CN116780734B - DC power supply parallel control circuit based on extremum control and control method thereof - Google Patents
DC power supply parallel control circuit based on extremum control and control method thereof Download PDFInfo
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
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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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
Abstract
The invention relates to the technical field of power supply control circuits, in particular to a direct-current power supply parallel control circuit based on extremum control and a control method thereof, wherein the parallel control circuit comprises a plurality of direct-current power supply modules which are connected in parallel, and the two ends of the direct-current power supply modules are respectively provided with an output positive end Vout n + and output negative terminal Vout n -; wherein, the output positive terminals Vout of the plurality of DC power supply modules n The positive terminals Vout+ are connected in parallel and combined into output positive terminals Vout+ which are connected with a load, and the negative terminals Vout of the DC power supply modules are respectively output n -maintaining a parallel connection after passing through the respective module current sampling shunts, respectively, a plurality of output negative terminals Vout n Merging into the output negative terminal Vout-and into the load. The invention can realize current sharing when the parallel operation of the multiple power supply modules can be completed by the universal operational amplifier without depending on an application specific integrated circuit.
Description
Technical Field
The invention relates to the technical field of power supply control circuits, in particular to a direct-current power supply parallel control circuit based on extremum control and a control method thereof.
Background
High demands for electrical energy are often involved, such as large machinery in industrial production, power plants, grid transmission systems, medical equipment, mining equipment, marine power systems, etc. In these applications, a reliable and efficient power supply is needed that provides high or ultra-high power. In order to meet the requirements of high-power and ultra-high-power supply, power supply technology and system integration technology are continuously developed.
In the high-power and ultra-high-power supply occasions, it is common to use a plurality of power supplies in parallel. By connecting multiple power supplies in parallel, their output currents and powers can be added to achieve higher output capability. This is important for some applications where the demand for electrical energy is high, such as industrial production facilities, power grid transmission, medical equipment, etc. The parallel use of multiple power supplies can also provide a backup power supply and a redundant design to ensure that the system can still work properly when one of the power supplies fails.
However, the existing parallel connection mode has a plurality of defects and shortcomings, including the following aspects:
1. no-load voltage is virtually high: when multiple power supplies are connected in parallel, if there is a difference in their output voltages, some of the power supplies may be in a light load or no load state, resulting in a problem that no load voltage is virtually high.
2. Dynamic response is poor: the dynamic response of the parallel power supply system is affected by the response speed of each power supply and the control loop. If the response speed of some power supplies is slow or the control loop is unstable, the dynamic response of the overall system may be affected.
3. The module current is not controlled at start-up: at start-up, if multiple power supplies are simultaneously put into operation, their currents may not be well controlled and current spikes or fluctuations may occur. This may cause instability to the system and load.
4. The voltage stabilizing precision is poor: when a plurality of power supplies are used in parallel, there may be problems in stability and accuracy of the output voltage due to differences in matching between the power supplies, error accumulation in the control system, and the like.
In summary, the conventional parallel connection method can seriously reduce the output characteristic index of the output power supply after use.
Disclosure of Invention
Accordingly, it is necessary to provide a dc power supply parallel control circuit based on extremum control and a control method thereof.
In a first aspect, the present invention provides an extremum control-based dc power supply parallel control circuit, where the parallel control circuit includes a plurality of dc power supply modules connected in parallel, and two ends of the dc power supply modules are respectively an output positive end Vout n + and output negative terminal Vout n -；
Wherein, the output positive terminals Vout of the plurality of DC power supply modules n The positive terminals Vout+ are connected in parallel and combined into output positive terminals Vout+ which are connected with a load, and the negative terminals Vout of the DC power supply modules are respectively output n -maintaining a parallel connection after passing through the respective module current sampling shunts, respectively, a plurality of output negative terminals Vout n -merging into the output negative terminal Vout-and into the load; the plurality of direct current power supply modules are kept connected through bus current signals Vcs-bus.
In one embodiment, a dc power module includes: the current-sharing circuit comprises a module voltage sampling unit, a module current sampling shunt, a current gain amplifier, a current bus buffer amplifier, a current local buffer amplifier, a current-sharing error amplifier and a current correction circuit.
Wherein, one end of the module voltage sampling unit and the output positive end Vout n The other end of the module voltage sampling unit is connected with one end of the module current sampling shunt, the positive phase input end of the current gain amplifier and the output negative end Vout respectively n The current-source voltage sampling unit is connected with the current correction circuit, the sampling voltage Vsen is input to the current correction circuit by the module voltage sampling unit, the other end of the module current sampling shunt is connected with the negative phase input end of the current gain amplifier, the output end of the current gain amplifier is connected with the positive phase input end of the current bus buffer amplifier, the output end of the current bus buffer amplifier is connected with the positive phase input end of the current local buffer amplifier, the output end of the current local buffer amplifier is connected with the negative phase input end of the current sharing error amplifier, the positive phase input end of the current sharing error amplifier outputs a bus current signal Vcs-bus, the output end of the current sharing error amplifier is connected with the other end of the current correction circuit, and the current correction circuit is connected with the output negative end Vout n -parallel connection.
In one embodiment, the module voltage sampling unit is configured to sample and measure the output current and the output voltage, and output a sampling voltage Vsen.
In one embodiment, the module current sampling shunt is configured to sample and shunt an output current of the local dc power module and convert the output current into a voltage signal.
In one embodiment, the current gain amplifier has a closed loop gain effect of 50-100 times for amplifying a weak small current or voltage signal split by the module current sampling splitter to 0-10V.
In one embodiment, the gain of the current bus buffer amplifier is 1, and the current bus buffer amplifier is used for combining the voltage signal amplified by the gain into a bus current signal Vcs-bus through a diode D1 and voltage signals with the same attribute in other direct current power supply modules;
the bus is used as a connecting line for transmitting bus current signals Vcs-bus among a plurality of direct current power supply modules, and the diode D1 is used for enabling the bus to only select the maximum value of voltages on all direct current power supply module channels as an extreme value of the parallel control circuit.
In one embodiment, the gain of the current local buffer amplifier is 1, and the current local buffer amplifier is used for generating the current reference signal Vcs-ref of the local dc power supply module by using impedance transformation on the voltage signal amplified and output by the current gain amplifier.
In one embodiment, the current equalizing error amplifier comprises a non-inverting input end, an inverting input end and an output end, wherein a bus current signal Vcs-bus is input through the non-inverting input end, and a current reference signal Vcs-ref is input through the inverting input end;
when the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current sharing error amplifier obtains a positive voltage signal Vs-adj, and the positive voltage signal Vs-adj is input into a current correction circuit for next stage processing to correct the output voltage of the local direct current power supply module;
when the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier is negative, and the diode D2 is isolated to terminate the output.
In one embodiment, the current correction circuit includes a photo coupler OC1 and a voltage sampling shunt resistor Rvb1, where the positive voltage signal Vs-adj drives the photo coupler OC1, and the output collector of the photo coupler OC1 shunts the sampling voltage Vsen of the voltage loop of the local dc power module through the resistor Rvb1, so that the component proportion of the sampling voltage Vsen is reduced, and the voltage negative feedback system of the local dc power module makes the final output current trend toward the current level of the dc power module with the maximum current value, so as to achieve the current sharing purpose of the dc power module in parallel control.
In a second aspect, the present invention also provides a control method for a dc power supply parallel control circuit based on extremum control, the control method comprising the steps of:
s1, sampling and splitting output current of a local direct current power supply module by using a module current sampling splitter, converting the output current into a voltage signal and inputting the voltage signal to a current gain amplifier;
s2, amplifying an input voltage signal to 0-10V by a current gain amplifier;
s3, the current bus buffer amplifier acquires an amplified voltage signal, and combines the voltage signal with voltage signals with the same attribute in other direct current power supply modules to form a bus current signal Vcs-bus;
s4, acquiring a voltage signal amplified by a current gain amplifier by using a current local buffer amplifier, and generating a current reference signal Vcs-ref of the local direct current power supply module by using impedance transformation;
s5, judging the numerical value relation between the bus current signal Vcs-bus and the current reference signal Vcs-ref by using a current sharing error amplifier;
s6, if the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current sharing error amplifier obtains a positive voltage signal Vs-adj, and step S8 is executed to carry out next stage processing to realize the correction of the output voltage of the local direct current power supply module;
s7, if the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier is negative, the output of the voltage signal is blocked, and the response is terminated;
s8, driving the current correction circuit to operate by utilizing the positive voltage signal Vs-adj, reducing the component proportion of the sampling voltage Vsen in the module voltage sampling unit, and adjusting the current level of the local direct current power supply module to realize current sharing of all the direct current power supply modules in the parallel control circuit.
The beneficial effects of the invention are as follows:
1. through the structure of the direct current power supply parallel control circuit based on extremum control, current sharing can be realized when a plurality of power supply modules are in parallel operation only by a general operational amplifier without depending on an application-specific integrated circuit, element selection is more flexible, a power supply system capable of meeting actual power requirements is easier to design, and the circuit structure is simple and practical and meets most application scenes; meanwhile, the used elements are general materials, and the factors of shortage of goods sources and unstable price do not exist, so that the design cost and the operation cost of the power supply system are greatly reduced.
2. The current balance distribution among the parallel power supply modules is realized through module voltage sampling and current balance control, so that the overload or light load of certain modules is avoided, and the stability and efficiency of the system are improved; secondly, the control mechanism of the current correction circuit can accurately adjust current distribution, so that balanced power supply of a load is realized, and the efficiency and performance index of the system are improved; in addition, through sampling and protection of module voltage, the power supply module is ensured to work in a safe range, and stable operation of the whole system and equipment is protected, so that the parallel circuit structure is ensured to realize functions of current balance, load balance, system protection and the like, and the power supply module has important application value and beneficial effect on high-power and ultra-high-power supply occasions.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:
fig. 1 is a schematic circuit diagram of a dc power supply parallel control circuit based on extremum control according to an embodiment of the present invention;
FIG. 2 is an enlarged view at A in FIG. 1;
FIG. 3 is an enlarged view of FIG. 1 at B;
fig. 4 is a flowchart of a control method of a dc power supply parallel control circuit based on extremum control according to an embodiment of the present invention.
Reference numerals: 1. a module voltage sampling unit; 2. a module current sampling shunt; 3. a current gain amplifier; 4. a current bus buffer amplifier; 5. a current local buffer amplifier; 6. a current equalizing error amplifier; 7. a current correction circuit.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1-3, a parallel control circuit for a dc power supply based on extremum control is provided, the parallel control circuit includes a plurality of dc power supply modules connected in parallel, and two ends of the dc power supply modules are respectively an output positive end Vout n + and output negative terminal Vout n -。
Wherein, the output positive terminals Vout of the plurality of DC power supply modules n The positive terminals Vout+ are connected in parallel and combined into output positive terminals Vout+ which are connected with a load, and the negative terminals Vout of the DC power supply modules are respectively output n -maintaining a parallel connection after passing through the respective module current sampling shunts, respectively, a plurality of output negative terminals Vout n -merging into the output negative terminal Vout-and into the load; the plurality of direct current power supply modules are kept connected through bus current signals Vcs-bus.
Specifically, the direct current power supply module and the port connection thereof in the invention comprise the following aspects:
direct current power supply module: a plurality of dc power modules, each module having an output positive terminal voutn+ and an output negative terminal Voutn-. The modules may be independent power supply units providing greater power output capability through parallel connection.
Output positive end combination: the output positive ends Voutn+ of the plurality of direct current power supply modules are combined into an output positive end Vout+ through parallel connection, so that output voltages of the plurality of modules can be overlapped and supplied to a load for use.
Output negative terminal combination: the output negative terminals Voutn of the direct current power supply modules are connected in parallel after passing through the corresponding module current sampling current splitters, and the output negative terminals Voutn are combined into an output negative terminal Vout-, so that the output negative terminals of the modules can be connected to the same load.
Bus current signal Vcs-bus: the plurality of direct current power supply modules are kept connected through bus current signals Vcs-bus, and the signals are used for detecting and transmitting information of current balance so as to realize balanced distribution of current among parallel modules.
The invention adopts the parallel control circuit structure to connect a plurality of direct current power supply modules in parallel, combines the output voltages of the direct current power supply modules into an output positive end, and connects the output negative end to the same load. By detecting and transmitting bus current signals, the current can be distributed uniformly among the parallel modules. The direct current power supply parallel control circuit based on extremum control can improve the power output capacity of the system and keep current balance, so that the stability and reliability of the system are improved.
In the description of the present invention, a dc power module includes: the current-sharing circuit comprises a module voltage sampling unit 1, a module current sampling shunt 2, a current gain amplifier 3, a current bus buffer amplifier 4, a current local buffer amplifier 5, a current-sharing error amplifier 6 and a current correction circuit 7.
As shown in fig. 1, a module voltage sampling unit 1 has one end and an output positive end Vout n The other end of the module voltage sampling unit 1 is connected with one end of the module current sampling shunt 2, the positive phase input end of the current gain amplifier 3 and the output negative end Vout respectively n The module voltage sampling unit 1 inputs the sampling voltage Vsen to the current correction circuit 7, the other end of the module current sampling shunt 2 is connected with the negative phase input end of the current gain amplifier 3, the output end of the current gain amplifier 3 is connected with the positive phase input end of the current bus buffer amplifier 4, the output end of the current bus buffer amplifier 4 is connected with the positive phase input end of the current sharing error amplifier 6, the positive phase input end of the current bus buffer amplifier 4 is connected with the positive phase input end of the current local buffer amplifier 5, the output end of the current local buffer amplifier 5 is connected with the negative phase input end of the current sharing error amplifier 6, the positive phase input end of the current sharing error amplifier 6 outputs a bus current signal Vcs-bus, the output end of the current sharing error amplifier 6 is connected with the other end of the current correction circuit 7, and the current correction circuit 7 is connected with the negative output end Vout n -parallel connection.
In the description of the present invention, the module voltage sampling unit 1 is used for sampling and measuring an output current and an output voltage, and outputting a sampling voltage Vsen.
As shown in fig. 2, the module voltage sampling unit 1 is composed of a resistor Rva and a resistor Rvb to form a voltage sample of the dc power module as a part of the voltage feedback. The resistor Rva and the resistor Rvb function to divide the output voltage of the dc power module into a lower voltage value for sampling and measurement. In general, the resistor Rva and the resistor Rvb form a voltage divider, and by adjusting the proportional relationship of the resistors, the output voltage can be reduced to a range suitable for sampling and measurement. The sampling voltage Vsen is a voltage signal output from the module voltage sampling unit 1, which can be used to feedback and control the output voltage of the power module. By measuring and feeding back the sampling voltage Vsen, voltage stability control and protection of the power supply module can be achieved.
In the description of the present invention, the module current sampling shunt 2 is used for sampling and shunting the output current of the local dc power supply module, and converting the output current into a voltage signal.
As shown in fig. 2, the module current sampling shunt 2 is composed of a resistor RCS, and is responsible for converting current into a voltage signal for sampling and shunting the output current of the dc power supply module. The resistor RCS plays a role in shunt in the circuit, and the output current of the direct-current power supply module is shunted into lower current through the resistor RCS so as to be converted into a voltage signal. The conversion is based on ohm's law, and the voltage across the resistor can be obtained according to the current passing through the resistor and the resistance of the resistor itself. The output current of the dc power supply module is converted into a voltage signal by means of a resistor RCS in the module current sampling shunt 2, which signal can be measured and fed back. Therefore, the output current can be sampled and monitored, and further the current stability control, protection and adjustment of the power supply module are realized.
In the description of the present invention, the closed loop gain effect of the current gain amplifier 3 is 50-100 times for amplifying a weak small current or voltage signal split through the module current sampling splitter 2 to 0-10V.
As shown in fig. 2, the current gain amplifier 3 is a differential gain amplifier composed of an operational amplifier OP1 and its peripheral resistor, the closed loop gain is set to be 50-100 times, and the weak current/voltage signal ratio of the preceding current divider is amplified to 0-10V.
In the description of the present invention, the gain of the current bus buffer amplifier 4 is 1, so that the voltage signal after gain amplification is combined into the bus current signal Vcs-bus through the diode D1 and the voltage signals with the same attribute as those in other dc power supply modules.
The bus is used as a connecting line for transmitting bus current signals Vcs-bus among a plurality of direct current power supply modules, and the diode D1 is used for enabling the bus to only select the maximum value of voltages on all direct current power supply module channels as an extreme value of the parallel control circuit.
As shown in fig. 2, the current bus buffer amplifier 4 is composed of an operational amplifier OP2 and has a bus current buffer with a gain of 1, and the voltage signal of 0-10V, which has been amplified before and is proportional to the output current, is synthesized by a diode D1 and the signal of the same attribute of other dc power supply modules to be used as a common bus current signal Vcs-bus, and the function of the diode D1 is to make the bus select only the maximum value, i.e. "extremum", of the voltages on the channels of the modules.
In the description of the present invention, the gain of the current local buffer amplifier 5 is 1, and the current reference signal Vcs-ref of the local dc power supply module is generated by using impedance transformation from the voltage signal amplified and output by the current gain amplifier 3.
As shown in fig. 2, the current local buffer amplifier 5 is a local buffer with the same gain as 1 and composed of an operational amplifier OP3, and the 0-10V signal output by the gain amplifier is used as a current reference signal Vcs-ref of the module after being subjected to impedance transformation.
In the description of the present invention, the current sharing error amplifier 6 includes a non-inverting input terminal, an inverting input terminal, and an output terminal, and the bus current signal Vcs-bus is input through the non-inverting input terminal, and the current reference signal Vcs-ref is input through the inverting input terminal.
When the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current sharing error amplifier 6 obtains a positive voltage signal Vs-adj, and the positive voltage signal Vs-adj is input into the current correction circuit 7 for next stage processing to correct the output voltage of the local direct current power supply module.
When the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier 6 is negative, and the diode D2 is isolated to terminate the output.
As shown in fig. 2, the current equalizing error amplifier 6 is a current equalizing error amplifier composed of an operational amplifier OP4, a bus current signal Vcs-bus and a current reference signal Vcs-ref of a local dc power supply module are respectively sent to a non-inverting input terminal and an inverting input terminal of the error amplifier, when the local reference value is lower than the bus current voltage value, the output terminal of the error amplifier obtains a positive voltage signal Vs-adj, and after entering the next stage of processing, the output voltage of the current module is corrected to make the output current rise towards the target value (the module current of the current maximum value); when the local reference voltage is higher than the bus current voltage value, the error amplifier output is negative, and is isolated by the diode D2, and the next stage of correction circuit does not respond.
Because the current equalizing circuit is only used as an auxiliary loop to correct the current of each module, the response speed of the error amplifier of the current equalizing circuit is lower than the loop response of the main voltage error amplifier of the module per se in order to ensure the stable signal of the system, the bandwidth of the current equalizing error amplifier is limited, and the bandwidth limitation is completed by R11 and C3; in addition, a proper amount of bias voltage bias is superimposed on the current reference signal Vcs-ref of the local direct-current power supply module, so that the working current of the module with corrected current is always slightly lower than the maximum value current module by a level, and the possible oscillation caused by a current sharing system due to critical operation is avoided.
In the description of the present invention, the current correction circuit 7 includes a photo coupler OC1 and a voltage sampling shunt resistor Rvb1, where the positive voltage signal Vs-adj drives the photo coupler OC1, and the output collector of the photo coupler OC1 shunts the sampling voltage Vsen of the voltage loop of the local dc power module through the resistor Rvb1, so that the component proportion of the sampling voltage Vsen is reduced, and the voltage negative feedback system of the local dc power module makes the final output current trend toward the current level of the dc power module with the maximum current, so as to achieve the current sharing purpose of the dc power module in parallel control.
As shown in fig. 2, the current correction circuit 7 is composed of a photocoupler OC1 and a voltage sampling shunt resistor Rvb 1. The signal Vs-adj output by the current equalizing error amplifier drives the photoelectric coupler OC1, the output collector of the photoelectric coupler OC1 shunts the voltage sampling voltage Vsen of the voltage loop of the module through Rvb1 to reduce the component of the Vsen proportionally, and the voltage negative feedback system of the direct current power supply module makes corresponding voltage to finally lead the output current of the module to trend towards the current level of the current maximum module to achieve the current equalizing purpose.
Referring to fig. 4, a control method of a dc power supply parallel control circuit based on extremum control includes the following steps:
s1, sampling and splitting output current of a local direct current power supply module by using a module current sampling splitter 2, and converting the output current into a voltage signal to be input to a current gain amplifier 3.
S2, amplifying the input voltage signal to 0-10V by the current gain amplifier 3.
And S3, the current bus buffer amplifier 4 acquires the amplified voltage signal, and combines the voltage signal with the same attribute in other direct current power supply modules to form a bus current signal Vcs-bus.
S4, the voltage signal amplified by the current gain amplifier 3 is obtained by using the current local buffer amplifier 5, and the current reference signal Vcs-ref of the local direct current power supply module is generated by using impedance transformation.
S5, judging the numerical relation between the bus current signal Vcs-bus and the current reference signal Vcs-ref by using the current sharing error amplifier 6.
And S6, if the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current sharing error amplifier 6 obtains a positive voltage signal Vs-adj, and the step S8 is executed to carry out the next stage of processing so as to realize the correction of the output voltage of the local direct current power supply module.
And S7, if the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current sharing error amplifier 6 is negative, the voltage signal output is blocked, and the response is terminated.
S8, driving the current correction circuit 7 to operate by utilizing the positive voltage signal Vs-adj, reducing the component proportion of the sampling voltage Vsen in the module voltage sampling unit 1, and adjusting the current level of the local direct current power supply module to realize the current sharing of all the direct current power supply modules in the parallel control circuit.
In summary, by means of the above technical solution, through the structure of the dc power supply parallel control circuit based on extremum control, current sharing can be achieved when the parallel operation of multiple power supply modules can be completed by only a general operational amplifier without depending on a special integrated circuit, element selection is more flexible, a power supply system capable of meeting actual power requirements is easier to design, and the circuit structure is simple and practical, thereby meeting most application scenarios; meanwhile, the used elements are general materials, and the factors of shortage of goods sources and unstable price do not exist, so that the design cost and the operation cost of the power supply system are greatly reduced. The current balance distribution among the parallel power supply modules is realized through module voltage sampling and current balance control, so that the overload or light load of certain modules is avoided, and the stability and efficiency of the system are improved; secondly, the control mechanism of the current correction circuit can accurately adjust current distribution, so that balanced power supply of a load is realized, and the efficiency and performance index of the system are improved; in addition, through sampling and protection of module voltage, the power supply module is ensured to work in a safe range, and stable operation of the whole system and equipment is protected, so that the parallel circuit structure is ensured to realize functions of current balance, load balance, system protection and the like, and the power supply module has important application value and beneficial effect on high-power and ultra-high-power supply occasions.
It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, these steps are not necessarily performed in order as indicated by the arrows. The steps are not strictly limited in order and may be performed in other orders, unless explicitly stated herein. Moreover, at least some of the steps in the flowcharts of the figures may include a plurality of sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, the order of their execution not necessarily being sequential, but may be performed in turn or alternately with other steps or at least a portion of the other steps or stages.
Claims (7)
1. The direct-current power supply parallel control circuit based on extremum control is characterized by comprising a plurality of direct-current power supply modules which are connected in parallel, wherein two ends of each direct-current power supply module are respectively an output positive end Voutn+ and an output negative end Voutn-;
the output positive ends Voutn+ of the plurality of direct current power supply modules are combined into an output positive end Vout+ through parallel connection, and the output positive end Vout+ is connected with a load;
the output negative terminals Voutn of the direct current power supply modules are respectively connected in parallel after passing through corresponding module current sampling shunts, and a plurality of the output negative terminals Voutn are combined into an output negative terminal Vout and are connected into a load;
the plurality of direct current power supply modules are kept connected through bus current signals Vcs-bus;
the DC power supply module includes: the current-sharing circuit comprises a module voltage sampling unit, a module current sampling shunt, a current gain amplifier, a current bus buffer amplifier, a current local buffer amplifier, a current-sharing error amplifier and a current correction circuit;
wherein one end of the module voltage sampling unit is connected with the output positive end Voutn+, the other end of the module voltage sampling unit is respectively connected with one end of the module current sampling shunt and the positive input end of the current gain amplifier, the module voltage sampling unit inputs sampling voltage Vsen to the current correction circuit, the other end of the module current sampling shunt is connected with the negative input end of the current gain amplifier, the output end of the current gain amplifier is connected with the positive input end of the current bus buffer amplifier, the current bus buffer amplifier output end is connected with the current sharing error amplifier positive input end, the current bus buffer amplifier positive input end is connected with the current local buffer amplifier positive input end, the current local buffer amplifier output end is connected with the current sharing error amplifier negative input end, the current bus buffer amplifier output end outputs a bus current signal Vcs-bus, the current sharing error amplifier output end is connected with the other end of the current correction circuit, and the current correction circuit is connected with the output negative terminal Voutn-in parallel;
the current equalizing error amplifier comprises a positive phase input end, a negative phase input end and an output end, wherein the bus current signal Vcs-bus is input through the positive phase input end, and the current reference signal Vcs-ref is input through the negative phase input end;
when the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier obtains a positive voltage signal Vs-adj and inputs the positive voltage signal Vs-adj to the current correcting circuit for next stage processing to correct the output voltage of the local direct current power supply module;
when the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier is negative, and the diode D2 is isolated to terminate output;
the current correction circuit comprises a photoelectric coupler OC1 and a voltage sampling shunt resistor Rvb1, the positive voltage signal Vs-adj drives the photoelectric coupler OC1, the output collector of the photoelectric coupler OC1 shunts the sampling voltage Vsen of a voltage loop of the local direct current power supply module through the resistor Rvb1, so that the component proportion of the sampling voltage Vsen is reduced, and a voltage negative feedback system of the local direct current power supply module enables the final output current to trend towards the current level of the direct current power supply module with the current maximum value, thereby realizing the current sharing purpose of the direct current power supply module in parallel control.
2. The extremum control-based dc power supply parallel control circuit of claim 1, wherein the module voltage sampling unit is configured to sample and measure the output current and the output voltage, and output a sampled voltage Vsen.
3. The extremum control based dc power supply shunt of claim 2, wherein the module current sampling shunt is configured to sample and shunt the output current of the local dc power supply module and convert the output current into a voltage signal.
4. A parallel control circuit for a dc power supply based on extremum control according to claim 3, wherein the closed loop gain effect of the current gain amplifier is 50-100 times for amplifying the weak current or voltage signal split by the module current sampling splitter to 0-10V.
5. The extremum control-based direct current power supply parallel control circuit according to claim 4, wherein the gain of the current bus buffer amplifier is 1, and the voltage signal after gain amplification is combined into a bus current signal Vcs-bus by a diode D1 with the same attribute as that of other direct current power supply modules;
and the diode D1 is used for enabling the bus to only select the maximum value of voltages on all channels of the direct current power supply modules as the extreme value of the parallel control circuit.
6. The extremum control-based dc power supply parallel control circuit of claim 5, wherein the gain of the current local buffer amplifier is 1, and the current local buffer amplifier is configured to generate a current reference signal Vcs-ref of the local dc power supply module by using impedance transformation from the voltage signal amplified by the current gain amplifier.
7. A control method of a dc power supply parallel control circuit based on extremum control, for implementing the dc power supply parallel control circuit based on extremum control according to any one of claims 1 to 6, characterized in that the control method comprises the steps of:
s1, sampling and splitting output current of a local direct current power supply module by using a module current sampling splitter, converting the output current into a voltage signal and inputting the voltage signal to a current gain amplifier;
s2, amplifying the input voltage signal to 0-10V by the current gain amplifier;
s3, the current bus buffer amplifier acquires an amplified voltage signal, and combines the voltage signal with voltage signals with the same attribute in other direct current power supply modules to form a bus current signal Vcs-bus;
s4, acquiring the amplified voltage signal of the current gain amplifier by using a current local buffer amplifier, and generating a current reference signal Vcs-ref of the local direct current power supply module by using impedance transformation;
s5, judging the numerical value relation between the bus current signal Vcs-bus and the current reference signal Vcs-ref by using a current sharing error amplifier;
s6, if the current reference signal Vcs-ref is lower than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier obtains a positive voltage signal Vs-adj, and step S8 is executed to carry out next stage processing to realize the correction of the output voltage of the local direct current power supply module;
s7, if the current reference signal Vcs-ref is higher than the bus current signal Vcs-bus, the output end of the current equalizing error amplifier is negative, the output of the voltage signal is blocked, and the response is terminated;
and S8, driving a current correction circuit to operate by using the positive voltage signal Vs-adj, reducing the component proportion of the sampling voltage Vsen in the module voltage sampling unit, and adjusting the current level of the local direct current power supply module to realize current sharing of all the direct current power supply modules in the parallel control circuit.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6236582B1 (en) * | 2000-02-01 | 2001-05-22 | Micro Linear Corporation | Load share controller for balancing current between multiple supply modules |
| CN103051189A (en) * | 2012-12-04 | 2013-04-17 | 大连海事大学 | Switch power supply paralleled current sharing control circuit applying UC3907 |
| CN108668403A (en) * | 2017-03-31 | 2018-10-16 | 赤多尼科两合股份有限公司 | A kind of LED constant pressures current-equalizing system |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6236582B1 (en) * | 2000-02-01 | 2001-05-22 | Micro Linear Corporation | Load share controller for balancing current between multiple supply modules |
| CN103051189A (en) * | 2012-12-04 | 2013-04-17 | 大连海事大学 | Switch power supply paralleled current sharing control circuit applying UC3907 |
| CN108668403A (en) * | 2017-03-31 | 2018-10-16 | 赤多尼科两合股份有限公司 | A kind of LED constant pressures current-equalizing system |
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