Output voltage stabilization control device, system and method

Abstract

The invention provides an output voltage stabilization control device, system and method, and the device comprises a voltage transformation and rectification module, a voltage stabilization module and a control module. The voltage transformation and rectification module is used for converting an alternating current into a direct current to generate a first output voltage; the voltage stabilization module is connected in series with the transformation rectification module and is used for converting the first output voltage to generate a second output voltage, and the sum of the first output voltage and the second output voltage is the total output voltage; the control module is connected with the voltage stabilization module and the transformation rectification module and is used for generating a gate pole control signal based on the first output voltage, the second output voltage and a preset reference voltage; wherein the voltage stabilizing module is used for converting a first output voltage based on a gate pole control signal so as to generate a second output voltage. According to the invention, the stable control of the output voltage of the transformation rectification module is realized, the method is suitable for application occasions requiring a narrow or even fixed input voltage range, the efficiency is high, and the cost is low.

Description

Technical Field

[0001] The present application belongs to the field of electric power technology, and in particular, relates to an output voltage stabilization control device, system and method. Background Art

[0002] Multi-pulse transformer rectifier is a power electronic device used for power conversion and power quality improvement. By using phase shift technology and multiple rectifier units, it can reduce the harmonic content and current distortion in the power system. It has the advantages of high reliability, high efficiency and low cost.

[0003] However, there is a technical limitation of the multi-pulse transformer-rectifier, that is, the output voltage is basically proportional to the effective value of the input AC voltage, and decreases slightly with the increase of the output load. This means that the output voltage of the multi-pulse transformer-rectifier is not fixed or controlled, but exists in a wider range. In some applications, such as charging piles with DC input and server power supplies in data centers, a narrower or even fixed input voltage range is required to meet power supply standards or achieve better performance.

[0004] like Figure 1 As shown in the figure, the most common solution is to connect a non-isolated DC / DC converter after the output voltage of the multi-pulse transformer rectifier to achieve a regulated output of the multi-pulse transformer rectifier. However, this solution is equivalent to adding a DC power supply with the same power as the transformer rectifier, and the whole system adds a conversion link, resulting in a decrease in overall efficiency and a significant increase in cost.

[0005] Therefore, an efficient and low-cost voltage regulation solution is needed to meet applications that require a narrow or even fixed input voltage range. Summary of the invention

[0006] The purpose of the present application is to provide an output voltage stabilization control device, system and method for solving the technical problems of low efficiency and high cost in existing voltage stabilization technical solutions.

[0007] In a first aspect, the present application provides an output voltage stabilization control device, including a transformer and rectifier module, a voltage stabilization module, and a control module:

[0008] The transformer and rectifier module is used to convert alternating current into direct current to generate a first output voltage;

[0009] The voltage stabilizing module is connected in series with the voltage transformation and rectification module, and is used to convert the first output voltage to generate a second output voltage, wherein the sum of the first output voltage and the second output voltage is the total output voltage;

[0010] The control module is connected to the voltage stabilizing module and the voltage transforming and rectifying module, and is used to generate a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage;

[0011] The voltage stabilization module is used for converting the first output voltage based on the gate control signal to generate the second output voltage.

[0012] In an implementation of the first aspect, the transformer-rectifier module includes a phase-shifting transformer and a plurality of three-phase rectifier bridges;

[0013] The phase-shifting transformer is used to convert the alternating current into multiple groups of three-phase voltages by winding phase shifting;

[0014] Each group of the three-phase rectifier bridges is connected to the phase-shifting transformer, and is used to input a group of the three-phase voltages and rectify the three-phase voltages;

[0015] A plurality of groups of output ends of the three-phase rectifier bridges are connected in parallel to output the first output voltage.

[0016] In an implementation manner of the first aspect, the number of groups of the three-phase voltage matches the number of groups of the three-phase rectifier bridge.

[0017] In an implementation of the first aspect, the voltage stabilization module includes an isolated DC / DC converter.

[0018] In an implementation manner of the first aspect, the second output voltage accounts for 10% to 20% of the total output voltage.

[0019] In an implementation of the first aspect, the control module includes a first comparator, a second comparator, a third comparator, a controller, and a pulse width modulation signal generator;

[0020] The first comparator is used to calculate the difference between the preset reference voltage and the first output voltage to generate a first control deviation;

[0021] The second comparator is connected to the first comparator and is used to calculate the difference between the second output voltage and the first control deviation to generate a second control deviation;

[0022] The third comparator is connected to the first comparator and is used to compare the first control deviation with a first preset threshold and a second preset threshold to generate an enable signal;

[0023] The controller is connected to the second comparator and is configured to generate a control voltage based on the second control deviation;

[0024] The pulse width modulation signal generator is connected to the controller and the third comparator, and is used to generate a gate control signal based on a control voltage and the enable signal.

[0025] In an implementation of the first aspect, the third comparator compares the first control deviation with a first preset threshold and a second preset threshold to generate an enable signal, including:

[0026] When the first control deviation is greater than the first preset threshold, the enable signal is at a high level;

[0027] When the first control deviation is less than the second preset threshold, the enable signal is at a low level.

[0028] In an implementation manner of the first aspect, the third comparator is a hysteresis comparator.

[0029] In an implementation of the first aspect, the pulse width modulation signal generator generates a gate control signal based on a control voltage and the enable signal, comprising:

[0030] When the enable signal is at a high level, the pulse width modulation signal generator generates a gate control signal based on the control voltage, and the gate control signal is at a low level;

[0031] When the enable signal is at a low level, the pulse width modulation signal generator does not operate, and the gate control signal is at a high level.

[0032] In an implementation of the first aspect, the voltage stabilizing module converts the first output voltage based on the gate control signal to generate the second output voltage, including:

[0033] When the gate control signal is at a low level, the voltage stabilizing module operates to convert the first output voltage into the second output voltage;

[0034] When the gate control signal is at a high level, the voltage stabilizing module does not operate, and the first output voltage is within a normal operating range.

[0035] In a second aspect, the present application provides an output voltage stabilization control system, comprising any of the above-mentioned output voltage stabilization control devices, a three-phase AC voltage source and a load;

[0036] The three-phase AC voltage source is used to input the AC power to the output voltage stabilization control device;

[0037] The load is configured to operate based on the second output voltage.

[0038] In a third aspect, the present application provides an output voltage stabilization control method, which is applied to a charging station, comprising:

[0039] converting the alternating current into direct current to generate a first output voltage;

[0040] converting the first output voltage to generate a second output voltage, wherein the sum of the first output voltage and the second output voltage is a total output voltage;

[0041] generating a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage;

[0042] Converting the first output voltage to generate a second output voltage includes converting the first output voltage based on the gate control signal to generate the second output voltage.

[0043] As described above, the output voltage stabilization control device, system and method described in the present application have the following beneficial effects:

[0044] (1) By connecting the output of the transformer-rectifier module and the output of the voltage stabilizing module in series, stable control of the output voltage of the transformer-rectifier module is achieved;

[0045] (2) The voltage stabilizing module can supplement the output of the transformer and rectifier module as needed, with the supplement range of 10% to 20%;

[0046] (3) Suitable for applications that require a narrow or even fixed input voltage range, with high efficiency and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the structure of an output voltage stabilization control device in the prior art.

[0048] Figure 2 Shown is a structural schematic diagram of the output voltage stabilization control device described in an embodiment of the present application.

[0049] Figure 3 Shown is a schematic diagram of the structure of the eighteen-pulse transformer rectifier described in an embodiment of the present application.

[0050] Figure 4 Shown is a schematic diagram of the topological structure of a three-level full-bridge LLC resonant converter according to an embodiment of the present application.

[0051] Figure 5 Shown is another structural schematic diagram of the output voltage stabilization control device described in an embodiment of the present application.

[0052] Figure 6 Shown is a schematic diagram of the structure of the control module described in an embodiment of the present application.

[0053] Figure 7 Shown is a schematic diagram of the structure of the output voltage stabilization control system described in an embodiment of the present application.

[0054] Figure 8 Shown is a flow chart of the output voltage regulation control method described in an embodiment of the present application.

[0055] Fig. 9 Another flow chart of the output voltage regulation control method described in an embodiment of the present application is shown.

[0056] Component number description

[0057] 1 Output voltage stabilization control device

[0058] 11 Transformer and rectifier modules

[0059] 12 Voltage regulator module

[0060] 13 Control Module

[0061] 131 First comparator

[0062] 132 Second comparator

[0063] 133 Third comparator

[0064] 134 Controller

[0065] 135 Pulse Width Modulation Signal Generator

[0066] 2 Three-phase AC voltage source

[0067] 3 Load

[0068] Steps S1 to S3

[0069] S21 Step DETAILED DESCRIPTION

[0070] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0071] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0072] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0073] The following embodiments of the present application provide an output voltage stabilization control device, system and method, which solves the technical problems of low efficiency and high cost in the existing voltage stabilization technical solutions, realizes stable control of the output voltage of the multi-pulse transformer rectifier, improves the efficiency of the overall system, reduces costs, and meets the requirements of the input voltage range of specific application scenarios. The technical solutions in the embodiments of the present application will be described in detail below in conjunction with the drawings in the embodiments of the present application.

[0074] like Figure 2 As shown, this embodiment provides an output voltage stabilization control device 1, including a voltage transformation and rectification module 11, a voltage stabilization module 12 and a control module 13.

[0075] The transformer and rectifier module 11 is used to convert alternating current into direct current to generate a first output voltage.

[0076] Specifically, the transformer and rectifier module 11 includes a phase-shifting transformer and a plurality of three-phase rectifier bridges.

[0077] The phase-shifting transformer is used to convert the alternating current into multiple groups of three-phase voltages through winding phase shifting.

[0078] Each group of the three-phase rectifier bridges is connected to the phase-shifting transformer, and is used to input a group of the three-phase voltages and rectify the three-phase voltages.

[0079] A plurality of groups of output ends of the three-phase rectifier bridges are connected in parallel to output the first output voltage.

[0080] In the embodiment of the present application, the number of groups of the three-phase voltage matches the number of groups of the three-phase rectifier bridges. For example, if the eighteen-pulse transformer-rectifier includes three three-phase rectifier bridges, the phase-shifting transformer converts the alternating current into three groups of three-phase voltages by winding phase shifting. Similarly, if the twelve-pulse transformer-rectifier includes two three-phase rectifier bridges, the phase-shifting transformer converts the alternating current into two groups of three-phase voltages by winding phase shifting; if the twenty-four-pulse transformer-rectifier includes four three-phase rectifier bridges, the phase-shifting transformer converts the alternating current into four groups of three-phase voltages by winding phase shifting.

[0081] In one embodiment, the transformer-rectifier module 11 is a multi-pulse transformer-rectifier. The multi-pulse transformer-rectifier is a commonly used AC / DC (alternating current / direct current) conversion power source, and its core is a multi-pulse rectifier transformer.

[0082] The multi-pulse rectifier transformer has multiple windings, and there is a certain phase difference between the windings. The multi-pulse rectifier transformer can decompose the input AC voltage into multiple phases of AC voltage, and each phase of the AC voltage is rectified by a three-phase diode rectifier bridge to convert it into a DC voltage. These three-phase diode rectifier bridges are connected in parallel on the DC side to form the first output voltage. Due to the large number of three-phase diode rectifier bridges, the three-phase diode rectifier bridges of each phase will be alternately turned on, thereby reducing the pulsation and harmonic components of the first output voltage.

[0083] In another embodiment, if Figure 3 As shown, the multi-pulse transformer-rectifier is an eighteen-pulse transformer-rectifier. In other embodiments, the transformer-rectifier module can also be a twelve-pulse transformer-rectifier or a twenty-four-pulse transformer-rectifier, etc., the difference being that the number of wave heads of the first output voltage in one cycle is different. This application does not limit the type of the transformer-rectifier.

[0084] The voltage stabilizing module is connected in series with the voltage transforming and rectifying module, and is used for converting the first output voltage to generate a second output voltage.

[0085] Specifically, the voltage stabilizing module 12 includes an isolated DC / DC converter for realizing direct current to direct current conversion.

[0086] In one embodiment, the isolated DC / DC converter used in the present application is a three-level full-bridge LLC resonant converter.

[0087] like Figure 4 As shown, in the main circuit of the three-level full-bridge LLC resonant converter, Vin is the primary voltage and Vout is the secondary voltage; C1 and C2 are split capacitors for providing a voltage of 0.5Vin; D1~D4 are clamping diodes, wherein the midpoint of the clamping diode is connected to the midpoint of the split capacitor, for balancing the voltage of the primary switch tube; C5 is the output filter capacitor; Q1~Q8 are the primary switch tubes, Q9 and Q10 are the secondary switch tubes; L1 is the resonant inductor; C3 and C4 are the resonant capacitors.

[0088] In other embodiments, the three-level full-bridge LLC can be replaced by other isolated DC / DC converters, such as forward, flyback, push-pull, etc. Isolated DC / DC converters with different topologies have different advantages and characteristics, and the appropriate topology type can be selected according to the specific application scenarios and design requirements.

[0089] like Figure 5 As shown, in the embodiment of the present application, the sum of the first output voltage and the second output voltage is the total output voltage.

[0090] In the voltage stabilization state, the total output voltage Vout is equal to the preset reference voltage Vref, which is a fixed value and remains unchanged during the entire regulation process. However, in order to reflect flexibility, the total output voltage is actually allowed to fluctuate. When the first output voltage changes with the grid voltage or load, the second output voltage needs to quickly track the change of its voltage setting value to ensure that the total output voltage is sufficiently stable.

[0091] Preferably, the second output voltage accounts for 10% to 20% of the total output voltage.

[0092] In the voltage stabilization control system, the output voltage can be adjusted in any proportion as needed. The stability of the output voltage is mainly affected by two factors: the input grid voltage and the load change. According to the standard, the 10kV system allows a maximum voltage deviation of + / -10%, which means that the fluctuation range of the input grid voltage is limited. On the other hand, the change in load will cause a voltage deviation of about 5%. Therefore, the actual voltage that needs to be supplemented usually does not exceed the range of 10% to 20%. The significance of defining this 10% to 20% supplementary range is that in order to achieve voltage stabilization, only an additional 10% to 20% of supplementary power is required, without the need to convert all the power. This means that the supplementary voltage can be achieved through a smaller power converter, thereby reducing costs and losses.

[0093] In this implementation, by defining a supplementary range of 10% to 20%, a supplementary voltage with only a small additional power is realized in the voltage stabilization control system, thereby reducing costs and losses. This solution has obvious advantages over other solutions and can meet the performance requirements of the voltage stabilization system.

[0094] It should be noted that the proportion parameter of 10% to 20% can be adjusted according to specific application needs and design requirements. In order to further reduce costs, the proportion parameter of 10% to 20% can be adjusted to within 5%, which can further reduce the variation range of the second output voltage, thereby reducing the requirements for the control circuit and components and reducing the cost of the system.

[0095] The control module 13 is connected to the voltage stabilizing module 12 and the voltage transforming and rectifying module 11 , and is configured to generate a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage.

[0096] like Figure 6As shown, in one embodiment, the control module 13 includes a first comparator 131 , a second comparator 132 , a third comparator 133 , a controller 134 and a pulse width modulation (PWM) signal generator 135 .

[0097] Specifically, the first comparator 131 is used to calculate the difference between the preset reference voltage and the first output voltage to generate a first control deviation.

[0098] The second comparator 132 is connected to the first comparator 131 and is configured to calculate a difference between the second output voltage and the first control deviation to generate a second control deviation.

[0099] The third comparator 133 is connected to the first comparator 131 and is used to compare the first control deviation with the first preset threshold and the second preset threshold to generate an enable signal.

[0100] The controller 134 is connected to the second comparator 132 and is configured to generate a control voltage based on the second control deviation.

[0101] The pulse width modulation signal generator 135 is connected to the controller 134 and the third comparator 133 , and is configured to generate a gate control signal based on the control voltage and the enable signal.

[0102] The preset reference voltage is Vref, the total output voltage is Vout, the first output voltage is Vc1, the first control deviation is Vref,c2, the second output voltage is Vc2, the second control deviation is ΔVc2, the first preset threshold is Vth1, the second preset threshold is Vth2, and the enable signal is en, then:

[0103] Vref—Vc1=Vref,c2

[0104] Vref,c2-Vc2=ΔVc2

[0105] In the embodiment of the present application, the third comparator 133 compares the first control deviation with the first preset threshold and the second preset threshold to generate an enable signal, including:

[0106] When the first control deviation is greater than the first preset threshold, the enable signal is at a high level.

[0107] When the first control deviation is less than the second preset threshold, the enable signal is at a low level.

[0108] For example, when Vref,c2 > Vth1, it is considered that the actual output voltage (the first output voltage) of the step-down rectification module deviates significantly from its set value, and the enable signal en = 1 is set; when Vref,c2 < Vth2, it is considered that the actual output voltage (the first output voltage) of the step-down rectification module is within the normal range, and the enable signal en = 0 is set.

[0109] In an embodiment of the present application, the third comparator 133 is a hysteresis comparator.

[0110] The hysteresis characteristic of the hysteresis comparator can be controlled by adjusting the gain and threshold of the positive feedback network. For example, increasing the gain of the positive feedback network can increase the amplitude of the hysteresis, and adjusting the threshold can change the trigger point of the hysteresis.

[0111] In this implementation, by regulating the gain and threshold parameters of the hysteresis comparator, sensitive detection of the first control deviation can be achieved.

[0112] In one embodiment, the pulse width modulation signal generator 135 generating the gate control signal based on the control voltage and the enable signal includes:

[0113] When the enable signal is at a high level, the pulse width modulation signal generator generates a gate control signal based on the control voltage, and the gate control signal is at a low level.

[0114] When the enable signal is at a low level, the pulse width modulation signal generator does not operate, and the gate control signal is at a high level.

[0115] The voltage regulation module 12 is used to convert the first output voltage based on the gate control signal to generate the second output voltage.

[0116] In one embodiment, the voltage regulation module 12 converting the first output voltage based on the gate control signal to generate the second output voltage includes:

[0117] When the gate control signal is at a low level, the voltage regulation module operates to convert the first output voltage into the second output voltage.

[0118] When the gate control signal is at a high level, the voltage regulation module does not operate, and the first output voltage is within the normal operating range.

[0119] The voltage stabilizing module is used to convert the first output voltage based on the gate control signal to generate the second output voltage, that is, the gate control signal is used to achieve stable output of the first output voltage by controlling the on and off of the switch tube in the voltage stabilizing module. The preset reference voltage is usually used as a reference point or reference signal to ensure the accuracy and stability of the total output voltage. In an embodiment of the present application, the gate control signal generated by the PWM signal generator is a PWM signal, and the pulse width of the PWM signal or the duty cycle of the PWM signal can be adjusted as needed to control the on time and off time of the switch tube.

[0120] like Figure 4 As shown, the switch tubes controlled by the gate control signal include primary switch tubes Q1 to Q8 and secondary switch tubes Q9 and Q10. These switch tubes can be MOSFETs (metal oxide semiconductor field effect transistors) or other types of electronic switches.

[0121] The primary switch tube (Q1~Q8) is located on the input power side of the three-level full-bridge LLC resonant converter, and is used to provide switching action to control the connection and disconnection of the input power. By periodically turning the primary switch tube on and off, the input power can be regulated. When the switch tube is turned on, the input current flows through the switch tube to supply the load circuit; when the switch tube is turned off, the input power is disconnected from the load circuit to avoid overload or other adverse conditions.

[0122] The secondary switch tube (Q9 and Q10) is located on the output voltage side of the three-level full-bridge LLC resonant converter and is used to control the stability of the output voltage. The output voltage can be adjusted by controlling the conduction and shutdown of the secondary switch tube. When the secondary switch tube is turned on, the output voltage can be passed to the load circuit; when the switch tube is turned off, the output voltage is cut off to avoid overvoltage or other abnormal conditions.

[0123] When the grid voltage is normal, the voltage stabilizer is generally not needed. The grid usually provides a stable voltage supply that can meet the working requirements of most electronic devices. At this time, the voltage stabilizer will not play a big role, so the use of the voltage stabilizer can be prohibited to extend its service life.

[0124] However, in some cases, the grid voltage may deviate significantly, such as the grid voltage being too high or too low. This may be caused by grid load changes, grid faults, or other factors. When the voltage deviates significantly, electronic equipment may be damaged or become unstable.

[0125] In order to protect electronic equipment from the influence of grid voltage deviation, a voltage stabilizer can be used to adjust the output voltage and keep it within the set range. When the grid voltage deviates greatly, the voltage stabilizer will automatically start and adjust the output voltage by adjusting the duty cycle of the PWM signal to keep it at a stable level.

[0126] In this implementation, by using the voltage stabilizer only when the grid voltage deviates seriously, its use frequency can be reduced, thereby extending its service life. This is because the voltage stabilizer generates a certain amount of heat and loss when working, and long-term work may cause a certain burden on it. When the grid voltage is normal, the voltage stabilizer can be in standby or off state, reducing its working time and load, which helps to extend its life.

[0127] like Figure 7 As shown, this embodiment provides an output voltage stabilization control system, comprising the output voltage stabilization control device 1 described in any one of the above items, a three-phase AC voltage source 2 and a load 3.

[0128] The three-phase AC voltage source 2 is connected to the output voltage stabilization control device 1 and is used to input the AC power to the output voltage stabilization control device 1 .

[0129] The load 3 is connected to the output voltage stabilization control device 1 and is configured to operate based on the second output voltage.

[0130] like Figure 8 As shown, this embodiment provides an output voltage stabilization control method, which is applied to a charging station and includes steps S1 to S3.

[0131] Step S1: Convert alternating current into direct current to generate a first output voltage.

[0132] Step S2: converting the first output voltage to generate a second output voltage, wherein the sum of the first output voltage and the second output voltage is a total output voltage.

[0133] Step S3: generating a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage.

[0134] like Fig. 9 As shown, converting the first output voltage to generate a second output voltage includes step S21.

[0135] Step S21: convert the first output voltage based on the gate control signal to generate the second output voltage.

[0136] It should be noted that steps S1 to S3 and step S21 in this embodiment correspond one-to-one to the structure, principle and embodiment of the above-mentioned output voltage stabilizing device, and thus will not be described in detail herein.

[0137] The technical solution of the present application and the technical effects achieved thereby will be described in detail below in conjunction with a specific embodiment.

[0138] The present application can be applied to a 500kW charging station system, with a three-phase 10kV input and an output charging voltage range of 200V to 750V. The input three-phase 10kV voltage range is + / -10%, that is, 9kV to 11kV, and the transformer-rectifier module also has a 5% load adjustment rate. For this reason, the input voltage of the transformer-rectifier module is designed to be 700V when the input is 9kV and the output is fully loaded. In this way, the voltage is about 736V when the input is 9kV and the output is no-load, and the voltage is 900V when the input is 11kV and the output is no-load. That is, the output voltage range of the transformer-rectifier module is 700V to 900V, which cannot meet the operating requirements of the charging pile.

[0139] In order to ensure that the charging pile has the required input voltage, the output voltage of the centralized power supply must be between 800V and 900V. Therefore, the rated output voltage of the voltage regulator module is designed to be 100V. When the voltage of the transformer-rectifier module is above 800V, the voltage regulator module does not operate; when the transformer-rectifier voltage is lower than 800V, the total output voltage is controlled above 800V by adjusting the voltage regulator module voltage. In the control logic setting, the output voltage is set at 850V. When the reference voltage differs from the actual output of the transformer-rectifier by less than 20V, the voltage regulator module is stopped. When the difference is more than 40V, the voltage regulator module is turned on. Figure 6 The parameters in are set as Vref=850V, Vth1=40V, Vth2=20V.

[0140] In this way, when the input voltage is 10kV, the output voltage of the transformer and rectifier module itself can basically meet the requirements of the charging pile, and there is no need to turn on the voltage stabilizing module. The voltage stabilizing module will only be turned on when the input voltage is reduced.

[0141] The maximum output voltage of the voltage regulator module is 100 V, the corresponding output voltage of the transformer and rectifier module is 700 V, and the total output voltage is 800 V. The efficiency of the transformer and rectifier module is 98.5%, the efficiency of the voltage regulator module is 96%, and the overall efficiency is 800 / (7 / 0.985+1 / 0.985 / 0.96)=98%.

[0142] From this embodiment, it can be seen that although the voltage stabilizing module is less efficient than the transformer rectifier module, the voltage stabilizing module accounts for a small proportion of the output power, and has little impact on the overall efficiency. Moreover, since the voltage stabilizing module is not a continuously running device, the voltage stabilizing module can be shut down when the grid voltage is normal, which is equivalent to extending the service life. Therefore, the voltage stabilizing module of this application has obvious advantages in efficiency and service life compared to other similar devices.

[0143] The protection scope of the output voltage stabilization control method described in the embodiment of the present application is not limited to the execution order of the steps listed in the present embodiment. All solutions implemented by adding, reducing or replacing steps in the prior art based on the principles of the present application are included in the protection scope of the present application.

[0144] The output voltage stabilization control device provided in the embodiment of the present application can implement the output voltage stabilization control method described in the present application, but the implementation device of the output voltage stabilization control method described in the present application includes but is not limited to the structure of the output voltage stabilization control device listed in the present embodiment. All structural deformations and replacements of the prior art made according to the principles of the present application are included in the protection scope of the present application.

[0145] In the several embodiments provided in the present application, it should be understood that the disclosed system, device or method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of modules / units is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules or units, which can be electrical, mechanical or other forms.

[0146] The modules / units described as separate components may or may not be physically separated, and the components displayed as modules / units may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules / units may be selected according to actual needs to achieve the purpose of the embodiments of the present application. For example, the functional modules / units in the various embodiments of the present application may be integrated into one processing module, or each module / unit may exist physically separately, or two or more modules / units may be integrated into one module / unit.

[0147] Those of ordinary skill in the art should further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0148] The descriptions of the processes or structures corresponding to the above-mentioned figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0149] In summary, the output voltage stabilization control device, system and method provided by the present application solve the technical problems of low efficiency and high cost in the existing voltage stabilization technical solutions. By connecting the output of the transformer and rectifier module and the output of the voltage stabilization module in series, stable control of the output voltage of the transformer and rectifier module is achieved; the voltage stabilization module can supplement the output of the transformer and rectifier module as needed, and the supplement range is 10% to 20%; it is suitable for applications that require a narrower or even fixed input voltage range, with high efficiency and low cost.

[0150] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. An output voltage stabilization control device, characterized in that: Including transformer and rectifier module, voltage stabilization module and control module: The transformer and rectifier module is used to convert alternating current into direct current to generate a first output voltage; The voltage stabilizing module is connected in series with the voltage transformation and rectification module, and is used to convert the first output voltage to generate a second output voltage, wherein the sum of the first output voltage and the second output voltage is the total output voltage; The control module is connected to the voltage stabilizing module and the voltage transforming and rectifying module, and is used to generate a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage; The voltage stabilization module is used for converting the first output voltage based on the gate control signal to generate the second output voltage.

2. The device according to claim 1, characterized in that The transformer and rectifier module includes a phase-shifting transformer and multiple groups of three-phase rectifier bridges; The phase-shifting transformer is used to convert the alternating current into multiple groups of three-phase voltages by winding phase shifting; Each group of the three-phase rectifier bridges is connected to the phase-shifting transformer, and is used to input a group of the three-phase voltages and rectify the three-phase voltages; A plurality of groups of output ends of the three-phase rectifier bridges are connected in parallel to output the first output voltage.

3. The device according to claim 2, characterized in that The number of groups of the three-phase voltage matches the number of groups of the three-phase rectifier bridge.

4. The device according to claim 1, characterized in that The voltage stabilizing module includes an isolated DC / DC converter.

5. The device according to claim 1, characterized in that The second output voltage accounts for 10% to 20% of the total output voltage.

6. The device according to claim 1, characterized in that The control module includes a first comparator, a second comparator, a third comparator, a controller and a pulse width modulation signal generator; The first comparator is used to calculate the difference between the preset reference voltage and the first output voltage to generate a first control deviation; The second comparator is connected to the first comparator and is used to calculate the difference between the second output voltage and the first control deviation to generate a second control deviation; The third comparator is connected to the first comparator and is used to compare the first control deviation with a first preset threshold and a second preset threshold to generate an enable signal; The controller is connected to the second comparator and is configured to generate a control voltage based on the second control deviation; The pulse width modulation signal generator is connected to the controller and the third comparator, and is used to generate the gate control signal based on the control voltage and the enable signal.

7. The device according to claim 6, characterized in that The third comparator compares the first control deviation with the first preset threshold and the second preset threshold to generate an enable signal, which includes: When the first control deviation is greater than the first preset threshold, the enable signal is at a high level; When the first control deviation is less than the second preset threshold, the enable signal is at a low level.

8. The device according to claim 6, characterized in that The third comparator is a hysteresis comparator.

9. The device according to claim 6, characterized in that The pulse width modulation signal generator generates a gate control signal based on the control voltage and the enable signal, comprising: When the enable signal is at a high level, the pulse width modulation signal generator generates a gate control signal based on the control voltage, and the gate control signal is at a low level; When the enable signal is at a low level, the pulse width modulation signal generator does not operate, and the gate control signal is at a high level.

10. The device according to claim 1, characterized in that The voltage stabilizing module converts the first output voltage based on the gate control signal to generate the second output voltage, including: When the gate control signal is at a low level, the voltage stabilizing module operates to convert the first output voltage into the second output voltage; When the gate control signal is at a high level, the voltage stabilizing module does not operate, and the first output voltage is within a normal operating range.

11. An output voltage stabilization control system, characterized in that: The device comprises the output voltage stabilization control device according to any one of claims 1 to 10, a three-phase AC voltage source and a load; The three-phase AC voltage source is used to input the AC power to the output voltage stabilization control device; The load is configured to operate based on the second output voltage.

12. An output voltage stabilization control method, applied to a charging station, characterized in that: include: converting the alternating current into direct current to generate a first output voltage; converting the first output voltage to generate a second output voltage, wherein the sum of the first output voltage and the second output voltage is a total output voltage; generating a gate control signal based on the first output voltage, the second output voltage and a preset reference voltage; The converting the first output voltage to generate a second output voltage includes converting the first output voltage based on the gate control signal to generate the second output voltage.

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