CN211127284U - Commercial power switching circuit for interactive inverter - Google Patents
Commercial power switching circuit for interactive inverter Download PDFInfo
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- CN211127284U CN211127284U CN201922152857.6U CN201922152857U CN211127284U CN 211127284 U CN211127284 U CN 211127284U CN 201922152857 U CN201922152857 U CN 201922152857U CN 211127284 U CN211127284 U CN 211127284U
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Abstract
The utility model discloses a commercial power switching circuit for an interactive inverter, which comprises a voltage comparison circuit and a switch switching circuit; the voltage comparison circuit comprises a rectifying circuit and a voltage comparator, wherein the input end of the rectifying circuit is connected with the mains supply, and the output end of the rectifying circuit is connected with the input end of the voltage comparator; the switch switching circuit comprises a switching circuit and a switching circuit, the input end of the switching circuit is connected with the output end of the voltage comparator, the switching circuit comprises a first input end, a second input end, a control end and an output end, the output end of the switching circuit is connected with the control end, the first input end is connected with a mains supply, the second input end is connected with an inversion loop, and the output end is connected with a load. Implement the utility model discloses, need not to occupy MCU (or control chip)'s interface resource, through voltage comparison circuit and switch switching circuit, just can realize the commercial power switching usage of interactive dc-to-ac converter with the help of simple components and parts.
Description
Technical Field
The utility model relates to a commercial power switches the field based on interactive dc-to-ac converter, especially relates to a commercial power switching circuit that interactive inverter used.
Background
An inverter (inverter) is a device that converts direct current into alternating current (generally, mains voltage, with a sinusoidal or square wave waveform), the direct current power source used is a storage battery, and a photovoltaic inverter uses a combination of a solar photovoltaic cell panel and the storage battery as input. From the input end, the inverter or the photovoltaic inverter is divided into two types, one type does not need to rely on commercial power, and the electric energy of the storage battery is inverted into the commercial power to supply power to the electric equipment (load). The accumulator of this type of inverter must be charged by other charging devices or by photovoltaic panels. The other is an interactive inverter with a mains supply input and an internal storage battery, when the voltage of the mains supply is normal, the mains supply is directly bypassed or subjected to necessary voltage stabilization to supply power to a load, the internal storage battery is charged, and when the mains supply is in a power failure or the voltage exceeds a normal range, the power is switched to an inverter loop to supply power to the load.
When the interactive inverter switches between the commercial power loop and the inverter loop, two problems must be solved. Firstly, detecting whether commercial power exists and whether the voltage is normal; second, the switching time must not exceed the requirements of the application (typically within 10 ms), with shorter times being better. The techniques for sampling and detecting the commercial power generally include the following methods: (1) the method comprises the following steps of reducing 220V alternating voltage by using a resistor, a capacitor or a transformer, rectifying and filtering the voltage to obtain direct current low voltage, isolating the voltage by using an optical coupler, and sending a sampling signal to an MCU (or a control chip); (2) a differential amplification circuit is formed by operational amplifiers, 220V alternating voltage is converted into a low-voltage m-shaped (steamed bread wave) signal, and the low-voltage m-shaped (steamed bread wave) signal is sent to an MCU A/D port for amplitude detection.
The above techniques require occupation of MCU (control chip) resources. For medium-low-end interactive inverters, the market demand is more focused on cost and reliability, so low-end cheap control chips are generally adopted, and the I/O ports are limited. When the commercial power detection and switching needs to be designed (or added), the I/O port is insufficient. If a higher-order control chip is replaced (re-type selection), not only the cost is greatly increased, but also the development progress is delayed, and development risks which are difficult to predict are brought.
SUMMERY OF THE UTILITY MODEL
The technical problem to be solved of the present invention is to provide a commercial power switching circuit for an interactive inverter, which can solve the problem that the existing commercial power switching method based on the interactive inverter must rely on MCU (or control chip) to detect and switch the commercial power.
In order to solve the above technical problem, the present invention provides a commercial power switching circuit for an interactive inverter, which includes a voltage comparison circuit and a switch switching circuit; the voltage comparison circuit comprises a rectifying circuit and a voltage comparator, wherein the input end of the rectifying circuit is connected with the mains supply, and the output end of the rectifying circuit is connected with the input end of the voltage comparator; the switch switching circuit comprises a switching circuit and a switching circuit, the input end of the switching circuit is connected with the output end of the voltage comparator, the switching circuit comprises a first input end, a second input end, a control end and an output end, the output end of the switching circuit is connected with the control end, the first input end is connected with a mains supply, the second input end is connected with an inversion loop, and the output end is connected with a load.
Preferably, the voltage comparator comprises a first comparator, a second comparator, a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, a fourth voltage dividing resistor and a comparison power supply; the inverting input end of the first comparator is connected with the direct-current power supply, the output end of the first comparator is connected with the non-inverting input end of the second comparator, the non-inverting input end of the first comparator is connected with the output end of the rectifying circuit through the first voltage-dividing resistor, and the non-inverting input end of the first comparator is grounded through the second voltage-dividing resistor; the output end of the second comparator is connected with the input end of the switch circuit, the inverting input end of the second comparator is connected with the output end of the rectifying circuit through a third voltage dividing resistor, and the inverting input end of the second comparator is grounded through the fourth voltage dividing resistor.
Preferably, the voltage comparator further comprises a power-off protection circuit, the power-off protection circuit comprises a diode and a fifth voltage-dividing resistor, one end of the fifth voltage-dividing resistor is connected with the direct-current power supply, and the other end of the fifth voltage-dividing resistor is connected with the non-inverting input end of the second comparator.
Preferably, the switching circuit includes an NPN type triode, a sixth voltage-dividing resistor, a seventh voltage-dividing resistor, and a zener diode; the base electrode of the NPN type triode is connected with the output end of the voltage comparator through the sixth voltage-dividing resistor and is grounded through the seventh voltage-dividing resistor; the collector of the NPN type triode is connected with the control end of the switching circuit; the emitting electrode of the NPN type triode is grounded; and the collector and the emitter of the NPN type triode are connected through a voltage stabilizing diode.
Preferably, the switching circuit comprises a double-pole double-throw relay, and the double-pole double-throw relay comprises two normally closed stationary contacts, two normally open stationary contacts, two movable contacts and a coil contact; the normally closed stationary contact is respectively connected with the inverter circuit; the normally open stationary contact is respectively connected with the mains supply; the movable contacts are respectively connected with a load; and the coil contact is respectively connected with the collector of the NPN type triode and a coil power supply.
Preferably, the switch switching circuit further comprises an acceleration circuit, wherein the acceleration circuit comprises a PNP type triode, a capacitor, a first current-limiting resistor, a second current-limiting resistor and a diode; the coil power supply is connected with the coil contact through the diode and is also connected with a collector electrode of the PNP type triode through the capacitor, and the collector electrode of the PNP type triode is grounded through the second current-limiting resistor; the base electrode of the PNP type triode is connected with the collector electrode of the NPN type triode through the first current limiting resistor; and the emitting electrode of the PNP type triode is connected with the coil power supply.
Preferably, a voltage reduction circuit is arranged between the rectification circuit and the mains supply.
Preferably, a filter circuit is arranged between the rectifying circuit and the voltage comparator.
Preferably, a rectifying diode is arranged between the filter circuit and the voltage comparator.
Implement the utility model has the advantages that:
the utility model provides a commercial power switching circuit that interactive inverter was used carries out voltage comparison and detection to the commercial power through voltage comparison circuit, according to commercial power voltage's size, exports corresponding level signal, switch switching circuit judges and switches the power supply mode of load according to level signal's height. The utility model discloses need not to occupy MCU (or control chip) IO port resource, through voltage comparison circuit and switch switching circuit, just can realize the commercial power switching usage of interactive dc-to-ac converter with the help of simple components and parts.
And simultaneously, the utility model discloses a charge pump principle of electric capacity provides a voltage that is twice the coil power in the twinkling of an eye at the circular telegram of relay coil, accelerates the switching speed of relay.
Drawings
Fig. 1 is a schematic diagram of a commercial power switching circuit for an interactive inverter according to the present invention;
fig. 2 is a circuit diagram of a voltage comparison circuit provided by the present invention;
fig. 3 is a circuit diagram of a switch switching circuit provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings. Only this statement, the utility model discloses the upper and lower, left and right, preceding, back, inside and outside etc. position words that appear or will appear in the text only use the utility model discloses an attached drawing is the benchmark, and it is not right the utility model discloses a concrete restriction.
As shown in fig. 1, the present invention provides a commercial power switching circuit for an interactive inverter, which includes a voltage comparison circuit and a switch switching circuit; the voltage comparison circuit comprises a rectification circuit 1 and a voltage comparator 2, wherein the input end of the rectification circuit 1 is connected with a mains supply, and the output end of the rectification circuit 1 is connected with the input end of the voltage comparator 2; the switch switching circuit comprises a switch circuit 3 and a switching circuit 4, wherein the input end of the switch circuit 3 is connected with the output end of the voltage comparator 2, the switching circuit 4 comprises a first input end, a second input end, a control end and an output end, the output end of the switch circuit 3 is connected with the control end, the first input end is connected with a mains supply, the second input end is connected with an inversion loop, and the output end is connected with a load.
The utility model discloses, carry out voltage comparison and detection to the commercial power through voltage comparison circuit, according to mains voltage's size, output corresponding level signal, through voltage comparison circuit and switch switching circuit, just can realize interactive dc-to-ac converter's commercial power with the help of simple components and parts and switch, switch switching circuit judges and switches the power supply mode of load according to level signal's height. The utility model discloses need not to occupy MCU (or control chip) interface.
As shown in fig. 2, the voltage comparator 2 includes a first comparator U1A, a second comparator U1B, a first voltage-dividing resistor R7, a second voltage-dividing resistor R8, a third voltage-dividing resistor R5, a fourth voltage-dividing resistor R6, and a dc power supply; the inverting input end of the first comparator U1A is connected with the DC power supply, the output end is connected with the non-inverting input end of the second comparator U1B, the non-inverting input end of the first comparator is connected with the output end of the rectifying circuit 1 through the first voltage-dividing resistor R7, and the non-inverting input end is also grounded through the second voltage-dividing resistor R8; the output end of the second comparator U1B is connected to the input end of the switch circuit 3, the inverting input end is connected to the output end of the rectifying circuit 1 through a third voltage-dividing resistor R5, and the inverting input end is also grounded through the fourth voltage-dividing resistor R6.
Preferably, a voltage reduction circuit is arranged between the rectifying circuit and a mains supply, and the voltage reduction circuit comprises R1, R2, R3 and R4 and is used for reducing the voltage of the mains supply, preventing the voltage comparator from being damaged due to overhigh voltage and facilitating the subsequent circuit design to better meet the safety regulation requirement.
Specifically, the dc power supply is connected to the inverting input terminal of the first comparator U1A through a pull-up resistor R11, the dc power supply is connected to the non-inverting input terminal of the second comparator U1B through a pull-up resistor R9, the dc power supply is connected to the output terminal of the second comparator U1B through a pull-up resistor R13, and the dc power supply is connected to the output terminal of the first comparator U1A through a pull-up resistor R12.
It should be noted that the voltage comparator is to be implemented such that when the mains voltage is between the first threshold and the second threshold, the voltage comparator outputs a high level, otherwise outputs a low level, and further analysis is made such that when the mains voltage is between the first threshold and the second threshold, the voltage at the non-inverting input (pin 3) of U1A should be higher than that at the inverting input, U1A outputs a high level, and at the same time, the voltage at the inverting input (pin 6) of U1B should be lower than that at the non-inverting input, and therefore U1B outputs a high level, i.e., I/P-R L Y is high, and when the mains voltage is lower than the first threshold, the voltage at the non-inverting input (pin 3) of U1A should be lower than that at the inverting input, and U1A outputs a low level, and at the inverting input (pin 6) of U1B should be higher than that at the non-inverting input, and therefore U1B outputs a low level, I/P-R L Y is a low level, and when the voltage at the non-inverting input (pin 6) is higher than that at the non-inverting input, and therefore the non-inverting input (pin 463) should be higher than that at the non-inverting input (pin 6853) output than that at the non-inverting input, and therefore the non-inverting input, and the non-inverting input.
Because the first threshold value and the second threshold value are set according to the actual requirements, the direct-current power supply and the corresponding voltage-dividing resistor need to be designed according to specific conditions. For example, a load in a certain area requires a mains voltage in the range of210-230V, when the commercial power is lower than 210 or higher than 230, the commercial power is not suitable for the normal work of the load, and the commercial power needs to be switched to a stable inversion loop. It can be known from simulation that the corresponding relationship between each voltage value of the input commercial power and Va is (i.e. V)Commercial powerVa): 200 to 104, 210 to 109, 230 to 119, 240 to 125. The dc power supply voltage (i.e., the reference voltage) is set to 5V, R7 ═ R5 ═ 910k, R8 ═ x, and R6 ═ y, and the circuit analysis and calculation result shows that: when the voltage of the mains supply is low, the mains supply needs to be switched to an inverter loop, the switched return difference voltage is 200-210V, namely when the mains supply is 200V, the voltage divided by R8 is less than 5V, when the mains supply is 210V, the voltage divided by R8 is more than 5V, and the calculation results show that: 43.75<x<45.96, taking x as 45 k; when the voltage is high and needs to be switched to an inverter loop, the switched return difference voltage is 230-240V, namely when the mains supply is 240V, the voltage divided by R6 is more than 5V, when the mains supply is 230V, the voltage divided by R6 is less than 5V, and the calculation shows that: 37.92<y<39.91, and y is 39 k. The divider resistance R8 of gained design is 45k, and R6 is 39k, satisfies the utility model discloses voltage comparator's output level requirement.
Preferably, the voltage comparator 2 further comprises a power-off protection circuit, the power-off protection circuit comprises a diode D6 and a fifth voltage-dividing resistor R10, one end of the fifth voltage-dividing resistor R10 is connected with a dc power supply, and the other end of the fifth voltage-dividing resistor R is connected with an inverting input end of the second comparator U1B. When the mains supply is in power failure or outage, the U1A outputs low level, the non-inverting input end of the U1B also outputs low level (a few tenths of volts), but the inverting input end of the U1B is 0V, the U1B outputs high level (5V), and wrong level output occurs. For this reason, by adding the power-off protection circuit composed of R10 and D6, when power is off, the inverting input level of U1B is always greater than the non-inverting input low level, and U1B will output the correct low level.
As shown in FIG. 3, the switching circuit 1 comprises an NPN type triode Q2, a sixth voltage-dividing resistor R17, a seventh voltage-dividing resistor R16 and a zener diode D8, the base of the NPN type triode Q2 is connected with the output end of the voltage comparator 2 through the sixth voltage-dividing resistor R17 and is grounded through the seventh voltage-dividing resistor R16, the collector of the NPN type triode Q2 is connected with the control end of the switching circuit 4, the emitter of the NPN type triode Q2 is grounded, the collector and the emitter of the NPN type triode Q2 are connected through the zener diode D8, the switching circuit 2 comprises a double-pole double-throw relay RY1, the double-pole double-throw relay 1 comprises two normally closed stationary contacts (RY 2, RY 7), two normally open stationary contacts (4, RY 5), two movable contacts (3,6) and coil contacts (8,1), the normally closed contacts (2, RY 7) are respectively connected with an inverter circuit (RY 37/96N), the commercial power contact (RY 4, the commercial power supply contact) is respectively connected with the stationary contacts (INV) and the movable contacts (INV) 34, INV) are respectively connected with the load coil (34/OUT 38, the load (L, the collector/OUT 38, the NPN) is respectively connected with the NPN 3/6).
It should be noted that, when the voltage comparator 2 outputs a high level, the NPN type triode Q2 is turned on, the coil is energized, the two moving contacts (3,6) are connected with the two normally open stationary contacts (4,5), and at this time, the inverter circuit switches to the mains supply to supply power to the load; when the voltage comparator 2 outputs a low level, the NPN type triode Q2 is cut off, the coil is not electrified, the two moving contacts (3,6) are connected with the two normally closed static contacts (2,7), and at the moment, the commercial power is switched to the inversion loop to supply power to the load, so that the stable power supply of the load is ensured.
Preferably, the switch switching circuit further comprises an acceleration circuit, wherein the acceleration circuit comprises a PNP-type triode Q1, a capacitor C3, a first current-limiting resistor, a second current-limiting resistor and a diode; the coil power supply (12V) is connected with the coil contact 1 through the diode D7 and is also connected with the collector electrode of the PNP type triode Q1 through the capacitor C3, and the collector electrode of the PNP type triode Q1 is grounded through the second current limiting resistor R15; the base electrode of the PNP type triode Q1 is connected with the collector electrode of the NPN type triode Q2 through the first current limiting resistor R14; the emitter of the PNP type triode Q2 is connected with the coil power supply (12V).
Note that Q1, D7, C3, and R15 constitute a relay switching acceleration circuit, and the following description is made using the charge pump principle: when Q2 is off (inverter output is in inverter mode), C3 is charged through D7 and R15, and the voltage across is close to 12V; when the Q2 is conducted, the Q1 is also conducted, at the moment, a 12V power supply is connected to the cathode of the C3 through the Q1, the voltage at two ends of a power supply voltage superposition capacitor is added to a relay coil together to form a voltage doubling effect, and the pull-in of a relay is accelerated, so that the conversion from an inversion mode to a mains supply is accelerated.
Preferably, rectifier circuit (the utility model discloses a full-bridge rectifier bridge, but not limited to this) and voltage comparator are between be equipped with filter circuit (filter capacitor C1 and the parallelly connected constitution of C2) for the filtering ripple improves voltage comparator circuit's stability.
Preferably, a rectifier diode is arranged between the filter circuit and the voltage comparator, and is used for preventing the filter capacitor from discharging to bring errors to the voltage comparator and influence the output level.
To sum up, the utility model provides a commercial power switching circuit that interactive inverter was used carries out voltage comparison and detection to the commercial power through voltage comparison circuit, according to commercial power voltage's size, exports corresponding level signal, switch switching circuit judges and switches the power supply mode of load according to level signal's height. The utility model discloses need not to occupy MCU (or control chip)'s interface resource, compare circuit and switch switching circuit through the voltage, just can realize interactive dc-to-ac converter's commercial power with the help of simple components and parts and switch the usage. Meanwhile, the design of the two groups of voltage resistors is matched, the multi-section voltage switching function is realized, and the switching speed of the switching circuit can be increased through the accelerating circuit.
The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations are also considered as the protection scope of the present invention.
Claims (9)
1. A commercial power switching circuit for an interactive inverter is characterized by comprising a voltage comparison circuit and a switch switching circuit;
the voltage comparison circuit comprises a rectifying circuit and a voltage comparator, wherein the input end of the rectifying circuit is connected with the mains supply, and the output end of the rectifying circuit is connected with the input end of the voltage comparator;
the switch switching circuit comprises a switching circuit and a switching circuit, the input end of the switching circuit is connected with the output end of the voltage comparator, the switching circuit comprises a first input end, a second input end, a control end and an output end, the output end of the switching circuit is connected with the control end, the first input end is connected with a mains supply, the second input end is connected with an inversion loop, and the output end is connected with a load.
2. The mains switching circuit for an interactive inverter as claimed in claim 1, wherein the voltage comparator comprises a first comparator, a second comparator, a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, a fourth voltage dividing resistor and a dc power supply;
the inverting input end of the first comparator is connected with the direct-current power supply, the output end of the first comparator is connected with the non-inverting input end of the second comparator, the non-inverting input end of the first comparator is connected with the output end of the rectifying circuit through the first voltage-dividing resistor, and the non-inverting input end of the first comparator is grounded through the second voltage-dividing resistor;
the output end of the second comparator is connected with the input end of the switch circuit, the inverting input end of the second comparator is connected with the output end of the rectifying circuit through a third voltage dividing resistor, and the inverting input end of the second comparator is grounded through the fourth voltage dividing resistor.
3. The commercial power switching circuit for the interactive inverter as claimed in claim 2, wherein the voltage comparator further comprises a power-off protection circuit, the power-off protection circuit comprises a diode and a fifth voltage-dividing resistor, one end of the fifth voltage-dividing resistor is connected to the dc power supply, and the other end of the fifth voltage-dividing resistor is connected to the inverting input terminal of the second comparator.
4. The commercial power switching circuit for the interactive inverter as claimed in claim 1, wherein the switching circuit comprises an NPN-type triode, a sixth voltage-dividing resistor, a seventh voltage-dividing resistor and a zener diode;
the base electrode of the NPN type triode is connected with the output end of the voltage comparator through the sixth voltage-dividing resistor and is grounded through the seventh voltage-dividing resistor;
the collector of the NPN type triode is connected with the control end of the switching circuit;
the emitting electrode of the NPN type triode is grounded;
and the collector and the emitter of the NPN type triode are connected through a voltage stabilizing diode.
5. The mains switching circuit for an interactive inverter as claimed in claim 4, wherein the switching circuit comprises a double-pole double-throw relay comprising two normally closed stationary contacts, two normally open stationary contacts, two moving contacts and a coil contact;
the normally closed stationary contact is respectively connected with the inverter circuit;
the normally open stationary contact is respectively connected with the mains supply;
the movable contacts are respectively connected with a load;
and the coil contact is respectively connected with the collector of the NPN type triode and a coil power supply.
6. The mains switching circuit for an interactive inverter as claimed in claim 5, wherein the switching circuit further comprises an accelerating circuit, the accelerating circuit comprising a PNP transistor, a capacitor, a first current limiting resistor, a second current limiting resistor and a diode;
the coil power supply is connected with the coil contact through the diode and is also connected with a collector electrode of the PNP type triode through the capacitor, and the collector electrode of the PNP type triode is grounded through the second current-limiting resistor;
the base electrode of the PNP type triode is connected with the collector electrode of the NPN type triode through the first current limiting resistor;
and the emitting electrode of the PNP type triode is connected with the coil power supply.
7. The utility power switching circuit of any one of claims 1 to 6, wherein a voltage reduction circuit is disposed between the rectification circuit and the utility power.
8. The utility power switching circuit of any one of claims 1 to 6, wherein a filter circuit is disposed between the rectifying circuit and the voltage comparator.
9. The commercial power switching circuit for the interactive inverter as claimed in claim 8, wherein a rectifying diode is disposed between the filter circuit and the voltage comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922152857.6U CN211127284U (en) | 2019-12-04 | 2019-12-04 | Commercial power switching circuit for interactive inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922152857.6U CN211127284U (en) | 2019-12-04 | 2019-12-04 | Commercial power switching circuit for interactive inverter |
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| Publication Number | Publication Date |
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| CN211127284U true CN211127284U (en) | 2020-07-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201922152857.6U Active CN211127284U (en) | 2019-12-04 | 2019-12-04 | Commercial power switching circuit for interactive inverter |
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| CN (1) | CN211127284U (en) |
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