Locking type shunt release control circuit
By designing a lock-release tripper control circuit, filtering rectification, signal processing and PWM control technology, the problem of heat-burning of the tripping coil in the prior art due to continuous power-on is solved, and higher reliability and anti-interference performance are achieved.
Patent Information
- Application Number
- CN202323509435.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-21
- Publication Date
- 2025-03-04
- Estimated Expiration
- 2033-12-21
AI Technical Summary
After the auxiliary contact is disconnected, the coil is continuously energized, causing the problem of heating and burning.
A lock-release tripper control circuit is designed, including a filtering rectification module, a power generation module, an input detection module, a signal processing and gate driving module and a trip coil driving module. By accurately controlling the initial working timing of the trip coil, a zero input voltage switch (ZVS) is realized, voltage shock is reduced, and controlled through PWM to achieve the lock-release effect.
It effectively prevents the tripping coil from being heated and burned due to continuous power-on, improves the reliability and anti-interference performance of the product, and at the same time, it achieves a good balance in lock-resistance force, tripper power consumption and coil temperature rise.
Smart Images
Figure CN222562599U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of shunt releasers, and in particular relates to a locking type shunt releaser control circuit. Background Art
[0002] Shunt release (undervoltage release) refers to a relay that causes the mechanical switch to open or close with or without delay when the terminal voltage of the relay or release drops to a predetermined value. The release is combined with the switch. When the external voltage drops, even slowly drops to 70% to 35% of the rated voltage, the undervoltage release combined with the switch should operate to disconnect the appliance.
[0003] The existing shunt release control circuit generally operates the shunt release by directly inputting AC power into the release coil. The high voltage at both ends of the coil cannot be automatically eliminated after the shunt release is operated. Once the auxiliary contact is disconnected for a timeout, the coil of the shunt release will be continuously energized and heat up and burn out. Utility Model Content
[0004] In view of the problems existing in the prior art, the utility model provides a locking type shunt release control circuit. When the shunt release detects a suitable input voltage, the tripping coil is driven and maintained in this state, thereby ensuring the reliability and safety of the product when in use.
[0005] The utility model provides a locking type shunt release control circuit, including a filter rectifier module, a power generation module, an input detection module, a signal processing and gate drive module and a release coil drive module;
[0006] The power generation module is respectively connected to the filter and rectifier module and the signal processing and gate drive module to supply power to them;
[0007] The filtering and rectifying module is connected to the zero-fire input module and is used to filter and rectify the input signal;
[0008] The input detection module is connected to the filtering and rectifying module, and is used to generate a timing control signal and a rising edge signal;
[0009] The signal processing and gate driving module is connected to the input detection module and the trip coil driving module respectively, and is used to digitally process the above-mentioned timing control signal and rising edge signal to generate the driving signal required by the trip coil driving module;
[0010] The trip coil driving module is connected to the trip coil and is used to drive the trip coil to operate and lock it.
[0011] In a preferred embodiment of the utility model, the filtering and rectifying module includes an input filter and a bridge rectifier connected thereto, and the input filter includes a secondary varistor and an inductor and a capacitor connected thereto.
[0012] In a preferred embodiment of the present invention, the input detection module includes a voltage divider circuit and a low-pass filter circuit connected thereto.
[0013] In a preferred embodiment of the utility model, the power generation module includes a current limiting resistor, a power switch tube and a linear voltage regulator, the current limiting resistor is connected to the input signal, and the power switch tube is respectively connected to the current limiting resistor and the linear voltage regulator.
[0014] In a preferred embodiment of the present utility model, the signal processing and gate driving module includes a signal processing module and a gate driving module;
[0015] The signal processing module is implemented by a single chip microcomputer, and includes an analog-to-digital converter, a low-pass filter, a hysteresis comparator, a side pressure detector and a timing controller. The analog-to-digital converter is connected to the low-pass filter, the low-pass filter is connected to the hysteresis comparator or the side pressure detector, and the hysteresis comparator and the side pressure detector are respectively connected to the timing controller;
[0016] The gate driving module is implemented by a totem pole or a dedicated gate driving chip.
[0017] In a preferred embodiment of the present invention, the trip coil driving module includes a connected diode and a MOS tube and a capacitor connected thereto.
[0018] Compared with the prior art, the beneficial effects of the utility model are as follows:
[0019] (1) The signal processing circuit based on single-chip microcomputer is adopted, and the digital filtering, digital hysteresis comparison and other technologies are adopted internally, which can effectively resist the fluctuation of input signal, the introduced noise, external interference and other non-ideal factors, and improve the overall anti-interference performance of the product;
[0020] (2) By detecting the zero-crossing point of the input signal and generating a corresponding reference clock signal, the starting working timing of the trip coil can be accurately controlled to achieve the goal of zero input voltage switching (ZVS), greatly reducing the voltage impact when the trip coil is switched, and improving product reliability;
[0021] (3) When the locking type release is working, it is controlled by PWM (pulse width modulation). Combined with the parameters of the trip coil, a good balance is achieved in terms of locking force, release power consumption, and trip coil temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1It is a principle block diagram of the control circuit of the locking type shunt release of the utility model;
[0023] Figure 2 This is a circuit schematic diagram of the filter and rectifier module of the utility model;
[0024] Figure 3 It is a circuit schematic diagram of the input detection module of the utility model;
[0025] Figure 4 It is a circuit schematic diagram of the power generation module of the utility model;
[0026] Figure 5 It is a principle block diagram of the signal processing and gate drive module of the utility model;
[0027] Figure 6 It is a circuit schematic diagram of the signal processing module of the utility model;
[0028] Figure 7 It is a circuit schematic diagram of the trip coil drive module of the utility model;
[0029] Figure 8 It is a circuit schematic diagram of the input signal of the utility model;
[0030] Fig. 9 It is a circuit schematic diagram of the input signal after full-bridge rectification of the utility model;
[0031] Fig.10 It is a circuit schematic diagram of the power generation module of the utility model generating two power supplies;
[0032] Fig.11 It is the circuit principle diagram of input signal detection and digital signal processing of the utility model;
[0033] Fig.12 It is a circuit schematic diagram of the gate drive signal of the utility model;
[0034] Fig.13 This is a circuit schematic diagram of the trip coil control of the utility model;
[0035] Fig.14 It is the relationship between the effective value of the coil current and the coil switch duty cycle of the utility model. DETAILED DESCRIPTION
[0036] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings.
[0037] The structure of the utility model is described in detail below in conjunction with the accompanying drawings.
[0038] like Figure 1A locking type shunt release control circuit shown in the figure includes a filter rectifier module, a power generation module, an input detection module, a signal processing and gate drive module and a trip coil drive module, wherein the power generation module is respectively connected to the filter rectifier module and the signal processing and gate drive module, the filter rectifier module is connected to the zero-fire input module, the input detection module is connected to the filter rectifier module, the signal processing and gate drive module is respectively connected to the input detection module and the trip coil drive module, and the trip coil drive module is connected to the trip coil; wherein the main functions of each module are as follows:
[0039] Filtering and rectification: The typical value of the input signal is 220V 50Hz. The input AC signal is filtered and rectified, and meets the EMC requirements and the indicators of lightning surge of control circuit products;
[0040] Power generation: Take power from the rectified VH to generate two power supplies: one power supply is used for the power supply VPS of the trip coil drive circuit, and the typical value of the power supply is 5V; the other power supply VCC is used for the signal processing circuit, and the typical value is 5V;
[0041] Input detection: detect the rectified signal VH and generate detected signals SN and SA, where SN retains the zero-crossing point of the AC signal, and the subsequent circuit is used to generate the timing control signal of the clock edge; SA is the filtered signal, which is used to generate the rising edge signal of the gate drive, that is, when the input VH reaches a certain value, the shunt release can start working;
[0042] Signal processing and gate drive: This module processes the SN and SA signals digitally. By processing the SN signal, it detects the zero-crossing point of the input AC signal and generates a timing clock SC to control the tripping device to accurately locate the zero-crossing point of the input signal, thereby reducing voltage shock. By digitally processing the SA signal and generating a PWM drive signal, the tripping coil is controlled to operate and lock.
[0043] Trip coil drive: This circuit is used to drive the trip coil and control the current flowing through the coil.
[0044] The circuit of the filter rectifier module is as follows Figure 2 As shown. The module consists of two parts: input filtering and bridge rectification. The input filtering consists of two-stage varistors to improve lightning surge performance. The two varistors are varistors RV1 and varistors RV2. Inductor L0 and capacitors C0 and C1 together form a π-type filter for input filtering. Bridge rectification uses a rectifier bridge to achieve full-wave rectification.
[0045] The circuit of the input detection module is as follows Figure 3As shown. The input signal is VH, R1 and R2 form a voltage divider circuit to convert the rectified signal into a low-voltage signal SN. RN1 and C1 form a low-pass filter circuit to obtain a smoother filtered signal SA. Both SN and SA will be output to the subsequent signal processing module. Zener diode Z1 is used for port protection to limit the amplitude of SA to not exceed the maximum input range of the subsequent circuit.
[0046] The circuit of the power generation module is as follows Figure 4 As shown. The input is VH, R5 is the current limiting resistor of the power branch, and R6 is the current limiting resistor of the voltage regulator branch. T1 is the power switch tube, which can be a triode or a MOS tube. The power generation module generates VPS through a linear power supply circuit, and then generates the power supply VCC through a linear regulator LDO. If the voltage value of the voltage regulator Z3 is VZ3, the value of the output voltage VPS is VPS=VZ3-VBE, that is, the voltage value of the output voltage VPS is about 0.7V lower than the voltage of the voltage regulator VZ3. Since the power consumption of the low-voltage circuit is low, a linear regulator LDO is used to convert VPS into a low-voltage power supply voltage VCC.
[0047] The signal processing and gate drive module includes a signal processing module and a gate drive module. The signal processing module is implemented by a single-chip microcomputer, and the gate drive module is implemented by a totem pole or a dedicated gate drive chip. The output control signal is directly output by the gate drive module to the trip coil drive circuit, such as Figure 5 The voltage value of the input signal VH is input to the single-chip microcomputer, and after the signal is processed inside the single-chip microcomputer, the control signal VG of the trip coil is output. The control signal VG is converted by the gate drive into the gate control signal VDG, and the amplitude and driving ability are improved, and then used to control the trip coil drive circuit.
[0048] The circuit of the signal processing module is as follows Figure 6 As shown. The sampled SA of the input signal VH after voltage reduction is sampled by the analog-to-digital converter (ADC) after analog-to-digital conversion, converted from an analog signal to a digital signal, and then passes through a low-pass filter to filter out high-frequency noise, and after hysteresis comparison by the hysteresis comparator, the signal SP is obtained, which is the starting edge of the trip coil control signal VG. The use of a hysteresis comparator can effectively avoid the zero-crossing oscillation of the comparator, reduce the probability of coil oscillation in the tripper, and improve reliability. The subsequent waveform of the control signal VG is generated by the microcontroller, thereby obtaining a complete control signal to control the opening and closing of the trip coil.
[0049] The circuit of the trip coil drive module is as follows Figure 7As shown. The MOS tube M1 receives the control of the driving signal VDG, and is turned on and off when powered on, so that the trip coil is turned on and has the function of shunt tripping. The diode DD is a freewheeling diode. When the MOS tube is turned off, it provides a current channel for the load coil to ensure reliable operation of the product. The capacitor CD is used to improve the EMC performance of the overall circuit.
[0050] The signal flow of the locking shunt release is described as follows:
[0051] The input part of the circuit is an AC signal input, such as Figure 8 shown.
[0052] After the AC input is full-wave rectified by the filter rectifier module, the output VH is obtained, such as Fig. 9 shown.
[0053] The VH signal generates two power supplies VPS and VCC through the power generation module. Fig.10 As shown, VPS is used for gate driving and has a higher voltage value (typically about 15V), and VCC is used for signal processing and has a lower voltage value (typically about 5V).
[0054] After the voltage VH is divided by the resistors of the input detection module, SN and SA are obtained. The SN signal retains the zero point of the VH signal (i.e., the zero-crossing point of the input AC signal), and SA is the waveform after VH is smoothed. After the SN and SA signals are digitally processed, the signal SC is obtained, and the rising edge of the signal SC is aligned with the zero-crossing point of the AC signal. Through the preset threshold Sth (representing the voltage increase value of SA and also representing the delayed response of the input signal), the timing SP for the trip coil to start is obtained (SP is equivalent to the enable signal, that is, after SP becomes high, the trip coil can start to act), such as Fig.11 shown.
[0055] The signal processing module obtains the gate drive signal VG (lower amplitude) and shifts the gate drive signal level to VDG (higher voltage amplitude, stronger driving capability) to drive the driving MOS of the trip coil, thereby controlling the switch of the trip coil, such as Fig.12 shown.
[0056] The control principle of the trip coil is as follows Fig.13 shown.
[0057] After rectification, the input AC signal obtains the signal VH, which is converted into a relatively smooth rising signal SA. When SA rises to the preset threshold value Sth, the enable step signal SP is output, indicating that the tripping coil can start working. After the VH signal is divided, the zero-crossing clock SC of the AC signal is obtained. When SP is at a high level and SC rises, the gate drive signal VG is generated. At this time, in terms of timing, there is a delay from the input signal to the tripping action from time 0 to time t1. The gate drive signal VG is fully open from time t1 to t2, ensuring that the tripping coil has the maximum pop-up force value, and the tripping is completed from time t1 to t2. After time t2, VG uses PWM control to maintain the state of the tripper. The duty cycle of the PWM signal determines the maintenance voltage and maintenance current of the tripping coil. The duty cycle of the PWM signal and the effective value of the coil current have an approximately linear relationship, such as Fig.14 As shown. Imax is the maximum current when the coil is turned on for a long time, which is related to the voltage difference between the two ends of the coil and the equivalent impedance of the coil. The duty cycle of the PWM signal determines the holding current of the coil, that is, the holding force value of the coil. The holding current of the coil also determines the temperature rise of the product when working for a long time. The smaller the coil current, the smaller the holding force and the lower the temperature rise; the larger the coil current, the higher the holding force and the higher the temperature rise. Therefore, the parameters of the locking type shunt release need to be determined according to the actual situation.
[0058] The above description is only a preferred embodiment of the present invention, and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this patent will not depart from the scope of the technical solution of the present invention.
Claims
1. A locking type shunt release control circuit, characterized in that: It includes a filter and rectifier module, a power generation module, an input detection module, a signal processing and gate drive module, and a trip coil drive module; The power generation module is respectively connected to the filter and rectifier module and the signal processing and gate drive module to supply power to them; The filtering and rectifying module is connected to the zero-fire input module and is used to filter and rectify the input signal; The input detection module is connected to the filtering and rectifying module, and is used to generate a timing control signal and a rising edge signal; The signal processing and gate driving module is connected to the input detection module and the trip coil driving module respectively, and is used to digitally process the above-mentioned timing control signal and rising edge signal to generate the driving signal required by the trip coil driving module; The trip coil driving module is connected to the trip coil and is used to drive the trip coil to operate and lock it.
2. The locking type shunt release control circuit according to claim 1, characterized in that: The filtering and rectifying module comprises an input filter and a bridge rectifier connected thereto, and the input filter comprises a secondary varistor and an inductor and a capacitor connected thereto.
3. The locking type shunt release control circuit according to claim 1, characterized in that: The input detection module includes a voltage divider circuit and a low-pass filter circuit connected thereto.
4. The locking type shunt release control circuit according to claim 1, characterized in that: The power generation module includes a current limiting resistor, a power switch tube and a linear voltage regulator. The current limiting resistor is connected to an input signal, and the power switch tube is connected to the current limiting resistor and the linear voltage regulator respectively.
5. The locking type shunt release control circuit according to claim 1, characterized in that: The signal processing and gate driving module includes a signal processing module and a gate driving module; The signal processing module is implemented by a single chip microcomputer, and includes an analog-to-digital converter, a low-pass filter, a hysteresis comparator, a side pressure detector and a timing controller. The analog-to-digital converter is connected to the low-pass filter, the low-pass filter is connected to the hysteresis comparator or the side pressure detector, and the hysteresis comparator and the side pressure detector are respectively connected to the timing controller; The gate driving module is implemented by a totem pole or a dedicated gate driving chip.
6. The locking type shunt release control circuit according to claim 1, characterized in that: The trip coil driving module includes a connected diode and a MOS tube and a capacitor connected thereto.