Controller for controlling and protecting switch

Abstract

The utility model discloses a controller for controlling and protecting a switch, which relates to the technical field of low-voltage electrical appliances, and comprises a controller for controlling and protecting a switch electrical appliance, the controller comprises an MCU core, a main circuit voltage signal conditioning circuit, an electromagnet driving circuit, a power supply rectifying and filtering circuit, a Bulk circuit and an LDO (Low Dropout Regulator) circuit; the main circuit voltage signal conditioning circuit rectifies, divides and filters the alternating voltage output from the MCU to obtain a voltage signal matched with an analog-to-digital converter of the MCU; the electromagnet drive circuit receives pulse signals sent by the PWM end of the MCU and controls the field effect transistor to be switched on or switched off. When the electromagnetic coil is used, the defects in the prior art are overcome by adopting the pulse width modulation technology and the electromagnetic coil, the simple structure of the single electromagnetic coil is kept, the temperature rise is reduced, the stability of the attraction force of the electromagnet can be kept under the condition of voltage fluctuation by utilizing the pulse width modulation technology, and the reliability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of low-voltage electrical appliances, in particular to a controller for controlling and protecting a switch. Background Art

[0002] The control and protection switches (CPS) on the market currently use electromagnets, which are the same as contactors in principle, for the main circuit connection operation. The design of the electromagnet requires a painful compromise between the two factors of electromagnet attraction and the temperature rise of the electromagnetic coil. Even so, the current control and protection switches still generally have the problem of high coil temperature, which seriously affects the service life of the product and is not conducive to energy saving and consumption reduction.

[0003] In order to solve the above problems, some products adopt the solution of double electromagnetic coils (such as Figure 2 As shown in Figure 1). One is the driving coil, which is used to provide sufficient suction to drive the switch to turn on; the other is the holding coil, which is used to hold after turning on. The holding coil has a high impedance, which ensures low power consumption, that is, reduces the temperature rise. However, this solution still has a defect, that is, voltage fluctuations will affect the holding force of the electromagnet; the voltage reduction leads to a decrease in the holding force. At this time, if the product is operated in a vibration or impact environment, it is easy to malfunction. Utility Model Content

[0004] In order to solve the deficiencies mentioned in the above background technology, the purpose of the present utility model is to provide a controller for controlling and protecting a switch.

[0005] The purpose of the utility model can be achieved through the following technical solutions:

[0006] A controller for controlling and protecting a switch, including a controller for controlling and protecting a switch electrical appliance, wherein the controller includes an MCU core, a main circuit voltage signal conditioning circuit, an electromagnet drive circuit, a power supply rectification filter, and a Bulk and LDO circuit;

[0007] The main circuit voltage signal conditioning circuit rectifies, divides, and filters the AC voltage output from the MCU to obtain a voltage signal that matches the analog-to-digital converter (ADC) of the MCU;

[0008] The electromagnet drive circuit is used to receive the pulse signal sent by the PWM terminal of the MCU, control the field effect tube to turn on or off, and then complete the connection and disconnection of the control and protection switch through the operating mechanism driven by the electromagnet;

[0009] The rectifier, filter, bulk and LDO circuits output voltage to the electromagnet, field effect tube and peripheral circuits after power rectification.

[0010] Furthermore, the main circuit voltage signal conditioning circuit receives the electrical signal output from the main circuit power supply, passes through the diode D5, divides the voltage through R5, and finally filters through the resistor R6 and C3, and outputs it to the MCU core and peripheral circuits.

[0011] Furthermore, the electromagnet drive circuit receives a pulse signal from the PWM port of the MCU core, and then allows the internal signal to be turned on through transistors Q1 and Q3, uses R1 for protection, and uses the MOS tube as an electronic switch to turn on and off the entire electromagnet drive circuit.

[0012] The power supply rectification and filtering and Bulk and LDO circuits are rectified through the rectifier bridge D3 to obtain the driving power supply HV of the electromagnet.

[0013] Beneficial effects of the utility model:

[0014] The utility model overcomes the defects in the prior art by adopting a solution of pulse width modulation technology plus an electromagnetic coil, maintains the simple structure of the single electromagnetic coil, reduces the temperature rise, and can use pulse width modulation technology to maintain the stability of the electromagnet holding force under voltage fluctuations, thereby improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The utility model is further described below in conjunction with the accompanying drawings.

[0016] Figure 1 This is a circuit diagram of a control and protection switch based on PWM technology;

[0017] Figure 2 This is a schematic diagram of the control circuit of the utility model;

[0018] Figure 3 This is a schematic diagram of the principle of dynamic adjustment of PWM duty cycle. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] In the description of the present invention, it should be understood that terms such as "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] A controller for controlling and protecting a switch, such as Figure 1 As shown, it includes a controller for controlling and protecting a switch electrical appliance, and the controller includes an MCU core, a main circuit voltage signal conditioning circuit, an electromagnet drive circuit, a power supply rectifier filter, and a Bulk and LDO circuit;

[0022] The main circuit voltage signal conditioning circuit rectifies, divides, and filters the AC voltage output from the MCU to obtain a voltage signal that matches the analog-to-digital converter (ADC) of the MCU;

[0023] The electromagnet drive circuit receives the pulse signal from the PWM terminal of the MCU, controls the field effect tube to turn on or off, and then completes the connection and disconnection of the control and protection switch through the operating mechanism driven by the electromagnet;

[0024] The rectifier, filter, bulk and LDO circuits output voltage to the electromagnet, field effect tube and peripheral circuits after power rectification.

[0025] The MCU samples the signal output by the voltage signal conditioning circuit in real time through the analog-to-digital converter, calculates the effective value of the voltage of the main circuit, and adjusts the pulse duty cycle of the MCU's PWM port according to the effective value. The pulse is output to the electromagnet drive circuit, so that the drive circuit can maintain the stability of the electromagnet holding voltage when the main circuit voltage changes.

[0026] The MCU adjusts the pulse duty cycle in real time according to the calculated voltage effective value; if the effective value increases, the duty cycle decreases, and if the effective value decreases, the duty cycle increases.

[0027] like Figure 3 As shown, the MCU detects the effective value of the voltage of the main circuit in real time and adjusts the duty cycle of the PWM pulse according to the value. If the voltage increases, the duty cycle of Q1 controlled by the MCU decreases, and in the extreme case it is not less than D / 2. When the voltage of the main circuit decreases, the duty cycle of Q1 is controlled to increase; when the voltage changes between 100% and 35% of the rated value, the duty cycle of Q1 changes between D and 1, showing a linear relationship.

[0028] The entire circuit is based on MCU as the core, as well as the main circuit voltage signal conditioning circuit, electromagnet drive circuit, power supply rectification and filtering, and Bulk and LDO circuits.

[0029] The main circuit voltage signal conditioning circuit obtains a voltage signal that matches the analog-to-digital converter (ADC) of the MCU after rectifying, dividing, and filtering the main circuit voltage. After power rectification and filtering and Bulk and LDO circuits, the driving power (HV) of the electromagnet, the driving power (9V) of the field effect transistor Q1, and the power (3.3V) of the MCU and its peripheral circuits are obtained. The electromagnet drive circuit receives the pulse signal sent by the PWM end of the MCU, controls the field effect transistor Q1 to turn on or off, and then completes the control and protection switch on and off through the operating mechanism driven by the electromagnet.

[0030] Through the operating mechanism of the electromagnet driven by electricity, the movable control and protection switch is affected by the operating mechanism, the operating mechanism is controlled, and the operating mechanism is driven to control and disconnect the control and protection switch in the circuit.

[0031] The MCU samples the voltage through the ADC terminal and calculates the effective value of the voltage of the main circuit. When the control and protection switch is powered and the effective value of the voltage is not less than 85% of the rated value, the MCU sends a low 100ms level pulse through the PWM terminal to drive the field effect Q1 to turn on, and then immediately switches to PWM mode and controls the duty cycle of Q1 to be equal to D (for example, 25%).

[0032] Through testing of actual products, this solution has achieved a holding power of 4.8VA after the electromagnet is attracted, which is only 0.3VA higher than the first-level energy efficiency required by GB 21518-2022 AC contactor energy efficiency limit values ​​and energy efficiency grades, and the temperature rise of the electromagnet coil is less than 5K. Both indicators have dropped to less than 10% of traditional products.

[0033] Compared to Figure 2 The present invention reduces the process difficulty and cost of the electromagnet coil.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. A controller for controlling and protecting a switch, characterized in that: A controller for controlling and protecting switchgear, the controller including an MCU core, a main circuit voltage signal conditioning circuit, an electromagnet drive circuit, a power supply rectifier filter, and a Bulk and LDO circuit; The main circuit voltage signal conditioning circuit rectifies, divides, and filters the AC voltage output from the MCU to obtain a voltage signal that matches the analog-to-digital converter (ADC) of the MCU; The electromagnet drive circuit is used to receive the pulse signal sent by the PWM terminal of the MCU, control the field effect tube to turn on or off, and then complete the connection and disconnection of the control and protection switch through the operating mechanism driven by the electromagnet; The rectifier, filter, bulk and LDO circuits output voltage to the electromagnet, field effect tube and peripheral circuits after power rectification.

2. A controller for controlling and protecting a switch according to claim 1, characterized in that: The main circuit voltage signal conditioning circuit receives the electrical signal output from the main circuit power supply, passes through the diode D5, divides the voltage through R5, and finally filters through the resistor R6 and C3, and outputs it to the MCU core and peripheral circuits.

3. A controller for controlling and protecting a switch according to claim 1, characterized in that: The electromagnet drive circuit receives the pulse signal from the PWM port of the MCU core, and then allows the internal signal to be turned on through transistors Q1 and Q3, uses R1 for protection, and uses the MOS tube as an electronic switch to turn on and off the entire electromagnet drive circuit.

4. A controller for controlling and protecting a switch according to claim 1, characterized in that: The power supply rectification and filtering and Bulk and LDO circuits are rectified through the rectifier bridge D3 to obtain the driving power supply HV of the electromagnet.

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