Voltage Stabilization Circuit Control Method, Control Device and Power Supply Equipment

Abstract

This application relates to the technical field of voltage stabilization circuit control, and particularly to a voltage stabilization circuit control method, a control device, and a power supply device. The steady-state circuit control method is as follows: continuously monitor the load current at the output end of the voltage stabilization circuit, determine whether the load current has changed suddenly. When the load current has not changed suddenly, control the operation of the voltage stabilization circuit based on the steady-state control strategy; when the load current has changed suddenly, control the operation of the voltage stabilization circuit based on the transient control strategy, that is, calculate the switch-on and switch-off moments according to the output capacitor charge balance principle, and synchronously switch on and off the main-phase switch circuit and the auxiliary-phase switch circuit in a timely manner. This voltage stabilization circuit control method, control device, and power supply device can quickly respond when the load current changes suddenly, enable the output current to quickly adapt to the sudden change of the load current, reduce the long-time fluctuation of the output voltage during transient operation, and improve the reliability and stability of power supply.

Description

Technical Field

[0001] The present application relates to the technical field of voltage stabilizing circuit control, and particularly to a voltage stabilizing circuit control method, a control device and a power supply device. Background Art

[0002] In the field of power electronics, an asymmetric multiphase Buck converter, as an important voltage regulator, is mainly used for outputting low voltage and large current. In a complex and diverse power system such as a microgrid, various distributed power sources, energy storage devices and various loads are intertwined, posing higher requirements for the stable conversion and efficient distribution of electric energy. The asymmetric multiphase Buck converter plays a key role in the microgrid power system. It realizes the DC-DC conversion of low voltage and large current by coupling multiple Buck circuits in parallel and conducting them in a specific conduction sequence. This unique working method can not only effectively improve the electric energy conversion efficiency, but also better meet the changing load demands in the microgrid.

[0003] In the microgrid architecture, a grid-forming inverter is a key interface connecting distributed power sources and the microgrid. As the output device of the front-stage asymmetric multiphase Buck converter, the grid-forming inverter has strict requirements for its front-stage voltage regulator. In the actual application of the microgrid power system, the load often jumps, the load current changes instantaneously, and the voltage across the output capacitor also changes accordingly, resulting in a change in the voltage across the load. The load will be in a voltage fluctuation state for a long time, which is likely to cause equipment failures and affect the reliability and stability of the power supply. Summary of the Invention

[0004] Based on this, it is necessary to provide a voltage stabilizing circuit control method, a control device and a power supply device that can solve the above technical problems, can quickly respond when the load current changes suddenly, reduce the long-term fluctuation of the output voltage during transient operation, and improve the reliability and stability of the power supply.

[0005] The above object of the present application is achieved by the following technical solutions.

[0006] In the first aspect of the present application, a voltage stabilizing circuit control method is provided. The voltage stabilizing circuit includes a main phase switch circuit, an auxiliary phase switch circuit and an output capacitor. The main phase switch circuit and the auxiliary phase switch circuit are connected in parallel with each other; the output capacitor is connected in parallel to the back ends of the main phase switch circuit and the auxiliary phase switch circuit;

[0007] The control method of the voltage stabilizing circuit is as follows: continuously monitor the load current at the output end of the voltage stabilizing circuit, obtain the load current value and determine whether a sudden change occurs; when the load current does not change suddenly, control the operation of the voltage stabilizing circuit based on the steady-state control strategy; when the load current changes suddenly, control the operation of the voltage stabilizing circuit based on the transient control strategy; the transient control strategy is: obtain the total inductor current values of the voltage stabilizing circuit before and after the sudden change of the load current, and compare the load current values before and after the sudden change; if the load current increases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current increases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to conduct simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously; if the load current decreases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current decreases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to conduct simultaneously.

[0008] In one embodiment, the method for determining the moment after the load current increases is as follows:

[0009] Determine the charging charge calculation equation of the output capacitor:

[0010] ,

[0011] where is the moment when the load current suddenly changes, is the moment when the total inductor current value is equal to the load current value after the sudden change of the load current, is the moment when each switch circuit of the voltage stabilizing circuit conducts simultaneously, is the moment when the sudden change of the load current ends, is the total inductor current value when each switch circuit of the voltage stabilizing circuit turns off simultaneously, is the load current value after the sudden change of the load current;

[0012] Determine the discharging charge calculation equation of the output capacitor:

[0013] ,

[0014] where is the total inductor current value when the load current suddenly changes;

[0015] The calculation equation for determining the slope of the total inductor current rise of the voltage stabilizing circuit is:

[0016] ,

[0017] in, is the slope of the total inductor current rise, is the main phase inductance of the voltage stabilizing circuit, is the auxiliary phase inductance value of the voltage stabilizing circuit, is the DC input voltage value of the voltage stabilizing circuit, is the DC output voltage value of the voltage stabilizing circuit;

[0018] The calculation equation for determining the slope of the total inductor current drop of the voltage stabilizing circuit is:

[0019] ,

[0020] in, is the slope of the total inductor current decrease;

[0021] Based on the condition that the charging charge and the discharging charge of the output capacitor are equal, the above equations are combined to determine :

[0022] ,

[0023] ,

[0024] .

[0025] In one embodiment, after the load current decreases, The time is determined as follows:

[0026] Determine the output capacitor charge calculation equation:

[0027] ,

[0028] in, is the moment when the load current suddenly changes. It is the moment when the total inductor current value is equal to the load current value after the load current changes suddenly. is the total inductor current value when the load current changes suddenly, is the load current value after the load current suddenly changes;

[0029] The calculation equation for determining the discharge charge of the output capacitor is:

[0030] ,

[0031] in, It is the moment when all the switch circuits of the voltage stabilizing circuit are turned on at the same time. is the moment when the load current mutation ends. is the total inductor current value when all switch circuits of the voltage stabilizing circuit are turned off at the same time;

[0032] The calculation equation for determining the slope of the total inductor current rise of the voltage stabilizing circuit is:

[0033] ,

[0034] in, is the slope of the total inductor current rise, is the auxiliary phase inductance value of the voltage stabilizing circuit, is the main phase inductance of the voltage stabilizing circuit, is the DC input voltage value of the voltage stabilizing circuit, is the DC output voltage value of the voltage stabilizing circuit;

[0035] The calculation equation for determining the slope of the total inductor current drop of the voltage stabilizing circuit is:

[0036] ,

[0037] in, is the slope of the total inductor current decrease;

[0038] Based on the condition that the charging charge amount and the discharging charge amount of the output capacitor of the voltage stabilizing circuit are equal, the above equations are combined to determine :

[0039] ,

[0040] ,

[0041] .

[0042] In one embodiment, the steady-state control strategy is: control the phase circuits of the main phase switch circuit to operate alternately in sequence, and control the auxiliary phase switch circuit to operate later than the main phase switch circuit, wherein the preset duty cycle of each phase switch circuit of the main phase switch circuit is , the phase of the auxiliary phase switch circuit is .

[0043] In one embodiment, the main phase switch circuit includes a three-phase switch circuit, each phase switch circuit is respectively connected in series with a first main phase inductor, a second main phase inductor and a third main phase inductor, and the inductance values of the first main phase inductor, the second main phase inductor and the third main phase inductor are the same; the auxiliary phase switch circuit is connected in series with an auxiliary phase inductor, and the inductance value of the auxiliary phase inductor is smaller than the inductance value of each main phase inductor of the main phase switch circuit.

[0044] In a second aspect of the present application, a control device is provided, including an inductance current sampling module, a load current sampling module, and a control module; the inductance current sampling module is used to obtain the total inductance current value of the voltage stabilizing circuit; the load current sampling module is used to obtain the load current value at the output end of the voltage stabilizing circuit; the control module controls the voltage stabilizing circuit based on the total inductance current value and the load current value by using the voltage stabilizing circuit control method described in the above embodiments.

[0045] In a third aspect of the present application, a power supply device is provided, including a control device, a voltage stabilizing circuit, and an inverter connected to the output end of the voltage stabilizing circuit; the control device obtains the total inductance current value and the load current value of the voltage stabilizing circuit, and controls the voltage stabilizing circuit based on the total inductance current value and the load current value by using the voltage stabilizing circuit control method described in the above embodiments.

[0046] The voltage stabilizing circuit control method of the embodiments of the present application is used to control the pre-stage voltage stabilizing circuit of the inverter. By collecting the load current in real time and judging whether the load current changes suddenly, when the load current changes suddenly, according to the mutation direction of the load current, the on-off time of each operating state is determined in combination with the output capacitor charge balance principle, and then the switching on and off of the main phase switch circuit and the auxiliary phase switch circuit are accurately controlled based on the on-off time. It has a relatively fast transient response speed, enables the output current to adapt to the sudden change of the load current, reduces the output capacitor voltage fluctuation ripple and recovery time during transient operation, avoids the load being in a voltage fluctuation state for a long time, improves the reliability and stability of power supply, and is more conducive to the popularization and application of the microgrid power system.

[0047] Further, when the voltage stabilizing circuit operates stably, by adjusting the phase of the auxiliary phase switch circuit, the peak value of the auxiliary phase inductance current is cancelled out with the valley value of the main phase inductance current, so that the output current ripple is reduced. Description of the Drawings

[0048] Figure 1 It is a schematic structural diagram of a voltage stabilizing circuit provided by an embodiment of the present application.

[0049] Figure 2 It is a schematic step diagram of a voltage stabilizing circuit control method provided by an embodiment of the present application.

[0050] Figure 3 It is a steady-state operation timing diagram of a voltage stabilizing circuit provided by an embodiment of the present application.

[0051] Figure 4 It is a timing diagram of a voltage stabilizing circuit provided by an embodiment of the present application when the load current increases transiently.

[0052] Figure 5The timing diagram of the voltage stabilizing circuit provided by an embodiment of the present application when the load current transiently decreases.

[0053] Figure 6 The structural block diagram of the control device provided by an embodiment of the present application.

[0054] Figure 7 The control schematic diagram of the voltage stabilizing circuit control method provided by an embodiment of the present application. Detailed implementation manners

[0055] To make the above objects, features, and advantages of the present application more obvious and understandable, the following provides a detailed description of the specific implementation manners of the present application. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0056] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0058] A voltage stabilizing circuit control method according to an embodiment of the present application is used to control the voltage stabilizing circuit of the front stage of an inverter, providing a stable output voltage and output current for the inverter to ensure that the inverter can invert direct current into alternating current with high quality and incorporate it into the microgrid.

[0059] For the convenience of understanding the technical solution, the voltage stabilizing circuit is introduced below first.

[0060] As Figure 1 shown, the front-stage voltage stabilizing circuit 20 of the inverter 30 is an asymmetric voltage regulator composed of a three-phase switch circuit as the main phase and a single-phase switch circuit as the auxiliary phase.

[0061] In this embodiment, the voltage stabilizing circuit 20 includes a main-phase switch circuit, an auxiliary-phase switch circuit, and an output capacitor C o, the main-phase switch circuit and the auxiliary-phase switch circuit are connected in parallel; the output capacitor C o is connected in parallel at the rear end of the main-phase switch circuit and the auxiliary-phase switch circuit. The difference between the load current generated after the load jumps and the equivalent inductor current is borne by the output capacitor C o , that is, the output capacitor C o discharges to supplement.

[0062] The main-phase switch circuit includes a three-phase switch circuit. Each main-phase switch circuit includes a switching tube, an inductor, and a diode. Among them, the first main-phase switch circuit includes the first switch S N1 , the first diode D1, and the first main-phase inductor L N1 . The second main-phase switch circuit includes the second switch S N2 , the second diode D2, and the second main-phase inductor L N2 . The third main-phase switch circuit includes the third switch S N3 , the third diode D3, and the third main-phase inductor L N3 .

[0063] The following takes the first main-phase switch circuit as an example for connection description. The connection of other main-phase switch circuits is the same as that of the first main-phase switch circuit. The first end of the first switch S N1 is used to connect to the positive pole of the DC input power supply. The second end of the first switch S N1 is connected to the first end of the first main-phase inductor L N1 and is connected to the cathode of the first diode D1. The second end of the first main-phase inductor L N1 is connected to the first end of the output capacitor C o ; the anode of the first diode D1 is connected to the negative pole of the DC input power supply and is connected to the second end of the output capacitor C o . The second end of each main-phase inductor is the main-phase current sampling end, which can be used to collect the main-phase inductor current.

[0064] The first end of the second switch S N2 is used to connect to the positive pole of the DC input power supply. The second end of the second switch S N2 is connected to the first end of the second main-phase inductor L N2 and is connected to the cathode of the second diode D2. The second end of the second main-phase inductor L N2 is connected to the first end of the output capacitor C o ; the anode of the second diode D2 is connected to the negative pole of the DC input power supply and is connected to the second end of the output capacitor C o .

[0065] The first end of the third switch S N3 is used to connect to the positive pole of the DC input power supply. The second end of the third switch S N3The second end of N3 is connected to the first end of the third main-phase inductor L N3 and is connected to the cathode of the third diode D3. The second end of the third main-phase inductor L o is connected to the first end of the output capacitor C o ; the anode of the third diode D3 is connected to the negative pole of the DC input power supply and is connected to the second end of the output capacitor C

[0066] The auxiliary-phase switching circuit includes a fourth switch S A , a fourth diode D4, and an auxiliary-phase inductor L A . The first end of the fourth switch S A is connected to the first ends of other main-phase switches and is connected to the positive pole of the DC input power supply. The second end of the fourth switch S A is connected to the cathode of the fourth diode D4 and is connected to the first end of the auxiliary-phase inductor L A ; the second end of the auxiliary-phase inductor L A is connected to the second ends of other main-phase inductors and is connected to the first end of the output capacitor C o , forming the positive pole of the output end of the voltage stabilization circuit 20; the anode of the fourth diode D4 is connected to the anodes of other main-phase diodes, is connected to the negative pole of the DC input power supply, and is connected to the second end of the output capacitor C o , forming the negative pole of the output end of the voltage stabilization circuit 20.

[0067] It should be noted that in the voltage stabilization circuit 20, the inductance values of the first main-phase inductor L N1 , the second main-phase inductor L N2 , and the third main-phase inductor L N3 are the same; the inductance value of the auxiliary-phase inductor L A is less than the inductance values of the main-phase inductors in the main-phase switching circuit.

[0068] Based on the above connection structure, the second ends of the main-phase inductors are the main-phase current sampling ends for collecting the main-phase inductor current; the second end of the auxiliary-phase inductor is the auxiliary-phase current sampling end for collecting the auxiliary-phase inductor current; after the main-phase inductors and the auxiliary-phase inductor are connected, a total inductor current sampling end A is formed for collecting the total inductor current; the total inductor current sampling end A is connected to the output capacitor C o to form an output current sampling end, which is also the load current sampling end B.

[0069] The output end of the voltage stabilization circuit 20 is used to connect to the inverter 30 to output a high-quality DC power supply for the inverter 30. The inverter 30 can be a grid-forming inverter; the output end of the inverter 30 is used to connect to the load to provide a transformed AC power supply for the load.

[0070] Such as Figure 2 ,Figure 7 As shown, a control method for a voltage stabilizing circuit includes:

[0071] S1: Monitor the load current at the output end of the voltage stabilizing circuit in real time, obtain the load current value, and determine whether a mutation occurs;

[0072] S2: When the load current does not mutate, control the operation of the voltage stabilizing circuit based on a steady-state control strategy;

[0073] S3: When the load current mutates, control the operation of the voltage stabilizing circuit based on a transient control strategy.

[0074] The transient control strategy includes:

[0075] Obtain the total inductor current values of the voltage stabilizing circuit before and after the load current mutation, and compare the load current values before and after the mutation;

[0076] If the load current increases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current increases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to conduct simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously;

[0077] If the load current decreases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current decreases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to conduct simultaneously.

[0078] Combined with Figure 4 and Figure 5 viewed, is the moment when the load current mutates, is the moment when the total inductor current value after the load current mutation is equal to the load current value (output current value), is the moment when each switch circuit of the voltage stabilizing circuit conducts simultaneously, is the moment when the load current mutation ends. The circuit parameters of the voltage stabilizing circuit include each main phase inductor value , auxiliary phase inductor value , the DC input voltage value of the voltage stabilizing circuit 20 , and the DC output voltage value of the voltage stabilizing circuit 20 .

[0079] The voltage stabilization circuit control method of the embodiment of the present application collects the load current in real time and determines whether the load current has a sudden change. When the load current has a sudden change, according to the mutation direction of the load current, combined with the circuit parameters and operating state of the voltage stabilization circuit, the on and off times of each operating state are determined, and then based on the on and off times, the switching on and off of the main phase switch circuit and the auxiliary phase switch circuit are accurately controlled, which has a relatively fast transient response speed, enables the output current to adapt to the sudden change of the load current, reduces the output capacitor voltage fluctuation ripple and recovery time during transient operation, avoids the load being in the voltage fluctuation state for a long time, improves the reliability and stability of the power supply, and is more conducive to the popularization and application of the microgrid power system.

[0080] Combined Figure 3 Looking at it, when the load of the microgrid does not change, the load current of the voltage stabilization circuit 20 does not have a sudden change, and the voltage stabilization circuit 20 can operate stably, but there will also be ripple in the output current. Therefore, corresponding steady-state control strategies also need to be adopted to control the voltage stabilization circuit 20.

[0081] Optionally, the steady-state control strategy is: controlling each phase circuit of the main phase switch circuit to operate alternately in sequence, and controlling the auxiliary phase switch circuit to operate lagging behind the main phase switch circuit. In this way, by adjusting the phase of the auxiliary phase switch circuit, the peak value of the auxiliary phase inductor current cancels out the valley value of the main phase inductor current , so as to reduce the output current ripple and obtain a higher-quality DC power supply output. Optionally, the main phase inductor current and the auxiliary phase inductor current can be sampled in real time to facilitate observing whether the peak value of the auxiliary phase inductor current cancels out the valley value of the main phase inductor current . Optionally, the total inductor current value at the total inductor current sampling terminal A can also be sampled in real time to facilitate observing the change of the total inductor current output after the main phase switch circuit and the auxiliary phase switch circuit are connected in parallel, and assist in realizing steady-state control.

[0082] The preset duty ratio of each phase switch circuit of the main phase switch circuit is , and the phase of the auxiliary phase switch circuit is . The phase of the auxiliary phase switch circuit lags behind any phase switch circuit of the main phase switch circuit. In this embodiment, the phase of the auxiliary phase switch circuit lags behind the phase of the first main phase switch circuit.

[0083] Generally, due to the frequent changes in the microgrid load, when there is a jump in the microgrid load, the load current will change instantaneously. However, the inductor of the switching circuit connected in series with the load has the characteristic of hindering the sudden change of current, and the output current cannot immediately follow the change of the load current. At this time, the difference between the load current generated after the load jump and the equivalent inductor current is borne by the output capacitor According to the characteristics of the output capacitor , the voltage across it will change accordingly, which in turn causes the voltage across the load to change, resulting in abnormal operation of the load. In order to make the output current of the voltage stabilizing circuit adapt to the load mutation and avoid the long-term fluctuation of the voltage across the load, it is necessary to determine the on-off time of each switching circuit according to the change of the load current.

[0084] In an optional embodiment, combined with Figure 4 When the load current increases, it is necessary to determine the time according to the operating state of the voltage stabilizing circuit for the purpose of controlling the voltage stabilizing circuit.

[0085] After the load current increases The method for determining the time is as follows:

[0086] Determine the charging charge calculation equation of the output capacitor:

[0087] ,

[0088] where is the time when the load current suddenly changes, is the time when the total inductor current value is equal to the load current value (output current value) after the load current suddenly changes, is the time when all switching circuits of the voltage stabilizing circuit are turned on simultaneously, is the time when the load current mutation ends, is the total inductor current value when all switching circuits of the voltage stabilizing circuit are turned off simultaneously, is the load current value after the load current mutation (output current value of the voltage stabilizing circuit).

[0089] Determine the discharging charge calculation equation of the output capacitor:

[0090] ,

[0091] where is the total inductor current value at the time of load current mutation.

[0092] The above charging charge calculation equation and discharging charge calculation equation of the output capacitor are determined by the circuit connection mode of the voltage stabilizing circuit.

[0093] Determine the calculation equation of the slope of the total inductor current rise of the voltage stabilizing circuit:

[0094] ,

[0095] in, is the slope of the total inductor current rise, is the auxiliary phase inductance value of the voltage stabilizing circuit, is the main phase inductance of the voltage stabilizing circuit, is the DC input voltage value of the voltage stabilizing circuit, is the DC output voltage value of the voltage stabilizing circuit.

[0096] Determine the calculation equation for the slope of the total inductor current drop in the voltage regulator circuit:

[0097] ,

[0098] in, is the slope of the total inductor current decrease.

[0099] The calculation equation for the slope of the total inductor current rise and the calculation equation for the slope of the total inductor current fall are determined according to the parallel relationship between the main phase inductance and the auxiliary phase inductance of the voltage stabilizing circuit.

[0100] Based on the condition that the charging charge and discharging charge of the output capacitor are equal, the above equations are combined to determine .

[0101] Combination Figure 4 From the perspective of the output capacitor charging charge is equal to the output capacitor discharging charge, the output capacitor discharging charge is equal to Time to The area of the triangle formed by the total inductor current and the load current at the moment, the output capacitor charge is equal to Time to The area of the triangle formed by the total inductor current and the load current at the moment is .

[0102] Combining the above equations, we can get , and The calculation formula is:

[0103] ,

[0104] ,

[0105] .

[0106] In an optional embodiment, in combination Figure 5 From the perspective of load current, when the load current decreases, it is necessary to redetermine the voltage according to the operating status of the voltage stabilization circuit. time, in order to control the voltage stabilizing circuit.

[0107] After the load current decreases The time is determined by:

[0108] Determine the output capacitor charge calculation equation:

[0109] ,

[0110] in, is the moment when the load current suddenly changes. It is the moment when the total inductor current value is equal to the load current value after the load current changes suddenly. is the total inductor current value when the load current changes suddenly, It is the load current value (output current value) after the load current changes suddenly.

[0111] The calculation equation to determine the discharge charge of the output capacitor is:

[0112] ,

[0113] in, It is the moment when all the switch circuits of the voltage stabilizing circuit are turned on at the same time. is the moment when the load current mutation ends. It is the total inductor current value when all switch circuits of the voltage regulator circuit are turned off at the same time.

[0114] Determine the calculation equation for the slope of the total inductor current rise in the voltage regulator circuit:

[0115] ,

[0116] in, is the slope of the total inductor current rise, is the auxiliary phase inductance value of the voltage stabilizing circuit, is the main phase inductance of the voltage stabilizing circuit, is the DC input voltage value of the voltage stabilizing circuit, is the DC output voltage value of the voltage stabilizing circuit.

[0117] Determine the calculation equation for the slope of the total inductor current drop in the voltage regulator circuit:

[0118] ,

[0119] in, is the slope of the total inductor current decrease.

[0120] Based on the condition that the charging charge and discharging charge of the output capacitor of the voltage regulator circuit are equal, the above equations are combined to determine .

[0121] Combined Figure 5 Viewed, according to the fact that the charging charge of the output capacitor is equal to the discharging charge of the output capacitor, and the charging charge of the output capacitor is equal to From the moment to The area of the triangle formed by the total inductor current and the load current from the moment to From the moment to The area of the triangle formed by the total inductor current and the load current from the moment to, that is .

[0122] By solving the above equations simultaneously, we can obtain 、 And Calculation formulas of:

[0123] ,

[0124] ,

[0125] .

[0126] It can be seen from the above embodiments that during transient operation, whether the load current increases or decreases, the on-off time can be calculated according to the output capacitor charge balance principle, and the main phase switch circuit and the auxiliary phase switch circuit are turned on and off simultaneously, so that the output current adapts to the sudden change of the load current, and the output capacitor voltage fluctuation ripple and recovery time during transient operation are reduced.

[0127] This voltage stabilization circuit control method divides the working state of the asymmetric voltage stabilization circuit into steady-state operation and transient operation. During steady-state operation, the phase of the auxiliary phase switch circuit is changed to reduce the total output inductor current ripple; during transient operation, the load change is judged by sampling the load current, and the on-off time of the main phase switch circuit and the auxiliary phase switch circuit is calculated, so as to realize transient minimum time control and effectively suppress the output capacitor voltage fluctuation, thereby providing a stable output voltage and a fast-response output current for the inverter.

[0128] In the specific control process, the load current is collected in real time, and it is judged whether the load current changes suddenly. When the load current changes suddenly, according to the mutation direction of the load current, the on-off time of each operating state is determined in combination with the output capacitor charge balance principle, and then the switching on and off of the main phase switch circuit and the auxiliary phase switch circuit are accurately controlled based on the on-off time. It has a fast transient response speed, enables the output current to quickly adapt to the sudden change of the load current, reduces the output capacitor voltage fluctuation ripple and recovery time during transient operation, avoids the load being in the voltage fluctuation state for a long time, improves the reliability and stability of the power supply, and is more conducive to the popularization and application of the microgrid power system.

[0129] Further, when the voltage stabilization circuit operates stably, by adjusting the phase of the auxiliary phase switch circuit, the peak value of the auxiliary phase inductor current is canceled with the valley value of the main phase inductor current, so that the output current ripple is reduced.

[0130] The embodiment of the present application also provides a control device, as Figure 6 shown. The control device includes an inductor current sampling module 101, a load current sampling module 102, and a control module 103.

[0131] The inductor current sampling module 101 is used to obtain the total inductor current value obtained by adding the main phase inductor current and the auxiliary phase inductor current of the voltage stabilization circuit; the load current sampling module 102 is used to obtain the load current value at the output end of the voltage stabilization circuit.

[0132] Based on the total inductor current value and the load current value, the control module 103 controls the voltage stabilization circuit by using the voltage stabilization circuit control method of the above embodiment.

[0133] The control module 103 generates an on-off control signal and transmits it to the on-off signal distribution module 104, and then the on-off signal distribution module 104 controls each pulse width modulation module 105 to generate corresponding pulse modulation signals PWM1~PWM n . Among them, the pulse modulation signal PWM1 is output to the first switch of the first main phase switch circuit, the pulse modulation signal PWM2 is output to the second switch of the second main phase switch circuit, the pulse modulation signal PWM3 is output to the third switch of the third main phase switch circuit, and the pulse modulation signal PWM4 is output to the fourth switch of the auxiliary phase switch circuit.

[0134] The embodiment of the present application also provides a power supply device, as Figure 1 shown. The power supply device includes a control device 10, a voltage stabilization circuit 20, and an inverter 30 connected to the output end of the voltage stabilization circuit 20; the control device 10 obtains the total inductor current value and the load current value of the voltage stabilization circuit 20, and based on the total inductor current value and the load current value, controls the voltage stabilization circuit 20 by using the voltage stabilization circuit control method of the above embodiment.

[0135] The above control device and power supply device can control the pre-stage voltage regulator to provide a stable voltage and a fast-response current; during steady-state operation, by adjusting the phase of the auxiliary phase switch circuit, the peak value of the auxiliary phase inductor current is canceled with the valley value of the main phase inductor current, so as to reduce the output current ripple; during transient operation, according to the output capacitor charge balance principle, the on-off time is calculated, and the main phase switch circuit and the auxiliary phase switch circuit are turned on and off simultaneously, so that the output current can quickly adapt to the sudden change of the load current, and the output capacitor voltage fluctuation ripple and the recovery time during transient operation are reduced.

[0136] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0137] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for controlling a voltage stabilizing circuit, characterized in that, The voltage stabilizing circuit includes a main phase switching circuit, an auxiliary phase switching circuit, and an output capacitor. The main phase switching circuit and the auxiliary phase switching circuit are connected in parallel with each other. The output capacitor is connected in parallel to the back ends of the main phase switching circuit and the auxiliary phase switching circuit. The main-phase switching circuit includes a multi-phase switching circuit, and the multi-phase switching circuit includes a first main-phase switching circuit, a second main-phase switching circuit, and a third main-phase switching circuit; among them, the first main-phase switching circuit includes a first switch S N1 , a first diode D1, and a first main-phase inductor L N1 , the second main-phase switching circuit includes a second switch S N2 , a second diode D2, and a second main-phase inductor L N2 , the third main-phase switching circuit includes a third switch S N3 , a third diode D3, and a third main-phase inductor L N3 ; the inductance values of each main-phase inductor are the same; The first switch S N1 has its first terminal for connection to the positive pole of the DC input power supply, and the second terminal of the first switch S N1 is connected to the first terminal of the first main-phase inductor L N1 and to the cathode of the first diode D1. The second terminal of the first main-phase inductor L N1 is connected to the first terminal of the output capacitor C o ; The first terminal of the second switch S N2 is used to connect to the positive pole of the DC input power supply. The second terminal of the second switch S N2 is connected to the first terminal of the second main-phase inductor L N2 and is connected to the cathode of the second diode D2. The second terminal of the second main-phase inductor L N2 is connected to the first terminal of the output capacitor C o ; The first terminal of the third switch S N3 is used to connect to the positive pole of the DC input power supply. The second terminal of the third switch S N3 is connected to the first terminal of the third main-phase inductor L N3 and is connected to the cathode of the third diode D3. The second terminal of the third main-phase inductor L N3 is connected to the first terminal of the output capacitor C o ; The anodes of the first diode D1, the second diode D2, and the third diode D3 are connected to the negative electrode of the DC input power supply and are connected to the second end of the output capacitor C o ; The auxiliary phase switching circuit includes a fourth switch S A , a fourth diode D4, and an auxiliary phase inductor ; The fourth switch S A has its first terminal for connection to the positive pole of the DC input power supply, and the second terminal of the fourth switch S A is connected to the cathode of the fourth diode D4 and is connected to the first terminal of the auxiliary-phase inductor L A ; the second terminal of the auxiliary-phase inductor L A is connected to the second terminals of other main-phase inductors and is connected to the first terminal of the output capacitor C o to form the positive pole of the output terminal of the voltage stabilization circuit; the anode of the fourth diode D4 is connected to the anodes of other main-phase diodes, is connected to the negative pole of the DC input power supply, and is connected to the second terminal of the output capacitor C o to form the negative pole of the output terminal of the voltage stabilization circuit; The auxiliary phase inductor has an inductance value smaller than that of the main phase inductor of the main phase switching circuit ; The control method of the voltage stabilizing circuit is as follows: Monitor the load current at the output end of the voltage stabilizing circuit in real time, obtain the load current value, and determine whether a sudden change occurs. When the load current does not change suddenly, control the operation of the voltage stabilizing circuit based on a steady-state control strategy. When the load current changes suddenly, control the operation of the voltage stabilizing circuit based on a transient control strategy. The steady-state control strategy is as follows: Control each phase circuit of the main phase switch circuit to operate alternately in sequence, and control the auxiliary phase switch circuit to operate lagging behind the main phase switch circuit, so that the peak value of the auxiliary phase inductor current cancels out the valley value of the main phase inductor current ; The preset duty ratio of each phase switch circuit of the main phase switch circuit is , and the phase of the auxiliary phase switch circuit is ; The transient control strategy is as follows: Obtain the total inductor current values of the voltage stabilizing circuit before and after the sudden change of the load current, and compare the load current values before and after the sudden change. If the load current increases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current increases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to conduct simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously; If the load current decreases, based on the circuit parameters of the voltage stabilizing circuit and the total inductor current value, determine the moment after the load current decreases, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn off simultaneously, and at the moment, control the main phase switch circuit and the auxiliary phase switch circuit to turn on simultaneously. Among them, the circuit parameters of the voltage stabilizing circuit include the main phase inductance value and the auxiliary phase inductance value .

2. The voltage stabilizing circuit control method according to claim 1, characterized in that, After the load current increases The method for determining the moment is as follows: Determine the calculation equation for the charging charge amount of the output capacitor: ， Among them, is the moment when the load current suddenly changes, is the moment when the total inductor current value is equal to the load current value after the load current suddenly changes, is the moment when each switching circuit of the voltage stabilizing circuit conducts simultaneously, is the moment when the load current sudden change ends, is the total inductor current value when each switching circuit of the voltage stabilizing circuit turns off simultaneously, is the load current value after the load current sudden change; Determine the calculation equation for the discharging charge amount of the output capacitor: ， Among them, is the total inductor current value when the load current changes suddenly; Determine the calculation equation for the rising slope of the total inductor current of the voltage stabilizing circuit: ， Among them, is the slope of the total inductor current rise, is the main-phase inductor value of the voltage regulator circuit, is the auxiliary-phase inductor value of the voltage regulator circuit, is the DC input voltage value of the voltage regulator circuit, is the DC output voltage value of the voltage regulator circuit; Determine the calculation equation for the falling slope of the total inductor current of the voltage stabilizing circuit: ， Among them, is the slope of the total inductor current drop; Based on the condition that the charging charge and the discharging charge of the output capacitor are equal, the above equations are combined to determine : ， ， 。 3. The voltage stabilizing circuit control method according to claim 1, characterized in that, After the load current decreases The method for determining the moment is as follows: Determine the calculation equation for the charging charge amount of the output capacitor: ， Among them, is the moment when the load current suddenly changes, is the moment when the total inductor current value is equal to the load current value after the load current suddenly changes, is the total inductor current value at the time of the load current sudden change, is the load current value after the load current sudden change; Determine the calculation equation for the discharging charge amount of the output capacitor: ， wherein, is the moment when each switching circuit of the voltage stabilizing circuit conducts simultaneously, is the moment when the sudden change of the load current ends, is the total inductor current value when each switching circuit of the voltage stabilizing circuit is turned off simultaneously; Determine the calculation equation for the rising slope of the total inductor current of the voltage stabilizing circuit: ， Among them, is the slope of the total inductor current rise, is the auxiliary phase inductor value of the voltage regulator circuit, is the main phase inductor value of the voltage regulator circuit, is the DC input voltage value of the voltage regulator circuit, is the DC output voltage value of the voltage regulator circuit; Determine the calculation equation for the falling slope of the total inductor current of the voltage stabilizing circuit: ， wherein, is the slope of the total inductor current decrease; Based on the condition that the charging charge and the discharging charge of the output capacitor are equal, the above equations are combined to determine : ， ， 。 4. The voltage stabilizing circuit control method according to claim 1, characterized in that The steady-state control strategy is as follows: Control each phase circuit of the main phase switch circuit to operate alternately in sequence, and control the auxiliary phase switch circuit to operate lagging behind the main phase switch circuit, where the preset duty cycle of each phase switch circuit of the main phase switch circuit is , and the phase of the auxiliary phase switch circuit is .

5. The voltage stabilizing circuit control method according to claim 1, characterized in that, The main phase switching circuit includes a three-phase switching circuit. A first main phase inductor, a second main phase inductor, and a third main phase inductor are respectively connected in series in each phase switching circuit. The inductance values of the first main phase inductor, the second main phase inductor, and the third main phase inductor are the same. An auxiliary phase inductor is connected in series in the auxiliary phase switching circuit. The inductance value of the auxiliary phase inductor is smaller than the inductance values of the main phase inductors in the main phase switching circuit.

6. A control device, characterized in that, It includes an inductor current sampling module, a load current sampling module, and a control module. The inductor current sampling module is used to obtain the total inductor current value of the voltage stabilizing circuit. The load current sampling module is used to obtain the load current value at the output end of the voltage stabilizing circuit. Based on the total inductor current value and the load current value, the control module controls the voltage stabilizing circuit by using the voltage stabilizing circuit control method described in any one of claims 1 to 5.

7. A power supply device, characterized in that, It includes a control device, a voltage stabilizing circuit, and an inverter connected to the output end of the voltage stabilizing circuit. The control device obtains the total inductor current value and the load current value of the voltage stabilizing circuit, and based on the total inductor current value and the load current value, controls the voltage stabilizing circuit by using the voltage stabilizing circuit control method described in any one of claims 1 to 5.

8. The power supply device according to claim 7, wherein The inverter is a grid-forming inverter.

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