CN204760998U - Circuit breaker intelligent control ware of multistage power supply - Google Patents

Abstract

The utility model discloses a circuit breaker intelligent controller for multi-stage power supply, which comprises a current transformer, a power supply unit and a control unit, and the control unit comprises a basic control module for realizing basic protection functions and a control module for realizing extended functions An expansion module, the basic control module includes a signal processing circuit sequentially connected to the measuring coil of the current transformer, a microprocessor, and a peripheral circuit, and the power supply unit includes a rectification circuit, an auxiliary power input terminal, a first DC/DC circuit, a second DC/DC circuit, a power detection circuit, a switch circuit, and a hysteresis circuit. The two DC/DC circuits in the utility model are independent of each other, and the first DC/DC circuit provides electric energy for the circuit realizing the basic protection, so a smaller output current can be selected to save cost; the utility model uses a hysteresis circuit to self-adapt Controlling the working status of the two DC/DC circuits can avoid the intermittent operation of the DC/DC circuit due to unstable input voltage, resulting in repeated power-on and power-off of the intelligent controller.

Description

An intelligent controller for circuit breaker with multi-stage power supply

technical field

The utility model relates to the technical field of circuit breakers, in particular to an intelligent controller for circuit breakers with multi-stage power supply.

Background technique

With the development of smart grid, the intelligence level of low-voltage circuit breakers is constantly improving, and the functions of intelligent controllers, which are the core components of circuit breakers, are also becoming more and more perfect. On the one hand, the measurement and protection functions of intelligent controllers are constantly improving, and the measurement and protection accuracy is also continuously improving; on the other hand, a series of extended functions such as diversification of display methods, self-diagnosis, and multi-protocol communication are also continuously applied. In the intelligent controller, this causes the overall power consumption of the intelligent controller to become larger and larger. However, when the intelligent controller is in the state of self-power supply (i.e. using current transformers and other devices to extract electric energy from the main circuit protected by the circuit breaker for use by the controller), especially when the system current is small, in order to ensure the normal operation of the intelligent controller , The current transformer needs to provide more energy, which will increase the volume and heat generation of the current transformer, which is not conducive to its miniaturization and low power consumption design, and will also increase its cost. For this reason, Chinese invention patent 200510065296 adopts the method of hierarchical control power supply, which can solve the above-mentioned shortcomings to a certain extent, but its second-stage power supply is provided by the first stage, so the first-stage power supply is required to have a larger output capacity, resulting in unnecessary waste.

Utility model content

The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art, and provide a circuit breaker intelligent controller with multi-level power supply, through which two independent DC/DC circuits provide high priority and low priority in the controller respectively. Powered by electrical components, and can adaptively distribute power according to actual power supply conditions.

The utility model specifically adopts the following technical solutions:

A circuit breaker intelligent controller for multi-stage power supply, including a current transformer, a power supply unit, and a control unit, the current transformer has a measuring coil for measurement and an energy coil for energy supply; the control unit includes a A basic control module for realizing basic protection functions and an expansion module for realizing extended functions, the basic control module includes a signal processing circuit, a microprocessor, and a peripheral circuit sequentially connected to the measuring coil of the current transformer; the power supply The unit includes a rectification circuit, an auxiliary power input terminal, a first DC/DC circuit, a second DC/DC circuit, a power detection circuit, a switch circuit, and a hysteresis circuit, and the input terminal of the rectification circuit is connected to the energy coil of the current transformer , the output end of the rectifier circuit and the input end of the auxiliary power supply are respectively connected to the input end of the first DC/DC circuit, one end of the switch circuit, and the input end of the hysteresis circuit through an anti-reverse diode, and the other end of the switch circuit is connected to the second end of the switch circuit. The input terminal of the DC/DC circuit and the input terminal of the auxiliary power supply are connected at the same point, the output terminal of the hysteresis circuit is connected with the control terminal of the first DC/DC circuit and the control terminal of the second DC/DC circuit at the same point, and the first DC/DC circuit is connected at the same point. The output end of the DC circuit is connected to the power input end of the basic control module, the output end of the second DC/DC circuit is connected to the power input end of the expansion module; the input end and the output end of the power detection circuit are respectively connected to the auxiliary power input end, the microprocessor , used to detect whether there is input at the input terminal of the auxiliary power supply; the control terminal of the switch circuit is connected to the microprocessor, and when the microprocessor detects that there is input at the input terminal of the auxiliary power supply through the power supply detection circuit, the control switch circuit is disconnected, and the When the power detection circuit detects that there is no input at the input terminal of the auxiliary power supply and the main loop current obtained by the measuring coil of the current transformer is greater than the preset current, the control switch circuit is turned on; the hysteresis circuit can be used when the input voltage is higher than the preset current. When the reference voltage is used, the first DC/DC circuit and the second DC/DC circuit are controlled to be turned on; otherwise, the first DC/DC circuit and the second DC/DC circuit are controlled to be turned off.

Compared with the prior art, the utility model has the following beneficial effects:

In addition to the self-function energy supply mode, the utility model can also use auxiliary power supply for power supply at the same time, and can adaptively distribute electric energy for power-consuming components with different priorities according to the actual power supply situation, which improves the work of the intelligent controller. reliability;

The two DC/DC circuits in the utility model are independent of each other, and the first DC/DC circuit provides electric energy for the circuit realizing basic protection, so a smaller output current can be selected to save costs;

The utility model uses a hysteresis circuit to self-adaptively control the working states of two DC/DC circuits, which can prevent the DC/DC circuits from working intermittently due to unstable input voltage, resulting in repeated power-on and power-off of the intelligent controller.

Description of drawings

Fig. 1 is the structural representation of the utility model circuit breaker intelligent controller;

Fig. 2 is a specific realization circuit diagram of hysteresis circuit;

Fig. 3 is a concrete realization circuit diagram of DC/DC circuit;

Fig. 4 is a specific implementation circuit diagram of the power detection circuit.

Detailed ways

Below in conjunction with accompanying drawing, technical scheme of the present utility model is described in detail:

Fig. 1 has shown the basic structure of the present utility model. As shown in Figure 1, the intelligent controller of the circuit breaker of the utility model includes three parts: a current transformer, a power supply unit, and a control unit. Among them, the current transformer in this embodiment has a double-coil structure, with a measuring coil and an energy coil. The measuring coil is used to measure the main circuit current and transmit the measurement signal to the control unit, and the energy coil is responsible for extracting electric energy from the main circuit. And it is provided to the control unit after being processed by the power supply unit. Of course, two independent current transformers can also be used instead of the above-mentioned current transformer with double coil structure, one for measurement and one for energy harvesting. The control unit is divided into two parts: the basic control module and the expansion module. The basic control module includes a signal processing circuit, a microprocessor (MCU), and a peripheral circuit connected to the measurement coil of the current transformer in sequence, and is used to complete the circuit breaker intelligence. The basic protection function of the controller; and the expansion module is used to complete the expansion function other than the basic protection function; the basic protection function and the expansion function can be divided according to the actual situation. The basic protection function in this embodiment refers to three sections Protection and grounding protection, extended functions can include parameter display, external communication and other extended protection functions. The power supply circuit of the present utility model includes a rectification circuit, an auxiliary power supply input terminal, a first DC/DC circuit, a second DC/DC circuit, a power supply detection circuit, a switch circuit, and a hysteresis circuit; as shown in Figure 1, the input of the rectification circuit terminal is connected to the energy coil of the current transformer, the output terminal of the rectifier circuit and the input terminal of the auxiliary power supply are respectively connected to the input terminal of the first DC/DC circuit, One end of the switch circuit and the input end of the hysteresis circuit are connected at the same point, the other end of the switch circuit is connected at the same point with the input end of the second DC/DC circuit and the input end of the auxiliary power supply, and the output end of the hysteresis circuit is connected with the first DC/DC The control terminal of the circuit and the control terminal of the second DC/DC circuit are connected at the same point, the output terminal of the first DC/DC circuit is connected to the power supply input terminal of the basic control module, and the output terminal of the second DC/DC circuit is connected to the power supply of the expansion module Input terminal; the input terminal and output terminal of the power detection circuit are respectively connected to the auxiliary power supply input terminal and the microprocessor to detect whether there is input at the auxiliary power supply input terminal; the control terminal of the switch circuit is connected to the microprocessor, and the microprocessor is in When the power detection circuit detects that there is an input at the input terminal of the auxiliary power supply, the control switch circuit is disconnected, and when the detection circuit detects that there is no input at the input terminal of the auxiliary power supply and the main loop current obtained by the measuring coil of the current transformer is greater than the preset When the current is flowing, the control switch circuit is turned on.

When the power detection circuit detects that there is an input at the input terminal of the auxiliary power supply, that is, when there is an auxiliary power supply, the microprocessor controls the switch circuit to disconnect. At this time, the second DC/DC circuit obtains power from the auxiliary power supply and supplies it to the expansion module; current mutual inductance The electrical energy extracted by the inverter and the electrical energy provided by the auxiliary power supply are supplied to the basic control module via the first DC/DC circuit. If the power supply detection circuit detects that there is no input to the input terminal of the auxiliary power supply, that is, there is no auxiliary power supply or the auxiliary power supply is abnormal, and the main loop current measured by the measuring coil is greater than a preset current (the preset current should be equal to or greater than the current mutual inductance that can be guaranteed) When the electric energy extracted by the current transformer is sufficient to make the basic control module and the expansion module work normally at the same time), the microprocessor controls the switch circuit to be turned on, and the electric energy extracted by the current transformer passes through the first DC/DC circuit, the second DC/ The DC circuit is supplied to the basic control module and the expansion module respectively. If the power detection circuit detects that there is no input to the input terminal of the auxiliary power supply, and the main loop current measured by the measuring coil is less than the preset current, it indicates that the electric energy extracted by the current transformer is not enough to make the basic control module and the expansion module work normally at the same time. At this time, the switch circuit is disconnected, the second DC/DC circuit has no input, the expansion module stops working, and the electric energy extracted by the current transformer is only supplied to the basic control module through the first DC/DC circuit. The hysteresis circuit controls the opening or closing of the DC/DC. It is a hysteresis comparator, which can avoid the constant change of the output voltage caused by the input voltage instability or interference, so that the DC/DC is in the repeated opening and closing state, causing the controller Can not work normally.

The hysteresis circuit, DC/DC circuit, power supply detection circuit, etc. involved in the utility model are all existing mature technologies, and suitable specific circuits can be selected according to actual conditions, and a specific example is given below.

Figure 2 has shown a specific implementation circuit of the hysteresis circuit. As shown in Figure 2, the hysteresis circuit collects the voltage of the rectifier circuit and the auxiliary power supply through resistors R1 and R2, and sends the collected voltage to pin 5 of the comparator N1 through R4. If the voltage is greater than the reference voltage Vref of the pin 6 of the comparator N1, the pin 7 of the comparator N1 outputs a high level to control the first DC/DC circuit and the second DC/DC circuit to be turned on. When the voltage of the rectifier circuit and the auxiliary power supply drops, the voltage of pin 5 of the comparator N1 is lower than the voltage Vref of pin 6 of the comparator N1, and the pin 7 of the comparator N1 outputs a low level to control the first DC/DC circuit, the second The DC/DC circuit is off. Comparator N1 preferably adopts AD8468.

Figure 3 shows a specific example of a DC/DC circuit. As shown in Figure 3, pin 5 of the DC-DC power supply chip N2 is the control terminal of the DC/DC circuit. When pin 5 of the DC-DC power supply chip N2 is at high level, the DC/DC circuit is turned on; when the DC-DC power supply When pin 5 of chip N2 is at low level, the DC/DC circuit is closed. The first and second DC/DC circuits may adopt the same circuit structure, or may be different. The DC-DC power supply chip N2 is preferably MAX5033.

Figure 4 shows an example of a power detection circuit. As shown in Figure 4, when there is an input to the input terminal of the auxiliary power supply, the transistor V1 is turned on, and the MCU detects a low level at this time; when the input of the auxiliary power supply is abnormal, the transistor V1 is turned off, and the MCU detects a high level at this time.

Claims (2)

1. a circuit breaker intelligent controller for multistage power supply, comprises current transformer, power subsystem, control unit, it is characterized in that, described current transformer has the measuring coil for measuring and the energy coil for energy supply, described control unit comprises the basic control module for realizing basic defencive function and the expansion module for realizing expanded function, and described basic control module comprises the signal processing circuit, microprocessor, the peripheral circuit that are connected successively with the measuring coil of described current transformer, described power subsystem comprises rectification circuit, accessory power supply input, one DC/DC circuit, 2nd DC/DC circuit, power sense circuit, switching circuit, return difference circuit, the input of rectification circuit is connected with the energy coil of described current transformer, the output of rectification circuit, accessory power supply input each via after a counnter attack diode with a DC/DC circuit input end, one end of switching circuit, return difference circuit input end concurrent connects, the other end of switching circuit and the input of the 2nd DC/DC circuit, accessory power supply input concurrent connects, the output of return difference circuit and the control end of a DC/DC circuit, the control end concurrent of the 2nd DC/DC circuit connects, the output of the one DC/DC circuit connects the power input of basic control module, the output of the 2nd DC/DC circuit connects the power input of expansion module, input, the output of power sense circuit connect accessory power supply input, microprocessor respectively, whether have input for detecting accessory power supply input, the control end of switching circuit is connected with microprocessor, and microprocessor is when detecting that by power sense circuit accessory power supply input has input, control switch circuit disconnects, detected by power sense circuit accessory power supply input without input and be greater than predetermined current by the main circuit current that the measuring coil of current transformer obtains time, control switch circuit turn-on, described return difference circuit when input voltage is higher than predetermined reference voltage, can control a DC/DC circuit and the unlatching of the 2nd DC/DC circuit, otherwise, control a DC/DC circuit and the closedown of the 2nd DC/DC circuit.

2. circuit breaker intelligent controller as claimed in claim 1, it is characterized in that, described basic defencive function is three section protection and ground protection.