CN209913738U - Discrete frequency conversion heavy load soft start system with overheat and overcurrent protection - Google Patents

Abstract

The utility model discloses a discrete frequency conversion heavy load soft start system with overheated overcurrent protection, including silicon controlled rectifier group module, silicon controlled rectifier group drive module, data analysis processing module, voltage acquisition module, current acquisition module, signal detection module, overcurrent protection module, overheat protection module, man-machine dialogue module, bypass control module and power module. The utility model discloses can form effective protection to the overheated problem of the too big, motor of the common starting current of heavily carrying the starting equipment, silicon controlled rectifier, avoid starting unusually to cause the irreversibility damage to the soft starting equipment of discrete frequency conversion, have simple structure, simple to operate, advantage that the cost is lower.

Description

Discrete frequency conversion heavy load soft start system with overheat and overcurrent protection

Technical Field

The utility model relates to an asynchronous machine heavy load starts technique, concretely relates to discrete frequency conversion heavy load soft start system with overheated overcurrent protection.

Background

In industrial applications, production plants with heavy-duty start are quite common, such as ball mills in the cement industry, rolling mills in the steel industry, belt conveyors in the coal mine industry. Because of the large starting torque, the wound-rotor asynchronous motor is widely applied to the heavy-load starting occasion, and has the following requirements on the starting performance: the starting torque is large, the starting current is small, the starting time is short, the power loss in the starting process is small, the starting equipment is simple, and the starting operation is convenient and reliable. For a heavy-duty start environment, the first two points may be significant.

The starting mode of the winding asynchronous motor can be divided into three modes of rotor string grading resistance, frequency sensitive rheostat and liquid resistance starting. The starting of the series grading resistor can not realize smooth regulation; the starting of the series frequency sensitive rheostat has the problem of larger starting current; although the series liquid resistance can meet the technical index of heavy-load starting, the series liquid resistance and the heavy-load starting have the common defects that the starting equipment is complex, the maintenance is inconvenient, and the power consumption in the starting process is large.

With the deep expansion of the heavy-load starting technology, the discrete frequency conversion soft start attracts attention as a starting mode for effectively improving the starting torque and reducing the starting current, but the conventional discrete frequency conversion soft start is not intelligent enough, and the overcurrent and overheat protection in the starting process is often ignored.

SUMMERY OF THE UTILITY MODEL

The utility model provides a not enough to prior art, the utility model provides a soft starting system of discrete frequency conversion heavy load with overheated overcurrent protection when restriction starting current, increase starting torque, protection starting equipment.

In order to achieve the above purpose, the technical scheme of the utility model is that:

a discrete frequency conversion heavy load soft start system with overheat and overcurrent protection comprises a silicon controlled set module, a silicon controlled set driving module, a data analysis processing module, a voltage acquisition module, a current acquisition module, a signal detection module, an overcurrent protection module, an overheat protection module, a man-machine conversation module, a bypass control module and a power supply module;

the silicon controlled rectifier group module is connected between a power supply and a motor, the silicon controlled rectifier group driving module is connected between the silicon controlled rectifier group module and the data analysis processing module, the voltage acquisition module, the signal detection module and the power supply module are connected between a power supply input end and the data analysis processing module, the current acquisition module is connected between a power supply output end and the data analysis processing module, the overcurrent protection module is connected between the current acquisition module and the data analysis processing module, the number of the overheat protection modules is two, one is connected between the silicon controlled rectifier group module and the data analysis processing module, the other is connected between the motor and the data analysis processing module, the man-machine conversation module is connected with the data analysis processing module, the bypass control module is connected to two ends of the silicon controlled rectifier group module in parallel, and.

Furthermore, the silicon controlled rectifier module consists of three groups of anti-parallel high-capacity thyristors which are respectively connected with a resistance-capacitance absorption loop in parallel and are respectively connected in series on a three-phase transmission line between a power supply and the motor; the thyristor driving module adopts three groups of pulse transformers and carries out pulse triggering control on the thyristor in a time-sharing multiplexing triggering mode.

Furthermore, the voltage acquisition module consists of a Hall voltage sensor, a current-limiting resistor and a filter capacitor; the current acquisition module consists of a current transformer and an amplifying circuit.

Furthermore, the signal detection module is composed of a synchronous voltage detection circuit and a thyristor voltage drop detection circuit.

Furthermore, the overcurrent protection module is composed of a comparator, a filter circuit, an isolation circuit and an amplifying circuit.

Furthermore, the overheating protection module is a temperature sensor, one overheating protection module is installed on a controllable silicon group of the controllable silicon group module, and the other overheating protection module is installed on a stator winding of the motor.

Furthermore, the man-machine conversation module comprises an external instruction input module, an information instruction output module and an LED display module.

Compared with the prior art, the beneficial effects of the utility model reside in that:

1. the device is provided with an overcurrent protection module and an overheat protection module, the data analysis processing module controls the on-off of the thyristor module through the bypass control module according to a current signal generated by the overcurrent protection module and a thyristor module temperature signal and a motor starting temperature signal acquired by the overheat protection module, so that the common problems of overlarge starting current, motor overheating and thyristor overheating of heavy-duty starting equipment are effectively protected, and the irreversibility damage to discrete frequency conversion soft starting equipment caused by abnormal starting is avoided.

2. The utility model discloses an overall design makes it still have simple structure, simple to operate, advantage that the cost is lower.

Drawings

Fig. 1 is a schematic structural diagram of a discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to the present invention;

description of reference numerals: 1-a thyristor group module; 2-a silicon controlled rectifier group driving module; 3-a data analysis processing module; 4-a voltage acquisition module; 5-a current collection module; 6-a signal detection module; 7-an over-current protection module; 8-an overheating protection module; 9-man-machine conversation module; 10-a bypass control module; 11-power supply module.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, a discrete frequency conversion heavy load soft start system with overheat and overcurrent protection comprises a thyristor group module 1, a thyristor group driving module 2, a data analysis processing module 3, a voltage acquisition module 4, a current acquisition module 5, a signal detection module 6, an overcurrent protection module 7, an overheat protection module 8, a man-machine conversation module 9, a bypass control module 10 and a power supply module 11.

The silicon controlled rectifier module 1 is composed of three groups of anti-parallel high-capacity thyristors (silicon controlled rectifiers) which are respectively connected with a resistance-capacitance absorption loop in parallel, and the three groups of silicon controlled rectifiers are respectively connected in series on a three-phase power transmission line which is connected with a power supply and a motor stator.

The silicon controlled rectifier group driving module 2 is connected between the silicon controlled rectifier group module 1 and the data analysis processing module 3, three groups of pulse transformers are adopted, and pulse signals output by the data analysis processing module 3 are isolated and amplified in a time-sharing multiplexing triggering mode to trigger the silicon controlled rectifier group module 1.

The data analysis processing module 3 can adopt an STM32 singlechip to perform real-time measurement, judgment, analysis and processing of field data, and realize man-machine conversation operation through the man-machine conversation module 10.

The voltage acquisition module 4 is connected between a power input end (between a power supply and the silicon controlled rectifier module 1) and the data analysis processing module 3, consists of a Hall voltage sensor, a current-limiting resistor and a filter capacitor, and transmits acquired voltage analog signals to an A/D signal input end of the data analysis processing module 3.

The current acquisition module 5 is connected between the power output end (between the silicon controlled rectifier module 1 and the motor) and the data analysis processing module 3, is composed of a current transformer and an amplifying circuit, and transmits the acquired current analog signal to the A/D signal input end of the data analysis processing module 3.

The signal detection module 6 is connected between the power input terminal and the data analysis processing module 3, is composed of a synchronous voltage detection circuit and a thyristor voltage drop detection circuit, and is used for detecting digital signals of voltage and current serving as trigger angle control references and sending the digital signals to the digital signal input terminal of the data analysis processing module 3.

The overcurrent protection module 7 is connected between the current acquisition module 5 and the data analysis processing module 3, and is composed of a comparator, a filter circuit, an isolation circuit and an amplification circuit, and after comparing, isolating and amplifying current signals acquired by the current acquisition module 5, digital input quantity is formed and is sent to the data analysis processing module 3.

The overheating protection module 8 is composed of two temperature sensors, one temperature sensor is arranged on a silicon controlled group of the silicon controlled group module 1, the other temperature sensor is arranged on a stator winding of the motor, and the collected temperature value of the silicon controlled group module 1 and the collected starting temperature value of the motor are respectively sent to the data analysis processing module 3.

The man-machine conversation module 9 is directly connected with the data analysis processing module 3, comprises an external instruction input module, an information instruction output module and an LED display module, and is responsible for synchronously displaying real-time output data of the data analysis processing module 3 and setting working parameters and controlling a starting process of the discrete frequency conversion system.

The bypass control module 10 is connected in parallel at two ends of the thyristor group module 1, the control end is connected with the data analysis processing module 3, and the discrete variable frequency heavy-load soft start system can be cut off by adopting common switching equipment, such as a relay, and by short-circuiting the thyristor group module 1.

The power supply module 11 is connected between the power supply input end and the data analysis processing module 3 and is responsible for supplying power to the whole system.

It should be noted that, above-mentioned each module is this technical field's conventional electronic components or typical circuit structure, no longer gives unnecessary details to its concrete structure, and in addition, the realization of each module function, especially data analysis processing module 3's discrete variable frequency control all can realize through prior art, and do not belong to the utility model discloses an innovation part.

The utility model discloses a soft start-up system of discrete frequency conversion heavy load, its specific operational mode mainly divide into following several points:

1. after the data analysis processing module 3 carries out real-time measurement and analysis on the voltage and current analog signals acquired by the voltage acquisition module 4 and the current acquisition module 5 and the digital signals of the voltage and the current which are detected by the signal detection module 6 and are used as the trigger angle control reference, according to the requirements of different frequency division of discrete frequency conversion, a trigger pulse signal corresponding to the discrete frequency conversion is generated and is isolated and amplified by the silicon controlled rectifier group driving module 2, regularly controlling the conduction time and the conduction sequence of three pairs of silicon controlled rectifiers of the silicon controlled rectifier group module 1, and the man-machine conversation module 9 directly connected with the discrete frequency conversion system is used for setting working parameters, controlling starting process and synchronously displaying real-time output data, finally achieving equivalent frequency conversion while reducing voltage, therefore, the starting torque is effectively improved, the starting current is reduced, and the starting torque margin and the starting efficiency are further improved.

2. The overcurrent protection module 7 compares, isolates and amplifies the current signals acquired by the current acquisition module 5 to form a digital input quantity, and sends the digital input quantity to the data analysis processing module 3; the overheating protection module 8 respectively transmits the acquired analog electric signals obtained by transmitting the temperature value of the silicon controlled rectifier module 1 and the starting temperature value of the motor to the data analysis processing module 3, and digital signals are formed after comparison; when the measured value is larger than the set value, the corresponding digital input quantity is set as '1', otherwise, the corresponding digital input quantity is set as '0'; the data analysis processing module 3 carries out OR operation on the three collected digital input quantities, if the result is set to be 0, the data analysis processing module 3 controls the gate pole of the silicon controlled rectifier set module 1 to be conducted, the discrete frequency conversion heavy load soft start system normally operates, if the result is set to be 1, the data analysis processing module 3 controls the gate pole of the silicon controlled rectifier set module 1 to be switched off, and meanwhile, the discrete frequency conversion heavy load soft start system is cut off through the bypass control module 10, so that the common problems of overlarge starting current, motor overheating and silicon controlled rectifier overheating of the heavy load starting equipment are effectively protected, and irreversible damage to the discrete frequency conversion soft start equipment caused by abnormal starting is avoided.

The above detailed description is specific to possible embodiments of the present invention, and the embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the scope of the present invention should be included within the scope of the present invention.

Claims (7)

1. The utility model provides a discrete frequency conversion heavy load soft start system with overheated overcurrent protection which characterized in that: the system comprises a silicon controlled rectifier module (1), a silicon controlled rectifier driving module (2), a data analysis processing module (3), a voltage acquisition module (4), a current acquisition module (5), a signal detection module (6), an overcurrent protection module (7), an overheat protection module (8), a man-machine conversation module (9), a bypass control module (10) and a power supply module (11);

the silicon controlled rectifier module (1) is connected between a power supply and a motor, the silicon controlled rectifier driving module (2) is connected between the silicon controlled rectifier module (1) and the data analysis processing module (3), the voltage acquisition module (4), the signal detection module (6) and the power supply module (11) are connected between the power supply input end and the data analysis processing module (3), the current acquisition module (5) is connected between the power supply output end and the data analysis processing module (3), the overcurrent protection module (7) is connected between the current acquisition module (5) and the data analysis processing module (3), the number of the overheat protection modules (8) is two, one is connected between the silicon controlled rectifier module (1) and the data analysis processing module (3), the other is connected between the motor and the data analysis processing module (3), and the man-machine conversation module (9) is connected with the data analysis processing module (3), the bypass control module (10) is connected in parallel at two ends of the silicon controlled rectifier module (1), and the control end of the bypass control module is connected with the data analysis processing module (3).

2. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the silicon controlled rectifier module (1) is composed of three groups of anti-parallel high-capacity thyristors which are respectively connected with a resistance-capacitance absorption loop in parallel and are respectively connected in series on a three-phase transmission line between a power supply and a motor; the thyristor group driving module (2) adopts three groups of pulse transformers and carries out pulse triggering control on the thyristor in a time-sharing multiplexing triggering mode.

3. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the voltage acquisition module (4) consists of a Hall voltage sensor, a current-limiting resistor and a filter capacitor; the current acquisition module (5) consists of a current transformer and an amplifying circuit.

4. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the signal detection module (6) is composed of a synchronous voltage detection circuit and a thyristor voltage drop detection circuit.

5. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the overcurrent protection module (7) is composed of a comparator, a filter circuit, an isolation circuit and an amplifying circuit.

6. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the overheating protection module (8) is a temperature sensor, one overheating protection module is arranged on a controllable silicon group of the controllable silicon group module (1), and the other overheating protection module is arranged on a stator winding of the motor.

7. The discrete frequency conversion heavy-load soft start system with overheat and overcurrent protection according to claim 1, wherein: the man-machine conversation module (9) comprises an external instruction input module, an information instruction output module and an LED display module.

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