CN110868077A - Topological structure of bidirectional DC converter and its control method - Google Patents

Abstract

The invention discloses a topological structure of a bidirectional direct current converter and a control method thereof, wherein the topological structure comprises N power modules, and each power module comprises a resonant network, and an input end, a first bridge converter, a high-frequency transformer, a second bridge converter and an output end which are sequentially connected; the resonant network is arranged between the first bridge converter and the high-frequency transformer, between the high-frequency transformer and the second bridge converter or arranged on the front side and the rear side of the high-frequency transformer, and the current ripple waves at the input end and the output end of the bidirectional direct current converter can be effectively reduced by configuring the trigger time of the control signals of each power module; the quasi-resonant conversion of the bidirectional direct current converter in a wide load range is realized by configuring the switching period of each power module, so that the input-output and efficiency characteristics of the bidirectional direct current converter are effectively improved, and extremely high efficiency is obtained in a wide range.

Description

Topological structure of bidirectional DC converter and its control method

technical field

The invention relates to the technical field of power electronic conversion, in particular to a topology structure of a bidirectional DC converter and a control method thereof.

Background technique

The bidirectional DC converter can realize the bidirectional flow of energy between two DC power sources, and is the core technology for applications such as energy storage, battery charging and discharging, and DC power distribution. With the increasing use of renewable energy, electric vehicles, and DC transmission in the power field, the demand for high-efficiency and high-performance bidirectional DC converters is increasing, which has broad market prospects.

At present, there are two main types of bidirectional DC converters at home and abroad: (1) Non-isolated DC converters, such as Buck-Boost converters, are widely used in battery charging and discharging systems, but their low gain and non-isolation characteristics limit the The application range of converters; (2) Isolated DC converters, such as bidirectional active bridge circuits (DAB), achieve high-gain conversion and electrical isolation through high-frequency transformers, which have attracted widespread attention, but have lower efficiency when the load changes With larger current ripple, it will bring greater damage to the DC power supply. Bidirectional DC converters at home and abroad have problems such as relatively low efficiency and large ripple.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a topology structure of a bidirectional DC converter and a control method thereof, which can effectively reduce the voltage and current ripple of the input and output terminals. Quasi-resonant conversion in the load range can effectively improve the efficiency in a wide load range.

A topology structure of a bidirectional DC converter provided according to an embodiment of the first aspect of the present invention includes:

N power modules, the input terminals of the N power modules are connected in series and the output terminals are connected in series, the input terminals are connected in series and the output terminals are connected in parallel, the input terminals are connected in parallel and the output terminals are connected in series, or the input terminals are connected in parallel and the output terminals are connected in parallel. The input end, the first bridge converter, the high frequency transformer, the second bridge converter and the output end; the resonant network is arranged between the first bridge converter and the high frequency transformer, and is arranged between the first bridge converter and the high frequency transformer. between the high-frequency transformer and the second bridge converter or on the front and rear sides of the high-frequency transformer;

A control circuit, connected to N power modules respectively, is used for outputting driving signals to control the N power modules, the switching period and duty cycle of the driving signals of each power module are consistent, and the driving signals of each power module are The trigger times of the signals differ by one-Nth of the switching period.

According to some embodiments of the present invention, the control circuit includes a sampling conditioning module, a phase locking module, a closed-loop control module, a driving module and a protection module, and the sampling conditioning module is used to measure the input terminal, the output terminal and all the the current of the resonant network, the phase locking module is used to adjust the switching period of the driving signal, the closed-loop control module is used to output a control signal to the driving module, and the protection module is used to output a protection signal to the driving module , the drive module is used to generate a drive signal according to the switching period, the control signal and the protection signal, the sampling conditioning module is respectively connected to the phase-locking module, the closed-loop control module and the protection module, the phase-locking module , The closed-loop control module and the protection module are respectively connected to the drive module.

According to some embodiments of the present invention, the resonant network consists of a resonant capacitor and a resonant inductor in series or consists of a resonant capacitor.

According to some embodiments of the present invention, the first bridge converter is a single-phase full-bridge circuit, including a first switch tube and a third switch tube as an upper bridge arm, and a second switch tube and a third switch tube as a lower bridge arm. Four switch tubes; the second bridge converter is a single-phase half-bridge circuit, including a fifth switch tube as an upper bridge arm and a sixth switch tube as a lower bridge arm.

According to some embodiments of the present invention, the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch are of Mosfet, Sic, GaN or IGBT fully controlled type device.

A control method applied to the topological structure of the bidirectional DC converter described in the embodiment of the first aspect according to the embodiment of the second aspect of the present invention includes the following control operations:

The sampling conditioning module performs:

Filtering the initial current value _isr of the resonant network to obtain a resonant filter current value _ir ;

Filtering the initial current value _iso of the output terminal to obtain the output filter current value _io ;

Filtering the initial current value i _si of the input terminal to obtain the input filter current value i _i ;

Send the output filter current value i _o to the closed-loop control module, send the resonant filter current value _ir to the phase locking module, and send the resonance filter current value _ir and the output filter current value i _o and the input filter current value i _i is sent to the protection module;

The phase lock module performs:

When the drive signal of the first switch tube changes from low to high, the size of the resonant filter current value _ir is detected: if _ir ≤ 0, increase the switching period; if _ir > _{ir min} , decrease Switching period; if 0<i _r <i _{r min} , keep the switching period unchanged;

sending the switching period T _s into the drive module;

When electrical energy flows from the input to the output, the closed-loop control module performs:

其中

为对应所述输出滤波电流值i_o的输出电流设定值；Calculate the output voltage error

in

is the output current setting value corresponding to the output filter current value i _o ;

Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fraction coefficient respectively, t is the time, and C is the integral Constant, its value is the integral value of the previous calculation, and C=0 in the first calculation;

Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1;

Generate control signal D: compare the modulation voltage u _f with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage u _f is greater than the instantaneous value of the sawtooth wave signal When , the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low;

sending the control signal D to the drive module;

When electrical energy flows from the input end to the output end, the drive module performs:

generating a DC level signal _urdc with a constant amplitude;

Generate the drive signal:

When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u _{If the rdc} is relatively large, the driving signals of the first switch tube and the fourth switch tube are output; if the DC level signal ur _{rdc is} small, the driving signals of the second switch tube and the third switch tube are output;

When the control signal D is low, the driving signals of the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all low;

When the protection signal P is high, the driving signals of the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all low;

sending the drive signal of the first switch tube to the phase lock module;

Send the driving signals of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to the first bridge converter of the first power module; send the first switch tube, The driving signals of the second switch tube, the third switch tube, and the fourth switch tube are delayed by T _s (k-1)/N, and sent to the first bridge converter of the kth power module, where 2≤k ≤N;

When electrical energy flows from the output to the input, the closed-loop control module performs:

其中

为对应所述输入滤波电流值i_i的输入电流设定值；Calculate the output voltage error

in

is the input current setting value corresponding to the input filter current value i _i ;

Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fraction coefficient respectively, t is the time, and C is the integral Constant, its value is the integral value of the previous calculation, and C=0 in the first calculation;

Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1;

Generate control signal D: compare the modulation voltage u _f with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage u _f is greater than the instantaneous value of the sawtooth wave signal When , the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low;

When electrical energy flows from the output terminal to the input terminal, the driving module performs:

generating a DC level signal _urdc with a constant amplitude;

Generate the drive signal:

When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u If the _rdc is large, the drive signal of the fifth switch tube is output; if the DC level signal ur _{rdc is} small, the drive signal of the sixth switch tube is output;

When the control signal D is low, the driving signals of the fifth switch tube and the sixth switch tube are both low;

When the protection signal P is high, the driving signals of the fifth switch tube and the sixth switch tube are both low;

sending the drive signal of the fifth switch tube to the phase lock module;

Send the drive signals of the fifth switch tube and the sixth switch tube to the first bridge converter of the first power module; delay the drive signals of the fifth switch tube and the sixth switch tube by T _s (k-1)/N, sent to the first bridge converter of the kth power module, where 2≤k≤N;

The protection module performs:

Detecting the size of the resonant filter current value _{ir: if ir > irmax , the} output protection signal P is low;

Detecting the magnitude of the output filter current value _io : if _io > _iomax , the output protection signal P is low;

If i _r <i _rmax and i _o <i _omax , the output protection signal is P.

The topological structure of the bidirectional DC converter and the control method thereof provided according to the embodiments of the present invention have at least the following beneficial effects: by configuring the triggering time of the control signal of each power module, the voltage and current ripple of the input and output terminals of the bidirectional DC converter can be effectively reduced By configuring the switching period of each power module, the quasi-resonant conversion of the bidirectional DC converter in a wide load range is realized, thereby effectively improving the input, output and efficiency characteristics of the bidirectional DC converter, and achieving extremely high efficiency in a wide range.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention is further described;

1 is an input parallel output series diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

FIG. 2 is an input parallel output parallel diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

FIG. 3 is an input series output series diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

4 is an input series and output parallel diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

5 is a timing diagram of driving signals of multiple power modules of a bidirectional DC converter topology according to an embodiment of the present invention;

6 is a schematic diagram of an input side compensation connection of a bidirectional DC converter topology provided by an embodiment of the present invention;

7 is a schematic diagram of an output side compensation connection of a bidirectional DC converter topology provided by an embodiment of the present invention;

FIG. 8 is a schematic diagram of compensation connection at the input and output sides of a bidirectional DC converter topology provided by an embodiment of the present invention;

9 is a single-phase full-bridge circuit diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

10 is a single-phase half-bridge circuit diagram of a bidirectional DC converter topology provided by an embodiment of the present invention;

11 is a structural diagram of a control circuit of a bidirectional DC converter topology provided by an embodiment of the present invention;

FIG. 12 is a schematic diagram of a power module circuit of a bidirectional DC converter topology according to an embodiment of the present invention.

Detailed ways

This part will describe the specific embodiments of the present invention in detail, and the preferred embodiments of the present invention are shown in the accompanying drawings. Each technical feature and overall technical solution of the invention should not be construed as limiting the protection scope of the invention.

In the description of the present invention, it should be understood that the azimuth description, such as the azimuth or position relationship indicated by up, down, front, rear, left, right, etc., is based on the azimuth or position relationship shown in the drawings, only In order to facilitate the description of the present invention and simplify the description, it is not indicated or implied that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including this number, above, below, within, etc. are understood as including this number. If it is described that the first and the second are only for the purpose of distinguishing technical features, it cannot be understood as indicating or implying relative importance, or indicating the number of the indicated technical features or the order of the indicated technical features. relation.

In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

The embodiment of the first aspect of the present invention provides a topology structure of a bidirectional DC converter, including:

N power modules 100, as shown in Figs. 1-4, the N power modules 100 have input terminals connected in series, output terminals connected in series, input terminals connected in series and output terminals connected in parallel, input terminals connected in parallel, output terminals connected in series, or input terminals connected in parallel and output terminals connected in parallel. As shown in FIGS. 6-8 , the power module 100 includes a resonant network 140 and an input terminal, a first bridge converter 110 , a high frequency transformer 120 , a second bridge converter 130 and an output terminal connected in sequence; the The resonant network 140 is arranged between the first bridge converter 110 and the high-frequency transformer 120, between the high-frequency transformer 120 and the second bridge converter 130, or between the high-frequency transformer 120 and the high-frequency transformer 130. The front and rear sides of the transformer 120 are provided;

The control circuit is connected to N power modules 100 respectively, and is used for outputting driving signals to control the N power modules 100. The switching period and duty cycle of the driving signals of each power module 100 are consistent. The triggering time of the driving signal of the module 100 differs by one-Nth of the switching period. The timing diagram of the driving signals of the multiple power modules is shown in FIG. 5 . Specifically, in an embodiment, three power modules 100 may be provided, all switching devices use Mosfet, the high-frequency transformer 120 has a turn ratio of 4:15, a rated frequency of 100 kHz, and an equivalent leakage inductance of 5.48 on the output side. uH, the resonant network 140 is composed of a resonant capacitor with a size of 0.47Uf.

11 , in some embodiments of the present invention, the control circuit includes a sampling conditioning module, a phase-locking module, a closed-loop control module, a driving module, and a protection module, and the sampling conditioning module is used to measure the input, all The current of the output terminal and the resonant network 140, the phase-locking module is used to adjust the switching period T _s of the driving signal, the closed-loop control module is used to output the control signal D to the driving module, and the protection module uses In order to output the protection signal P to the driving module, the driving module is used to generate a driving signal according to the switching period T _s , the control signal D and the protection signal P, and the sampling conditioning module is respectively connected to the phase locking module, the The closed-loop control module and the protection module, the phase lock module, the closed-loop control module and the protection module are respectively connected to the drive module.

Referring to FIG. 12 , in some embodiments of the present invention, the resonant network 140 is composed of a resonant capacitor and a resonant inductor connected in series. Besides, the resonant network 140 may also consist of only resonant capacitors.

In some embodiments of the present invention, as shown in FIG. 9 , the first bridge converter 110 is a single-phase full-bridge circuit, including a first switch K1, a third switch K3 and a The second switch tube K2 and the fourth switch tube K4 of the lower bridge arm; as shown in FIG. 10 , the second bridge converter 130 is a single-phase half-bridge circuit, including the fifth switch tube K5 and the upper bridge arm. As the sixth switch tube K6 of the lower bridge arm.

According to some embodiments of the present invention, the first switch tube K1, the second switch tube K2, the third switch tube K3, the fourth switch tube K4, the fifth switch tube K5 and the sixth switch tube K6 are Mosfet, Sic, GaN or IGBT fully controlled devices.

A control method applied to the topological structure of the bidirectional DC converter described in the embodiment of the first aspect according to the embodiment of the second aspect of the present invention includes the following control operations:

(1) The sampling conditioning module executes:

(1.1) Filter the initial current value _isr of the resonant network 140 to obtain the resonance filter current value _ir ;

(1.2) filter the initial current value _iso of the output terminal to obtain the output filter current value _io ;

(1.3) filter the initial current value i _si of the input terminal to obtain the input filter current value i _i ;

(1.4) Send the output filter current value i _o to the closed-loop control module, send the resonance filter current value _ir to the phase locking module, and send the resonance filter current value _ir , the output filter current value ir The value i _o and the input filter current value i _i are sent to the protection module;

(2) The phase-locked module executes:

(2.1) When the driving signal of the first switch tube K1 changes from low to high, detect the size of the resonant filter current value _ir : if _ir ≤ 0, increase the switching period; if _ir > _{ir min} , reduce the switching period; if 0<i _r <i _{r min} , keep the switching period unchanged;

(2.2) sending the switching period T _s into the drive module;

(3) When electrical energy flows from the input end to the output end, the closed-loop control module executes:

其中

为对应所述输出滤波电流值i_o的输出电流设定值；(3.1) Calculate the output voltage error

in

is the output current setting value corresponding to the output filter current value i _o ;

(3.2) Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fractional coefficient respectively, t is the time, C is the integral constant, its value is the integral value in the last calculation, and C=0 in the first calculation;

(3.3) Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1;

(3.4) Generate control signal D: compare the modulation voltage _uf with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage _uf is greater than the sawtooth wave When the instantaneous value of the signal, the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low;

(3.5) sending the control signal D to the drive module;

(4) When electric energy flows from the input end to the output end, the driving module executes:

(4.1) generating a DC level signal _urdc with an amplitude of 0.48;

(4.2) Generate the drive signal:

When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u _{If the rdc} is relatively large, the drive signals of the first switch tube K1 and the fourth switch tube K4 are output; if the DC level signal _{urdc is} small, the drive signals of the second switch tube K2 and the third switch tube K3 are output;

When the control signal D is low, the driving signals of the first switch tube K1, the second switch tube K2, the third switch tube K3, and the fourth switch tube K4 are all low;

When the protection signal P is high, the driving signals of the first switch tube K1, the second switch tube K2, the third switch tube K3, and the fourth switch tube K4 are all low;

(4.3) sending the drive signal of the first switch tube K1 to the phase-locking module;

(4.4) Send the driving signals of the first switch tube K1, the second switch tube K2, the third switch tube K3, and the fourth switch tube K4 to the first bridge converter 110 of the first power module 100 ; Delay the drive signal of the first switch tube K1, the second switch tube K2, the third switch tube K3, and the fourth switch tube K4 by T _s (k-1)/N, and send it to the k-th described power the first bridge converter 110 of the module 100, wherein 2≤k≤N;

(5) When electrical energy flows from the output end to the input end, the closed-loop control module executes:

其中

为对应所述输入滤波电流值i_i的输入电流设定值；(5.1) Calculate the output voltage error

in

is the input current setting value corresponding to the input filter current value i _i ;

(5.2) Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fraction coefficient respectively, t is the time, C is the integral constant, its value is the integral value in the last calculation, and C=0 in the first calculation;

(5.3) Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1;

(5.4) Generate control signal D: compare the modulation voltage _uf with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage _uf is greater than the sawtooth wave When the instantaneous value of the signal, the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low;

(6) When electric energy flows from the output end to the input end, the drive module executes:

(6.1) Generate a DC level signal _urdc with a constant amplitude;

(6.2) Generate the drive signal:

When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u If the _rdc is larger, the drive signal of the fifth switch tube K5 is output; if the DC level signal _{urdc is} smaller, the drive signal of the sixth switch tube K6 is output;

When the control signal D is low, the driving signals of the fifth switch tube K5 and the sixth switch tube K6 are both low;

When the protection signal P is high, the driving signals of the fifth switch tube K5 and the sixth switch tube K6 are both low;

(6.3) sending the drive signal of the fifth switch tube K5 to the phase lock module;

(6.4) Send the drive signals of the fifth switch K5 and the sixth switch K6 to the first bridge converter 110 of the first power module 100; send the fifth switch K5 and the sixth switch K6 to the first bridge converter 110 of the first power module 100; The driving signal of the switch tube K6 is delayed by T _s (k-1)/N, and sent to the first bridge converter 110 of the kth power module 100, where 2≤k≤N;

(7) The protection module performs:

Detecting the size of the resonant filter current value _ir : if _ir > _{ir max} , the output protection signal P is low;

Detecting the magnitude of the output filter current value i _o : if i _o >i _{o max} , the output protection signal P is low;

If i _r <i _{r max} and i _o <i _{o max} , the output protection signal is P.

According to the topology structure of the bidirectional DC converter and the control method thereof provided by the embodiments of the present invention, by configuring the triggering time of the control signal of each power module 100, the voltage and current ripples of the input and output terminals of the bidirectional DC converter can be effectively reduced; The switching period of the power module 100 realizes the quasi-resonant conversion of the bidirectional DC converter in a wide load range, thereby effectively improving the input, output and efficiency characteristics of the bidirectional DC converter, and achieving extremely high efficiency in a wide range.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various modifications can be made without departing from the purpose of the present invention. kind of change.

Claims (6)

1. a bidirectional DC converter topology structure, is characterized in that, comprises: N power modules, the input terminals of the N power modules are connected in series and the output terminals are connected in series, the input terminals are connected in series and the output terminals are connected in parallel, the input terminals are connected in parallel and the output terminals are connected in series, or the input terminals are connected in parallel and the output terminals are connected in parallel. The input end, the first bridge converter, the high frequency transformer, the second bridge converter and the output end; the resonant network is arranged between the first bridge converter and the high frequency transformer, and is arranged between the first bridge converter and the high frequency transformer. between the high-frequency transformer and the second bridge converter or on the front and rear sides of the high-frequency transformer; A control circuit, connected to N power modules respectively, is used for outputting driving signals to control the N power modules, the switching period and duty cycle of the driving signals of each power module are consistent, and the driving signals of each power module are The trigger times of the signals differ by one-Nth of the switching period. 2. The topology of a bidirectional DC converter according to claim 1, wherein the control circuit comprises a sampling conditioning module, a phase locking module, a closed-loop control module, a driving module and a protection module, and the sampling conditioning module used to measure the current of the input terminal, the output terminal and the resonant network, the phase-locked module is used to adjust the switching period of the driving signal, the closed-loop control module is used to output the control signal to the driving module, The protection module is used to output a protection signal to the drive module, and the drive module is used to generate a drive signal according to the switching period, the control signal and the protection signal, and the sampling conditioning module is respectively connected to the phase locking module, the The closed-loop control module and the protection module, the phase lock module, the closed-loop control module and the protection module are respectively connected to the drive module. 3 . The topology of a bidirectional DC converter according to claim 1 , wherein the resonant network consists of a resonant capacitor and a resonant inductor in series or consists of a resonant capacitor. 4 . 4 . The topology of a bidirectional DC converter according to claim 2 , wherein the first bridge converter is a single-phase full-bridge circuit, comprising a first switch tube as an upper bridge arm, a third The switch tube, the second switch tube and the fourth switch tube as the lower bridge arm; the second bridge converter is a single-phase half-bridge circuit, including the fifth switch tube as the upper bridge arm and the third switch tube as the lower bridge arm Six switch tubes. 5 . The topology of a bidirectional DC converter according to claim 4 , wherein the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the third switch The six switches are Mosfet, Sic, GaN or IGBT fully controlled devices. 6. A control method applied to the bidirectional DC converter topology according to claim 4, characterized in that, comprising the following control operations: The sample conditioning module performs: v _o Filtering the initial current value _isr of the resonant network to obtain a resonant filter current value _ir ; Filtering the initial current value _iso of the output terminal to obtain the output filter current value _io ; Filtering the initial current value i _si of the input terminal to obtain the input filter current value i _i ; Send the output filter current value i _o to the closed-loop control module, send the resonant filter current value _ir to the phase locking module, and send the resonance filter current value _ir and the output filter current value i _o and the input filter current value i _i is sent to the protection module; The phase lock module performs: When the driving signal of the first switch tube changes from low to high, the size of the resonant filter current value ir is detected: if _ir ≤ 0, increase the switching period; if _ir > _irmin , _decrease the switching period cycle; if 0<i _r <i _rmin , keep the switching cycle unchanged; sending the switching period T _s into the drive module; When electrical energy flows from the input to the output, the closed-loop control module performs: Calculate the output voltage error

in

is the output current setting value corresponding to the output filter current value i _o ; Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fraction coefficient respectively, t is the time, and C is the integral Constant, its value is the integral value of the previous calculation, and C=0 in the first calculation; Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1; Generate control signal D: compare the modulation voltage u _f with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage u _f is greater than the instantaneous value of the sawtooth wave signal When , the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low; sending the control signal D to the drive module; When electrical energy flows from the input end to the output end, the drive module performs: generating a DC level signal _urdc with a constant amplitude; Generate the drive signal: When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u _{If the rdc} is relatively large, the driving signals of the first switch tube and the fourth switch tube are output; if the DC level signal ur _{rdc is} small, the driving signals of the second switch tube and the third switch tube are output; When the control signal D is low, the driving signals of the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all low; When the protection signal P is high, the driving signals of the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are all low; sending the drive signal of the first switch tube to the phase lock module; Send the driving signals of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to the first bridge converter of the first power module; send the first switch tube, The driving signals of the second switch tube, the third switch tube, and the fourth switch tube are delayed by T _s (k-1)/N, and sent to the first bridge converter of the kth power module, where 2≤k ≤N; When electrical energy flows from the output to the input, the closed-loop control module performs: Calculate the output voltage error

in

is the input current setting value corresponding to the input filter current value i _i ; Calculate the modulation voltage u _f =1+K _p e _i +K _i (∫e _i dt+C), where K _p and K _i are the output current proportional coefficient and output current fraction coefficient respectively, t is the time, and C is the integral Constant, its value is the integral value in the last calculation, C=0 in the first calculation; Limit the output value of the modulation voltage u _f : if u _f ≤ 0, then u _f =0; if u _f ≥ 1, then u _f =1; Generate control signal D: compare the modulation voltage u _f with a sawtooth wave signal whose period is 10 times the switching period T _s and whose amplitude is 1. When the modulation voltage u _f is greater than the instantaneous value of the sawtooth wave signal When , the control signal D is high, and when the modulation voltage u _f is less than the instantaneous value of the sawtooth wave signal, the control signal D is low; When electrical energy flows from the output terminal to the input terminal, the driving module performs: generating a DC level signal _urdc with a constant amplitude; Generate the drive signal: When the control signal D is high and the protection signal P is low, the DC level signal _urdc is compared with the sawtooth wave signal whose period is the switching period T _s and whose amplitude is 1. If the DC level signal u If the _rdc is large, the drive signal of the fifth switch tube is output; if the DC level signal ur _{rdc is} small, the drive signal of the sixth switch tube is output; When the control signal D is low, the driving signals of the fifth switch tube and the sixth switch tube are both low; When the protection signal P is high, the driving signals of the fifth switch tube and the sixth switch tube are both low; sending the drive signal of the fifth switch tube to the phase lock module; Send the drive signals of the fifth switch tube and the sixth switch tube to the first bridge converter of the first power module; delay the drive signals of the fifth switch tube and the sixth switch tube by T _s (k-1)/N, sent to the first bridge converter of the kth power module, where 2≤k≤N; The protection module performs: Detecting the size of the resonant filter current value _{ir: if ir > irmax , the} output protection signal P is low; Detecting the magnitude of the output filter current value _io : if _io > _iomax , the output protection signal P is low; If i _r <i _rmax and i _o <i _omax , the output protection signal is P.

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