PLC power supply circuit

Abstract

The utility model relates to a PLC power supply circuit. The circuit comprises a power supply circuit and a PLC (Programmable Logic Controller); the input end of the power supply circuit is respectively connected with the output end of the main power supply loop and the output end of the standby power supply loop, and the output end of the power supply circuit is connected with the power supply input end of the PLC; the power supply circuit is used for respectively receiving alternating current input by the main power supply loop and the standby power supply loop, protecting the alternating current, eliminating noise, rectifying and filtering the alternating current, converting the alternating current into direct current, and inputting the direct current into the PLC; and the PLC is used for running when the direct current is received and stopping running when the direct current is not received. According to the invention, the main power supply loop and the standby power supply loop are directly connected to the power supply circuit, so that the requirement of a power supply switching device is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to industrial automation power supply technical field especially relates to a PLC power supply circuit. BACKGROUND

[0002] In modern industrial automation system, PLC (Programmable Logic Controller) is widely used in various control tasks, such as production line automation control, equipment state monitoring, etc. In the prior art, in order to ensure the continuous operation of PLC and its related equipment, the main and standby power supply modules are provided with power switching devices in the power supply circuit of PLC, and the switching of main and standby power supply modules is realized through the power switching devices. However, during the switching process of main and standby power supply modules, a short-time power failure phenomenon may occur, and the electromagnetic generated in the power switching moment may interfere with the normal operation of the system in which the PLC is located. Therefore, there is an urgent need for a PLC power supply circuit to optimize the main and standby power supply modules and ensure stable and reliable power supply. SUMMARY

[0003] Therefore, it is necessary to provide a PLC power supply circuit to solve the above technical problems.

[0004] In a first aspect, a PLC power supply circuit is provided, which comprises a power supply circuit and a PLC programmable controller.

[0005] The input end of the power supply circuit is connected to the output end of the main power supply circuit and the output end of the standby power supply circuit, respectively, and the output end of the power supply circuit is connected to the power input end of the PLC.

[0006] The power supply circuit is used to receive the AC power input by the main power supply circuit and the standby power supply circuit, respectively, and to protect, eliminate noise, rectify and filter the AC power, convert the AC power into DC power, and input the DC power to the PLC.

[0007] The PLC is used to run when receiving the DC power and stop running when not receiving the DC power.

[0008] As an optional implementation, the power supply circuit comprises a first power supply front-end protection rectification filter circuit, a second power supply front-end protection rectification filter circuit and an integrated DC-DC circuit, an input end of the first power supply front-end protection rectification filter circuit is connected to the main power supply circuit, an input end of the second power supply front-end protection rectification filter circuit is connected to the standby power supply circuit, output ends of the first power supply front-end protection rectification filter circuit and the second power supply front-end protection rectification filter circuit are connected in parallel and then connected to an input end of the integrated DC-DC circuit, and an output end of the integrated DC-DC circuit is connected to a power input end of the PLC, wherein,

[0009] The first power supply front-end protection rectification filter circuit is configured to receive alternating current input from the main power supply circuit, protect the alternating current, eliminate noise, rectify and filter the alternating current, and convert the alternating current into direct current.

[0010] The second power supply front-end protection rectification filter circuit is configured to receive alternating current input from the standby power supply circuit, protect the alternating current, eliminate noise, rectify and filter the alternating current, and convert the alternating current into direct current.

[0011] The integrated DC-DC circuit is configured to convert the received direct current into direct current with a preset voltage value required by the PLC.

[0012] As an optional implementation, the first power supply front-end protection rectification filter circuit comprises a first power supply input protection circuit, a first EMI noise suppression circuit, a first rectification circuit and a first filter circuit, wherein,

[0013] The first power supply input protection circuit is connected to the first EMI noise suppression circuit, the first EMI noise suppression circuit is connected to the first rectification circuit, and the first rectification circuit is connected to the first filter circuit.

[0014] The first power supply input protection circuit is configured to reduce a resistance value of a voltage-dependent resistor in the first power supply input protection circuit when a voltage of input alternating current is too high, and burn out a fuse in the first power supply input protection circuit when a surge current is received.

[0015] The first EMI noise suppression circuit is configured to eliminate differential mode noise and common mode noise of alternating current output from the first power supply input protection circuit and suppress electromagnetic interference.

[0016] The first rectification circuit is configured to convert alternating current output from the first EMI noise suppression circuit into pulsating direct current.

[0017] The first filter circuit is configured to filter the direct current and input the filtered direct current to the integrated DC-DC circuit.

[0018] As an optional implementation, the second power supply front-end protection rectification filter circuit comprises a second power supply input protection circuit, a second EMI noise suppression circuit, a second rectification circuit and a second filter circuit.

[0019] The second power supply input protection circuit is connected to the second EMI noise suppression circuit, the second EMI noise suppression circuit is connected to the second rectification circuit, and the second rectification circuit is connected to the second filter circuit.

[0020] The second power supply input protection circuit is configured to reduce the resistance value of a voltage-dependent resistor in the second power supply input protection circuit when the voltage of the input alternating current is too high, and burn out a fuse in the second power supply input protection circuit when a surge current is received.

[0021] The second EMI noise suppression circuit is configured to eliminate differential mode noise and common mode noise of the alternating current output by the second power supply input protection circuit and suppress electromagnetic interference.

[0022] The second rectification circuit is configured to convert the alternating current output by the second EMI noise suppression circuit into pulsating direct current.

[0023] The second filter circuit is configured to filter the direct current and input the filtered direct current to the integrated DC-DC circuit.

[0024] As an optional implementation, the first power supply input protection circuit comprises a fuse, a voltage-dependent resistor and a thermistor.

[0025] One end of the fuse is connected to one end of the voltage-dependent resistor and the first EMI noise suppression circuit, respectively, and the other end of the fuse is connected to the live wire of the main power supply circuit. One end of the voltage-dependent resistor is connected to one end of the thermistor and the first EMI noise suppression circuit, respectively, and the other end of the voltage-dependent resistor is connected to the neutral wire of the main power supply circuit. One end of the thermistor is connected to the other end of the voltage-dependent resistor and the first EMI noise suppression circuit, respectively, and the other end of the thermistor is connected to the neutral wire of the main power supply circuit.

[0026] As an optional implementation, the first EMI noise suppression circuit comprises a common mode inductor, a first capacitor, a second capacitor, a third capacitor, a first resistor and a second resistor.

[0027] One end of the first capacitor is connected to the first power input protection circuit, one end of the first resistor, one end of the third capacitor, and one end of the first winding of the common mode inductor, respectively, the other end of the first capacitor is connected to the other end of the second capacitor and the ground, one end of the second capacitor is connected to the first power input protection circuit and one end of the second resistor, respectively, the other end of the third capacitor and one end of the second winding of the common mode inductor, the other end of the first resistor is connected to the other end of the second resistor, the other end of the first winding of the common mode inductor is connected to the first rectifier circuit, and the other end of the second winding of the common mode inductor is connected to the first rectifier circuit.

[0028] As an optional implementation, the first rectifier circuit comprises a first diode, a second diode, a third diode, and a fourth diode.

[0029] The anode of the first diode is connected to the first EMI noise suppression circuit and the cathode of the second diode, respectively, the cathode of the first diode is connected to the cathode of the third diode and the first filter circuit, respectively, the anode of the second diode is connected to the anode of the fourth diode and the first filter circuit, and the ground, the anode of the third diode is connected to the first EMI noise suppression circuit and the cathode of the fourth diode, respectively.

[0030] As an optional implementation, the first filter circuit comprises a fourth capacitor, a fifth capacitor, and an electrolytic capacitor.

[0031] The anode of the electrolytic capacitor is connected to the first rectifier circuit and one end of the fourth capacitor, respectively, the cathode of the electrolytic capacitor is connected to the first rectifier circuit, one end of the fifth capacitor, and the other end of the fourth capacitor, respectively, and the other end of the fifth capacitor is grounded.

[0032] As an optional implementation, the first power input protection circuit and the second power input protection circuit are the same, the first EMI noise suppression circuit and the second EMI noise suppression circuit are the same, the first rectifier circuit and the second rectifier circuit are the same, and the first filter circuit and the second filter circuit are the same.

[0033] As an optional implementation, the second power input protection circuit is connected to the zero line and the live line of the standby power supply circuit.

[0034] The utility model provides a kind of circuit of PLC power supply, the technical scheme provided by the utility model embodiment at least brings following beneficial effects: the AC power of main power supply power loop and standby power supply power loop input is converted into DC by power supply circuit, and stable power supply service is provided for PLC.It ensures that standby power supply power loop can seamlessly take over work in the case where main power supply power loop appears power failure, eliminates the problem of short-time power failure, effectively reduces the risk of equipment restart, enhances the anti-interference ability of PLC belonging system.It ensures that PLC system can continuously and stably operate under various working conditions, while reducing the complexity and cost of operation and maintenance.At the same time, the wiring design of the power module is simple and clear, and the main and standby power supply power loop can be directly connected to the power module, greatly simplifying the installation process, improving the processing efficiency of power supply circuit and the convenience and reliability of PLC system.

[0035] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0037] Figure 1 The structure diagram of the circuit of PLC power supply provided by the utility model embodiment is shown in the figure.

[0038] Figure 2 The structure diagram of the power supply circuit provided by the utility model embodiment is shown in the figure.

[0039] Figure 3 The circuit diagram of the first power supply front stage protection rectifier filter circuit provided by the utility model embodiment is shown in the figure.

[0040] Figure 4 The structure diagram of the circuit of PLC power supply provided by the prior art of the utility model embodiment is shown in the figure. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the utility model more clear, the following will be further described in detail by combining with the drawings and embodiments.The specific embodiments described here are only used to explain the present application, and are not used to limit the utility model.

[0042] Figure 1The utility model provides a kind of circuit structure diagram of PLC power supply for the embodiment of the utility model.As shown in Figure 1 The input end of power supply circuit 13 is connected with the output end of main power supply circuit 11 and the output end of backup power supply circuit 12 respectively, and the output end of power supply circuit 13 is connected with the power input end of PLC 14.Main power supply circuit 11 is used to supply power for PLC 14.Backup power supply circuit 12 is used to supply power for PLC 14.Main power supply circuit 11 and backup power supply circuit 12 supply power for PLC 14 simultaneously, and when main power supply circuit 11 or backup power supply circuit 12 is damaged, the other power supply circuit continues to supply power for PLC 14.

[0043] Power supply circuit 13 is used to receive AC power input by main power supply circuit 11 and backup power supply circuit 12 respectively, protect AC power, eliminate noise, rectify and filter, convert AC power into DC power, and input DC power into PLC 14.

[0044] PLC 14 is used to run when receiving DC power and stop running when not receiving DC power.

[0045] Figure 2 The utility model provides a kind of circuit structure diagram of power supply for the embodiment of the utility model.As shown in Figure 2 Power supply circuit 13 includes first power front-end protection rectifier filter circuit 131, second power front-end protection rectifier filter circuit 132 and integrated DC-DC circuit 133, the input end of first power front-end protection rectifier filter circuit 131 is connected with main power supply circuit 11, the input end of second power front-end protection rectifier filter circuit 132 is connected with backup power supply circuit 12, the output end of first power front-end protection rectifier filter circuit 131 and second power front-end protection rectifier filter circuit 132 is connected with integrated DC-DC circuit 133 in parallel, and integrated DC-DC circuit 133 is connected with the power input end of PLC 104.

[0046] First power front-end protection rectifier filter circuit 131 is used to receive AC power input by main power supply circuit 11, protect AC power, eliminate noise, rectify and filter, and convert AC power into DC power.

[0047] Second power front-end protection rectifier filter circuit 132 is used to receive AC power input by backup power supply circuit 12, protect AC power, eliminate noise, rectify and filter, and convert AC power into DC power.

[0048] The integrated DC-DC circuit 133 is used for converting the received direct current into direct current with preset voltage value required by the PLC 104. The integrated DC-DC circuit 133 has an ultra-wide input voltage range of 250VDC-1500VDC, has a high isolation voltage of 4000VAC, meets the industrial working temperature, and has a conversion efficiency of greater than 90%.

[0049] Figure 3 A circuit diagram of the first power supply front-end protection rectification filtering circuit is provided for the embodiment of the utility model. As shown in the figure, Figure 3 The first power supply front-end protection rectification filtering circuit 131 includes a first power supply input protection circuit 1311, a first EMI noise suppression circuit 1312, a first rectification circuit 1313 and a first filtering circuit 1314.

[0050] The first power supply input protection circuit 1311 is connected with the first EMI noise suppression circuit 1312, the first EMI noise suppression circuit 1312 is connected with the first rectification circuit 1313, and the first rectification circuit 1313 is connected with the first filtering circuit 1314. The first power supply input protection circuit 1311 is used for reducing the resistance value of the voltage-dependent resistor in the first power supply input protection circuit 1311 when the voltage of the input alternating current is too high, and burning out the fuse in the first power supply input protection circuit 1311 when receiving the inrush current. The first EMI noise suppression circuit 1312 is used for eliminating the differential mode noise and common mode noise of the alternating current output by the first power supply input protection circuit 1311 and suppressing electromagnetic interference. The first rectification circuit 1313 is used for converting the alternating current output by the first EMI noise suppression circuit 1312 into pulsating direct current. The first filtering circuit 1314 is used for filtering the direct current and inputting the filtered direct current into the integrated DC-DC circuit 133.

[0051] As an optional implementation, the first power supply input protection circuit 1311 includes a fuse F1, a voltage-dependent resistor RV1 and a thermistor TH1.

[0052] One end of the fuse F1 is connected to one end of the pressure sensitive resistor RV1 and the first EMI noise suppression circuit 1312, respectively, and the other end of the fuse F1 is connected to the live wire of the main power supply circuit 11. The other end of the pressure sensitive resistor RV1 is connected to one end of the thermal resistor TH1 and the first EMI noise suppression circuit 1312, respectively, and the other end of the thermal resistor TH1 is connected to the zero wire of the main power supply circuit 11. The fuse F1 is used to protect the subsequent circuit by burning out when a long time surge, large current or short circuit occurs, and is connected in series to the live wire L. The pressure sensitive resistor RV1 is used for lightning protection. That is, when the voltage of the alternating current exceeds its working voltage, the resistance of the pressure sensitive resistor RV1 decreases, and the high voltage energy is consumed to prevent the high voltage from being introduced to the subsequent stage. The thermal resistor TH1 is used to suppress the inrush current at the start-up, and to protect the circuit from the circuit impact, and is connected in series to the live wire L or the zero wire N, and a thermal resistor with a negative temperature coefficient is selected. In this way, the PLC can be protected from the voltage fluctuation and the inrush current at the input end of the power supply.

[0053] As an optional embodiment, the first EMI noise suppression circuit 1312 includes a common mode inductor LF1, a first capacitor CY1, a second capacitor CY2, a third capacitor CX1, a first resistor R1 and a second resistor R2.

[0054] One end of the first capacitor CY1 is connected to the first power input protection circuit 1311, one end of the first resistor R1, one end of the third capacitor CX1, and one end of the first winding of the common mode inductor LF1, respectively, and the other end of the first capacitor CY1 is connected to the other end of the second capacitor CY2 and grounded. One end of the second capacitor CY2 is connected to the first power input protection circuit 1311 and one end of the second resistor R2, respectively, and the other end of the third capacitor CX1 and one end of the second winding of the common mode inductor LF1. The other end of the first resistor R1 is connected to the other end of the second resistor R2. The other end of the first winding of the common mode inductor LF1 is connected to the first rectifier circuit 1313, and the other end of the second winding of the common mode inductor LF1 is connected to the first rectifier circuit 1313. Among them, the first capacitor CY1, the second capacitor CY2, and the third capacitor CX1 are discharged as safety capacitors. The third capacitor CX1 is directly connected between the live wire L and the neutral wire N, which can eliminate the differential mode noise in the power line. The common mode inductor LF1, the first capacitor CY1, and the second capacitor CY2 can filter out the common mode noise in the input power line. The first capacitor CY1 and the second capacitor CY2 are connected to the ground at the neutral wire N and the live wire L. The first resistor R1 and the second resistor R2 are discharge resistors for discharging the first capacitor CY1, the second capacitor CY2, and the third capacitor CX1. Since the first capacitor CY1, the second capacitor CY2, and the third capacitor CX1 still have a high voltage of 220V after the power supply circuit 13 is powered off, if not discharged, it will be transmitted to the exposed plug along the power line, which has the risk of electric shock. By connecting the first resistor R1 and the second resistor R2 to discharge the voltage, safety is ensured. Two resistors in series are used to improve the power of the resistor to prevent damage, and the resistance value is generally selected to be 500K or more to M ohm level. Thus, electromagnetic interference can be suppressed, and the stability of power supply can be improved.

[0055] Further, the EMI filter can also be improved, a more efficient filter can be used, the existing power supply design can be improved, a more efficient EMI filter or advanced electromagnetic compatibility technology can be adopted to improve the anti-interference ability of the system.

[0056] As an optional implementation, the first rectifier circuit 1313 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

[0057] The positive pole of the first diode D1 is connected to the first EMI noise suppression circuit 1312 and the negative pole of the second diode D2 respectively, the negative pole of the first diode D1 is connected to the negative pole of the third diode D3 and the first filter circuit 1314 respectively, the positive pole of the second diode D2 is connected to the positive pole of the fourth diode D4 and the first filter circuit 1314 respectively and grounded, the positive pole of the third diode D3 is connected to the first EMI noise suppression circuit 1312 and the negative pole of the fourth diode D4 respectively. The first rectifier circuit 1313 adopts single-phase bridge rectifier circuit to convert alternating current into pulsating direct current. The first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 are rectifier diodes, and four diodes require high voltage and large current to adapt to the power demand. The first diode D1 and the fourth diode D4 are turned on when the positive half cycle of the input alternating current, and the second diode D2 and the third diode D3 are turned on when the negative half cycle of the alternating current. In this way, the alternating current can be converted into pulsating direct current with constant direction by alternately turning on the first diode D1 and the fourth diode D4, and the second diode D2 and the third diode D3. The highest value of the voltage of the pulsating direct current is 1.414 (square root 2) times the voltage of the input alternating current.

[0058] As an optional implementation, the first filter circuit 1314 includes electrolytic capacitor C1, fourth capacitor C3 and fifth capacitor C2.

[0059] The positive pole of the electrolytic capacitor C1 is connected to the first rectifier circuit 1313 and one end of the fourth capacitor C3, respectively, and the negative pole of the electrolytic capacitor C1 is connected to the first rectifier circuit 1313, one end of the fifth capacitor C2 and the other end of the fourth capacitor C3, respectively, and the other end of the fifth capacitor C2 is grounded. Among them, the electrolytic capacitor C1 is large capacity and high voltage. Attention should be paid to the positive and negative poles of the electrolytic capacitor C1 during welding. The capacity of the capacitor is selected to be about 22uF-100uF, which is selected according to the output power of the power supply and the fluctuation range of the power grid voltage. Since the larger the filter capacitor capacity is, the smaller the low-frequency cutoff frequency is, and the better the filtering effect is, it is necessary to determine according to the actual power requirement. The electrolytic capacitor C1 filters the pulsating direct current voltage after rectification, so that the output direct current voltage is smoother (the charging and discharging effect of the capacitor makes the output voltage tend to be smooth). In addition, the large-capacity electrolytic capacitor C1 also has a freewheeling effect, which can continue to provide current to the load for a short time when the input power is off, thereby maintaining the stability of the power supply when the main power supply or other power supply is lost. This freewheeling effect is particularly important for power-sensitive equipment, and can avoid device restart caused by short-time power failure. The fourth capacitor C3 is a ceramic capacitor, and a small-capacity 10nF ceramic capacitor is connected in parallel, which is mainly used to filter high-frequency noise in the direct current power supply, making the direct current power supply smoother. The fifth capacitor C2 is an isolation filter capacitor. In this circuit, in addition to the basic filtering effect, the most important thing is to play an isolation role. On the one hand, when the power supply system fails, such as abnormal high ground potential of the power supply, the fifth capacitor C2 can prevent the abnormal potential from being transmitted to other parts of the device, avoiding electric shock of the operator or damage to the equipment. By properly balancing and guiding the potential difference between the power supply ground and the ground, it can improve the safety of the system. On the other hand, it can reduce the formation of ground loops, which can cause ground to flow between different grounds, thereby generating interference signals. Because this power supply module is connected to two different line AC power supplies with different ground lines, special attention should be paid to the formation of ground loops due to different ground line potentials. The capacitor helps to maintain the stability of the power supply and the integrity of the signal, ensuring that the PLC system can work normally and reliably. Figure 3 As shown in FIG. 13B, the first filter circuit 1314 outputs direct current (voltage V+ and V-), and is connected in parallel to the input end of the integrated DC-DC circuit to form a complete power supply circuit.

[0060] As an optional embodiment, the second power supply front-end protection rectifier filter circuit 132 includes a second power supply input protection circuit 1321, a second EMI noise suppression circuit 1322, a second rectifier circuit 1323 and a second filter circuit 1324.

[0061] The second power input protection circuit 1321 is connected with the second EMI noise suppression circuit 1322, the second EMI noise suppression circuit 1322 is connected with the second rectifier circuit 1323, and the second rectifier circuit 1323 is connected with the second filter circuit 1324. The second power input protection circuit 1321 is used for reducing the resistance value of a voltage-dependent resistor in the second power input protection circuit 1321 when the voltage of the input alternating current is too high, and burning out a fuse in the second power input protection circuit 1321 when receiving a surge current. The second EMI noise suppression circuit 1322 is used for eliminating the differential mode noise and common mode noise of the alternating current output by the second power input protection circuit 1322 and suppressing electromagnetic interference. The second rectifier circuit 1323 is used for converting the alternating current output by the second EMI noise suppression circuit 1322 into pulsating direct current. The second filter circuit 1324 is used for filtering the direct current and inputting the filtered direct current into the integrated DC-DC circuit 133.

[0062] As an optional implementation, the first power input protection circuit 1311 and the second power input protection circuit 1321 are the same, the first EMI noise suppression circuit 1312 and the second EMI noise suppression circuit 1322 are the same, the first rectifier circuit 1313 and the second rectifier circuit 1323 are the same, and the first filter circuit 1314 and the second filter circuit 1324 are the same.

[0063] As an optional implementation, the second power input protection circuit 1321 is connected with the zero line and the live line of the backup power supply circuit 12.

[0064] Figure 4 A structural schematic diagram of a circuit of a PLC power supply in the prior art is provided for the embodiment of the utility model. As shown in the figure, Figure 4 When the main power supply circuit and the backup power supply circuit supply power to the PLC through the AC / DC power supply module, an additional power supply switching device needs to be installed. This not only increases the hardware cost, but also may cause higher cost due to the need to provide other auxiliary equipment during installation. During the power supply switching process through the power supply switching device, a short-time power failure phenomenon may occur, which poses a threat to power-sensitive equipment and may cause equipment restart and production interruption, resulting in huge economic losses. At the same time, the electromagnetic interference generated instantaneously during power switching may affect the normal operation of the PLC system, may cause data errors and program abnormalities, and further affect the production process. The complex wiring of the power supply switching device increases the installation difficulty, and a large amount of manpower and time is consumed for checking and troubleshooting during later maintenance, significantly increasing the operating cost.

[0065] Further, the power supply circuit of the application is installed in the PLC system, connecting the main power supply circuit and the backup power supply circuit. After installation, the power supply circuit is debugged to check whether the power supply circuit can work normally and provide stable DC power for the PLC system. Then the main power supply circuit and the backup power supply circuit are powered in turn, and then the main power supply circuit and the backup power supply circuit supply power together, and the power supply circuit outputs stable DC voltage.

[0066] Further, in addition to the technical solutions described in this application, a double-input power supply circuit can also be provided: the double-input configuration is similar to the application, and a double-input power supply circuit is used, but a different switching mechanism (such as a mechanical switch or a relay) is still used to switch the main and backup power supply circuits.

[0067] Improvements can also be made by using an external switching device, which can still use a traditional power supply switching device to switch between the main and backup power supply circuits. This solution may require additional wiring and installation, but can provide redundancy protection in some cases. Redundant power supply: distributed power supply system, in some applications, multiple redundant power supplies can be combined together to ensure the reliability of the power source, which can provide additional flexibility to the system. Battery or energy storage system: use of backup battery: in critical applications, short-term power interruption can be solved by battery or UPS (Uninterruptible Power Supply). This solution has a higher cost, but can provide excellent power supply stability.

[0068] The embodiment of the utility model provides a kind of circuit of PLC power supply, and the main backup power supply circuit is connected to power supply circuit by parallel design after passing through power supply circuit, and it is powered for PLC.Just, by directly connecting the main power supply circuit and the backup power supply circuit to the power supply circuit, the need for additional power switching devices is eliminated, reducing production costs. Seamless power switching, in the case of power failure of the main power supply circuit, the backup power supply circuit can immediately take over power supply, avoiding short power failure problems and improving the stability and operational reliability of the equipment. Simplify wiring and maintenance, the integrated design of power supply circuit makes wiring simple and convenient, reducing the complexity and cost of maintenance work. Integrated circuit design: power input protection circuit can protect the system from overvoltage and surge current. EMI noise suppression circuit can effectively reduce electromagnetic interference in the power supply, improving the stability of the system. Rectifier circuit can convert alternating current into smooth direct current. Filtering circuit can further reduce power ripple to ensure the stability of output current.

[0069] It should be noted that the relative terms, such as first and second, and the like, are used herein only to distinguish one entity or operation from another, and do not necessarily require or imply any actual such relationship or order between such entities or operations. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0070] It should also be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for display, analyzed data, etc.) involved in the utility model are all information and data authorized by the user or fully authorized by all parties.

[0071] Each embodiment in the specification is described in a related manner, and the same and similar parts between each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can be referred to the part of the method embodiment.

[0072] The technical features of the above embodiments can be combined arbitrarily, and in order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the specification.

[0073] The above-described embodiments only express several implementation manners of the utility model, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which are within the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A PLC powered circuit, characterized in that, The circuit includes a power supply circuit and a PLC programmable controller; The input terminal of the power supply circuit is connected to the output terminal of the main power supply circuit and the output terminal of the backup power supply circuit, respectively, and the output terminal of the power supply circuit is connected to the power input terminal of the PLC. The power supply circuit is used to receive AC power input from the main power supply circuit and the backup power supply circuit respectively, and to protect the AC power, eliminate noise, rectify and filter it, convert the AC power into DC power, and input the DC power to the PLC. The PLC is configured to operate when it receives the DC power and to stop operating when it does not receive the DC power.

2. The circuit of claim 1, wherein, The power supply circuit includes a first power supply pre-stage protection rectifier and filter circuit, a second power supply pre-stage protection rectifier and filter circuit, and an integrated DC-DC circuit. The input terminal of the first power supply pre-stage protection rectifier and filter circuit is connected to the main power supply circuit, and the input terminal of the second power supply pre-stage protection rectifier and filter circuit is connected to the backup power supply circuit. The output terminals of the first and second power supply pre-stage protection rectifier and filter circuits are connected in parallel and then connected to the input terminal of the integrated DC-DC circuit. The output terminal of the integrated DC-DC circuit is connected to the power input terminal of the PLC. The first power supply front-end protection rectifier and filter circuit is used to receive the AC power input from the main power supply circuit, and to protect the AC power, eliminate noise, rectify and filter it, and convert the AC power into DC power. The second power supply front-end protection rectifier and filter circuit is used to receive the AC power input from the backup power supply circuit, and to protect the AC power, eliminate noise, rectify and filter it, and convert the AC power into DC power. The integrated DC-DC circuit is used to convert the received DC power into DC power with a preset voltage value required by the PLC.

3. The circuit of claim 2, wherein, The first power supply pre-stage protection rectifier and filter circuit includes a first power input protection circuit, a first EMI noise suppression circuit, a first rectifier circuit, and a first filter circuit; wherein, The first power input protection circuit is connected to the first EMI noise suppression circuit, the first EMI noise suppression circuit is connected to the first rectifier circuit, and the first rectifier circuit is connected to the first filter circuit. The first power input protection circuit is used to reduce the resistance value of the varistor in the first power input protection circuit when the voltage of the input AC power is too high, and to burn out the fuse in the first power input protection circuit when a surge current is received. The first EMI noise suppression circuit is used to eliminate the differential-mode noise and common-mode noise of the AC power output from the first power input protection circuit and suppress electromagnetic interference. The first rectifier circuit is used to convert the alternating current output by the first EMI noise suppression circuit into pulsating direct current; The first filtering circuit is used to filter the DC power and input the filtered DC power to the integrated DC-DC circuit.

4. The circuit of claim 3, wherein, The second power supply pre-stage protection rectifier and filter circuit includes a second power input protection circuit, a second EMI noise suppression circuit, a second rectifier circuit, and a second filter circuit; wherein, The second power input protection circuit is connected to the second EMI noise suppression circuit, the second EMI noise suppression circuit is connected to the second rectifier circuit, and the second rectifier circuit is connected to the second filter circuit. The second power input protection circuit is used to reduce the resistance value of the varistor in the second power input protection circuit when the voltage of the input AC power is too high, and to burn out the fuse in the second power input protection circuit when a surge current is received. The second EMI noise suppression circuit is used to eliminate the differential-mode noise and common-mode noise of the AC power output from the second power input protection circuit and suppress electromagnetic interference. The second rectifier circuit is used to convert the AC power output by the second EMI noise suppression circuit into pulsating DC power; The second filter circuit is used to filter the DC power and input the filtered DC power to the integrated DC-DC circuit.

5. The circuit of claim 3, wherein, The first power input protection circuit includes a fuse, a varistor, and a thermistor; One end of the fuse is connected to one end of the varistor and the first EMI noise suppression circuit, and the other end of the fuse is connected to the live wire of the main power supply circuit. The other end of the varistor is connected to one end of the thermistor and the first EMI noise suppression circuit, and the other end of the thermistor is connected to the neutral wire of the main power supply circuit.

6. The circuit of claim 3, wherein, The first EMI noise suppression circuit includes a common-mode inductor, a first capacitor, a second capacitor, a third capacitor, a first resistor, and a second resistor; One end of the first capacitor is connected to the first power input protection circuit, one end of the first resistor, one end of the third capacitor, and one end of the first winding of the common-mode inductor. The other end of the first capacitor is connected to the other end of the second capacitor and grounded. One end of the second capacitor is connected to the first power input protection circuit and one end of the second resistor. The other end of the third capacitor is connected to one end of the second winding of the common-mode inductor. The other end of the first resistor is connected to the other end of the second resistor. The other end of the first winding of the common-mode inductor is connected to the first rectifier circuit. The other end of the second winding of the common-mode inductor is connected to the first rectifier circuit.

7. The circuit of claim 3, wherein, The first rectifier circuit includes a first diode, a second diode, a third diode, and a fourth diode; The anode of the first diode is connected to the first EMI noise suppression circuit and the cathode of the second diode, respectively. The cathode of the first diode is connected to the cathode of the third diode and the first filter circuit, respectively. The anode of the second diode is connected to the anode of the fourth diode and the first filter circuit and grounded, respectively. The anode of the third diode is connected to the first EMI noise suppression circuit and the cathode of the fourth diode, respectively.

8. The circuit of claim 3, wherein, The first filter circuit includes a fourth capacitor, a fifth capacitor, and an electrolytic capacitor; The positive terminal of the electrolytic capacitor is connected to one end of the first rectifier circuit and one end of the fourth capacitor, respectively. The negative terminal of the electrolytic capacitor is connected to one end of the first rectifier circuit, one end of the fifth capacitor, and the other end of the fourth capacitor, respectively. The other end of the fifth capacitor is grounded.

9. The circuit according to claim 4, characterized in that, The first power input protection circuit and the second power input protection circuit are the same, the first EMI noise suppression circuit and the second EMI noise suppression circuit are the same, the first rectifier circuit and the second rectifier circuit are the same, and the first filter circuit and the second filter circuit are the same.

10. The circuit according to claim 9, characterized in that, The second power input protection circuit is connected to the neutral and live wires of the backup power supply circuit.

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