CN213185487U - Power circuit of photovoltaic inverter - Google Patents
Power circuit of photovoltaic inverter Download PDFInfo
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- CN213185487U CN213185487U CN202022060297.4U CN202022060297U CN213185487U CN 213185487 U CN213185487 U CN 213185487U CN 202022060297 U CN202022060297 U CN 202022060297U CN 213185487 U CN213185487 U CN 213185487U
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Abstract
The utility model provides a photovoltaic inverter power supply circuit, which collects the temperature of a storage battery on the one hand by arranging a temperature control switch circuit; on the other hand, the voltage-controlled rectifier is used as a switch, when the collected temperature of the storage battery is too high, the temperature-controlled switch circuit is conducted, a line between the temperature-controlled switch circuit and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the temperature-controlled switch circuit, and the output end of the third voltage comparator outputs a high level to the pulse enabling end of the PWM control chip; when the collected temperature of the storage battery is normal, the temperature control switch circuit is cut off, a line between the temperature control switch circuit and the inverting input end of the third voltage comparator is disconnected, and the third voltage comparator is used as a voltage comparator when the output voltage of the storage battery is undervoltage, so that the storage battery protection circuit can share one voltage comparator when the temperature of the storage battery is too high and the output voltage of the storage battery is undervoltage, the integration level is high, and the problem of low integration level of the storage battery protection circuit in the existing photovoltaic inverter is solved.
Description
Technical Field
The utility model relates to an inverter technical field especially relates to a photovoltaic inverter power supply circuit.
Background
The photovoltaic inverter is a power supply for converting chemical energy of a solar cell irradiated by light into direct current to alternating current for output, and is widely used because the photovoltaic inverter is beneficial to energy conservation and emission reduction and greatly reduces the electricity consumption cost. The photovoltaic inverter generally adopts a high-frequency DC/AC conversion technology, low-voltage direct current of a storage battery connected to a center tap of a transformer is inverted into high-voltage alternating current through a direct current boosting module, the high-voltage alternating current is rectified into high-voltage direct current above 300V through a high-frequency rectifying and filtering circuit, and finally 220V power-frequency alternating current is obtained through a power-frequency inverting circuit and is used for a load. In order to improve the safety of the photovoltaic inverter, protective circuits for overvoltage, overcurrent, undervoltage and overtemperature of a storage battery are usually arranged in the photovoltaic inverter, so that although the safety of the photovoltaic inverter is improved, four hardware circuits are required to be correspondingly arranged for simultaneously arranging the protective circuits for overvoltage, overcurrent, undervoltage and overtemperature, the photovoltaic inverter is heavy in size, and the problem of low integration level exists.
Therefore, in order to solve the above problem, the utility model provides a photovoltaic inverter power supply circuit optimizes the structure of battery excessive pressure, overflows, under-voltage and excess temperature protection circuit, improves battery protection circuit integrated level, solves the problem that battery protection circuit integrated level is low among the current photovoltaic inverter.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a photovoltaic inverter power supply circuit optimizes the structure of battery excessive pressure, overflows, under-voltage and excess temperature protection circuit, improves battery protection circuit integrated level, solves the problem that battery protection circuit integrated level is low among the current photovoltaic inverter.
The technical scheme of the utility model is realized like this: the utility model provides a photovoltaic inverter power supply circuit, which comprises a PWM control chip, a storage battery, a push-pull type direct current booster circuit and a transformer, and also comprises a reference voltage, a first voltage comparator, a second voltage comparator, a third voltage comparator and a temperature control switch circuit;
the negative output end of the storage battery is grounded, the negative output end and the grounded intermediate connecting point of the storage battery are electrically connected with the inverted input end of the first voltage comparator, the non-inverting input end of the first voltage comparator is grounded, and the output end of the first voltage comparator is electrically connected with the pulse enable end of the PWM control chip;
the positive output end of the storage battery is electrically connected with the non-inverting input end of the second voltage comparator, the reference voltage is electrically connected with the inverting input end of the second voltage comparator, and the output end of the second voltage comparator is electrically connected with the pulse enabling end of the PWM control chip;
the positive output end of the storage battery is respectively electrically connected with the inverting input end of the third voltage comparator and the center tap of the transformer, the temperature control switch circuit is electrically connected with the inverting input end of the third voltage comparator, the reference voltage is electrically connected with the non-inverting input end of the third voltage comparator, the output end of the third voltage comparator is electrically connected with the pulse enable end of the PWM control chip, the PWM output end of the PWM control chip is electrically connected with the input end of the push-pull type direct current booster circuit, the output end of the push-pull type direct current booster circuit is electrically connected with the two ends of the primary side of the transformer, and the secondary side of the transformer outputs high-voltage alternating current voltage.
On the basis of the above technical solution, preferably, the first voltage comparator includes a potentiometer R5, a first operational amplifier LM324, a resistor R39, a resistor R40, a resistor R51, a resistor R52, capacitors C22-C24, a diode D8, and a diode D11;
the negative output end and the grounded middle connection point of the storage battery are electrically connected with the third pin of a potentiometer R5, the second pin of the potentiometer R5 is electrically connected with one end of a resistor R39, the second pin of the potentiometer R5 is electrically connected with the first pin thereof, the other end of the resistor R39 is electrically connected with the inverting input end of the first operational amplifier LM324 through a resistor R51, one end of a resistor R40 is electrically connected with a reference voltage, the other end of the resistor R40 and one end of a capacitor C23 are respectively electrically connected with the other end of a resistor R39, the other end of a capacitor C23 is grounded, a capacitor C24 is connected in parallel with the two ends of a capacitor C23, one end of the resistor R52 is grounded, the other end of the resistor R52 and the negative end of a diode D8 are respectively electrically connected with the non-inverting input end of the first operational amplifier LM324, the output end of the first operational amplifier LM324 is respectively electrically connected with the positive electrode of a diode D8 and the positive electrode of a diode D11, the negative electrode of a diode D686, the capacitor C22 is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier LM 324.
On the basis of the above technical solution, preferably, the second voltage comparator includes resistors R41-R43, a second operational amplifier LM324, and diodes D9-D10;
the positive electrode output end of the storage battery is electrically connected with one end of a resistor R41, the other end of the resistor R41 is electrically connected with the non-inverting input end of the second operational amplifier LM324 and one end of a resistor R42 respectively, the other end of the resistor R42 is grounded, the reference voltage is electrically connected with the inverting input end of the second operational amplifier LM324, the output end of the second operational amplifier is electrically connected with the positive electrode of a diode D9 and the positive electrode of a diode D10 respectively, the negative electrode of a diode D10 is electrically connected with the pulse enabling end of the PWM control chip, and the negative electrode of a diode D9 is electrically connected with the non-inverting input end of the second operational amplifier LM324 through the resistor R43.
On the basis of the above technical solution, preferably, the third voltage comparator includes a resistor R44, a resistor R47, a capacitor C25, a diode D14, and a third operational amplifier LM 324;
the positive electrode output end of the storage battery is electrically connected with the inverting input end of the third operational amplifier LM324 through the resistor R44, the reference voltage is electrically connected with the non-inverting input end of the third operational amplifier LM324 through the resistor R47, one end of the capacitor C25 is grounded, the other end of the capacitor C25 is electrically connected with the non-inverting input end of the third operational amplifier LM324, and the output end of the third operational amplifier LM324 is electrically connected with the pulse enabling end of the PWM control chip through the forward-conducted diode D14.
On the basis of the technical scheme, the automatic control device preferably further comprises a self-locking circuit;
the output end of the third voltage comparator is electrically connected with the input end of the self-locking circuit, and the output end of the self-locking circuit is electrically connected with the inverted input end of the third voltage comparator.
Still further preferably, the self-locking circuit comprises a resistor R48, a resistor R49 and an NPN type triode Q1;
the output end of the third voltage comparator is electrically connected with one end of a resistor R48, the other end of the resistor R48 is electrically connected with the base of an NPN type triode Q1, the emitter of the NPN type triode Q1 is grounded, and the collector of the NPN type triode Q1 is electrically connected with the inverting input end of the third voltage comparator through a resistor R49.
On the basis of the above technical solution, preferably, the temperature-controlled switch circuit includes a thermistor R80, a resistor R50, a power supply VCC, a polar capacitor C2, and a PNP-type triode Q2;
the power source VCC is respectively electrically connected with one end of the resistor R50 and the anode of the polar capacitor C2, the cathode of the polar capacitor C2 is grounded, the other end of the resistor R50 is respectively electrically connected with the base of the PNP type triode Q2 and one end of the thermistor R80, the other end of the thermistor R80 is grounded, the collector of the PNP type triode Q2 is grounded, and the emitter of the PNP type triode Q2 is electrically connected with the inverting input end of the third voltage comparator.
The utility model discloses a photovoltaic inverter power supply circuit has following beneficial effect for prior art:
(1) the temperature of the storage battery is collected on one hand by arranging the temperature control switch circuit; on the other hand, the voltage-controlled rectifier is used as a switch, when the acquired temperature of the storage battery is too high, the temperature-controlled switch circuit is conducted, a line between the temperature-controlled switch circuit and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the temperature-controlled switch circuit, the potential of the inverting input end of the third voltage comparator is 0, and the output end of the third voltage comparator outputs a high level to the pulse enable end of the PWM control chip; when the collected temperature of the storage battery is normal, the temperature control switch circuit is cut off, a line between the temperature control switch circuit and the inverting input end of the third voltage comparator is disconnected, and the third voltage comparator is used as a voltage comparator when the output voltage of the storage battery is undervoltage; the voltage comparator can be shared when the temperature of the storage battery is too high and the output voltage of the storage battery is high, the integration level is high, and the problem of low integration level of a storage battery protection circuit in the conventional photovoltaic inverter is solved;
(2) through setting up self-locking circuit, when battery output voltage is undervoltage, the output high level of third voltage comparator's output drives self-locking circuit and switches on, self-locking circuit carries out the partial pressure to battery output voltage, the battery output voltage who inputs the inverting input of third voltage comparator reduces, the output voltage value of third voltage comparator constantly risees, make the output lock of third voltage comparator at the high level state, when battery output voltage is undervoltage, because of electrostatic interference, external noise leads to the battery to export the voltage of the inverting input of third voltage comparator to have the shake, make the unstable technical problem of output voltage of third voltage comparator.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a system structure diagram of a power circuit of a photovoltaic inverter of the present invention;
fig. 2 is a circuit diagram of a battery protection circuit in a power circuit of a photovoltaic inverter.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.
As shown in fig. 1, the utility model discloses a photovoltaic inverter power supply circuit, it includes PWM control chip, battery, push-pull type direct current boost circuit, transformer, reference voltage, first voltage comparator, second voltage comparator, third voltage comparator, temperature detect switch circuit and self-locking circuit.
And the storage battery is used for providing working voltage for the transformer. The positive output end of the storage battery is electrically connected with the non-inverting input end of the second voltage comparator, the inverting input end of the third voltage comparator and the center tap of the transformer respectively, the negative output end of the storage battery is grounded, and the negative output end of the storage battery and the grounded middle connecting point are electrically connected with the inverting input end of the first voltage comparator. As shown in fig. 2, BAT + represents the positive output terminal of the secondary battery.
A reference voltage used as a reference voltage. The reference voltage is respectively electrically connected with the inverting input end of the second voltage comparator and the non-inverting input end of the third voltage comparator. As shown in fig. 2, in the present embodiment, the reference voltage is set to + 5V.
The first voltage comparator forms a storage battery overcurrent protection circuit, detects whether the output current of the storage battery is overcurrent or not in real time, when the output current of the storage battery is overcurrent, the output end of the first voltage comparator outputs a high level to the pulse enabling end of the PWM control chip, and the PWM output end of the PWM control chip stops outputting PWM pulse signals to drive the push-pull type direct current booster circuit to work. The inverting input end of the first voltage comparator is electrically connected with the negative output end of the storage battery and the grounded middle connection point, the non-inverting input end of the first voltage comparator is grounded, and the output end of the first voltage comparator is electrically connected with the pulse enabling end of the PWM control chip. Preferably, in this embodiment, as shown in fig. 2, the first operational amplifier in the first voltage comparator is an LM324 operational amplifier; U4C represents a first operational amplifier, and IPK represents the current flowing from the negative output terminal of the battery to the inverting input terminal of the first voltage comparator.
Preferably, in this embodiment, as shown in fig. 2, the first voltage comparator includes a potentiometer R5, a first operational amplifier LM324, a resistor R39, a resistor R40, a resistor R51, a resistor R52, capacitors C22-C24, a diode D8, and a diode D11; the negative output end and the grounded middle connection point of the storage battery are electrically connected with the third pin of a potentiometer R5, the second pin of the potentiometer R5 is electrically connected with one end of a resistor R39, the second pin of the potentiometer R5 is electrically connected with the first pin thereof, the other end of the resistor R39 is electrically connected with the inverting input end of the first operational amplifier LM324 through a resistor R51, one end of a resistor R40 is electrically connected with a reference voltage, the other end of the resistor R40 and one end of a capacitor C23 are respectively electrically connected with the other end of a resistor R39, the other end of a capacitor C23 is grounded, a capacitor C24 is connected in parallel with the two ends of a capacitor C23, one end of the resistor R52 is grounded, the other end of the resistor R52 and the negative end of a diode D8 are respectively electrically connected with the non-inverting input end of the first operational amplifier LM324, the output end of the first operational amplifier LM324 is respectively electrically connected with the positive electrode of a diode D8 and the positive electrode of a diode D11, the negative electrode of a diode D686, the capacitor C22 is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier LM 324.
Wherein, the potentiometer R5 is a protection resistor, and the resistance value of the potentiometer is adjusted to prevent the circuit current from being too large and the first operational amplifier LM324 from being burnt; the resistor R39 and the resistor R51 are load resistors and prevent the short circuit from breaking down; the resistor R40 and the resistor R52 are pull-up resistors, so that the reference voltage is more stable; the capacitors C23-C24 are filter capacitors and filter circuit interference signals; the capacitor C22 is a compensation capacitor for compensating the phase effect caused by the input capacitance of the first operational amplifier LM 324; the first operational amplifier LM324 is a current comparator for comparing current values input by the non-inverting input terminal and the inverting input terminal; the diode D8 is a limiting diode, and voltage instability caused by circuit interference or noise is prevented; the diode D11 is a clamping diode, when the output voltage of the output end of the first operational amplifier LM324 is less than 0.6V, the diode D11 is cut off, so that the output voltage of the output end of the first operational amplifier LM324 is prevented from having errors due to interference, and the pulse enable end of the PWM control chip judges that the received signal is at a high level within an error range; when the current value of the storage battery input by the inverting input end of the first operational amplifier LM324 is smaller than the current value input by the non-inverting input end of the first operational amplifier LM324, the first operational amplifier LM324 outputs a high level, the diode D8 and the diode D11 are conducted, and the high level is output to the pulse enable end of the PWM control chip; the output current of the first operational amplifier LM324 is fed back to the non-inverting input end through the diode D8, so that the output of the operational amplifier LM324 is more stable; when the value of the battery current input from the inverting input terminal of the first operational amplifier LM324 is greater than the value of the battery current input from the non-inverting input terminal of the first operational amplifier LM324, the first operational amplifier LM324 outputs a low level, and the diode D8 and the diode D11 are turned off.
And the second voltage comparator forms a storage battery overvoltage protection circuit, detects whether the output voltage of the storage battery is overvoltage in real time, when the output voltage of the storage battery is overvoltage, the output end of the second voltage comparator outputs a high level to the pulse enabling end of the PWM control chip, and the PWM output end of the PWM control chip stops outputting PWM pulse signals to drive the push-pull type direct current booster circuit to work. The non-inverting input end of the second voltage comparator is electrically connected with the positive output end of the storage battery, the inverting input end of the second voltage comparator is electrically connected with the reference voltage, and the output end of the second voltage comparator is electrically connected with the pulse enabling end of the PWM control chip. Preferably, in this embodiment, as shown in fig. 2, the LM324 operational amplifier is selected as the second operational amplifier in the second voltage comparator; U4D denotes a second operational amplifier.
Preferably, in the embodiment, as shown in fig. 2, the second voltage comparator includes resistors R41-R43, a second operational amplifier LM324, and diodes D9-D10; the positive electrode output end of the storage battery is electrically connected with one end of a resistor R41, the other end of the resistor R41 is electrically connected with the non-inverting input end of the second operational amplifier LM324 and one end of a resistor R42 respectively, the other end of the resistor R42 is grounded, the reference voltage is electrically connected with the inverting input end of the second operational amplifier LM324, the output end of the second operational amplifier is electrically connected with the positive electrode of a diode D9 and the positive electrode of a diode D10 respectively, the negative electrode of a diode D10 is electrically connected with the pulse enabling end of the PWM control chip, and the negative electrode of a diode D9 is electrically connected with the non-inverting input end of the second operational amplifier LM324 through the resistor R43.
The resistor R41 is a pull-up resistor, so that the reference voltage is more stable; the resistor R42 is a protection resistor, and prevents the second operational amplifier LM324 from zero drift; the second operational amplifier LM324 is a voltage comparator for comparing the voltage values input by the non-inverting input terminal and the inverting input terminal; the diode D9 is a limiting diode, and voltage instability caused by circuit interference or noise is prevented; the resistor R43 is a positive feedback resistor, so that the output voltage value of the output end of the second operational amplifier LM324 is more stable; the diode D10 is a clamping diode, when the output voltage of the output end of the second operational amplifier LM324 is less than 0.6V, the diode D10 is cut off, so that the output voltage of the output end of the second operational amplifier LM324 is prevented from having errors due to interference, and the pulse enable end of the PWM control chip judges that the received signal is at a high level within an error range; when the output voltage value of the storage battery input to the non-inverting input end of the second operational amplifier LM324 is greater than the voltage value of the non-inverting input end of the second operational amplifier LM324, the second operational amplifier LM324 outputs a high level, the diode D9 and the diode D10 are conducted, and the high level is output to the pulse enable end of the PWM control chip; when the battery output voltage value input to the non-inverting input terminal of the second operational amplifier LM324 is smaller than the voltage value of the non-inverting input terminal of the second operational amplifier LM324, the second operational amplifier LM324 outputs a low level, and the diode D9 and the diode D10 are turned off; the output voltage of the second operational amplifier LM324 is fed back to the non-inverting input terminal through the diode D9 and the resistor R43, so that the high level output by the second operational amplifier LM324 is more stable.
On one hand, the third voltage comparator detects whether the output voltage of the storage battery is undervoltage or not in real time; on the other hand, whether the temperature of the storage battery is too high is detected; when the output voltage of the storage battery is undervoltage, the output end of the third voltage comparator outputs a high level to the pulse enable end of the PWM control chip, and the PWM output end of the PWM control chip stops outputting PWM pulse signals to drive the push-pull type direct current booster circuit to work; when the storage battery is over-temperature, the output end of the third voltage comparator outputs a high level to the pulse enabling end of the PWM control chip, and the PWM output end of the PWM control chip stops outputting PWM pulse signals to drive the push-pull type direct current booster circuit to work. The reverse phase input end of the third voltage comparator is electrically connected with the positive electrode output end of the storage battery and the temperature control switch circuit respectively, the in-phase input end of the third voltage comparator is electrically connected with the reference voltage, and the output end of the third voltage comparator is electrically connected with the pulse enabling end of the PWM control chip. Preferably, in this embodiment, as shown in fig. 2, the LM324 operational amplifier is selected as the third operational amplifier in the third voltage comparator; U4A corresponds to the third operational amplifier.
Preferably, in this embodiment, as shown in fig. 2, the third voltage comparator includes a resistor R44, a resistor R47, a capacitor C25, a diode D14, and a third operational amplifier LM 324; the positive electrode output end of the storage battery is electrically connected with the inverting input end of the third operational amplifier LM324 through the resistor R44, the reference voltage is electrically connected with the non-inverting input end of the third operational amplifier LM324 through the resistor R47, one end of the capacitor C25 is grounded, the other end of the capacitor C25 is electrically connected with the non-inverting input end of the third operational amplifier LM324, and the output end of the third operational amplifier LM324 is electrically connected with the pulse enabling end of the PWM control chip through the forward-conducted diode D14.
The resistor R47 is a pull-up resistor, so that the reference voltage is more stable; the capacitor C25 is a filter capacitor for filtering circuit interference signals; the resistor R44 is a load resistor to prevent the short circuit from breaking down; the third operational amplifier LM324 is a voltage comparator for comparing the voltage values input by the non-inverting input terminal and the inverting input terminal; the diode D14 is a clamping diode, when the output voltage of the output end of the third operational amplifier LM324 is less than 0.6V, the diode D14 is cut off, so that the output voltage of the output end of the third operational amplifier LM324 is prevented from having errors due to interference, and the PWM pulse enabling end judges that the received signal is at a high level within an error range; when the output voltage value of the storage battery collected by the inverting input end of the third operational amplifier LM324 is smaller than the voltage value of the non-inverting input end of the third operational amplifier LM324, the third operational amplifier LM324 judges that the output voltage of the storage battery is under-voltage, at the moment, the output end of the third operational amplifier LM324 outputs high level, the diode D14 is conducted, and the high level is output to the pulse enable end of the PWM control chip; when the output voltage value of the storage battery collected by the inverting input end of the third operational amplifier LM324 is smaller than the voltage value of the non-inverting input end of the third operational amplifier LM324, the third operational amplifier LM324 judges that the output voltage of the storage battery is not under-voltage, at this time, the output end of the third operational amplifier LM324 outputs a low level, and the diode D14 is cut off.
The self-locking circuit, when the battery output voltage is undervoltage, the output high level of the output of the third voltage comparator drives the self-locking circuit to conduct, the self-locking circuit divides the voltage of the battery output, the battery output voltage input to the inverting input end of the third voltage comparator is reduced, the voltage value of the output end of the third voltage comparator is continuously increased, the output of the output end of the third voltage comparator is locked in a high level state, and the technical problem that the voltage output to the inverting input end of the third voltage comparator by the battery is jittered due to electrostatic interference and external noise when the voltage of the battery output is undervoltage is solved, and the voltage output by the output end of the third voltage comparator is unstable. The input end of the self-locking circuit is electrically connected with the output end of the third voltage comparator, and the output end of the self-locking circuit is electrically connected with the inverted input end of the third voltage comparator. Preferably, in this embodiment, as shown in fig. 2, the self-locking circuit is a triode self-locking circuit.
Preferably, in this embodiment, as shown in fig. 2, the self-locking circuit includes a resistor R48, a resistor R49, and an NPN transistor Q1; the output end of the third voltage comparator is electrically connected with one end of a resistor R48, the other end of the resistor R48 is electrically connected with the base of an NPN type triode Q1, the emitter of the NPN type triode Q1 is grounded, and the collector of the NPN type triode Q1 is electrically connected with the inverting input end of the third voltage comparator through a resistor R49. As shown in fig. 2, the base of the NPN transistor Q1 corresponds to the input terminal of the latch circuit; the collector of the NPN type triode Q1 correspondingly represents the output end of the self-locking circuit.
The resistor R48 and the resistor R49 are current-limiting resistors, and the NPN type triode Q1 is prevented from being broken down due to short circuit; the NPN type triode Q1 is a common emitter amplifying circuit; when the output voltage of the storage battery is judged to be in an undervoltage state by the third operational amplifier LM324, the third operational amplifier LM324 outputs a high level to drive the NPN type triode Q1 to be conducted, the grounded NPN type triode Q1 divides the output voltage of the storage battery, and the output voltage of the storage battery input to the inverting input end of the third operational amplifier LM324 is reduced, so that the output end of the third operational amplifier LM324 always outputs a high level; the output voltage of the storage battery is judged to be not undervoltage through the third operational amplifier LM324, and the NPN type triode Q1 is in a cut-off state and does not work.
The temperature control switch circuit collects the temperature of the storage battery on one hand; on the other hand, the voltage-controlled rectifier is used as a switch, when the acquired temperature of the storage battery is too high, the temperature-controlled switch circuit is conducted, a line between the temperature-controlled switch circuit and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the temperature-controlled switch circuit, the potential of the inverting input end of the third voltage comparator is 0, and the output end of the third voltage comparator outputs a high level to the pulse enable end of the PWM control chip; when the collected temperature of the storage battery is normal, the temperature control switch circuit is cut off, a line between the temperature control switch circuit and the inverting input end of the third voltage comparator is disconnected, and the third voltage comparator is used as a voltage comparator when the output voltage of the storage battery is undervoltage; the voltage comparator can be shared when the temperature of the storage battery is too high and the output voltage of the storage battery is high, the integration level is small in size and high, and the problem that the integration level of a storage battery protection circuit in the existing photovoltaic inverter is low is solved. The temperature control switch circuit is electrically connected with the inverting input end of the third voltage comparator.
Preferably, as shown in fig. 2, the temperature-controlled switch circuit includes a thermistor R80, a resistor R50, a power source VCC, a polar capacitor C2, and a PNP-type triode Q2; the power source VCC is respectively electrically connected with one end of the resistor R50 and the anode of the polar capacitor C2, the cathode of the polar capacitor C2 is grounded, the other end of the resistor R50 is respectively electrically connected with the base of the PNP type triode Q2 and one end of the thermistor R80, the other end of the thermistor R80 is grounded, the collector of the PNP type triode Q2 is grounded, and the emitter of the PNP type triode Q2 is electrically connected with the inverting input end of the third voltage comparator.
The polar capacitor C2 is used for filtering an interference harmonic signal output by the power supply VCC; the resistor R50 is a current-limiting resistor, so that the PNP type triode Q2 is prevented from being burnt out due to overlarge current; the PNP type triode Q2 is a switching tube; when the temperature of a storage battery in the photovoltaic inverter is overhigh, the resistance value of the thermistor R80 is almost 0, a power supply VCC is grounded through a resistor R50, the base electrode of the PNP type triode Q2 is grounded, the PNP type triode Q2 is conducted, a circuit between the PNP type triode Q2 and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the PNP type triode Q2, the potential of the inverting input end of the third voltage comparator is 0, the output end of the third voltage comparator outputs a high level to the pulse enabling end of the PWM control chip, the PWM control chip stops working, and the photovoltaic inverter system stops working. When the temperature of a storage battery in the photovoltaic inverter is normal, the resistance value of the thermistor R80 is large, and the base input high level of the PNP type triode Q2 is cut off.
The output end of the third voltage comparator outputs a high level when the storage battery is over-temperature or the output voltage of the storage battery is under-voltage, and the pulse enable end of the PWM control chip controls the PWM output end to stop outputting PWM pulse signals to drive the push-pull type direct current booster circuit to work; when the storage battery is not over-temperature or the output voltage of the storage battery is not under-voltage, the output end of the third voltage comparator outputs a low level, and the pulse enabling end of the PWM control chip controls the PWM output end to normally output PWM pulse signals to drive the push-pull type direct current booster circuit to work. The pulse enable end of the PWM control chip is electrically connected with the output end of the third voltage comparator, and the PWM output end of the PWM control chip is electrically connected with the input end of the push-pull type direct current booster circuit. Preferably, in this embodiment, the PWM control chip is an SG3525 chip, where SHUT represents a pulse enable terminal of the PWM control chip, and OUTA and OUTB represent PWM output terminals of the PWM control chip.
The push-pull type direct current booster circuit is used for amplifying a PWM pulse signal output by a PWM output end of the PWM control chip; the transformer is matched to convert the low-voltage direct current of the storage battery connected to the center tap of the transformer into low-voltage alternating current. The input end of the push-pull type direct current booster circuit is electrically connected with the PWM output end of the PWM control chip, and the output end of the push-pull type direct current booster circuit is electrically connected with two ends of the primary side of the transformer. Preferably, in this embodiment, the push-pull dc boost circuit may be driven by parallel field effect transistors or transistors, and the number and type of the parallel field effect transistors or transistors are not limited.
And the transformer is used for generating low-voltage alternating current in cooperation with the push-pull type direct current booster circuit and boosting and outputting high-voltage alternating current. The center tap of the transformer is electrically connected with the positive output end of the storage battery, two ends of the primary side of the transformer are respectively electrically connected with the output end of the push-pull type direct current booster circuit, and the secondary side of the transformer outputs high-voltage alternating current voltage. Preferably, in this embodiment, the transformer is a single-phase transformer.
The utility model discloses a theory of operation is: in a normal state, the output end of the third voltage comparator outputs a low level, and the self-locking circuit does not work; the pulse enable end of the PWM control chip defaults that a received signal is low level, the PWM control chip works normally, a PWM pulse signal is output to the push-pull type direct current booster circuit to be amplified, the push-pull type direct current booster circuit is matched with the transformer to convert low-voltage direct current of a storage battery connected to a center tap of the transformer into low-voltage alternating current, and the low-voltage alternating current is boosted by the transformer and finally output high-voltage alternating current;
when the storage battery is over-temperature, the temperature control switch circuit is conducted, a circuit between the temperature control switch circuit and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the temperature control switch circuit, the potential of the inverting input end of the third voltage comparator is 0, and the output end of the third voltage comparator outputs high level to the pulse enable end of the PWM control chip to control the PWM control chip to stop working;
when the voltage of the positive output end of the storage battery is under voltage, the output voltage value of the storage battery acquired by the inverting input end of the third voltage comparator is smaller than the voltage value of the non-inverting input end of the third voltage comparator, the output end of the third voltage comparator outputs high level to the pulse enabling end of the PWM control chip, and the PWM control chip stops working; meanwhile, the output end of the third voltage comparator outputs a high level to drive the self-locking circuit, the self-locking circuit is conducted to divide the output voltage of the storage battery, and the output voltage of the storage battery input to the inverting input end of the third voltage comparator is reduced, so that the output end of the third voltage comparator always outputs the high level.
The beneficial effect of this embodiment does: the temperature of the storage battery is collected on one hand by arranging the temperature control switch circuit; on the other hand, the voltage-controlled rectifier is used as a switch, when the acquired temperature of the storage battery is too high, the temperature-controlled switch circuit is conducted, a line between the temperature-controlled switch circuit and the inverting input end of the third voltage comparator is conducted, the inverting input end of the third voltage comparator is grounded through the temperature-controlled switch circuit, the potential of the inverting input end of the third voltage comparator is 0, and the output end of the third voltage comparator outputs a high level to the pulse enable end of the PWM control chip; when the collected temperature of the storage battery is normal, the temperature control switch circuit is cut off, a line between the temperature control switch circuit and the inverting input end of the third voltage comparator is disconnected, and the third voltage comparator is used as a voltage comparator when the output voltage of the storage battery is undervoltage; the voltage comparator can be shared when the temperature of the storage battery is too high and the output voltage of the storage battery is high, the integration level is high, and the problem of low integration level of a storage battery protection circuit in the conventional photovoltaic inverter is solved;
through setting up self-locking circuit, when battery output voltage is undervoltage, the output high level of third voltage comparator's output drives self-locking circuit and switches on, self-locking circuit carries out the partial pressure to battery output voltage, the battery output voltage who inputs the inverting input of third voltage comparator reduces, the output voltage value of third voltage comparator constantly risees, make the output lock of third voltage comparator at the high level state, when battery output voltage is undervoltage, because of electrostatic interference, external noise leads to the battery to export the voltage of the inverting input of third voltage comparator to have the shake, make the unstable technical problem of output voltage of third voltage comparator.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. The utility model provides a photovoltaic inverter power supply circuit, its includes PWM control chip, battery, push-pull direct current boost circuit and transformer, its characterized in that: the circuit also comprises a reference voltage, a first voltage comparator, a second voltage comparator, a third voltage comparator and a temperature control switch circuit;
the negative output end of the storage battery is grounded, the negative output end and the grounded intermediate connecting point of the storage battery are electrically connected with the inverted input end of the first voltage comparator, the non-inverting input end of the first voltage comparator is grounded, and the output end of the first voltage comparator is electrically connected with the pulse enable end of the PWM control chip;
the positive electrode output end of the storage battery is electrically connected with the non-inverting input end of the second voltage comparator, the reference voltage is electrically connected with the inverting input end of the second voltage comparator, and the output end of the second voltage comparator is electrically connected with the pulse enable end of the PWM control chip;
the positive output end of the storage battery is electrically connected with the inverting input end of the third voltage comparator and the center tap of the transformer respectively, the temperature control switch circuit is electrically connected with the inverting input end of the third voltage comparator, the reference voltage is electrically connected with the non-inverting input end of the third voltage comparator, the output end of the third voltage comparator is electrically connected with the pulse enable end of the PWM control chip, the PWM output end of the PWM control chip is electrically connected with the input end of the push-pull type direct current booster circuit, the output end of the push-pull type direct current booster circuit is electrically connected with the two ends of the primary side of the transformer, and the secondary side of the transformer outputs high-voltage alternating current voltage.
2. A photovoltaic inverter power circuit as claimed in claim 1 wherein: the first voltage comparator comprises a potentiometer R5, a first operational amplifier LM324, a resistor R39, a resistor R40, a resistor R51, a resistor R52, capacitors C22-C24, a diode D8 and a diode D11;
the middle connection point of the negative output end and the ground of the storage battery is electrically connected with the third pin of the potentiometer R5, the second pin of the potentiometer R5 is electrically connected with one end of a resistor R39, the second pin of the potentiometer R5 is electrically connected with the first pin thereof, the other end of a resistor R39 is electrically connected with the inverting input end of the first operational amplifier LM324 through a resistor R51, one end of the resistor R40 is electrically connected with a reference voltage, the other end of the resistor R40 and one end of a capacitor C23 are respectively electrically connected with the other end of a resistor R39, the other end of the capacitor C23 is grounded, a capacitor C24 is connected in parallel with the two ends of a capacitor C23, one end of the resistor R52 is grounded, the other end of the resistor R52 and the negative electrode of the diode D8 are respectively electrically connected with the non-inverting input end of the first operational amplifier LM324, the output end of the first operational amplifier LM324 is respectively electrically connected with the positive electrode of the diode D58, the negative electrode of the diode D11 is electrically connected with the pulse enable end of the PWM control chip, and the capacitor C22 is connected between the inverting input end and the output end of the operational amplifier LM324 in parallel.
3. A photovoltaic inverter power circuit as claimed in claim 1 wherein: the second voltage comparator comprises resistors R41-R43, a second operational amplifier LM324 and diodes D9-D10;
the positive output end of the storage battery is electrically connected with one end of a resistor R41, the other end of the resistor R41 is electrically connected with the non-inverting input end of a second operational amplifier LM324 and one end of a resistor R42 respectively, the other end of the resistor R42 is grounded, the reference voltage is electrically connected with the inverting input end of the second operational amplifier LM324, the output end of the second operational amplifier is electrically connected with the positive electrode of a diode D9 and the positive electrode of a diode D10 respectively, the negative electrode of a diode D10 is electrically connected with the pulse enabling end of the PWM control chip, and the negative electrode of the diode D9 is electrically connected with the non-inverting input end of the second operational amplifier LM324 through the resistor R43.
4. A photovoltaic inverter power circuit as claimed in claim 1 wherein: the third voltage comparator comprises a resistor R44, a resistor R47, a capacitor C25, a diode D14 and a third operational amplifier LM 324;
the positive electrode output end of the storage battery is electrically connected with the inverting input end of the third operational amplifier LM324 through the resistor R44, the reference voltage is electrically connected with the non-inverting input end of the third operational amplifier LM324 through the resistor R47, one end of the capacitor C25 is grounded, the other end of the capacitor C25 is electrically connected with the non-inverting input end of the third operational amplifier LM324, and the output end of the third operational amplifier LM324 is electrically connected with the pulse enabling end of the PWM control chip through the forward conducted diode D14.
5. A photovoltaic inverter power circuit as claimed in claim 1 wherein: the device also comprises a self-locking circuit;
the output end of the third voltage comparator is electrically connected with the input end of the self-locking circuit, and the output end of the self-locking circuit is electrically connected with the inverted input end of the third voltage comparator.
6. A photovoltaic inverter power circuit as claimed in claim 5 wherein: the self-locking circuit comprises a resistor R48, a resistor R49 and an NPN type triode Q1;
the output end of the third voltage comparator is electrically connected with one end of a resistor R48, the other end of the resistor R48 is electrically connected with the base electrode of an NPN type triode Q1, the emitting electrode of the NPN type triode Q1 is grounded, and the collector electrode of the NPN type triode Q1 is electrically connected with the inverting input end of the third voltage comparator through a resistor R49.
7. A photovoltaic inverter power circuit as claimed in claim 1 wherein: the temperature control switch circuit comprises a thermistor R80, a resistor R50, a power supply VCC, a polar capacitor C2 and a PNP type triode Q2;
the power VCC is respectively with the one end of resistance R50 and the anodal electric connection of polarity electric capacity C2, polarity electric capacity C2's negative pole ground connection, resistance R50's the other end respectively with PNP type triode Q2's base and thermistor R80's one end electric connection, thermistor R80's the other end ground connection, PNP type triode Q2's collecting electrode ground connection, PNP type triode Q2's projecting pole and third voltage comparator's inverting input electric connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022060297.4U CN213185487U (en) | 2020-09-19 | 2020-09-19 | Power circuit of photovoltaic inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022060297.4U CN213185487U (en) | 2020-09-19 | 2020-09-19 | Power circuit of photovoltaic inverter |
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| Publication Number | Publication Date |
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| CN213185487U true CN213185487U (en) | 2021-05-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202022060297.4U Active CN213185487U (en) | 2020-09-19 | 2020-09-19 | Power circuit of photovoltaic inverter |
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| CN (1) | CN213185487U (en) |
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