Constant current to constant voltage conversion method with series input and parallel output

Abstract

The application provides a constant-current-to-constant-voltage conversion system with series input and parallel output, comprising: n constant-current-to-constant-voltage conversion modules and n control modules, wherein n is an integer greater than or equal to 2; the constant-current-to-constant-voltage conversion module j comprises: a shunt regulator circuit j and an LLC resonant circuit j; j is the number of the constant-current-to-constant-voltage conversion module, and j is a positive integer from 1 to n; the control module j comprises: a first driving circuit j1, a second driving circuit j2, a controller j and an acquisition circuit j; the input ends of the shunt regulator circuits are connected in series, the output ends of the shunt regulator circuits are connected in cascade with the input ends of the corresponding LLC resonant circuits, and the output ends of the LLC resonant circuits are connected in parallel; according to the change of the output power, the system can realize the smooth switching in / out of the modules independently, the modules are independently controlled and do not affect each other, so that the output power of the system is not unevenly distributed, and the output power regulation of the system is more flexible.

Description

Technical Field

[0001] This invention relates to the field of power automation, and in particular to a constant current to constant voltage conversion method with series input and parallel output. Background Technology

[0002] The deep sea contains abundant resources and possesses unique spatial advantages and value. Submarine fiber optic transmission systems and seabed observation networks are important means of exploring marine resources and ensuring marine security. Ensuring the normal operation of submarine fiber optic transmission systems and seabed observation networks is one of the key links in exploring marine resources and ensuring marine security. The power supply system is a prerequisite for the normal operation of equipment such as submarine transmission systems and observation networks.

[0003] Currently, for submarine power supply environments, constant current power supply has better fault tolerance. When the cable is short-circuited, the power supply circuit between the fault point and the constant current source can still work normally, making it more suitable for underwater power supply systems with high short-circuit failure rates.

[0004] However, existing constant current to constant voltage multi-module coordinated control technologies mainly focus on input voltage equalization / output current equalization control. Each control method ultimately aims to evenly distribute the output power of each module, but it cannot flexibly adjust the output power. At low power output, the equalization control strategy of the conversion system suffers from inefficiency.

[0005] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a constant current to constant voltage conversion system with series input and parallel output, comprising: n constant current to constant voltage conversion modules and n control modules, where n is an integer greater than or equal to 2;

[0007] The constant current to constant voltage conversion module j includes: a shunt regulator circuit j and an LLC resonant circuit j; j is the number of the constant current to constant voltage conversion module, and j takes a positive integer from 1 to n;

[0008] The control module j includes: a first drive circuit j1, a second drive circuit j2, a controller j, and a data acquisition circuit j;

[0009] The input terminals of each shunt regulator circuit are connected in series, the output terminal of each shunt regulator circuit is cascaded with the input terminal of the corresponding LLC resonant circuit, and the output terminals of each LLC resonant circuit are connected in parallel.

[0010] The controller j is electrically connected to both the first drive circuit j1 and the second drive circuit j2. The first drive circuit j1 is electrically connected to the input terminal of the shunt regulator circuit j. The acquisition circuit j is electrically connected to the output terminal of the LLC resonant circuit j. The second drive circuit j2 is electrically connected to the input terminal j of the switching transistor of the LLC resonant circuit j.

[0011] Preferably, the shunt regulator circuit j uses a switching transistor Q. j1 As an input terminal.

[0012] Preferably, the LLC resonant circuit j includes: the input terminal of the switching transistor j, the inverter circuit j, the resonant circuit j, and the high-frequency isolation transformer T. rj 1. Rectifier circuit j and output terminal j;

[0013] Switch input terminal j, inverter circuit j, resonant circuit j, high-frequency isolation transformer T rj The rectifier circuit j and the output terminal j are connected electrically in sequence.

[0014] The input terminal j of the switching transistor includes: the first switching transistor S j1 Second switch S j2 The input terminal j of the switching transistor is used to receive the constant frequency output signal generated by the controller j;

[0015] The inverter circuit j adopts either a full-bridge inverter circuit or a half-bridge inverter circuit;

[0016] The resonant circuit j includes: resonant inductor L rj Resonant capacitor C rj And excitation inductance L mj ;

[0017] The rectifier circuit j adopts a full-wave rectifier circuit or a bridge rectifier circuit;

[0018] The output terminal j includes: output filter capacitor C oj and output resistance R out ;

[0019] Output filter capacitor C oj and output resistance R out All are electrically connected to the acquisition circuit.

[0020] A constant current to constant voltage conversion method with series input and parallel output includes:

[0021] S1: The acquisition circuit obtains the output voltage and output current of the corresponding LLC resonant circuit in real time;

[0022] S2: The controller calculates and obtains the PWM drive signal for the corresponding shunt regulator circuit by using the output voltage and output current.

[0023] S3: Controls the operation of the corresponding shunt regulator circuit through the PWM drive signal.

[0024] Preferably, step S1 specifically includes:

[0025] The acquisition circuit j obtains the output filter capacitor C. oj Output current i oj Obtain the output resistance R out Output voltage V out .

[0026] Preferably, step S2 specifically includes:

[0027] S21: Output voltage V out and output current i oj Input controller j, calculate and obtain the output voltage error value e ju The calculation formula is: e ju =V refj -V out ;

[0028] Among them, V refj This is the reference value for the output voltage of the constant current to constant voltage converter module j;

[0029] S22: Through the output voltage error value e ju Calculate the feedback current reference value i of the current regulator circuit j. j * The calculation formula is:

[0030] i j * =K pj1 e uj +K ij1 ×(∫e uj dt+C j1 )

[0031] Among them, K pj1 and K ij1 These are the proportional and integral coefficients of the output voltage of the shunt regulator circuit j, respectively, where t is time and C is the output voltage coefficient. j1 It is the first integral constant;

[0032] S23: By feedback current reference value i j * The output current error value e is calculated. ji The calculation formula is: e ji =i j * -i oj ;

[0033] S24: Through the output current error value e jiCalculate the duty cycle instruction D j The calculation formula is:

[0034] D j =K pj2 e ij +K ij2 ×(∫e ij dt+C j2 );

[0035] Among them, K pj2 and K ij2 These are the proportional and integral coefficients of the output current of the shunt regulator circuit j, respectively, where t is time and C is the output current proportional coefficient and integral coefficient. j2 It is the second integral constant;

[0036] S25: According to duty cycle instruction D j The magnitude of the signal generates the PWM drive signal for the current shunt regulator circuit j.

[0037] Preferably, the output voltage V out The process for determining the value is as follows:

[0038] Based on the output resistance R out The power is used to determine the number of the constant current to constant voltage converter module that meets the output voltage conditions of the constant current to constant voltage converter system;

[0039] Output voltage V out The value is determined by the minimum value among the output voltage reference values ​​of the constant current to constant voltage converter module that meets the output voltage condition;

[0040] The constant current to constant voltage converter module with the smallest output voltage reference value has an output voltage error of 0, while the output voltage error values ​​of other constant current to constant voltage converter modules that meet the output voltage conditions are always positive.

[0041] Preferably, step S3 specifically includes:

[0042] The PWM drive signal of the shunt regulator circuit j controls the switching transistor Q. j1 The switching on or off is controlled by the switching transistor Q. j1 The status control corresponds to the device.

[0043] The present invention has the following beneficial effects:

[0044] 1. The present invention employs a modular design and control of multiple constant current to constant voltage conversion modules, which enables the constant current to constant voltage conversion system to have high redundancy and fault tolerance.

[0045] 2. Power compensation is performed using the output voltage reference value of the constant current to constant voltage converter module, and the output power is coordinated and adjusted to stabilize the voltage output of the constant current to constant voltage converter system.

[0046] 3. The constant current to constant voltage converter system provides all the output power through a few constant current to constant voltage converter modules, thereby achieving high-efficiency operation of the converter system when the power output is low; according to the change of output power, the system can autonomously realize the smooth switching in / out of the modules, and each module is independently controlled without affecting each other, thereby realizing uneven distribution of the system's output power and making the system's output power adjustment more flexible. Attached Figure Description

[0047] Figure 1 This is a structural diagram of a combination of multiple constant current to constant voltage conversion modules;

[0048] Figure 2 A structural diagram of a constant current to constant voltage converter system with series input and parallel output;

[0049] Figure 3 Here is a diagram of the controller structure;

[0050] Figure 4 This is a first embodiment of a combination of multiple constant current to constant voltage conversion modules;

[0051] Figure 5 This is a second embodiment of a combination of multiple constant current to constant voltage conversion modules;

[0052] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0054] Reference Figure 1-2 The present invention provides a constant current to constant voltage conversion system with series input and parallel output, comprising: n constant current to constant voltage conversion modules and n control modules, where n is an integer greater than or equal to 2;

[0055] The constant current to constant voltage conversion module j includes: a shunt regulator circuit j and an LLC resonant circuit j; j is the number of the constant current to constant voltage conversion module, and j takes a positive integer from 1 to n;

[0056] The control module j includes: a first drive circuit j1, a second drive circuit j2, a controller j, and a data acquisition circuit j;

[0057] The input terminals of each shunt regulator circuit are connected in series, the output terminal of each shunt regulator circuit is cascaded with the input terminal of the corresponding LLC resonant circuit, and the output terminals of each LLC resonant circuit are connected in parallel.

[0058] The controller j is electrically connected to both the first drive circuit j1 and the second drive circuit j2. The first drive circuit j1 is electrically connected to the input terminal of the shunt regulator circuit j. The acquisition circuit j is electrically connected to the output terminal of the LLC resonant circuit j. The second drive circuit j2 is electrically connected to the input terminal j of the switching transistor of the LLC resonant circuit j.

[0059] Specifically, each controller uses an independent digital chip, selecting any chip from models such as ARM, DSP, and FPGA; (See reference) Figure 3 The controller adopts dual PI control. Each acquisition circuit acquires the output current ioj and output voltage Vout of the corresponding constant current to constant voltage conversion module. The output voltage and output current of the constant current to constant voltage conversion module are adjusted by dual PI control through voltage outer loop control and current inner loop control.

[0060] Furthermore, the shunt regulator circuit j uses a switching transistor Q. j1 As an input terminal.

[0061] Specifically, the shunt regulator circuit j includes a first shunt circuit and a second shunt circuit;

[0062] The first shunt circuit consists of a switching transistor Q. j1 diode D j1 and filter capacitor C j1 constitute;

[0063] The second shunt circuit consists of the switching transistor Q. j1 diode D j1 Filter capacitor C j1 and capacitance V cbj constitute;

[0064] The positive terminal of constant current source I is connected to the switching transistor Q of shunt regulator circuit 1. 11 The drain of the constant current source I is connected to the switching transistor Q of the shunt regulator circuit n. n1 The source stage, the switching transistor Q j1 Source stage and switching transistor Q (j+1)1 Drains are connected in series.

[0065] Furthermore, the LLC resonant circuit j includes: the input terminal of the switching transistor j, the inverter circuit j, the resonant circuit j, and the high-frequency isolation transformer T. rj 1. Rectifier circuit j and output terminal j;

[0066] Switch input terminal j, inverter circuit j, resonant circuit j, high-frequency isolation transformer T rj The rectifier circuit j and the output terminal j are connected electrically in sequence.

[0067] The input terminal j of the switching transistor includes: the first switching transistor S j1 Second switch S j2The input terminal j of the switching transistor is used to receive the constant frequency output signal generated by the controller j;

[0068] The inverter circuit j adopts either a full-bridge inverter circuit or a half-bridge inverter circuit;

[0069] The resonant circuit j includes: resonant inductor L rj Resonant capacitor C rj And excitation inductance L mj ;

[0070] The rectifier circuit j adopts a full-wave rectifier circuit or a bridge rectifier circuit;

[0071] The output terminal j includes: output filter capacitor C oj and output resistance R out ;

[0072] Output filter capacitor C oj and output resistance R out All are electrically connected to the acquisition circuit.

[0073] Specifically, when the inverter circuit j adopts a full-bridge inverter circuit, the full-bridge inverter circuit consists of four identical switching transistors S j1 S j2 S j3 and S j4 Composition; In a full-bridge inverter circuit, the switching transistor S j1 S j4 The driving waveform is the same, and the switching transistor S j2 S j3 The driving waveform is the same, and the switching transistor S j1 S j4 Drive waveform and switching transistor S j2 S j3 The driving waveforms are complementary and both have a duty cycle of 50%.

[0074] When the inverter circuit j adopts a half-bridge inverter circuit, the half-bridge inverter circuit consists of two identical switching transistors S j1 and S j2 Composition; In a half-bridge inverter circuit, the switching transistor S j1 and switching transistor S j2 The driving waveforms are complementary and both have a duty cycle of 50%.

[0075] The full-bridge inverter circuit or half-bridge inverter circuit uses any one of the following switching transistors: MOSFET, BJT, and IGBT; the switching frequency of the full-bridge inverter circuit or half-bridge inverter circuit is fixed and equal to the LLC resonant frequency, and its resonant frequency is determined by the following formula:

[0076] When the rectifier circuit j uses a full-wave rectifier circuit, the full-wave rectifier circuit consists of two identical rectifier diodes D rj1 and Drj2 Composition; When the rectifier circuit j adopts a bridge rectifier circuit, the bridge rectifier circuit consists of four identical rectifier diodes D rj1 D rj2 D rj3 and D rj4 constitute;

[0077] Figure 4 In the first embodiment of the combination of multiple constant current to constant voltage conversion modules, the shunt regulator circuit adopts a first shunt circuit, the inverter circuit adopts a full-bridge inverter circuit, and the rectifier circuit adopts a bridge rectifier circuit.

[0078] Figure 5 In the second embodiment of the combination of multiple constant current to constant voltage conversion modules, the shunt regulator circuit adopts a second shunt circuit, the inverter circuit adopts a half-bridge inverter circuit, and the rectifier circuit adopts a full-wave rectifier circuit.

[0079] This invention provides a constant current to constant voltage conversion method with series input and parallel output, comprising:

[0080] S1: The acquisition circuit obtains the output voltage and output current of the corresponding LLC resonant circuit in real time;

[0081] Step S1 specifically involves: the acquisition circuit j acquiring the output filter capacitor C. oj Output current i oj Obtain the output resistance R out Output voltage V out ;

[0082] S2: The controller calculates and obtains the PWM drive signal for the corresponding shunt regulator circuit by using the output voltage and output current.

[0083] S3: Control the operation of the corresponding shunt regulator circuit through the PWM drive signal;

[0084] Step S3 is as follows:

[0085] The PWM drive signal of the shunt regulator circuit j controls the switching transistor Q. j1 The switching on or off is controlled by the switching transistor Q. j1 The status control corresponds to the device.

[0086] Furthermore, step S2 specifically involves:

[0087] S21: Output voltage V out and output current i oj Input controller j, calculate and obtain the output voltage error value e ju The calculation formula is: e ju =V refj -V out ;

[0088] Among them, V refj This is the reference value for the output voltage of the constant current to constant voltage converter module j;

[0089] S22: Through the output voltage error value e ju Calculate the feedback current reference value i of the current regulator circuit j. j * The calculation formula is:

[0090] i j * =K pj1 e uj +K ij1 ×(∫e uj dt+C j1 )

[0091] Among them, K pj1 and K ij1 These are the proportional and integral coefficients of the output voltage of the shunt regulator circuit j, respectively, where t is time and C is the output voltage coefficient. j1 It is the first integral constant;

[0092] S23: By feedback current reference value i j * The output current error value e is calculated. ji The calculation formula is: e ji =i j * -i oj ;

[0093] S24: Through the output current error value e ji Calculate the duty cycle instruction D j The calculation formula is:

[0094] D j =K pj2 e ij +K ij2 ×(∫e ij dt+C j2 );

[0095] Among them, K pj2 and K ij2 These are the proportional and integral coefficients of the output current of the shunt regulator circuit j, respectively, where t is time and C is the output current proportional coefficient and integral coefficient. j2 It is the second integral constant;

[0096] S25: According to duty cycle instruction D j The magnitude of the signal generates the PWM drive signal for the current shunt regulator circuit j.

[0097] Furthermore, the output voltage V outThe process for determining the value is as follows:

[0098] Based on the output resistance R out The power is used to determine the number of the constant current to constant voltage converter module that meets the output voltage conditions of the constant current to constant voltage converter system;

[0099] Output voltage V out The value is determined by the minimum value among the output voltage reference values ​​of the constant current to constant voltage converter module that meets the output voltage condition;

[0100] The constant current to constant voltage converter module with the smallest output voltage reference value has an output voltage error of 0, while the output voltage error values ​​of other constant current to constant voltage converter modules that meet the output voltage conditions are always positive.

[0101] Specifically, taking the constant current to constant voltage converter module 1, constant current to constant voltage converter module 2, and constant current to constant voltage converter module 3 satisfying the output voltage condition as an example, let V ref1 >V ref3 >V ref2 After the constant current to constant voltage conversion system stabilizes its output, the error values ​​of each output voltage satisfy the following conditions:

[0102] Output voltage error value e of constant current to constant voltage converter module 1 1u =V ref1 -V ref2 The output voltage error value e of the constant current to constant voltage converter module 3 is a constant positive value. 3u =V ref3 -V ref2 The output voltage error value e of the constant current to constant voltage converter module 2 is a constant positive value. 2u =V ref2 -V ref2 It is 0.

[0103] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0104] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the unit claims listing several devices, several of these devices may be embodied by the same hardware item. The use of the terms first, second, and third, etc., does not indicate any order and can be interpreted as identifiers.

[0105] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A constant current to constant voltage conversion method with series input and parallel output, based on a constant current to constant voltage conversion system with series input and parallel output, characterized in that, The constant-current-to-constant-voltage conversion system comprises n constant-current-to-constant-voltage conversion modules and n control modules, n being an integer greater than or equal to 2; The constant-current-to-constant-voltage conversion module j comprises a shunt regulator circuit j and an LLC resonant circuit j; j is the number of the constant-current-to-constant-voltage conversion module, and j is a positive integer from 1 to n; The control module j comprises a first driving circuit j1, a second driving circuit j2, a controller j, and an acquisition circuit j; The input ends of the shunt regulator circuits are connected in series, the output ends of the shunt regulator circuits are connected in cascade with the input ends of the corresponding LLC resonant circuits, and the output ends of the LLC resonant circuits are connected in parallel; The controller j is electrically connected with the first driving circuit j1 and the second driving circuit j2, the first driving circuit j1 is electrically connected with the input end of the shunt regulator circuit j, the acquisition circuit j is electrically connected with the output end of the LLC resonant circuit j, and the second driving circuit j2 is electrically connected with the switch input end j of the LLC resonant circuit j; The constant-current-to-constant-voltage conversion method comprises: S1: The acquisition circuit acquires the output voltage and the output current of the corresponding LLC resonant circuit in real time; S2: The controller calculates the PWM driving signal of the corresponding shunt regulator circuit through the output voltage and the output current; Step S2 is specifically: S21: output voltage V out and output current i oj input controller j, calculate the output voltage error value e ju , the calculation formula is: e ju = V refj -V out ; V refj is the output voltage reference value of the constant-current-to-constant-voltage conversion module j; S22: calculating the feedback current reference value i of the shunt regulator circuit j by the output voltage error value e ju calculating the feedback current reference value i of the shunt regulator circuit j j * , the calculation formula is: i j * = K pj1 e uj + K ij1 × ( ∫ e uj dt + C j1 ) Wherein, K pj1 and K ij1 are output voltage proportional coefficient and output voltage integral coefficient of the shunt regulator circuit j respectively, t is time, C j1 is the first integral constant; S23: obtain the output current error value e by feeding back the current reference value i j * obtain the output current error value e by calculating ji , the calculation formula is: e ji = i j * - i oj ; S24: outputting the current error value e ji The duty command D is calculated j The calculation formula is: D j = K pj2 e ij + K ij2 × ( ∫ e ij dt + C j2 ) ; Wherein, K pj2 and K ij2 are the output current proportional coefficient and the output current integral coefficient of the shunt regulator circuit j respectively, t is time, C j2 is the second integral constant; S25: generating a PWM drive signal of the shunt regulator circuit j according to the duty ratio command D j of the size; The output voltage V out The determination process of the value of V is as follows: According to the output resistance R out , the number of constant-current to constant-voltage conversion modules satisfying the constant-current to constant-voltage conversion system output voltage condition is determined. Output voltage V out The value is determined by the minimum of the output voltage reference values of the constant current to constant voltage conversion modules that satisfy the output voltage condition; The output voltage error value of the constant-current-to-constant-voltage conversion module with the minimum output voltage reference value is 0, and the output voltage error values of the other constant-current-to-constant-voltage conversion modules meeting the output voltage condition are always positive values; S3: The operation of the corresponding shunt regulator circuit is controlled through the PWM driving signal.

2. The constant current to constant voltage conversion method of claim 1, wherein, The shunt regulator circuit j employs a switching transistor Q j1 As an input end; the LLC resonant circuit j includes a switching transistor input end j, an inverter circuit j, a resonant circuit j, a high-frequency isolation transformer T rj , a rectifier circuit j and an output end j; Switching tube input end j, inverter circuit j, resonance circuit j, high-frequency isolation transformer T rj , rectifier circuit j and output end j are electrically connected in sequence; The switch tube input end j comprises a first switch tube S j1 and a second switch tube S j2 , and the switch tube input end j is used for receiving a constant frequency output signal generated by the controller j. The inverter circuit j adopts a full-bridge inverter circuit or a half-bridge inverter circuit; The resonance circuit j comprises a resonance inductance L rj , a resonance capacitance C rj and an excitation inductance L mj ; The rectifier circuit j adopts a full-wave rectifier circuit or a bridge rectifier circuit; The output j comprises an output filter capacitor C oj and an output resistor R out ; An output filter capacitor C oj and an output resistor R out are electrically connected with the acquisition circuit j; Step S1 is specifically: The acquisition circuit j obtains an output filter capacitor C oj The output output current i oj , the output resistance R out The output output voltage V out .

3. The method of claim 1, wherein the constant current to constant voltage conversion is performed in series input and parallel output. The shunt regulator circuit j employs a switching transistor Q j1 As an input end; the LLC resonant circuit j includes a switching transistor input end j, an inverter circuit j, a resonant circuit j, a high-frequency isolation transformer T rj , a rectifier circuit j and an output end j; Switching tube input end j, inverter circuit j, resonance circuit j, high-frequency isolation transformer T rj , rectifier circuit j and output end j are electrically connected in sequence; The switch tube input end j comprises a first switch tube S j1 and a second switch tube S j2 , and the switch tube input end j is used for receiving a constant frequency output signal generated by the controller j; The inverter circuit j adopts a full-bridge inverter circuit or a half-bridge inverter circuit; The resonance circuit j comprises a resonance inductance L rj , a resonance capacitance C rj and an excitation inductance L mj ; The rectifier circuit j adopts a full-wave rectifier circuit or a bridge rectifier circuit; The output j comprises an output filter capacitor C oj and an output resistor R out ; An output filter capacitor C oj and an output resistor R out are electrically connected with the acquisition circuit j; Step S3 is specifically: The PWM drive signal of the shunt regulator circuit j controls the switch Q j1 on or off, and the corresponding device is controlled through the state of the switch Q j1 .

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