CN203289072U - Electro-hydraulic servo valve over-current protector - Google Patents

Abstract

An electro-hydraulic servo valve overcurrent protector relates to the technical field of overcurrent protection. It is to solve the current problem that there is no overcurrent protection for electro-hydraulic servo valve amplifiers. The utility model provides an overcurrent protector for an electro-hydraulic servo valve, which includes a microcontroller unit for receiving current information output by an overcurrent protection circuit in real time and judging its size to control the current protection unit and overcurrent display The unit performs corresponding actions; the current protection unit is used to detect the bidirectional current flowing through the servo valve coil and cut off the current loop when the current is over-current; the over-current indication unit displays the over-current information in the form of a light-emitting tube. The utility model is suitable for the field of electronic technology.

Description

An electro-hydraulic servo valve overcurrent protector

technical field

The utility model relates to the field of overcurrent protection.

Background technique

The electro-hydraulic servo valve is a precision hydraulic component with complex processing technology and high price, and requires professional maintenance. The over-current protection of the servo valve coil during use can prolong the service life of the electro-hydraulic servo valve and improve the system performance. operational reliability.

Utility model content

The purpose of the utility model is to solve the current problem that the electro-hydraulic servo valve cannot be protected from overcurrent. The utility model designs an overcurrent protector for an electro-hydraulic servo valve.

An electro-hydraulic servo valve overcurrent protector described in the utility model includes an electro-hydraulic servo valve amplifier, a current protection unit and a microcontroller; the current signal output end of the electro-hydraulic servo valve amplifier is connected to the current signal input of the current protection unit terminal, the No. 1 current signal output terminal of the current protection unit is connected to the servo valve coil, and the No. 2 current signal output terminal of the current protection unit is connected to the current signal input terminal of the microcontroller;

The current protection unit includes a mode control switch, a first sampling resistor, a first bidirectional current detection chip and a filter circuit; the filter circuit includes a second sampling resistor, a third sampling resistor, a first capacitor, a second capacitor and a second bidirectional current detection chip ;

In the current protection unit, the output end of the current signal of the electro-hydraulic servo valve amplifier is connected to the moving end of the analog switch, one static end of the analog switch is connected to one end of the sampling resistor, and the other end of the sampling resistor is connected to the positive side of the first bidirectional current detection chip. The other end of the sampling resistor is used as the No. 1 current signal output end of the current protection unit, and the other static end of the analog control switch is simultaneously connected to one end of the sampling resistor and the negative input end of the first bidirectional current detection chip. The output end of a bidirectional current detection chip is connected to one end of the second sampling resistor, and the other end of the second sampling resistor is connected to one end of the first capacitor and one end of the third sampling resistor at the same time, and the other end of the third sampling resistor is respectively connected to the second capacitor One end of the first capacitor and the positive input end of the second bidirectional current detection chip, the other end of the second capacitor is grounded, and the other end of the first capacitor is connected to the negative input end and output end of the second bidirectional current detection chip; The output end of the bidirectional current detection chip is the second current signal output end of the current protection unit;

Both the power supply end of the first bidirectional current detection chip and the power supply end of the second bidirectional current detection chip are connected with a 15V power supply.

An electro-hydraulic servo valve overcurrent protector described in the utility model uses a bidirectional current detection chip to detect the current of the electro-hydraulic servo valve, uses a model control switch to connect and disconnect the current loop, and uses a microcontroller as a The discrimination of the over-current information makes the over-current protector of the servo valve have better dynamic performance, and ensures the reliable protection of the servo valve without affecting the matching performance of the original servo amplifier and the servo valve. The utility model has reasonable structural design, small size, convenient connection with the electro-hydraulic servo valve and its amplifier, and can reliably protect the electro-hydraulic servo valve.

Description of drawings

Fig. 1 is a block diagram of the overall structure of the utility model; Fig. 2 is a schematic diagram of the structure of the current protection unit 2 of the utility model; Fig. 3 is a schematic diagram of the structure of the overcurrent indicating unit 5 of the utility model.

Detailed ways

Specific Embodiment 1: The present embodiment will be described below with reference to FIG. 1 and FIG. 2. An electro-hydraulic servo valve overcurrent protector described in this embodiment includes an electro-hydraulic servo valve amplifier 1, a current protection unit 2 and a micro-controller device 4; the current signal output terminal of the electro-hydraulic servo valve amplifier 1 is connected to the current signal input terminal of the current protection unit 2, the first current signal output terminal of the current protection unit 2 is connected to the servo valve coil 3, and the second terminal of the current protection unit 2 No. current signal output terminal is connected to the current signal input terminal of microcontroller 4;

The current protection unit 2 includes a mode control switch 6, a first sampling resistor R1, a first bidirectional current detection chip U1 and a filter circuit 7; the filter circuit 7 includes a second sampling resistor R2, a third sampling resistor R3, a first capacitor C1, a first Two capacitors C2 and a second bidirectional current detection chip U2;

In the current protection unit 2, the current signal output end of the electro-hydraulic servo valve amplifier 1 is connected to the moving end of the analog switch 6, one static end of the analog switch 6 is connected to one end of the sampling resistor R1, and the other end of the sampling resistor R1 is connected to the first bidirectional The positive input end of the current detection chip U1, the other end of the sampling resistor R1 is used as the first current signal output end of the current protection unit 2, and the other static end of the analog control switch 6 is simultaneously connected to one end of the sampling resistor R1 and the first The negative input terminal of the bidirectional current detection chip U1, the output terminal of the first bidirectional current detection chip U1 is connected to one end of the second sampling resistor R2, and the other end of the second sampling resistor R2 is connected to one end of the first capacitor C1 and the third sampling resistor One end of the resistor R3 and the other end of the third sampling resistor R3 are respectively connected to one end of the second capacitor C2 and the positive input end of the second bidirectional current detection chip U2, the other end of the second capacitor C2 is grounded, and the other end of the first capacitor C1 One end is simultaneously connected to the negative input terminal and output terminal of the second bidirectional current detection chip U2; the output terminal of the second bidirectional current detection chip U2 is the No. 2 current signal output terminal of the current protection unit 2;

Both the power terminal of the first bidirectional current detection chip U1 and the power terminal of the second bidirectional current detection chip U2 are connected to a 15V power supply.

working principle:

The principle of the electro-hydraulic servo valve overcurrent protector is shown in Figure 1. The current signal output by the electro-hydraulic servo valve amplifier is output to the servo valve coil through the current protection unit. The current protection unit checks the flowing current and transmits the current information to the micro The controller and the microcontroller judge the overcurrent of the servo valve according to the received signal, and control the current protection unit and the overcurrent display unit to perform corresponding actions. It is mainly composed of the following parts:

The current protection unit is used to detect the bidirectional current flowing through the servo valve coil and feed back the current information to the microcontroller in real time, and at the same time switch on and off the current loop according to the control instructions sent by the microcontroller;

The microcontroller is used to receive the current information output by the over-current protection circuit in real time and judge its size, and then control the current protection unit and the over-current display unit to perform corresponding actions;

The over-current indication unit mainly receives the over-current indication information sent by the microcontroller and displays the over-current information in the form of light-emitting diodes.

Specific Embodiment 2: This embodiment is described in conjunction with FIG. 3. This embodiment further defines the electro-hydraulic servo valve overcurrent protector described in Specific Embodiment 1. It also includes an overcurrent indicating unit as described in this embodiment. 5. The indication signal output end of the microcontroller 4 is connected to the signal input end of the overcurrent indication unit 5 .

Embodiment 3: This embodiment further defines the overcurrent protector for an electro-hydraulic servo valve described in Embodiment 1. The microcontroller 4 described in this embodiment is a 16-bit single-chip microcomputer, which contains 12 bit A/D converter.

The principle of the above-mentioned current protection unit 2 is as follows:

The current output by the electro-hydraulic servo valve amplifier 1 is output to the coil of the electro-hydraulic servo valve through the normally closed contact of the mold control switch and the sampling resistor R1. The first bidirectional current detection chip U1 collects the voltage information at both ends of the sampling resistor, and the The second-order active filter network circuit composed of R2, sampling resistor R3, capacitor C1, capacitor C2 and the second bidirectional current detection chip U2 is input to the A/D of the microcontroller, and the microcontroller collects the signal according to the size of the A/D Control the control pin of the analog switch, and then control the connection and disconnection of the current loop;

When the current signal received by the microcontroller 4 is less than the reference signal, that is, when the current flowing through the electro-hydraulic servo valve is less than the rated current, the controller outputs a signal to control the analog switch and the overcurrent indicating circuit 5, and the normally closed contact of the analog switch contacts pass, the over-current circuit does not issue an over-current warning;

When the signal received by the microcontroller 4 is greater than the reference signal, that is, when the servo valve current is greater than the rated current, the controller outputs a signal to control the analog control switch and the overcurrent indicating circuit 5, the normally open contact of the analog control switch is connected, and the overcurrent circuit An overcurrent warning is issued.

Claims (3)

1. An electro-hydraulic servo valve overcurrent protector is characterized in that: it comprises an electro-hydraulic servo valve amplifier (1), a current protection unit (2) and a microcontroller (4); the electro-hydraulic servo valve amplifier (1) The current signal output terminal of the current protection unit (2) is connected to the current signal input terminal of the current protection unit (2), the No. 1 current signal output terminal of the current protection unit (2) is connected to the servo valve coil (3), and the No. 2 current signal output terminal of the current protection unit (2) The current signal output terminal is connected to the current signal input terminal of the microcontroller (4); The current protection unit (2) includes a mode control switch (6), a first sampling resistor (R1), a first bidirectional current detection chip (U1) and a filter circuit (7); the filter circuit (7) includes a second sampling resistor (R2 ), the third sampling resistor (R3), the first capacitor (C1), the second capacitor (C2) and the second bidirectional current detection chip (U2); In the current protection unit (2), the current signal output end of the electro-hydraulic servo valve amplifier (1) is connected to the moving end of the analog control switch (6), and one static end of the analog control switch (6) is connected to one end of the sampling resistor (R1). The other end of the sampling resistor (R1) is connected to the positive input end of the first bidirectional current detection chip (U1), and the other end of the sampling resistor (R1) is used as the No. 1 current signal output end of the current protection unit (2), analog The other static end of the control switch (6) is simultaneously connected to one end of the sampling resistor (R1) and the negative input end of the first bidirectional current detection chip (U1), and the output end of the first bidirectional current detection chip (U1) is connected to the second One end of the sampling resistor (R2), and the other end of the second sampling resistor (R2) are simultaneously connected to one end of the first capacitor (C1) and one end of the third sampling resistor (R3), and the other ends of the third sampling resistor (R3) are respectively Connect one end of the second capacitor (C2) to the positive input end of the second bidirectional current detection chip (U2), the other end of the second capacitor (C2) is grounded, and the other end of the first capacitor (C1) is simultaneously connected to the second bidirectional current detection chip (U2). The negative input terminal and output terminal of the current detection chip (U2); the output terminal of the second bidirectional current detection chip (U2) is the second current signal output terminal of the current protection unit (2); Both the power supply terminal of the first bidirectional current detection chip (U1) and the power supply terminal of the second bidirectional current detection chip (U2) are connected with a 15V power supply. 2. A kind of electro-hydraulic servo valve overcurrent protector according to claim 1, characterized in that: it also includes an overcurrent indication unit (5), and the indication signal output terminal of the microcontroller (4) is connected to the overcurrent indication Signal input of unit (5). 3. An electro-hydraulic servo valve overcurrent protector according to claim 1, characterized in that: the microcontroller (4) is a 16-bit single-chip microcomputer, and the single-chip microcomputer includes a 12-bit A/D converter.

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