CN114552979A - Bidirectional constant-current-to-constant-voltage conversion circuit and system - Google Patents
Bidirectional constant-current-to-constant-voltage conversion circuit and system Download PDFInfo
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- CN114552979A CN114552979A CN202210228543.3A CN202210228543A CN114552979A CN 114552979 A CN114552979 A CN 114552979A CN 202210228543 A CN202210228543 A CN 202210228543A CN 114552979 A CN114552979 A CN 114552979A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
- H02M1/092—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices the control signals being transmitted optically
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- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The application discloses a bidirectional constant-current-to-constant-voltage conversion circuit and a system, which comprise a current direction adjusting circuit, a voltage clamping circuit, an energy storage filter circuit and a voltage conversion module; the current direction adjusting circuit is connected with the input end of the voltage power taking module and is used for converting bidirectional current into unidirectional current; the energy storage filter circuit is connected with the current direction adjusting circuit and is used for filtering alternating current ripple current; the voltage clamping circuit is connected with the current direction adjusting circuit and is used for shunting redundant current after the over-voltage current conversion module and stabilizing voltage at two ends; the voltage conversion module is connected with the output ends of the current direction adjusting circuit and the voltage power taking module and used for converting voltage. The bidirectional constant-current-to-constant-voltage conversion circuit and the system solve the problems of over-complex system, over-low reliability and maintainability and the like in constant-current power supply.
Description
Technical Field
The invention relates to the technical field of constant current to constant voltage circuits, in particular to a bidirectional constant current to constant voltage circuit and a system.
Background
In daily life and industrial systems, general circuits and devices work on the basis of constant voltage, the input end of the circuits and the devices is fixed voltage, the voltage can be alternating current voltage or direct current voltage, and the working devices with fixed voltage are characterized in that a plurality of working devices can be connected in parallel. For example, the operating voltage of the household appliances is AC220V, and in this case, a plurality of household appliances are connected in parallel to an AC220V power grid, the voltage is fixed, and the current in the system increases with the increase of the power of the electric devices. For example, in industrial equipment, the whole system is composed of many electric devices, such as various position sensors, photoelectric sensors, speed sensors, contact sensors, photographing devices, triggering and sensing devices, and the working voltage of the electric devices is direct current DC48V or direct current DC24V, and the devices working at the same voltage are connected in parallel.
However, not all devices or systems are operated based on a constant voltage, some devices and systems are operated based on a constant current, and the operation of the devices is more stable only when driven by a constant current. For example, one is an LED light source, generally, when the LED light source is driven by a constant current, the light intensity generated by the LED light source is more stable, because of the current-voltage characteristic of the LED, if the LED light source is driven by a voltage, a weak voltage fluctuation can generate a large light intensity change, which causes unstable light intensity when the voltage is working, and when the LED light source is driven by a current, the generated light intensity changes in proportion to the current, and the constant current corresponds to the constant light intensity; the other device working at constant current is a solid laser, also called as an LD laser, which is widely used in civil, industrial and military applications at present, and is a very common laser, and the driving of the core laser is generally constant current driven, so that the output power of the laser is more stable by the constant current driving.
Then, in the market, there are few methods for converting constant current into constant voltage, and one of the solutions that can be inquired for converting constant current into constant voltage is to use a switch to perform a current splitting manner, such as the invention patents of china "a power supply and method for converting constant current into constant voltage (CN 106647908A) and" a circuit for converting single-line constant current into constant voltage (CN 104967326A). In the methods, constant current is subjected to duty ratio modulation and bypass through a bypass switch, redundant current of a voltage conversion circuit connected in parallel with the constant current is output through a switch bypass, the power consumption of the designed system on the bypass switch and a matching resistor is high, a new circuit topology and structure are needed by adopting a switch modulation method, the number of components is large, the circuit is complex, and the reliability of the system is reduced. Another solution is to use power matching. The voltage detection module and the current detection module are required to be designed in the circuit to respectively detect voltage and current, a special power matcher circuit is adopted to carry out power matching according to the requirement of the system on constant voltage output power so as to maintain the voltage at two ends of the power change circuit stable, the scheme converts redundant power of the system into heat power consumption of the power matcher circuit, the detection of the related voltage and current is relatively complex, and the reliability of the system is reduced.
The schemes solve the application requirement of converting constant current into constant voltage to a certain extent, but the schemes design a novel current type switching power supply topological structure aiming at the modulation change of the constant current by utilizing a switch, and cannot utilize the existing topological structure of a mature voltage type switching power supply, so that the system becomes more complex and the reliability is reduced; meanwhile, the existing scheme can only work in the application occasions of unidirectional constant current power supply, so that the application of the constant current power supply is limited, and the product has the function of bidirectional constant current power supply in the application of some systems.
Disclosure of Invention
In view of this, the present invention provides a bidirectional constant current to constant voltage circuit and system to overcome the defects of complexity, low reliability and low maintainability in the prior art.
In order to solve the above technical problem, an embodiment of a first aspect of the present invention provides a bidirectional constant current to constant voltage circuit, including a voltage power-taking module;
the voltage power taking module is used for converting constant current into constant voltage, and comprises a current direction adjusting circuit, a voltage clamping circuit, an energy storage filter circuit and a voltage conversion module;
the input end of the current direction adjusting circuit is connected with a constant current power supply, and the current direction adjusting circuit is used for converting bidirectional current into unidirectional current;
the energy storage filter circuit is connected with the output end of the current direction adjusting circuit and is used for filtering alternating current ripple current;
the voltage clamping circuit is connected with the output end of the current direction adjusting circuit and is used for shunting redundant current after the current flows through the voltage conversion module and stabilizing the voltage at two ends;
the input end of the voltage conversion module is connected with the output end of the current direction adjusting circuit, the output end of the voltage conversion module is connected with a load, and the voltage conversion module is used for converting constant voltage.
In some embodiments, the voltage taking module comprises at least 2 groups of the voltage conversion modules;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel through the corresponding Schottky diode and then is used for being connected with the positive end of the load, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then is used for being connected with the negative end of the load.
In some embodiments, the voltage taking module comprises at least 2 sets of the voltage conversion modules;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the positive end of the corresponding load, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the negative end of the corresponding load.
In some embodiments, the voltage conversion module includes an isolated power circuit, a soft start circuit, and an output filter circuit;
the input end of the isolation power supply circuit is connected with the output end of the current direction adjusting circuit, the output end of the isolation power supply circuit is connected with the output filter circuit, and the isolation power supply circuit is used for converting a constant current into an isolated constant voltage and outputting the isolated constant voltage to the output end of the voltage power taking module;
the slow starting circuit is connected with the output end of the current direction adjusting circuit, the slow starting circuit is connected with the enabling end of the isolation power circuit, and the slow starting circuit is used for controlling the isolation power circuit to realize slow starting when power is on;
the output filter circuit is connected with the isolation power supply circuit and is used for filtering signals of the isolation power supply circuit.
In some embodiments, the voltage power-taking module further includes a low-frequency ac signal circuit, and the low-frequency ac signal circuit is connected to the input end of the current direction adjusting circuit, and is configured to detect a short-circuit fault at the input end and/or the output end of the voltage power-taking module.
In some embodiments, the low frequency ac signal circuit includes a first capacitor; the first capacitor is a non-polar capacitor and is used for isolating direct current from alternating current.
In some embodiments, the current direction adjustment circuit is a full bridge rectifier circuit comprising a first diode, a second diode, a third diode, and a fourth diode;
the cathode of the first diode is used as the output end of the current direction adjusting circuit and is connected with the anode of the second diode, the cathode of the second diode is connected with the anode of the fourth diode and the input end of the current direction adjusting circuit, the cathode of the fourth diode is connected with the anode of the third diode and the output end of the current direction adjusting circuit, the cathode of the third diode is used as the input end of the current direction adjusting circuit and is connected with the anode of the first diode
In some embodiments, the voltage clamping circuit includes N regulation circuits, each regulation circuit including a zener diode;
the cathode of a voltage stabilizing diode in the 1 st voltage stabilizing circuit is connected with the first terminal of the voltage clamping circuit, the anode of a voltage stabilizing diode in the N-1 st voltage stabilizing circuit is connected with the cathode of a voltage stabilizing diode in the N-th voltage stabilizing circuit, and the anode of a voltage stabilizing diode in the N-th voltage stabilizing circuit is connected with the second terminal of the voltage clamping circuit;
wherein N is a positive integer not less than 2, and N =2,3.
In some embodiments, the tank filter circuit comprises a seventh diode, a third resistor, a second capacitor, and a third capacitor;
the anode of the seventh diode is connected with the first terminal of the second capacitor, the second terminal of the second capacitor is connected with the second terminal of the third capacitor, the first terminal of the third capacitor is connected with the anode of the seventh diode, and the third resistor is connected in parallel at two ends of the seventh diode and the second capacitor.
In some embodiments, the isolated power supply circuit is implemented in one of a forward, flyback, half-bridge, or full-bridge topology.
In some embodiments, the output filter circuit includes a fifth capacitor and a fourth resistor, and the fifth capacitor is connected in parallel across the fourth resistor.
In some embodiments, the slow start circuit comprises an eighth capacitor, a ninth capacitor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a three-terminal adjustable reference source, a ninth diode and an optocoupler;
the eighth capacitor is connected with the first terminal and the second terminal of the slow starting circuit, one end of the fifth resistor is connected with the first terminal of the slow starting circuit, the other end of the fifth resistor is connected with one end of the sixth resistor, the other end of the sixth resistor is connected with the second terminal of the slow starting circuit, the common end of the fifth resistor and the sixth resistor is connected with the control end of the three-end adjustable reference source, the anode of the three-end adjustable reference source is connected with the second terminal of the slow starting circuit, the ninth capacitor is connected in parallel with the two terminals of the sixth resistor, one end of the seventh resistor is connected with the first terminal of the slow starting circuit, the other end of the seventh resistor is connected with the cathode of the ninth diode and the first input terminal of the optical coupler, the anode of the ninth diode is connected with the second terminal of the slow starting circuit, and the cathode of the ninth diode is connected with the first input terminal of the optical coupler, the second input terminal of the optical coupler is connected with the cathode of the three-terminal adjustable reference source, the first output terminal of the optical coupler is connected with the second terminal of the slow starting circuit, the second output terminal of the optical coupler is connected with one end of the eighth resistor, the other end of the eighth resistor is connected with the third terminal of the slow starting circuit, and the fifth resistor, the sixth resistor and the ninth capacitor form a charging circuit;
wherein the ninth diode is a zener diode.
In addition, an embodiment of a second aspect of the present invention provides a bidirectional constant current to constant voltage system, which includes a constant current power supply, at least 1 load, and at least 1 set of any one of the circuits described in the embodiments of the first aspect; each load is connected with at most 1 group of voltage power-taking modules, and each group of voltage power-taking modules are connected in series and then connected in series with the constant current power supply.
In some embodiments, at least 2 sets of constant current sources are included; each group of voltage power taking modules is connected in series and then is connected in series with each group of constant current power supplies; the load is a camera, a light source or a communication module.
Through the technical scheme, the invention at least has the following beneficial effects:
(1) the constant current to constant voltage can be realized by adopting a voltage conversion switch circuit implementation scheme without designing a new current conversion switch circuit, so that the designed circuit is relatively simple and has high practicability;
(2) the requirement of bidirectional constant current to constant voltage is met, and a low-frequency alternating current signal path is provided to facilitate the troubleshooting and positioning of short-circuit faults;
(3) the single-voltage output, redundant parallel voltage output and double-circuit voltage output functions can be realized, the circuit structure is simple, the number of components is small, and the reliability of the system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram of a bidirectional constant current to constant voltage circuit according to an embodiment of the present invention;
fig. 2 is a second schematic diagram of a bidirectional constant current to constant voltage conversion circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a voltage power-taking module according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a voltage power-taking module with redundancy backup in an embodiment of the present invention;
FIG. 5 is a schematic diagram of a voltage power-taking module with two voltage outputs according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a slow start circuit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of an application of the embodiment of the invention in a machine vision remote monitoring system.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Fig. 1 is a schematic diagram of a bidirectional constant current to constant voltage conversion circuit according to an embodiment of the present invention. The provided bidirectional constant-current-to-constant-voltage conversion circuit comprises: a voltage power taking module 100;
the voltage electricity taking module 100 is used for converting a constant current into a constant voltage, an input end of the voltage electricity taking module 100 may be directly or indirectly connected to a constant current power supply through a power supply conductor, and an output end of the voltage electricity taking module 100 is connected to a load; the voltage output by the voltage power taking module 100 is a constant voltage, and can be provided to any constant-voltage power load meeting the power requirement.
The voltage power-taking module 100 comprises a current direction adjusting circuit 104, a voltage clamping circuit 105, an energy storage filter circuit 106 and a voltage conversion module 200;
the input end of the current direction adjusting circuit 104 is connected with a constant current power supply, and the current direction adjusting circuit 104 is used for converting bidirectional current into unidirectional current;
the energy storage filter circuit 106 is connected to the output end of the current direction adjusting circuit 104, and the energy storage filter circuit 106 is used for filtering alternating current ripple current (the alternating current ripple current refers to a higher harmonic component in the current, which may cause a change in current or voltage amplitude value, which may cause breakdown, and since the alternating current ripple current is an alternating current component, dissipation may occur on the capacitor, and if the ripple component of the current is too large, the ripple current exceeds the maximum allowable ripple current of the capacitor, which may cause the capacitor to burn out);
the voltage clamp circuit 105 is connected to the output end of the current direction adjusting circuit 104, and the voltage clamp circuit 105 is used for shunting the redundant current after the current flows through the voltage conversion module 200 and stabilizing the voltages at the two ends;
the input end of the voltage conversion module 200 is connected to the output end of the current direction adjusting circuit 104, the output end of the voltage conversion module 200 is connected to the load, and the voltage conversion module 200 is used for converting the voltage.
In some embodiments, the voltage conversion module 200 includes an isolated power circuit 108, a soft start circuit 107, and an output filter circuit 109;
the input end of the isolation power supply circuit 108 is connected with the output end of the current direction adjusting circuit 104, the output end of the isolation power supply circuit 108 is connected with the output filter circuit 109, and the isolation power supply circuit 108 is used for converting a constant current into an isolated constant voltage and outputting the constant voltage to the output end of the voltage power-taking module 100;
the slow starting circuit 107 is connected with the output end of the current direction adjusting circuit 104, the slow starting circuit 107 is connected with the enabling end of the isolation power supply circuit 108, and the slow starting circuit 107 is used for controlling the isolation power supply circuit 108 to realize slow starting when being electrified;
the output filter circuit 109 is connected to the isolation power supply circuit 108, and the output filter circuit 109 is used for filtering signals of the isolation power supply circuit.
Fig. 2 is a second schematic diagram of a bidirectional constant current to constant voltage conversion circuit according to an embodiment of the present invention. In some embodiments, as shown in fig. 2, the voltage taking module 100 further includes a low-frequency ac signal circuit 103, and the low-frequency ac signal circuit 103 is connected to an input terminal of the current direction adjusting circuit 104, and is configured to detect a short-circuit fault at an input terminal and/or an output terminal of the voltage taking module 100.
The rest of the voltage taking module 100 is the same as that in the above embodiments, and is not described herein again.
Fig. 3 is a schematic diagram of a voltage power-taking module in an embodiment of the invention. In some embodiments, as shown in fig. 3, the current direction adjusting circuit 104 is a full bridge rectification circuit, and includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; the cathode of the first diode D1 is connected to the anode of the second diode D2 as the output terminal of the current direction adjustment circuit 104, the cathode of the second diode D2 is connected to the anode of the fourth diode D4 and the input terminal of the current direction adjustment circuit 104, the cathode of the fourth diode D4 is connected to the anode of the third diode D3 and the output terminal of the current direction adjustment circuit 104, and the cathode of the third diode D3 is connected to the anode of the first diode D1 as the input terminal of the current direction adjustment circuit 104.
Illustratively, the voltage clamp circuit 105 includes N regulation circuits, each regulation circuit including a zener diode; the cathode of a voltage stabilizing diode in the 1 st voltage stabilizing circuit is connected with the first terminal of the voltage clamping circuit 105, the anode of a voltage stabilizing diode in the N-1 st voltage stabilizing circuit is connected with the cathode of a voltage stabilizing diode in the N-th voltage stabilizing circuit, and the anode of a voltage stabilizing diode in the N-th voltage stabilizing circuit is connected with the second terminal of the voltage clamping circuit 105; wherein N is a positive integer not less than 2, and N =2,3.
Illustratively, the tank filter circuit 106 includes a seventh diode D7, a third resistor R3, a second capacitor C2, and a third capacitor C3; an anode of the seventh diode D7 is connected to the first terminal of the second capacitor D2, the second terminal of the second capacitor D2 is connected to the second terminal of the third capacitor D3, the first terminal of the third capacitor D3 is connected to an anode of the seventh diode D7, and the third resistor R3 is connected in parallel to the seventh diode and the second capacitor C2.
Specifically, the second capacitor C2 in the energy storage filter circuit 106 is generally an energy storage capacitor with an ultra-large capacity. The second capacitor C2 may be a tantalum capacitor if extremely high reliability requirements are considered. The capacitance value of the second capacitor C2 is selected according to the system power and the system surge recovery time: aiming at system power, mainly when the current is powered down for about 50ms, the stable work of an isolation power supply circuit 108 connected with the energy storage filter circuit 106 in parallel can be ensured; and the stable operation of the isolation power supply circuit 108 connected with the energy storage filter circuit 106 in parallel is ensured aiming at the system surge recovery time, namely the arrival time of the surge current.
The main function of the third resistor R3 and the seventh diode D7 in the energy storage filter circuit 106 is that when the second capacitor C2 is charged, the third resistor R3 limits the excessive current flowing through the second capacitor C2, which results in the too small current supplied to the rear-end isolated power supply circuit 108, and thus the isolated power supply circuit 108 cannot stably operate; when the second capacitor C2 discharges, the seventh diode D7 discharges to ensure stable operation of the rear-end isolated power supply circuit 108. In order to reduce the thermal power consumption of the system, the seventh diode D7 may be a schottky diode with low forward voltage drop.
For example, the implementation of the isolated power supply circuit 108 may be one of forward, flyback, half-bridge, or full-bridge. In particular, the isolated power circuit 108 may employ a brick-type isolated power module.
Illustratively, the output filter circuit 109 includes a fifth capacitor C5 and a fourth resistor R4, and the fifth capacitor C5 is connected in parallel to two ends of the fourth resistor R4. Specifically, the fifth capacitor C5 is a filter capacitor; the fourth resistor R4 is a power matching resistor, and a suitable specification and model needs to be selected according to the characteristics of the isolated power supply circuit 108, so that the isolated power supply circuit 108 operates at low power consumption when the load 110 is open-circuited (i.e., the power consumed by the load is very small and close to 0W). In this embodiment, this power matching resistor may also be placed in the isolated power supply circuit 108.
Illustratively, the low frequency ac signal circuit 103 includes a first capacitor C1; the first capacitor C1 is a non-polar capacitor, such as a magnetic dielectric capacitor, for isolating dc power from ac power, and has a capacitance value large enough to provide a low-impedance path for the lowest tens of hertz.
The current flowing from the input end of the voltage power-taking module 100 enters the current direction adjusting circuit 104, and the current flowing from the current direction adjusting circuit 104 respectively enters the voltage clamping circuit 105 and the isolation power supply circuit 108; the terminals of the tank filter circuit 106 are respectively connected between the two output terminals of the current direction adjusting circuit 104; the slow start circuit 107 obtains the voltage at the output end of the current direction adjusting circuit 104 and outputs a signal to control the isolation power circuit 108 to perform slow start; the isolation power supply circuit 108 converts the constant current into an isolated constant voltage and outputs the isolated constant voltage to the output end of the voltage power-taking module 100; the output filter circuit 109 filters the output voltage of the isolated power supply circuit 108 and provides a matched resistance to operate the isolated power supply circuit 108 in a minimum power state.
The input end of the voltage power-taking module 100 inputs a constant current, the output end outputs a constant voltage, and the input end and the output end of the voltage power-taking module 100 are isolated, the isolation voltage should not be less than the highest working voltage of the system, and the highest working voltage of the system is generally the highest output voltage of the constant current power supply.
Since the input of the voltage-taking module 100 is mainly a constant current, not a commonly understood constant voltage. Therefore, the circuit includes a voltage clamp circuit 105 for limiting the voltage at the input terminal to the operating range of the isolated power supply circuit 108. It should be noted that, for the input being a constant current, after the power of the load 110 is determined, the voltage at the input end of the voltage power-taking module 100 is determined. If the power of the load 110 changes, the voltage at the input terminal of the voltage-taking module 100 changes. If the power variation of the load 110 is large (assuming no-load or full-load), the voltage at the input end of the voltage power-taking module 100 is zero at this time, because the output power is zero or the maximum voltage (total power divided by current), the voltage power-taking module 100 is required to have a very high input voltage adaptation range, which is difficult to implement by a general circuit, but this embodiment is skillfully implemented.
FIG. 6 is a diagram of a slow start circuit according to an embodiment of the present invention. In some embodiments, as shown in fig. 6, the slow start circuit 107 includes an eighth capacitor C8, a ninth capacitor C9, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a three-terminal adjustable reference source U3, a ninth diode D9, and an optical coupler U4;
an eighth capacitor C8 is connected with a first terminal and a second terminal of the slow starting circuit 107, one end of a fifth resistor R5 is connected with the first terminal of the slow starting circuit 107, the other end of the fifth resistor R5 is connected with one end of a sixth resistor R6, the other end of the sixth resistor R6 is connected with the second terminal of the slow starting circuit 107, the common end of the fifth resistor R5 and the sixth resistor R6 is connected with the control end of a three-terminal adjustable reference source U3, the anode of the three-terminal adjustable reference source U3 is connected with the second terminal of the slow starting circuit 107, a ninth capacitor C9 is connected with the two terminals of the sixth resistor R6 in parallel, one end of the seventh resistor R7 is connected with the first terminal of the slow starting circuit 107, the other end of the seventh resistor R7 is connected with the cathode of a ninth diode C9 and the first input terminal of the optical coupler, the anode of the ninth diode C9 is connected with the second terminal of the slow starting circuit 107, and the cathode of the ninth diode D9 is connected with the first input terminal of the U4, a second input terminal of the optical coupler U4 is connected with a cathode of a three-terminal adjustable reference source U3, a first output terminal of the optical coupler U4 is connected with a second terminal of the slow starting circuit 107, a second output terminal of the optical coupler U4 is connected with one end of an eighth resistor R8, the other end of the eighth resistor R8 is connected with a third terminal of the slow starting circuit 107, and the fifth resistor R5, the sixth resistor R6 and the ninth capacitor D9 form a charging circuit; diodes of a first input terminal and a second input terminal of the optocoupler U4 determine whether to start the optocoupler U4 to work according to whether an anode and a cathode of the three-terminal adjustable reference source U3 are turned on. The ninth diode D9 is a zener diode.
The operation principle of the slow start circuit 107 is as follows: when the current comes, the voltage of the ninth capacitor C9 at the starting moment is 0V, that is, the control end of the three-end adjustable reference source U3 is 0V, at this time, the input end of the optocoupler U4 is not started, the output terminal two of the optocoupler U4 is in a high-impedance state, that is, the terminal three of the slow start circuit 107 is in a high-impedance output state, and at this time, the isolation power circuit 108 can be controlled not to work; when the voltage of the ninth capacitor C9 is increased to about 1.24V after charging, the anode and the cathode of the three-terminal adjustable reference source U3 are turned on to clamp the voltage, the input terminal of the optical coupler U4 is turned on at this time, the first output terminal and the second output terminal of the optical coupler U4 are low-resistance, the third terminal of the slow start circuit 107 is connected to the second terminal, and the start operation of the isolation power circuit 108 can be controlled at this time.
Fig. 4 is a schematic diagram of a voltage power-taking module with redundant backup in an embodiment of the present invention. In some embodiments, as shown in fig. 4, the voltage taking module 100 includes at least 2 sets of voltage converting modules;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit 104, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit 104;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel through the corresponding Schottky diode and then is used for being connected with the positive end of the load 110, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then is used for being connected with the negative end of the load 110.
In this embodiment, there are 2 groups of voltage conversion modules, and two groups of voltage conversion modules connected in parallel are the same, so as to realize the same output voltage conversion function, and the positive electrode of the input end of the voltage conversion module is independently protected by a fuse tube F1 and a fuse tube F2.
The voltage conversion modules are replaced by a mode of redundancy backup by adopting the voltage conversion modules connected in parallel, and the reliability of the system is improved.
The rest of the voltage taking module 100 is the same as that in the above embodiments, and is not described herein again.
Fig. 5 is a schematic diagram of a voltage power-taking module with two voltage outputs according to an embodiment of the present invention. In some embodiments, as shown in fig. 5, the voltage taking module 100 includes at least 2 groups of voltage conversion modules, which can implement various types of voltage output;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit 104, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit 104;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the positive end of the corresponding load, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the negative end of the corresponding load.
The rest of the voltage taking module 100 is the same as that in the above embodiments, and is not described herein again.
Fig. 7 is a schematic diagram of an application of the embodiment of the invention in a machine vision remote monitoring system. In some embodiments, as shown in fig. 7, a system includes a constant current source, at least 1 load, and at least 1 set of any of the above embodiments; each load is connected with at most 1 group of voltage power-taking modules, and each group of voltage power-taking modules are connected in series and then connected in series with the constant-current power supply.
Illustratively, the system may include at least 2 sets of constant current sources; each group of voltage power taking modules is connected in series and then is connected in series with each group of constant current power supplies; the load may be a camera, a light source or a communication module. The reliability of the whole system is improved by at least 2 groups of constant current power supplies.
Specifically, the constant current source provides a constant current for the machine vision remote monitoring system 700, the constant current sequentially flows through the voltage power-taking modules 100 connected in series via power lines, the voltage power-taking modules 100 output a constant voltage, and the constant voltage is respectively provided to the camera 701, the light source 702, and the communication module 703. The camera 701 is used for photographing or shooting a monitored area; the light source 702 provides supplementary light to the monitoring area according to the change of the light intensity of the environment, so that the camera 701 can shoot a clearer picture; the communication module 703 may be a wired communication module or a wireless communication module, and is used for transmitting the pictures or videos taken by the camera 701 to the user.
The constant current power supply of the embodiment can be very close to a machine vision remote monitoring system, such as several meters or dozens of meters, and also can be very far away, such as several kilometers or dozens of kilometers, so that the application of the scheme is more flexible. For example, in an underwater monitoring system, because of lack of illumination underwater, the system cannot adopt a scheme combining solar energy and storage battery energy storage like a street lamp monitoring system, and cannot adopt conventional constant-voltage power supply like monitoring equipment of a building (because voltage drop of the constant-voltage power supply during long-distance transmission can influence the work of parallel equipment in the system), and the system adopts constant-current power supply, so that the system has obvious advantages. On the other hand, one or more than one machine vision remote monitoring system 700 can be used in series, which saves a lot of cables, so that the whole system can work by connecting various machine vision remote monitoring systems 700 in series with only two wires, unlike a constant voltage power supply system, which needs to consider the transmission distance and the voltage drop caused by the power consumption.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (14)
1. A bidirectional constant current-to-constant voltage circuit is characterized by comprising a voltage power taking module;
the voltage power taking module is used for converting constant current into constant voltage, and comprises a current direction adjusting circuit, a voltage clamping circuit, an energy storage filter circuit and a voltage conversion module;
the input end of the current direction adjusting circuit is connected with a constant current power supply, and the current direction adjusting circuit is used for converting bidirectional current into unidirectional current;
the energy storage filter circuit is connected with the output end of the current direction adjusting circuit and is used for filtering alternating current ripple current;
the voltage clamping circuit is connected with the output end of the current direction adjusting circuit and is used for shunting redundant current after the current flows through the voltage conversion module and stabilizing the voltage at two ends;
the input end of the voltage conversion module is connected with the output end of the current direction adjusting circuit, the output end of the voltage conversion module is connected with a load, and the voltage conversion module is used for converting constant voltage.
2. The circuit of claim 1, wherein the voltage taking module comprises at least 2 groups of the voltage conversion modules;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel through the corresponding Schottky diode and then is used for being connected with the positive end of the load, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then is used for being connected with the negative end of the load.
3. The circuit of claim 1, wherein the voltage taking module comprises at least 2 groups of the voltage conversion modules;
the positive electrodes of the input ends of each group of voltage conversion modules are connected in parallel through corresponding protective tubes and then connected with the input end of the current direction adjusting circuit, and the negative electrodes of the input ends of each group of voltage conversion modules are connected in parallel and then connected with the other input end of the current direction adjusting circuit;
the positive electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the positive end of the corresponding load, and the negative electrode of the output end of each group of voltage conversion modules is connected in parallel and then used for being connected with the negative end of the corresponding load.
4. The circuit of claim 1, 2 or 3, wherein the voltage conversion module comprises an isolated power circuit, a soft start circuit and an output filter circuit;
the input end of the isolation power supply circuit is connected with the output end of the current direction adjusting circuit, the output end of the isolation power supply circuit is connected with the output filter circuit, and the isolation power supply circuit is used for converting a constant current into an isolated constant voltage and outputting the isolated constant voltage to a load;
the slow starting circuit is connected with the output end of the current direction adjusting circuit, the slow starting circuit is connected with the enabling end of the isolation power supply circuit, and the slow starting circuit is used for controlling the isolation power supply circuit to realize slow starting when the power is on;
the output filter circuit is connected with the isolation power supply circuit and is used for filtering signals of the isolation power supply circuit.
5. The circuit according to claim 1, 2 or 3, wherein the voltage power-taking module further comprises a low-frequency alternating-current signal circuit, and the low-frequency alternating-current signal circuit is connected with the input end of the current direction adjusting circuit and is used for detecting a short-circuit fault at the input end and/or the output end of the voltage power-taking module.
6. The circuit of claim 5, wherein the low frequency ac signal circuit comprises a first capacitor; the first capacitor is a non-polar capacitor and is used for isolating direct current from alternating current.
7. The circuit of claim 1, 2 or 3, wherein the current direction adjusting circuit is a full bridge rectifier circuit comprising a first diode, a second diode, a third diode and a fourth diode;
the cathode of the first diode is used as the output end of the current direction adjusting circuit and connected with the anode of the second diode, the cathode of the second diode is connected with the anode of the fourth diode and the input end of the current direction adjusting circuit, the cathode of the fourth diode is connected with the anode of the third diode and the output end of the current direction adjusting circuit, and the cathode of the third diode is used as the input end of the current direction adjusting circuit and connected with the anode of the first diode.
8. The circuit of claim 1, 2 or 3, wherein the voltage clamping circuit comprises N regulation circuits, each regulation circuit comprising a zener diode;
the cathode of a voltage stabilizing diode in the 1 st voltage stabilizing circuit is connected with the first terminal of the voltage clamping circuit, the anode of a voltage stabilizing diode in the N-1 st voltage stabilizing circuit is connected with the cathode of a voltage stabilizing diode in the N-th voltage stabilizing circuit, and the anode of a voltage stabilizing diode in the N-th voltage stabilizing circuit is connected with the second terminal of the voltage clamping circuit;
wherein N is a positive integer not less than 2, and N =2,3.
9. The circuit of claim 1, 2 or 3, wherein the tank filter circuit comprises a seventh diode, a third resistor, a second capacitor and a third capacitor;
the anode of the seventh diode is connected with the first terminal of the second capacitor, the second terminal of the second capacitor is connected with the second terminal of the third capacitor, the first terminal of the third capacitor is connected with the anode of the seventh diode, and the third resistor is connected in parallel at two ends of the seventh diode and the second capacitor.
10. The circuit of claim 4, wherein the isolated power supply circuit is implemented in one of a forward, flyback, half-bridge, or full-bridge topology.
11. The circuit of claim 4, wherein the output filter circuit comprises a fifth capacitor and a fourth resistor, and wherein the fifth capacitor is connected in parallel across the fourth resistor.
12. The circuit of claim 4, wherein the slow start circuit comprises an eighth capacitor, a ninth capacitor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a three-terminal adjustable reference source, a ninth diode and an optocoupler;
the eighth capacitor is connected with the first terminal and the second terminal of the slow starting circuit, one end of the fifth resistor is connected with the first terminal of the slow starting circuit, the other end of the fifth resistor is connected with one end of the sixth resistor, the other end of the sixth resistor is connected with the second terminal of the slow starting circuit, the common end of the fifth resistor and the sixth resistor is connected with the control end of the three-end adjustable reference source, the anode of the three-end adjustable reference source is connected with the second terminal of the slow starting circuit, the ninth capacitor is connected in parallel with the two terminals of the sixth resistor, one end of the seventh resistor is connected with the first terminal of the slow starting circuit, the other end of the seventh resistor is connected with the cathode of the ninth diode and the first input terminal of the optical coupler, the anode of the ninth diode is connected with the second terminal of the slow starting circuit, and the cathode of the ninth diode is connected with the first input terminal of the optical coupler, the second input terminal of the optical coupler is connected with the cathode of the three-terminal adjustable reference source, the first output terminal of the optical coupler is connected with the second terminal of the slow starting circuit, the second output terminal of the optical coupler is connected with one end of the eighth resistor, the other end of the eighth resistor is connected with the third terminal of the slow starting circuit, and the fifth resistor, the sixth resistor and the ninth capacitor form a charging circuit;
wherein the ninth diode is a zener diode.
13. A bi-directional constant current to constant voltage system comprising a constant current source, at least 1 load and at least 1 set of any one of the circuits of claims 1-12;
each load is connected with at most 1 group of voltage power-taking modules, and each group of voltage power-taking modules are connected in series and then connected in series with the constant current power supply.
14. The system of claim 13, comprising at least 2 sets of constant current sources; each group of voltage power taking modules is connected in series and then is connected in series with each group of constant current power supplies; the load is a camera, a light source or a communication module.
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CN115395636A (en) * | 2022-08-08 | 2022-11-25 | 桂林电子科技大学 | Redundant backup constant-current-to-constant-voltage power supply circuit and control method |
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CN115395636A (en) * | 2022-08-08 | 2022-11-25 | 桂林电子科技大学 | Redundant backup constant-current-to-constant-voltage power supply circuit and control method |
CN115395636B (en) * | 2022-08-08 | 2024-04-30 | 桂林电子科技大学 | Redundant backup constant-current-constant-voltage power supply circuit and control method |
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