CN107706917B - AC/DC micro-grid hybrid power supply - Google Patents
AC/DC micro-grid hybrid power supply Download PDFInfo
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- CN107706917B CN107706917B CN201711047558.5A CN201711047558A CN107706917B CN 107706917 B CN107706917 B CN 107706917B CN 201711047558 A CN201711047558 A CN 201711047558A CN 107706917 B CN107706917 B CN 107706917B
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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
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/02—Circuit arrangements for ac mains or ac distribution networks using a single network for simultaneous distribution of power at different frequencies; using a single network for simultaneous distribution of ac power and of dc power
Abstract
The invention provides an alternating current/direct current micro-grid hybrid power supply, which comprises an AC/DC converter, a first DC/DC converter and a second DC/DC converter; the AC/DC converter is connected with the AC micro-grid and is used for converting the AC provided by the AC micro-grid into DC; the first DC/DC converter is connected with the AC/DC converter and is used for providing a first output voltage Uo1 and providing a first control voltage Vcc1 for the second DC/DC converter; the second DC/DC converter is connected with the direct current micro-grid and is used for providing a second output voltage Uo2 and providing a second control voltage Vcc2 for the first DC/DC converter; the positive polarity ends of the two DC/DC converters are connected and serve as the positive polarity end of the output of the hybrid power supply, and the negative polarity ends of the two DC/DC converters are connected and serve as the negative polarity end of the output of the hybrid power supply. The AC/DC micro-grid hybrid power supply provided by the invention realizes seamless switching between the DC micro-grid and the AC micro-grid through the mutual power supply of the two DC/DC converters and the automatic start operation of the control loop, reduces the system loss and improves the power supply efficiency.
Description
Technical Field
The invention relates to the technical field of power systems, in particular to an alternating current-direct current micro-grid hybrid power supply.
Background
Traditional alternating current distribution systems face a series of problems such as high line loss, power quality disturbance, voltage drop and the like, and the ever-increasing power demands of power consumers are difficult to meet. Compared with an alternating-current power distribution network, the direct-current power supply effectively solves the power quality problems of harmonic waves, unbalanced three phases and the like, has obvious advantages in improving the power supply quality, and cannot completely replace the alternating-current power distribution network in a short time. Therefore, the construction of an alternating current-direct current hybrid power distribution network on the basis of an alternating current power distribution network is a development trend of a future power distribution network.
In the prior art, when a certain power supply fails, an AC/DC dual-path power supply auxiliary power supply can be switched to another power supply through a mechanical switch or a power electronic switch. The method for switching the power supply through the electronic switch is commonly used as follows: and detecting whether the current power supply fails or not by using the loop voltage detection circuit, and if the current power supply fails, starting the switching circuit to switch the power supply to another power supply, thereby ensuring that the power failure does not occur.
However, in the scheme in the prior art, thyristors are connected in series in a main circuit, so that the loss is increased, the efficiency is reduced, the switching time is too long, and the requirement of an auxiliary power supply of an alternating-current/direct-current hybrid micro-grid interconnection converter cannot be met.
Disclosure of Invention
First, the technical problem to be solved
The invention aims to provide an alternating current/direct current micro-grid hybrid power supply, which solves the technical problems of long switching time between sub-grids of a hybrid power supply grid, large system loss and low efficiency in the prior art.
(II) technical scheme
In order to solve the technical problems, in one aspect, the present invention provides an ac/dc micro-grid hybrid power supply, including:
an AC/DC converter, a first DC/DC converter, and a second DC/DC converter;
the first end of the AC/DC converter is connected with the AC micro-grid, and the second end of the AC/DC converter is connected with the first end of the first DC/DC converter and is used for converting the AC provided by the AC micro-grid into DC;
the second end of the first DC/DC converter is connected with the second end of the second DC/DC converter, the third end of the first DC/DC converter is connected with the third end of the second DC/DC converter, and the second DC/DC converter is used for providing a first output voltage Uo1 and a first control voltage Vcc1;
the first end of the second DC/DC converter is connected with the direct current micro-grid and is used for providing a second output voltage Uo2 and providing a second control voltage Vcc2 for the first DC/DC converter;
the positive polarity end of the first DC/DC converter is connected with the positive polarity end of the second DC/DC converter to serve as an output positive polarity end of the hybrid power supply, and the negative polarity end of the first DC/DC converter is connected with the negative polarity end of the second DC/DC converter to serve as an output negative polarity end of the hybrid power supply.
Further, the AC/DC converter comprises a rectifier bridge circuit, a starting current limiting resistor and a filter capacitor circuit;
the alternating current provided by the alternating current micro-grid is converted into direct current after sequentially passing through the rectifier bridge circuit, the starting current limiting resistor and the filter capacitor circuit.
Further, the first DC/DC converter comprises a first power conversion main circuit, a first feedback regulation circuit and a first PWM control circuit;
one end of the first PWM control circuit is connected with the first feedback regulating circuit, the other end of the first PWM control circuit is connected with the primary side of the first power conversion main circuit, one end of the first feedback regulating circuit is connected with the first PWM control circuit, and the other end of the first feedback regulating circuit is connected with the secondary side of the first power conversion main circuit;
the first feedback regulating circuit is used for detecting the conversion amount of the first output voltage Uo1, the first PWM control circuit is used for regulating a first PWM control signal output by the first feedback regulating circuit according to the conversion amount of the first output voltage Uo1, and the first power conversion main circuit is used for regulating the first output voltage Uo1 according to the first PWM control signal.
Further, the first power conversion main circuit includes a first transformer;
the first transformer includes a first auxiliary winding that supplies power to the first PWM control circuit and a second auxiliary winding that provides a first control voltage Vcc1 for the second DC/DC converter.
Further, the first PWM control circuit and the first feedback regulation circuit are connected through a first isolation device.
Further, the second DC/DC converter comprises a second power conversion main circuit, a second feedback regulating circuit and a second PWM control circuit;
one end of the second PWM control circuit is connected with the second feedback regulating circuit, the other end of the second PWM control circuit is connected with the primary side of the second power conversion main circuit, one end of the second feedback regulating circuit is connected with the second PWM control circuit, and the other end of the second feedback regulating circuit is connected with the secondary side of the second power conversion main circuit;
the second feedback regulating circuit is used for detecting the conversion amount of the second output voltage Uo2, the second PWM control circuit is used for regulating a second PWM control signal output by the second feedback regulating circuit according to the conversion amount of the second output voltage Uo2, and the second power conversion main circuit regulates the second output voltage Uo2 according to the second PWM control signal.
Further, the second power conversion main circuit includes a second transformer;
the second transformer includes a third auxiliary winding that supplies the second PWM control circuit and a fourth auxiliary winding that provides the second control voltage Vcc2 for the first DC/DC converter.
Further, the second PWM control circuit and the second feedback regulation circuit are connected through a second isolation device.
(III) beneficial effects
The AC/DC micro-grid hybrid power supply provided by the invention realizes seamless switching between the DC micro-grid and the AC micro-grid through the mutual power supply of the two DC/DC converters and the automatic start operation of the control loop, reduces the system loss and improves the power supply efficiency.
Drawings
Fig. 1 is a schematic structural diagram of an ac/dc micro-grid hybrid power supply according to an embodiment of the invention;
fig. 2 is a circuit diagram of an ac/dc micro-grid hybrid power supply according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1:
fig. 1 is a schematic structural diagram of an ac/dc micro-grid hybrid power supply according to an embodiment of the present invention, as shown in fig. 1, an embodiment of the present invention provides an ac/dc micro-grid hybrid power supply, including:
an AC/DC converter, a first DC/DC converter, and a second DC/DC converter;
the first end of the AC/DC converter is connected with the AC micro-grid, and the second end of the AC/DC converter is connected with the first end of the first DC/DC converter and is used for converting the AC provided by the AC micro-grid into DC;
the second end of the first DC/DC converter is connected with the second end of the second DC/DC converter, the third end of the first DC/DC converter is connected with the third end of the second DC/DC converter, and the second DC/DC converter is used for providing a first output voltage Uo1 and a first control voltage Vcc1;
the first end of the second DC/DC converter is connected with the direct current micro-grid and is used for providing a second output voltage Uo2 and providing a second control voltage Vcc2 for the first DC/DC converter;
the positive polarity end of the first DC/DC converter is connected with the positive polarity end of the second DC/DC converter to serve as an output positive polarity end of the hybrid power supply, and the negative polarity end of the first DC/DC converter is connected with the negative polarity end of the second DC/DC converter to serve as an output negative polarity end of the hybrid power supply.
Specifically, as shown in fig. 1, the ac/dc micro-grid hybrid power supply provided by the embodiment of the present invention is powered by two paths of ac micro-grid and dc micro-grid, and outputs the required isolated dc voltage. The AC micro-grid voltage is converted into direct-current voltage through the AC/DC converter and then is input into the first DC/DC converter, and the first DC/DC converter can output voltage required by a load when working normally. The direct current micro-grid voltage is directly input into the second DC/DC converter, and the second DC/DC converter can also output the voltage required by the load when working normally. The positive ends of the first DC/DC converter and the second DC/DC converter are directly connected and serve as the positive output end of the whole hybrid power supply; the negative polarity end of the first DC/DC converter and the second DC/DC converter are directly connected to be used as the output negative polarity end of the whole hybrid power supply. The first DC/DC converter provides a path of first control voltage Vcc1 for a second PWM control circuit of the second DC/DC converter; the second DC/DC converter provides a path of second control voltage Vcc2 to the first PWM control circuit of the first DC/DC converter.
Assume that the hybrid power supply requires an output voltage Uo.
After the system is powered on, if only the alternating current micro-grid voltage is normal, the first DC/DC converter works and outputs a voltage Uo1, and the second DC/DC converter does not work. If only the direct current microgrid voltage is normal, the second DC/DC converter will operate and output a voltage Uo2, and the first DC/DC converter will not operate. Due to the variability of device parameters, although Uo, uo1, uo2 are very close, there is always variability.
After the system is electrified, if the voltages of the alternating current micro-grid and the direct current micro-grid are normal, the first DC/DC converter and the second DC/DC converter work, as Uo1 and Uo2 are not strictly equal, if Uo1> Uo2, after the output voltage of the hybrid power supply reaches Uo2, as the output voltage of the first DC/DC converter does not reach Uo1 yet, the internal PWM control signal of the first DC/DC converter is kept, so that the output voltage is continuously increased. Meanwhile, since the output voltage of the second DC/DC converter is already greater than Uo2, the PWM control signal inside the second DC/DC converter will be blocked, and thus the second DC/DC converter stops operating. Thereafter, the first DC/DC converter continues to operate until the output voltage reaches Uo1 and remains in an operating state, continuously supplying power to the load, while the first DC/DC converter also maintains the normal first control voltage Vcc1 supplied to the second PWM control circuit of the second DC/DC converter. The second PWM control circuit of the second DC/DC converter is not powered down although it is stopped.
If at a certain moment, the AC micro-grid breaks down, the first PWM control circuit of the first DC/DC converter automatically increases the duty ratio of the first PWM control signal to the maximum value, but the output voltage cannot be maintained at Uo1 and gradually decreases because the main circuit is powered down, and after the output voltage is lower than Uo2, the second PWM control circuit of the second DC/DC converter is always in a non-powered down state and the feedback voltage is lower than a given voltage, so that the second PWM control circuit starts to adjust and increases the duty ratio of the second PWM control signal, thereby controlling the output voltage to be equal to Uo2. The whole regulating process does not need to restart the second PWM control circuit in the second DC/DC converter, so the response speed is very fast, thereby ensuring that the fluctuation of the output voltage is in a normal range and realizing seamless switching.
When the AC micro-grid fault is eliminated and the voltage is recovered, the first PWM control circuit of the first DC/DC converter automatically adjusts the output voltage to Uo1, and the second DC/DC converter is out of operation.
If Uo1 is less than Uo2, the alternating current micro-grid voltage and the direct current micro-grid voltage are exchanged in the process, the direct current micro-grid is preferentially used in normal operation, and when the direct current micro-grid fails, the alternating current micro-grid is seamlessly switched to provide an auxiliary power supply. And after the direct-current micro-grid is recovered, the direct-current micro-grid is seamlessly switched to the direct-current micro-grid.
The difference between Uo1 and Uo2 can be automatically realized by using parameters of the device, and can also be set in a control circuit according to the power supply priority of the AC/DC micro-grid. The path with the higher output voltage will be used preferentially.
The AC/DC micro-grid hybrid power supply provided by the invention realizes seamless switching between the DC micro-grid and the AC micro-grid through the mutual power supply of the two DC/DC converters and the automatic start operation of the control loop, reduces the system loss and improves the power supply efficiency.
Example 2:
this embodiment is substantially the same as embodiment 1, and for brevity of description, in the description of this embodiment, the same technical features as embodiment 1 will not be described, and only the differences between this embodiment and embodiment 1 will be described.
Fig. 2 is a circuit diagram of an ac/dc micro-grid hybrid power supply according to an embodiment of the present invention, as shown in fig. 2, and an embodiment of the present invention provides an ac/dc micro-grid hybrid power supply.
Further, the AC/DC converter comprises a rectifier bridge circuit, a starting current limiting resistor and a filter capacitor circuit;
the alternating current provided by the alternating current micro-grid is converted into direct current after sequentially passing through the rectifier bridge circuit, the starting current limiting resistor and the filter capacitor circuit.
Further, the first DC/DC converter comprises a first power conversion main circuit, a first feedback regulation circuit and a first PWM control circuit;
one end of the first PWM control circuit is connected with the first feedback regulating circuit, the other end of the first PWM control circuit is connected with the primary side of the first power conversion main circuit, one end of the first feedback regulating circuit is connected with the first PWM control circuit, and the other end of the first feedback regulating circuit is connected with the secondary side of the first power conversion main circuit;
the first feedback regulating circuit is used for detecting the conversion amount of the first output voltage Uo1, the first PWM control circuit is used for regulating a first PWM control signal output by the first feedback regulating circuit according to the conversion amount of the first output voltage Uo1, and the first power conversion main circuit is used for regulating the first output voltage Uo1 according to the first PWM control signal.
Further, the first power conversion main circuit includes a first transformer;
the first transformer includes a first auxiliary winding that supplies power to the first PWM control circuit and a second auxiliary winding that provides a first control voltage Vcc1 for the second DC/DC converter.
Further, the first PWM control circuit and the first feedback regulation circuit are connected through a first isolation device.
The first isolation device may be a photocoupler, a magnetic isolation device, or other isolation devices with the same function. In practice, different isolation devices may be selected as appropriate.
Further, the second DC/DC converter comprises a second power conversion main circuit, a second feedback regulating circuit and a second PWM control circuit;
one end of the second PWM control circuit is connected with the second feedback regulating circuit, the other end of the second PWM control circuit is connected with the primary side of the second power conversion main circuit, one end of the second feedback regulating circuit is connected with the second PWM control circuit, and the other end of the second feedback regulating circuit is connected with the secondary side of the second power conversion main circuit;
the second feedback regulating circuit is used for detecting the conversion amount of the second output voltage Uo2, the second PWM control circuit is used for regulating a second PWM control signal output by the second feedback regulating circuit according to the conversion amount of the second output voltage Uo2, and the second power conversion main circuit regulates the second output voltage Uo2 according to the second PWM control signal.
Further, the second power conversion main circuit includes a second transformer;
the second transformer includes a third auxiliary winding that supplies the second PWM control circuit and a fourth auxiliary winding that provides the second control voltage Vcc2 for the first DC/DC converter.
Further, the second PWM control circuit and the second feedback regulation circuit are connected through a second isolation device.
The second isolation device may be a photocoupler, a magnetic isolation device, or other isolation devices with the same function. In practice, different isolation devices may be selected as appropriate.
Specifically, ac microgrid voltage PhaseA, phaseB and PhaseC are input to rectifier bridges composed of D3, D4, D5, D8, D9, and D10 via fuses F1, F2, and F3. After the current limiting resistor NTC1 is started, the capacitors C1, C2, C5 and C6 support the DC bus voltage with smaller fluctuation. And then passes through a first power conversion main circuit consisting of a transformer T1, a power field effect transistor Q1, a diode D6 on the secondary side and capacitors C3 and C4. The control of the first power conversion main circuit is completed by a first feedback regulating circuit connected with the secondary side of the first power conversion main circuit and a first PWM control circuit connected with the primary side of the first power conversion main circuit, wherein a main control chip of the first feedback regulating circuit is U2 (TL 431), and a main control chip of the first PWM control circuit is U1 (UCC 38C 45). The primary side and secondary side isolation is realized through a photoelectric coupler U3. The amplitude of the output voltage is controlled by resistors R18 and R25. Uo1= (2.5V/R25) × (r18+r25). When the first power conversion main circuit works normally, if the first feedback regulating circuit detects that the output voltage deviates from Uo1, the U2 (TL 431) can automatically regulate the K end voltage, so that the current passing between the 1 pin, the 2 pin, the 4 pin and the 3 pin of the optocoupler U3 is changed, the 1 pin voltage of the U1 (UCC 38C 45) is changed, the duty ratio of the first PWM control signal output by the 6 th pin of the U1 (UCC 38C 45) is finally changed, the energy transferred from the first power conversion main circuit to the secondary side is regulated, and the output voltage is regulated towards the direction of reducing errors.
The positive end Udc+ and the negative end Udc-of the direct current micro-grid voltage Udc respectively pass through a fuse tube F4 and a fuse tube F5 and an input capacitor C18 after a current limiting resistor NTC2 is started to become the input direct current bus voltage of the second power conversion main circuit. The second power conversion main circuit consists of a transformer T2, a power field effect transistor Q2, a diode D17 on the secondary side and capacitors C16 and C17. The control of the second power conversion main circuit is completed by a second feedback regulating circuit connected with the secondary side of the second power conversion main circuit and a second PWM control circuit connected with the primary side of the second power conversion main circuit, wherein the main control chip of the second feedback regulating circuit is U5 (TL 431), and the main control chip of the second PWM control circuit is U4 (UCC 38C 45). The primary side and secondary side isolation is realized through a photoelectric coupler U6. The amplitude of the output voltage is controlled by resistors R38 and R45. Uo2= (2.5V/R45) × (r38+r45). When the second power conversion main circuit works normally, if the second feedback regulating circuit detects that the output voltage deviates from Uo2, the voltage of the K end of the second power conversion main circuit is automatically regulated by U5 (TL 431), so that the current passing between pins 1 and 2 and pins 4 and 3 of an optocoupler U6 is changed, the voltage of pin 1 of U4 (UCC 38C 45) is changed, the duty ratio of a second PWM control signal output by pin 6 of U4 (UCC 38C 45) is finally influenced, and the energy transferred from the second power conversion main circuit to the secondary side is regulated, so that the output voltage is regulated towards the direction of reducing errors.
When the first power conversion main circuit works normally, the windings between the pins 9 and 10 of the transformer T1 can provide Vcc for the main control chip U1 (UCC 38C 45) through the diode D14, the resistors R19, R20, R22, ZD2 and C15 and the diode D13; the winding between pins 11, 12 of transformer T1 provides a first control voltage Vcc1 to a main control chip U4 (UCC 38C 45) via diode D2, resistors R39, R40, R42, ZD4, C27, and diode D21.
When the second power conversion main circuit works normally, the windings between the pins 9 and 10 of the transformer T2 can provide Vcc for the main control chip U4 (UCC 38C 45) through the diode D22, the resistors R39, R40, R42, ZD4 and C27 and the diode D21; the windings between pins 11, 12 of transformer T2 may provide a second control voltage Vcc2 to the main control chip U1 (UCC 38C 45) via diode D15, resistors R19, R20, R22, ZD2, C15, diode D13.
If the hybrid power supply is only connected with the AC micro-grid voltage, but the DC micro-grid voltage is not connected with the AC micro-grid voltage, the AC micro-grid voltage charges the capacitor C12 through the rectifier bridge, the diode D1 and the resistors R12-R17. After the voltage of C12 reaches the starting voltage of U1 (UCC 38C 45), U1 (UCC 38C 45) begins to operate. The secondary side voltage starts to increase until the output voltage reaches Uo1. The first PWM control signal is then output, and the output voltage is maintained at Uo1 at a certain PWM duty cycle. While the winding output voltage between pins 9, 10 of T1 provides the Vcc required for operation for U1 (UCC 38C 45). The winding output voltage between pins 11, 12 of T1 provides the first control voltage Vcc1 required for operation for U4 (UCC 38C 45). However, since the dc microgrid voltage is not connected, the second power conversion main circuit does not output electric energy.
If the hybrid power supply is only connected to the direct current micro-grid voltage, but not connected to the alternating current micro-grid voltage, the direct current micro-grid voltage charges the capacitor C24 through the diode D10 and the resistors R34 to R37, and after the voltage of the capacitor C24 reaches the starting voltage of U4 (UCC 38C 45), the U4 (UCC 38C 45) starts to work. The secondary side voltage starts to increase until the output voltage reaches Uo2, and then a second PWM control signal is output, and the output voltage is maintained to Uo2 at a certain PWM duty cycle. While the winding output voltage between pins 9, 10 of T2 provides the Vcc required for operation for U4 (UCC 38C 45). The winding output voltage between pins 11, 12 of T1 provides the second control voltage Vcc2 required for operation for U1 (UCC 38C 45). However, since the ac microgrid voltage is not connected, the first power conversion main circuit does not output electric power.
If the auxiliary power supply is connected to the AC and DC micro-grid voltages at the same time, the AC micro-grid is preferentially used, namely Uo2< Uo1, and at the beginning stage, both the two power conversion main circuits start to work, and the starting time is determined by the respective charging resistor, capacitor and input voltage. After the C12 voltage reaches the starting voltage of U1 (UCC 38C 45), the first power conversion main circuit starts to work; after the C24 voltage reaches the U4 (UCC 38C 45) start-up voltage, the second power conversion main circuit starts to operate. Thereafter, the voltages of the output capacitances C3, C4, C16, C17 start to increase, and since they are connected in parallel, their voltages are completely equal. When the voltages on these four capacitors reach Uo2, the first power conversion main circuit still continues to operate to increase the output voltage due to Uo2< Uo1, but since the output voltage is greater than Uo 2= (2.5V/R45) × (r38+r45), more current is injected into C25, C26 through R38, so that the K terminal voltage of U5 (TL 431) decreases, the currents in pins 1, 2, 4, 3 in U6 increase, the voltage in pin 1 of U4 decreases, and the duty cycle of the 6-pin output second PWM control signal decreases and eventually disappears, so that the second power conversion main circuit stops operating. The windings between pins 9, 10 and pins 11, 12 of T2 no longer output power. However, since the first power conversion main circuit is operating normally at this time, the winding between the pins 11, 12 of T1 can output electric energy to maintain the first control voltage Vcc1 required for the normal operation of U4, so that U4 can respond quickly to the change in the secondary side voltage. The output of the whole power supply eventually stabilizes at uo1= (2.5V/R25) (r18+r25) set by U2, R18 and R25.
Thereafter, if the ac microgrid fails and the dc microgrid remains normal, the output voltage will not remain at Uo1 and gradually drop, and after the second feedback regulation circuit detects that the output voltage is below Uo2, U5 (TL 431) begins to regulate, the voltage across C26 increases, the potential of pin K of U5 increases, and the current passing between pins 1, 2 and 4, 3 of U6 decreases. Since the voltage of pin 1 of U4 increases and Vcc of U4 is always in the normal range, U4 can immediately increase the duty ratio of the output of the second PWM control signal, and the second power conversion main circuit starts to operate, controlling the output voltage of the entire power supply to uo2= (2.5V/R45) ×r38+r45 set by U5, R38, and R45. Thereby providing auxiliary power from the dc microgrid. In this case, since the second power conversion main circuit is in an operating state, the winding between the pins 11, 12 of the transformer T2 can output electric power to maintain the second control voltage Vcc2 required for the normal operation of the U1, so that the output first PWM control signal of the U1 maintains the maximum duty ratio.
When the ac microgrid voltage is recovered to be normal, since the second control voltage Vcc2 required for normal operation of U1 is maintained normal and the output first PWM control signal of U1 is maintained at the maximum duty ratio, the first power conversion main circuit immediately starts operation and adjusts the output voltage to uo1= (2.5V/R25) (r18+r25) set by U2, R18 and R25. Meanwhile, as the output voltage is larger than Uo2= (2.5V/R45) = (R38+R45) set by U5, R38 and R45, the second power conversion main circuit stops working, and finally returns to the working state that the AC micro-grid is used for supplying power preferentially when the two micro-grids are normal.
The priority of use of the ac/dc two microgrid voltages may be randomly generated by the parameter differences of U2, R18, R25, U5, R38 and R45. Or may be manually set by selecting parameters. The setting method may be to set the output voltage of the inverter having a higher priority to be slightly higher than the output voltage of the inverter having a lower priority.
The AC/DC micro-grid hybrid power supply provided by the invention realizes seamless switching between the DC micro-grid and the AC micro-grid through the mutual power supply of the two DC/DC converters and the automatic start operation of the control loop, reduces the system loss and improves the power supply efficiency.
Claims (7)
1. An ac/dc micro-grid hybrid power supply, comprising:
an AC/DC converter, a first DC/DC converter, and a second DC/DC converter;
the first end of the AC/DC converter is connected with the AC micro-grid, and the second end of the AC/DC converter is connected with the first end of the first DC/DC converter and is used for converting the AC provided by the AC micro-grid into DC;
the second end of the first DC/DC converter is connected with the second end of the second DC/DC converter, the third end of the first DC/DC converter is connected with the third end of the second DC/DC converter, and the second DC/DC converter is used for providing a first output voltage Uo1 and a first control voltage Vcc1;
the first end of the second DC/DC converter is connected with the direct current micro-grid and is used for providing a second output voltage Uo2 and providing a second control voltage Vcc2 for the first DC/DC converter;
the positive polarity end of the first DC/DC converter is connected with the positive polarity end of the second DC/DC converter and is used as an output positive polarity end of the hybrid power supply, and the negative polarity end of the first DC/DC converter is connected with the negative polarity end of the second DC/DC converter and is used as an output negative polarity end of the hybrid power supply;
the first DC/DC converter comprises a first power conversion main circuit, a first feedback regulating circuit and a first PWM control circuit;
one end of the first PWM control circuit is connected with the first feedback regulating circuit, the other end of the first PWM control circuit is connected with the primary side of the first power conversion main circuit, one end of the first feedback regulating circuit is connected with the first PWM control circuit, and the other end of the first feedback regulating circuit is connected with the secondary side of the first power conversion main circuit;
the second DC/DC converter comprises a second power conversion main circuit, a second feedback regulating circuit and a second PWM control circuit;
one end of the second PWM control circuit is connected with the second feedback regulating circuit, the other end of the second PWM control circuit is connected with the primary side of the second power conversion main circuit, one end of the second feedback regulating circuit is connected with the second PWM control circuit, and the other end of the second feedback regulating circuit is connected with the secondary side of the second power conversion main circuit;
the second feedback regulating circuit is used for detecting the conversion amount of the second output voltage Uo2, the second PWM control circuit is used for regulating a second PWM control signal output by the second feedback regulating circuit according to the conversion amount of the second output voltage Uo2, and the second power conversion main circuit regulates the second output voltage Uo2 according to the second PWM control signal.
2. The hybrid power supply of claim 1, wherein the AC/DC converter comprises a rectifier bridge circuit, a start-up current limiting resistor, and a filter capacitor circuit;
the alternating current provided by the alternating current micro-grid is converted into direct current after sequentially passing through the rectifier bridge circuit, the starting current limiting resistor and the filter capacitor circuit.
3. The hybrid power supply of claim 1, wherein the power supply comprises,
the first feedback regulating circuit is used for detecting the conversion amount of the first output voltage Uo1, the first PWM control circuit is used for regulating a first PWM control signal output by the first feedback regulating circuit according to the conversion amount of the first output voltage Uo1, and the first power conversion main circuit is used for regulating the first output voltage Uo1 according to the first PWM control signal.
4. The hybrid power supply of claim 3, wherein the first power conversion main circuit comprises a first transformer;
the first transformer includes a first auxiliary winding that supplies power to the first PWM control circuit and a second auxiliary winding that provides a first control voltage Vcc1 for the second DC/DC converter.
5. A hybrid power supply as claimed in claim 3, wherein the first PWM control circuit and the first feedback regulation circuit are connected by a first isolation device.
6. The hybrid power supply of claim 1, wherein the second power conversion main circuit comprises a second transformer;
the second transformer includes a third auxiliary winding that supplies the second PWM control circuit and a fourth auxiliary winding that provides the second control voltage Vcc2 for the first DC/DC converter.
7. The hybrid power supply of claim 1, wherein the second PWM control circuit and the second feedback regulation circuit are connected by a second isolation device.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101150260A (en) * | 2006-09-19 | 2008-03-26 | 宝山钢铁股份有限公司 | Power supply switch and anti-jump control method and device |
| CN101197540A (en) * | 2007-12-11 | 2008-06-11 | 艾默生网络能源有限公司 | Dc converter |
| CN101345478A (en) * | 2007-07-12 | 2009-01-14 | 半导体元件工业有限责任公司 | Power supply controller and method therefor |
| CN101364767A (en) * | 2007-08-08 | 2009-02-11 | 株式会社瑞萨科技 | Semiconductor circuit and switching power supply apparatus |
| CN101577490A (en) * | 2008-05-08 | 2009-11-11 | 通用汽车环球科技运作公司 | Systems and methods for multiple source power conversion |
| CN101582643A (en) * | 2008-05-14 | 2009-11-18 | 富士电机电子技术株式会社 | Switching power supply |
-
2017
- 2017-10-31 CN CN201711047558.5A patent/CN107706917B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101150260A (en) * | 2006-09-19 | 2008-03-26 | 宝山钢铁股份有限公司 | Power supply switch and anti-jump control method and device |
| CN101345478A (en) * | 2007-07-12 | 2009-01-14 | 半导体元件工业有限责任公司 | Power supply controller and method therefor |
| CN101364767A (en) * | 2007-08-08 | 2009-02-11 | 株式会社瑞萨科技 | Semiconductor circuit and switching power supply apparatus |
| CN101197540A (en) * | 2007-12-11 | 2008-06-11 | 艾默生网络能源有限公司 | Dc converter |
| CN101577490A (en) * | 2008-05-08 | 2009-11-11 | 通用汽车环球科技运作公司 | Systems and methods for multiple source power conversion |
| CN101582643A (en) * | 2008-05-14 | 2009-11-18 | 富士电机电子技术株式会社 | Switching power supply |
Non-Patent Citations (2)
| Title |
|---|
| Study of Vehicle Power Supply with AC and DC Mixed Output;Xing Wu Yang,et al;《Advanced Materials Research》(第3247期);1225-1229 * |
| 三电平DC/AC电源转换技术研究;李瑞生等;《电力系统保护与控制》;第44卷(第20期);24-30 * |
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Application publication date: 20180216 Assignee: Yantai Jingwei Electronic Co.,Ltd. Assignor: Beijing University of Civil Engineering and Architecture Contract record no.: X2023980041476 Denomination of invention: A Hybrid AC/DC Microgrid Power Supply Granted publication date: 20230721 License type: Common License Record date: 20230908 |