltage present between the terminals of a lightning protection device when a lightning discharge current passes through it.

Overpressure: for all electrical equipment, a rated voltage is provided, but in practice, the operation under the rated voltage cannot be completely guaranteed, the range is near the rated voltage, generally within +/-15%, and in order to protect the electrical equipment and the process quality, if the rated voltage is higher than + 15% of the rated voltage, the voltage is over-voltage.

Overflowing: the overcurrent refers to the current exceeding the rated current of the electrical equipment, and the loop current larger than the rated current carrying amount of the loop conductor is the overcurrent and comprises overload current and short-circuit current; wherein: the overcurrent before the circuit insulation is damaged is called overload current, and the overcurrent after the circuit insulation is damaged is called short-circuit current.

The embodiment of the application provides a protection circuit, which aims to solve the technical problems in the prior art.

The following describes the technical solutions of the present application and how to solve the technical problems in the prior art in detail with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

The embodiment of the present application provides a protection circuit, as shown in fig. 1, fig. 1 is a block diagram of a structure of the protection circuit provided in the embodiment of the present application, the protection circuit is used for a wind turbine generator system, an input interface 11 of the protection circuit is connected with a power supply 10 of a pitch controller, an output interface 12 of the protection circuit is connected with a pitch controller 13, and the protection circuit includes: an anti-surge protection circuit 14, a main protection circuit 15, a switching circuit 16, and a current sensor 17 connected between the input interface 11 and the output interface 12; the input end of the anti-surge protection circuit 14 is connected with the input interface 11; the control end of the switch circuit 16 is connected with the main protection circuit 15, the input end of the switch circuit is connected with the output end of the anti-surge protection circuit 14 and the main protection circuit 15, and the output end of the switch circuit is connected with one end of the current sensor 17 and the main protection circuit 15; the other end of the current sensor 17 is connected to the output interface 12 and the main protection circuit 15.

A main protection circuit 15 for clamping a control terminal voltage of the switching circuit 16 when detecting that the input voltage of the switching circuit 16 is surged, so that the output voltage of the switching circuit 16 is limited within a specified voltage range; and when the instantaneous overcurrent of the output current of the switch circuit 16 is detected by the current sensor 17, limiting the output current of the switch circuit 16 or controlling the switch circuit 16 to be in a closed state; and controlling the switch circuit 16 to be in a closed state when detecting that the input voltage of the switch circuit 16 is continuously overvoltage and/or the input current of the switch circuit 16 is continuously overcurrent in a set period.

The protection circuit that this application embodiment provided's input interface is connected with the power of becoming the oar controller, and output interface is connected with becoming the oar controller, and this protection circuit includes: the protection circuit comprises an anti-surge protection circuit, a main protection circuit, a switching circuit and a current sensor, wherein the anti-surge protection circuit, the main protection circuit, the switching circuit and the current sensor are connected between an input interface and an output interface; when the instantaneous overcurrent of the output current of the switch circuit is detected by the current sensor, the output current of the switch circuit is limited, or the switch circuit is controlled to be in a closed state; when the input voltage of the switch circuit is continuously over-voltage and/or the input current of the switch circuit is continuously over-current in a set time period, the switch circuit is controlled to be in a closed state, so that the protection circuit provided by the embodiment of the application can solve the problems of over-voltage, over-current and surge of the PLC power circuit, and the reliability of the PLC power circuit is improved; and the protection circuit can ensure that the residual voltage is low enough, plays a good role in protecting weak current systems such as PLC (programmable logic controller) and the like which are easy to be interfered, and greatly improves the reliability of the wind generating set.

Alternatively, as shown in fig. 2, the main protection circuit 15 in the embodiment of the present application includes an integrated circuit 151 and a configuration circuit 152, and the configuration circuit 152 is disposed outside the integrated circuit 151; the configuration circuit 152 includes a current limiting circuit 1521 and a switch threshold setting circuit 1522.

Specifically, one end of the current limiting circuit 1521 is connected to the input terminal of the switch circuit 16, and the other end is connected to the integrated circuit 151, and is configured to cooperate with the integrated circuit 151 to limit the current generated when the switch circuit 16 is detected; the switch threshold setting circuit 1522 has a first terminal connected to the control terminal of the switch circuit 16, a second terminal connected to the integrated circuit 151, and a third terminal connected to a ground terminal (not shown) for cooperating with the integrated circuit 151 to set the threshold of the switch circuit 16.

Specifically, the integrated circuit 151 is configured to control the switch circuit 16 to be in an off state through the switch threshold setting circuit 1522 when detecting that the input voltage of the switch circuit 16 is continuously overvoltage and/or the input current of the switch circuit 16 is continuously overcurrent within a set period; and a voltage clamp circuit 1522 for clamping the control terminal voltage of the switching circuit 16 when detecting that the input voltage of the switching circuit 16 is surged, so that the output voltage of the switching circuit 16 is limited within a specified voltage range.

Optionally, as shown in fig. 2, the configuration circuit in the embodiment of the present application further includes a fault setting circuit 1523 and a device protection circuit 1524.

Specifically, one end of the fault setting circuit 1523 is connected to the integrated circuit 151, and the other end is connected to a ground terminal (not shown in the figure), for setting the off time of the switch circuit 16 and the cooling period of the integrated circuit 151 at the time of a fault; the device protection circuit 1524 has a first terminal connected to the input terminal of the switch circuit 16, a second terminal connected to the integrated circuit 151, and a third terminal connected to a ground terminal (not shown in the figure), and is configured to cooperate with the integrated circuit 151 to protect the switch circuit 16 and the current sensor 17 when the integrated circuit 151 detects that the input voltage of the switch circuit 16 is continuously over-voltage and/or the input current of the switch circuit 16 is continuously over-current during a set period.

In an optional implementation manner, the protection circuit provided in this embodiment of the present application further includes a tank circuit 18, as shown in fig. 3, where the tank circuit 18 is connected between the current sensor 17 and the output interface 12, and is used for supplying power to the pitch controller 13 when the switch circuit 16 is in the off state; according to the energy storage circuit, the pitch controller can be powered down to store data after the power supply fails.

In an alternative implementation manner, as shown in fig. 3, the anti-surge protection circuit 14 in the embodiment of the present application includes a first-stage protection circuit 141, a delay overcurrent protection circuit 142, and a second-stage protection circuit 143 that are connected in series in sequence; a first stage protection circuit 141 for absorbing energy generated by a surge to reduce a voltage value input to the delay overcurrent protection circuit 142; the delay overcurrent protection circuit 142 is used for prolonging the transmission time of surge energy to a circuit connected behind the delay overcurrent protection circuit 142 when a surge comes; the second-stage protection circuit 143 is configured to absorb energy generated by the common-mode surge and the differential-mode surge input through the delay overcurrent protection circuit 142; the arrangement of the first-stage protection circuit, the delay overcurrent protection circuit and the second-stage protection circuit in the embodiment of the application can improve the reliability of the protection circuit.

The protection circuit provided by the embodiment of the application is described in detail below with reference to a specific circuit diagram.

As shown in fig. 4, fig. 4 is a circuit structure diagram of a protection circuit according to an embodiment of the present application, where a current limiting circuit 1521 in the embodiment of the present application includes a first resistor R6; the switch threshold setting circuit 1522 includes a second resistor R9, a third resistor R14, and a first capacitor C11; the fault setting circuit 1523 includes a second capacitor C16; the device protection circuit 1524 includes a fourth resistor R7, a third capacitor C10, and a first unidirectional transient diode D7. The second capacitor C16 is used to set the off time of the switch circuit 16 and the cooling period of the integrated circuit 151; wherein: the first unidirectional transient diode D7 plays a role in clamping protection when the input voltage is over-voltage, and the fourth resistor R7 and the third capacitor C10 form an RC filter when encountering short-duration peak conditions, so that a certain protection effect is achieved on the circuit; the current generated when the drain and source of the nmos type field effect transistor Q1 are detected flows through the first resistor R6, and the first resistor R6 is suitable for limiting the current generated when the detection is performed within a certain range under the condition of the peak input voltage.

Specifically, one end of the first resistor R6 is connected to the integrated circuit 151, and the other end is connected to the input terminal of the switch circuit 16; one end of the second resistor R9 is connected to the control end of the switch circuit 16, and the other end is connected to the integrated circuit 151; the third resistor R14 and the first capacitor C11 are connected in series between the other end of the second resistor R9 and the ground GND; one end of the second capacitor C16 is connected to the integrated circuit 151, and the other end is connected to the ground GND; one end of the fourth resistor R7 is connected to the input end of the switch circuit 16, and the other end is connected to the integrated circuit 151, one end of the third capacitor C10, and one end of the first unidirectional transient diode D7; the other end of the third capacitor C10 is connected to the ground GND, and the other end of the first unidirectional transient diode D7 is connected to the ground GND.

Optionally, as shown in fig. 4, the configuration circuit 152 in the embodiment of the present application further includes a second unidirectional transient diode D5, one end of the second unidirectional transient diode D5 is connected to the other end of the second resistor R9, the other end of the second unidirectional transient diode D5 is connected to the other end of the current sensor 17, the other end of the current sensor is connected to the integrated circuit 151, and the second unidirectional transient diode D5 plays a role of clamp protection when the output voltage is over-voltage.

Alternatively, as shown in fig. 4, the switch circuit 16 in the embodiment of the present application is an N-type metal oxide semiconductor type field effect transistor, and a gate of the N-type metal oxide semiconductor type field effect transistor is connected to a gate signal output terminal in the integrated circuit 151. Of course, in practical applications, the switching circuit 16 may also select other types of thin film transistors.

Specifically, the embodiment of the present application employs the application specific integrated circuit 151, the integrated circuit 151 can provide the protection function of overvoltage and overcurrent from 4V to 72V, and the design method of the serial N-type mosfet replaces the traditional protection circuit composed of a bulky inductor, a capacitor, a TVS and a fuse, thereby saving the space of the circuit board, realizing continuous operation during the transient power supply or current surge, protecting the downstream electronic components from the damage of input overvoltage up to the rating of the nmos mosfet, and simultaneously avoiding the power supply from output overload. In addition, the conventional protection circuit may blow a fuse or burn a TVS, and thus needs to be repaired, and the integrated circuit 151 in the embodiment of the present invention can withstand a reverse input of up to 60V, and can perform a reverse protection function well.

Specifically, in the embodiment of the present application, when the integrated circuit 151 detects that the input voltage of the switching circuit 16 is in surge, the integrated circuit 151 reduces the excessive voltages at the input end and the output end of the switching circuit 16, and meanwhile, the switching threshold setting circuit 1522 clamps the gate voltage of the switching circuit, so that the output voltage of the switching circuit is limited within a specified voltage range, and the specified voltage can be set according to the requirement of the safety voltage in actual design, thus allowing the use of downstream electronic components with lower rated voltage, and saving the cost.

Specifically, in the embodiment of the present application, during the output overload or short circuit period, the integrated circuit 151 limits the output current of the switching circuit 16, or controls the switching circuit 16 to be in the off state, so that the forward path can be adjusted to a current limit value set by the current sensor 17. In addition, the provision of integrated circuit 151 enables switching circuitry 16 to be controlled to turn off in a shorter time for sustained over-voltages and over-currents.

Specifically, since the integrated circuit 151 in the embodiment of the present application can suppress a surge (overvoltage), and the nature of the circuit board hot plugging is that the circuit is damaged due to the surge caused by the moment of plugging and unplugging, the integrated circuit 151 can also control the surge current during the hot plugging of the circuit board power supply.

Specifically, the integrated circuit 151 in the embodiment of the present application is configured to have an automatic retry function, in which the circuit automatically retries every certain time (e.g., 1 second) after the overvoltage or short-circuit protection, and turns on the switch circuit 16 to turn on the power supply after the overvoltage, short-circuit, or reverse connection is detected to disappear, so as to ensure that the subsequent circuit restarts without human intervention. When an overvoltage or overcurrent reverse condition is detected, the switching circuit 16 is kept off so that the subsequent circuits are still in the protection mode. The function is very suitable for the application of the variable pitch PLC, when the power supply has a fault, service personnel cannot arrive at the site in time for processing, the self-diagnosis self-debugging function of the protection circuit saves a large amount of work of the service personnel, and the efficiency is improved.

As shown in fig. 4, the energy storage circuit 18 in the embodiment of the present application includes a plurality of super capacitors (ten super capacitors are shown in the figure as C3, C4, C6, C7, C8, C9, C12, C13, C14, and C15) connected in series in sequence, for two super capacitors (C3 and C15) located at two ends, one end of the C3 is connected between the current sensor 17 and the output interface 12, one end of the C15 is connected to the ground GND, and each super capacitor is connected in parallel to a resistor, and optionally, all resistors have equal resistance values.

Of course, in practical design, the energy storage circuit 18 in the embodiment of the present application may also include a battery or an emergency power supply.

In specific implementation, a super capacitor C3 is connected in parallel with a resistor R4, a super capacitor C4 is connected in parallel with a resistor R5, a super capacitor C6 is connected in parallel with a resistor R10, a super capacitor C7 is connected in parallel with a resistor R11, a super capacitor C8 is connected in parallel with a resistor R12, a super capacitor C9 is connected in parallel with a resistor R13, a super capacitor C12 is connected in parallel with a resistor R16, a super capacitor C13 is connected in parallel with a resistor R17, a super capacitor C14 is connected in parallel with a resistor R18, and a super capacitor C15 is connected in parallel with a resistor R19. Such as: the rated voltage value of the selected super capacitor monomer is 2.7V, the capacitance value is 2F, and the energy storage system formed by the super capacitor monomer can maintain the voltage drop of 2.4V and the power output of 2A/200ms, so that emergency power supply is provided for PLC emergency treatment and recording.

As shown in fig. 4, the first stage protection circuit 141 in the embodiment of the present application includes a gas discharge diode D2, a first terminal of the gas discharge diode D2 is connected to the input interface 11, a second terminal thereof is connected to the ground terminal, and a third terminal thereof is connected to the protection ground terminal PGND; of course, in actual design, a voltage dependent resistor may be used instead of the gas discharge diode D2, and in specific implementation, one end of the voltage dependent resistor is connected to the input interface, and the other end is connected to the ground terminal.

Specifically, the gas discharge diode D2 adopted in the embodiment of the present application has the main characteristics of large through-current energy, which can reach tens of KA to hundreds of KA, extremely high insulation resistance, no leakage, no aging failure, no polar bidirectional protection, and extremely small static capacitance, is particularly suitable for the coarse protection of high-speed network communication equipment, and can be widely used for the first-stage lightning surge protection of various power supplies and signal lines. The gas discharge diode D2 can provide effective protection for surge with the rising speed from 100V/s to 1000V/us, and the parameters of the gas discharge diode D2 selected by the embodiment of the invention are the glow discharge voltage of 75V-200V and the discharge current of 5 kA.

As shown in fig. 4, the delay overcurrent protection circuit 142 in the embodiment of the present application includes a fifth resistor R1, a sixth resistor R15, a first self-recovery fuse F1, and a second self-recovery fuse F2; the fifth resistor R1 and the first self-recovery fuse F1 are sequentially connected in series between the first end of the gas discharge diode D2 and the second-stage protection circuit 143; the sixth resistor R15 and the second self-recovery fuse F2 are sequentially connected in series between the second terminal of the gas discharge diode D2 and the ground terminal.

Of course, in practical design, an inductor may be used instead of the resistor, and specifically, the delay overcurrent protection circuit 142 includes a first inductor (corresponding to the position of the fifth resistor R1), a second inductor (corresponding to the position of the sixth resistor R15), a first self-recovery fuse F1, and a second self-recovery fuse F2; the first inductor and the first self-recovery fuse are sequentially connected in series between the first end of the gas discharge diode and the second-stage protection circuit; the second inductor and the second self-recovery fuse are sequentially connected in series between the second end of the gas discharge diode and the ground terminal.

Specifically, in the embodiment of the present application, the resistance values of the fifth resistor R1 and the sixth resistor R15 do not exceed 2 ohms, the power is not less than 1 watt, and 1A is selected for the first self-recovery fuse F1 and the second self-recovery fuse F2. The time-delay overcurrent protection circuit 142 is used for forming a time-delay circuit by a resistor and a self-recovery fuse, when surge impact occurs, the gas discharge diode D2 of the first-stage protection circuit 141 is firstly operated to discharge temporarily, most energy is absorbed, and after certain discharge, the subsequent protection circuit can operate to further reduce voltage.

As shown in fig. 4, the second-stage protection circuit 143 in the embodiment of the present application includes a first bi-directional transient diode D1, a second bi-directional transient diode D6, and a third bi-directional transient diode D4; the first bi-directional transient diode D1 and the second bi-directional transient diode D6 are connected in series, one end of the first bi-directional transient diode D1 is connected to the first self-recovery fuse F1, one end of the second bi-directional transient diode D6 is connected to the ground terminal, and the node between the first bi-directional transient diode D1 and the second bi-directional transient diode D6 is connected to the protection ground terminal PGND; the first bi-directional transient diode D1 and the second bi-directional transient diode D6 are connected in series and then connected in parallel with the third bi-directional transient diode D4.

Specifically, in the embodiment of the present application, the reverse blocking voltage of the first bi-directional transient diode D1, the second bi-directional transient diode D6, and the third bi-directional transient diode D4 is 33V, the power is 5KW, the first bi-directional transient diode D1 and the second bi-directional transient diode D6 protect the common mode surge of the power supply input, and the third bi-directional transient diode D4 protects the differential mode surge of the power supply input. The protection circuit formed by the first bi-directional transient diode D1, the second bi-directional transient diode D6 and the third bi-directional transient diode D4 can generally pass the standard surge test of 2 KV.

As shown in fig. 4, the input interface 11 in the embodiment of the present application includes a first lead, a second lead, a third lead, and a fourth lead; the first lead is connected with the first-stage protection circuit 141, and outputs a voltage value required by the variable pitch controller; the second lead and the third lead are both connected with a shielding layer (PE) of the cable; the fourth lead is connected with the grounding end; the output interface 12 includes a fifth lead, a sixth lead, a seventh lead, and an eighth lead; the fifth lead and the sixth lead are both connected with the current sensor 17; the seventh lead and the eighth lead are both connected with the ground terminal. The input interface and the output interface of the protection circuit provided by the embodiment of the application are simple in wiring because of only four lines, and the existing wind generating set is convenient to modify and upgrade.

The working principle of the protection circuit provided by the embodiment of the present application is briefly described below with reference to fig. 4.

As shown in fig. 4, when a surge occurs, the first-stage protection circuit 141 protects the surge first, and the first-stage protection circuit 141 acts fastest and absorbs most energy; then, the RC circuit formed by the resistor R2 and the capacitor C5 filters out the high frequency interference part, and plays a certain role in protecting the switch circuit 16 and the integrated circuit 151; then, when the integrated circuit detects that the power supply voltage and the current are normal, the switch circuit 16 is controlled to be stably in an open state, and when the current sensor 17 detects that the current is excessive, the switch circuit 16 is controlled to be in a closed state, or the output current of the switch circuit 16 is limited; when the integrated circuit detects that the input voltage of the switch circuit 16 is continuously over-voltage and/or the input current of the switch circuit 16 is continuously over-current in a set period, the switch circuit 16 is controlled to be in a closed state.

As shown in fig. 4, when the switch circuit 16 is normally turned on, the capacitor C1 and the capacitor C2 perform a filtering function to provide clean dc to the subsequent circuits, and the power indicator D3 is turned on and the resistor R3 performs a current limiting function. The resistor R8 is a current limiting resistor for the fault output of the integrated circuit 151.

To sum up, this application embodiment becomes oar controller's power is reconnected to and is become oar controller behind the protection circuit, and protection circuit and the power that becomes oar controller and the oar controller are the series relation, and this protection circuit can not influence the function of original circuit, and this protection circuit has following beneficial effect:

firstly, the protection circuit provided by the embodiment of the application can solve the problems of overvoltage, overcurrent and surge of the PLC power supply circuit, and improves the reliability of the PLC power supply circuit; and the protection circuit can ensure that the residual voltage is low enough, plays a good role in protecting weak current systems such as PLC (programmable logic controller) and the like which are easy to be interfered, and greatly improves the reliability of the wind generating set.

Secondly, the protection circuit that this application embodiment provided still includes energy storage circuit, after the main power source loses, can meet an urgent need and carry out data storage to follow-up failure analysis.

Thirdly, the integrated circuit included in the protection circuit provided by the embodiment of the application has an automatic restart function, and can be automatically restarted at intervals after overvoltage or overcurrent protection, so that the restart of a subsequent circuit is ensured under the condition of no human intervention.

Fourth, the protection circuit that this application embodiment provided can resist the surge impact that brings because the hot plug.

Fifth, the input interface and the output interface of the protection circuit provided by the embodiment of the application all have only four lines, the wiring is simple, and the existing wind generating set is convenient to modify and upgrade.

The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.

Claims

1. A protection circuit for a wind turbine generator system, characterized in that an input interface (11) of the protection circuit is connected to a power supply (10) of a pitch controller, and an output interface (12) is connected to the pitch controller (13), the protection circuit comprising: the anti-surge protection circuit (14), the main protection circuit (15), the switch circuit (16) and the current sensor (17) are connected between the input interface (11) and the output interface (12);

the input end of the anti-surge protection circuit (14) is connected with the input interface (11);

the control end of the switch circuit (16) is connected with the main protection circuit (15), the input end of the switch circuit is connected with the output end of the anti-surge protection circuit (14) and the main protection circuit (15), and the output end of the switch circuit is connected with one end of the current sensor (17) and the main protection circuit (15);

the other end of the current sensor (17) is connected with the output interface (12) and the main protection circuit (15);

the main protection circuit (15) is used for clamping the control end voltage of the switch circuit (16) when detecting that the input voltage of the switch circuit (16) generates surge, so that the output voltage of the switch circuit (16) is limited within a specified voltage range; and limiting the output current of the switch circuit (16) or controlling the switch circuit (16) to be in a closed state when the instantaneous overcurrent of the output current of the switch circuit (16) is detected by the current sensor (17); and controlling the switch circuit (16) to be in a closed state when detecting that the input voltage of the switch circuit (16) is continuously overvoltage and/or the input current of the switch circuit (16) is continuously overcurrent in a set period.

2. Protection circuit according to claim 1, characterized in that the main protection circuit (15) comprises an integrated circuit (151) and a configuration circuit (152), the configuration circuit (152) being arranged outside the integrated circuit (151);

the configuration circuit (152) comprises a current limiting circuit (1521) and a switch threshold setting circuit (1522);

one end of the current limiting circuit (1521) is connected with the input end of the switch circuit (16), and the other end of the current limiting circuit is connected with the integrated circuit (151) and is used for matching with the integrated circuit (151) to limit the current generated when the switch circuit (16) is detected;

a first end of the switch threshold setting circuit (1522) is connected with a control end of the switch circuit (16), a second end is connected with the integrated circuit (151), and a third end is connected with a grounding end and is used for being matched with the integrated circuit (151) to set a threshold of the switch circuit (16);

the integrated circuit (151) is used for controlling the switch circuit (16) to be in a closed state through a switch threshold setting circuit (1522) when detecting that the input voltage of the switch circuit (16) is continuously overvoltage and/or the input current of the switch circuit (16) is continuously overcurrent in a set period; and the control end voltage of the switch circuit (16) is clamped through the switch threshold value setting circuit (1522) when the input voltage of the switch circuit (16) is detected to surge, so that the output voltage of the switch circuit (16) is limited within a specified voltage range.

3. The protection circuit of claim 2, wherein the configuration circuit (152) further comprises a fault setting circuit (1523) and a device protection circuit (1524);

one end of the fault setting circuit (1523) is connected with the integrated circuit (151), and the other end of the fault setting circuit is connected with a ground terminal, and is used for setting the turn-off time of the switch circuit (16) and the cooling period of the integrated circuit (151) during fault;

the first end of the device protection circuit (1524) is connected with the input end of the switch circuit (16), the second end of the device protection circuit is connected with the integrated circuit (151), and the third end of the device protection circuit is connected with the grounding end and is used for matching with the integrated circuit (151) to protect the switch circuit (16) and the current sensor (17) when the integrated circuit (151) detects that the input voltage of the switch circuit (16) is continuously overvoltage and/or the input current of the switch circuit (16) is continuously overcurrent in a set period.

4. The protection circuit according to claim 2, wherein the integrated circuit (151) is configured with an automatic retry function.

5. The protection circuit of claim 3, wherein the current limiting circuit (1521) comprises a first resistor; the switch threshold setting circuit (1522) comprises a second resistor, a third resistor and a first capacitor; the fault setting circuit (1523) comprises a second capacitance; the device protection circuit (1524) comprises a fourth resistor, a third capacitor and a first unidirectional transient diode;

one end of the first resistor is connected with the integrated circuit (151), and the other end of the first resistor is connected with the input end of the switch circuit (16);

one end of the second resistor is connected with the control end of the switch circuit (16), and the other end of the second resistor is connected with the integrated circuit (151);

the third resistor and the first capacitor are connected in series between the other end of the second resistor and a ground terminal;

one end of the second capacitor is connected with the integrated circuit (151), and the other end of the second capacitor is connected with a grounding end;

one end of the fourth resistor is connected with the input end of the switch circuit (16), and the other end of the fourth resistor is connected with the integrated circuit (151), one end of the third capacitor and one end of the first unidirectional transient diode;

the other end of the third capacitor is connected with a grounding end, and the other end of the first unidirectional transient diode is connected with the grounding end.

6. The protection circuit according to claim 5, wherein the configuration circuit (152) further comprises a second unidirectional transient diode, one end of the second unidirectional transient diode is connected to the other end of the second resistor, the other end of the second unidirectional transient diode is connected to the other end of the current sensor (17), and the other end of the current sensor (17) is connected to the integrated circuit (151).

7. The protection circuit according to claim 6, wherein the switching circuit (16) is an N-type metal oxide semiconductor field effect transistor having a gate connected to a gate signal output in the integrated circuit (151).

8. The protection circuit according to any of claims 1-7, further comprising a tank circuit (18), wherein the tank circuit (18) is connected between the current sensor (17) and the output interface (12) for providing electrical power to the pitch controller (13) when the switching circuit (16) is in the off-state.

9. The protection circuit according to claim 8, wherein the energy storage circuit (18) comprises a plurality of super capacitors connected in series in sequence, for two super capacitors located at two ends, one end of one super capacitor is connected between the current sensor (17) and the output interface (12), one end of the other super capacitor is connected with a ground terminal, and each super capacitor is provided with a resistor in parallel;

or, the energy storage circuit (18) comprises a battery;

or, the energy storage circuit (18) comprises an emergency power supply.

10. The protection circuit according to claim 1, wherein the anti-surge protection circuit (14) comprises a first stage protection circuit (141), a time-delay overcurrent protection circuit (142) and a second stage protection circuit (143) which are connected in series in sequence;

the first-stage protection circuit (141) is used for absorbing energy generated by surge so as to reduce the voltage value input to the time-delay overcurrent protection circuit (142);

the delay overcurrent protection circuit (142) is used for prolonging the transmission time of surge energy to a circuit connected behind the delay overcurrent protection circuit (142) when a surge comes;

the second-stage protection circuit (143) is used for absorbing energy generated by common mode surges and differential mode surges input by the time-delay overcurrent protection circuit (142).

11. The protection circuit according to claim 10, wherein the first stage protection circuit (141) comprises a gas discharge diode, a first terminal of the gas discharge diode is connected to the input interface (11), a second terminal of the gas discharge diode is connected to a ground terminal, and a third terminal of the gas discharge diode is connected to a protection ground terminal; or the like, or, alternatively,

the first-stage protection circuit (141) comprises a voltage dependent resistor, one end of the voltage dependent resistor is connected with the input interface (11), and the other end of the voltage dependent resistor is connected with a grounding end.

12. The protection circuit of claim 11, wherein the delayed overcurrent protection circuit (142) comprises a fifth resistor, a sixth resistor, a first self-healing fuse, and a second self-healing fuse;

the fifth resistor and the first self-recovery fuse are sequentially connected in series between the first end of the gas discharge diode and the second-stage protection circuit (143);

the sixth resistor and the second self-recovery fuse are sequentially connected in series between the second end of the gas discharge diode and the ground terminal;

the first inductor and the first self-recovery fuse are sequentially connected in series between the first end of the gas discharge diode and the second-stage protection circuit (143);

the second inductor and the second self-recovery fuse are sequentially connected in series between the second end of the gas discharge diode and the grounding end.

13. The protection circuit of claim 12, wherein the second stage protection circuit (143) comprises a first bi-directional transient diode, a second bi-directional transient diode, and a third bi-directional transient diode;

the first bi-directional transient diode and the second bi-directional transient diode are connected in series, one end of the first bi-directional transient diode is connected with the first self-recovery fuse, one end of the second bi-directional transient diode is connected with a ground terminal, and a node between the first bi-directional transient diode and the second bi-directional transient diode is connected with a protection ground terminal;

14. Protection circuit according to claim 10, characterized in that the input interface (11) comprises a first, a second, a third and a fourth lead;

the first lead is connected with the first-stage protection circuit (141), and the first lead outputs a voltage value required by the pitch controller;

the second lead and the third lead are both connected with a shielding layer of a cable;

the fourth lead is connected with a grounding end;

the output interface (12) comprises a fifth lead, a sixth lead, a seventh lead and an eighth lead;

the fifth lead and the sixth lead are both connected with the current sensor (17);

and the seventh lead and the eighth lead are both connected with a grounding end.

15. A pitch system, comprising a pitch controller (13), a power supply (10) for the pitch controller, and a protection circuit according to any of claims 1-14.