An electric energy / signal synchronous transmission system and method for electric vehicle charging piles

Abstract

The application relates to the technical field of charging systems, and particularly discloses an electric energy / signal synchronous transmission system and method for electric vehicle charging piles, wherein the charging pile system is composed of multiple module stacks, and taking a double module as an example, the system comprises a charging pile module circuit 1, a charging pile module circuit 2, a signal generation system 1, a driving system 1, a signal demodulation system 1, a signal generation system 2, a driving system 2 and a signal demodulation system 2. The charging pile module circuit 1 comprises a three-phase full-bridge rectifier circuit 1, a double active bridge DC / DC circuit 1 and a double active bridge DC / DC circuit 2, and the charging pile module circuit 2 comprises a three-phase full-bridge rectifier circuit 2, a double active bridge DC / DC circuit 3 and a double active bridge DC / DC circuit 4. The application adopts a novel signal transmission mode, embeds signals into output voltage ripples by controlling the switching frequency of power tubes and combining a frequency shift keying modulation mode, and realizes bidirectional transmission of signals through modulation and demodulation of the output voltage ripples. The system electric energy and signal transmission share a coupling channel, the signal transmission process does not affect the output electric energy quality, meanwhile, the two double active bridge circuits in the module can be fully utilized for double-frequency parallel transmission, the signal transmission rate is increased, the system has good anti-noise capability, and the flexibility of system application is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging systems, in particular to an electric energy / signal synchronous transmission system and method for electric vehicle charging piles. BACKGROUND

[0002] At present, electric vehicle charging pile systems are developing towards higher efficiency, lighter weight, higher power density and wider output range. The traditional charging pile system usually adopts a single structure, and the power configuration flexibility and power density are not high, while the large power charging pile constructed by stacking standard charging modules can provide an effective solution. The module series-parallel stacking can solve the problem of high voltage and current stress, the module is designed according to the low voltage system, and the reliability and safety are high; the power configuration is flexible; each module can be replaced, and the expansibility is good; a higher switching frequency can be used, and the efficiency and power density are higher.

[0003] Although the stacked charging pile module structure can solve the problems of the traditional single charging pile structure, such as low power configuration flexibility and power density, and insufficient emergency capability of sudden failure, there are still some key technical problems to be solved in the multi-module stacking. Communication is needed between modules to realize the cooperative control and state monitoring of multi-modules, and communication failure can cause system function paralysis, causing huge economic loss and personal safety problems. Therefore, improving the emergency communication capability of the charging system is a necessary measure to ensure the reliability and safety of electric vehicle charging, but the existing related methods and technical means still have many problems such as insufficient emergency communication capability between modules.

[0004] Reliable communication between electric vehicle charging pile modules is a prerequisite for safe and efficient operation of the modular stacked charging system. The charging pile is always threatened by the safety of various types of communication information, and various threat elements change over time, such as poor communication environment, equipment performance degradation, and human damage, which seriously affect the safe and reliable operation of the system. Communication interruption will cause the state monitoring, cooperative control and other functions of the charging system to be unable to implement, and the charging operation cannot be carried out. Although CAN bus or GPRS wireless public network can also be used as the emergency communication network of the charging pile, it is still difficult to be widely used in electric vehicles that are relatively sensitive to price. SUMMARY

[0005] In view of the defects of the prior art, the present application aims to provide an electric energy / signal synchronous transmission system and method for electric vehicle charging piles based on frequency shift keying, which aims to solve the problems of weak emergency communication capability, weak anti-interference capability of electric energy and signal transmission path, and low communication rate in the case of multi-module stacking of the existing charging pile.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions.

[0007] The application discloses an electric energy / signal synchronous transmission system and method for an electric vehicle charging pile, which comprises charging pile module circuit 1, charging pile module circuit 2, signal generating system 1, driving system 1, signal demodulation system 1, signal generating system 2, driving system 2 and signal demodulation system 2. The charging pile module circuit 1 comprises three-phase full-bridge rectifier circuit 1, double active bridge DC / DC circuit 1 and double active bridge DC / DC circuit 2, the charging pile module circuit 2 comprises three-phase full-bridge rectifier circuit 2, double active bridge DC / DC circuit 3 and double active bridge DC / DC circuit 4, the charging pile module circuit 1 is identical in structure with the charging pile module circuit 2, the signal generating system 1 is connected with the charging pile module circuit 1 through the driving system 1, the charging pile module circuit 1 is further connected with the signal demodulation system 1 and the charging pile module circuit 2, the signal generating system 2 is connected with the charging pile module circuit 2 through the driving system 2, and the charging pile module circuit 2 is further connected with the signal demodulation system 2.

[0008] As a further technical scheme of the application, the driving system 1 and the driving system 2 are identical in structure, the driving system 1 comprises driving subsystem 1 and driving subsystem 2, the driving subsystem 1 and the driving subsystem 2 are identical in structure, the driving subsystem 1 comprises triangular carrier generator 1, control quantity adjuster 1, phase shift calculator 1, phase shift calculator 2, phase shift calculator 3, phase shift calculator 4, comparator 1, comparator 2, comparator 3, comparator 4, NOT gate 1, NOT gate 2, NOT gate 3 and NOT gate 4, the control quantity adjuster output is connected with the four phase shift calculators, the phase shift calculator outputs are respectively compared with the triangular carrier generator output to generate the driving signals of the switch tubes S1, S3, Q1, Q3, S5, S7, Q5 and Q7, and the comparator outputs are respectively connected with the NOT gates to generate the driving signals of the switch tubes S2, S4, Q2, Q4, S6, S8, Q6 and Q8.

[0009] As a further technical scheme of the application, the charging pile module circuit 1 and the charging pile module circuit 2 are identical in structure, the charging pile module circuit 1 and the charging pile module circuit 2 are connected in parallel at the input and output, the charging pile module circuit 1 comprises three-phase full-bridge rectifier circuit 1, double active bridge DC / DC circuit 1 and double active bridge DC / DC circuit 2, the double active bridge DC / DC circuit 1 and the double active bridge DC / DC circuit 2 are identical in structure and are connected in the input parallel and output series mode, the double active bridge DC / DC circuit 1 comprises primary side full-bridge circuit, inductor L1, high-frequency transformer T1, secondary side full-bridge circuit and capacitor C1, the primary side full-bridge circuit is connected with the three-phase rectifier circuit and the inductor L1, the high-frequency transformer is connected with the inductor L1 and the secondary side full-bridge circuit, and the gate electrodes of the switch tubes in the primary side full-bridge circuit and the secondary side full-bridge circuit are connected with the driving subsystem 1.

[0010] As a further technical scheme of the present application: the signal demodulation system 1 and the signal demodulation system 2 are the same in structure, the signal demodulation system 1 comprises a sampling module 1, a band-pass filter 1, an FFT demodulation module 1 and a threshold value judge 1, the sampling module 1 is connected with the band-pass filter 1, the band-pass filter 1 is connected with the FFT demodulation module 1, the FFT demodulation module 1 is connected with the threshold value judge 1, and the threshold value judge 1 demodulates the signal 2 generated by the signal demodulation system 2.

[0011] An electric energy / signal synchronous transmission system and method for electric vehicle charging piles, using the above system, the specific method is as follows: signal generation system 1 and signal generation system 2 are used to generate signals that need to be sent, combined with a frequency shift keying modulation mode, drive system 1 sends trigger pulses 1 and trigger pulses 2 of different frequencies to control the power switches of double active bridge DC / DC circuits 1 and double active bridge DC / DC circuits 2 respectively, to generate voltage ripples containing two specific frequency components on the load and power the load, and drive system 2 sends trigger pulses 3 and trigger pulses 4 of different frequencies, and the frequencies are different from those of trigger pulses 1 and trigger pulses 2, to control double active bridge DC / DC circuits 3 and double active bridge DC / DC circuits 4 respectively, to generate voltage ripples containing two specific frequency components on the load and power the load.

[0012] As a further technical scheme of the present application: the signal demodulation system 1 and the signal demodulation system 2 are the same in structure, the signal demodulation system 1 comprises a sampling module 1, a band-pass filter 1, an FFT demodulation module 1 and a threshold value judge 1, the sampling module 1 is connected with the band-pass filter 1, the band-pass filter 1 is connected with the FFT demodulation module 1, the FFT demodulation module 1 is connected with the threshold value judge 1, and the threshold value judge 1 demodulates the signal 2 generated by the signal demodulation system 2.

[0013] Compared with the prior art, the present application has the beneficial technical effects as follows: on the one hand, the present application adopts electric energy / signal synchronous transmission, takes the power switches in the charging module as a data modulation execution mechanism, derives a voltage ripple signal containing load data information on the power bus, takes the power bus as a data transmission medium without relying on an independent communication channel, realizes signal transmission between different charging modules under the premise of ensuring charging electric energy quality, and reduces the system size and cost; on the other hand, the present application fully utilizes the topological characteristics of the double DAB DC / DC converters in the charging pile module, controls each DC / DC converter to operate at different frequencies through a frequency shift keying modulation mode, generates ripple signals containing more communication frequencies on the module output side, and improves the communication rate of the charging pile module through parallel+serial transmission signals. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a block diagram of the electric energy / signal synchronous transmission system and method for electric vehicle charging piles of the present application.

[0015] Figure 2 It is a circuit topology diagram of the present application.

[0016] Figure 3 is a signal generation system 1, driving system 1 schematic diagram.

[0017] Figure 4 is a signal demodulation system 1 schematic diagram.

[0018] Figure 5 is a signal generation system 2, driving system 2 schematic diagram.

[0019] Figure 6 is a signal demodulation system 2 schematic diagram. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0021] As shown in Figure 1 , an electric energy / signal synchronous transmission system and method for electric vehicle charging piles, taking a dual-module system structure as an example, includes a charging pile module circuit 1, a charging pile module circuit 2, a signal generation system 1, a driving system 1, a signal demodulation system 1, a signal generation system 2, a driving system 2, and a signal demodulation system 2. The charging pile module circuit 1 and the charging pile module circuit 2 are structurally identical. The signal generation system 1 is connected to the charging pile module circuit 1 through the driving system 1. The charging pile module circuit 1 is also connected to the signal demodulation system 1 and the charging pile module circuit 2. The signal generation system 2 is connected to the charging pile module circuit 2 through the driving system 2. The charging pile module circuit 2 is also connected to the signal demodulation system 2.

[0022] As shown in Figure 2As shown, the charging pile module circuit 1 includes a three-phase full-bridge rectifier circuit 1, a dual active bridge DC / DC circuit 1 and a dual active bridge DC / DC circuit 2, the charging pile module circuit 2 includes a three-phase full-bridge rectifier circuit 2, a dual active bridge DC / DC circuit 3 and a dual active bridge DC / DC circuit 4, the charging pile module circuit 1 and the charging pile module circuit 2 are structurally identical and connected in parallel, the three-phase full-bridge rectifier circuit 1 in the module 1 is connected to the power grid at the input side and connected to the rear stage composed of the dual active bridge DC / DC circuits 1 and 2 connected in parallel at the output side, the dual active bridge DC / DC circuits 1 and 2 are structurally identical, the dual active bridge DC / DC circuit 1 includes a primary side full-bridge circuit, an inductor L1, a high-frequency transformer T1, a secondary side full-bridge circuit and a capacitor C1, the primary side full-bridge circuit is connected to the three-phase rectifier circuit and the inductor L1, the high-frequency transformer is connected to the inductor L1 and the secondary side full-bridge circuit, and the gate electrodes of the switching tubes in the primary side full-bridge circuit and the secondary side full-bridge circuit are connected to the driving subsystem 1.

[0023] The energy transmission mode of the present application is as follows.

[0024] The three-phase full-bridge rectifier in the front stage of the charging pile module adopts an SVPWM modulation mode to rectify the three-phase alternating current into constant voltage direct current, and the dual active bridge DC / DC converter in the rear stage adopts a phase-shift modulation mode to output a direct current voltage and connect a load side.

[0025] The phase-shift modulation is a modulation method with fixed switching frequency, in which the transmission power direction and size are controlled by controlling the phase-shift time between the driving signals of the power tubes. Taking the dual active bridge DC / DC circuit 1 under single phase-shift modulation as an example, the driving signals of the power tubes are all square wave signals with a frequency of f1 and a duty cycle of 50%, the driving signals of the upper and lower power tubes in the same bridge arm are complementary, and the driving signals of the opposite power tubes are synchronous, i.e. S1 and S2, S3 and S4, Q1 and Q2, Q3 and Q4 are complementary, the phase-shift time between S1 and Q1 between the two full-bridges is the inter-bridge phase-shift ratio d1, and when there is other optimization requirement, the intra-bridge phase-shift between the two bridge arms in the bridge, i.e. the phase-shift time between S1 and S3 and Q1 and Q3, can be introduced, and when the intra-bridge phase-shiftes of the two sides are equal, it is double phase-shift modulation, otherwise it is triple phase-shift modulation.

[0026] The modulation modes of the dual active bridge DC / DC circuits 2, 3 and 4 are similar, and the switching frequencies thereof are f2, f3 and f4 respectively, and the inter-bridge phase-shift ratios thereof are d2, d3 and d4 respectively.

[0027] The dual active bridge DC / DC converter first inversely converts the intermediate-stage direct current into a high-frequency alternating square wave voltage through the primary side full-bridge, then passes through the energy storage inductor and the high-frequency isolation transformer, and finally rectifies the high-frequency alternating current to a direct current load voltage through the secondary side full-bridge, so that the dual active bridge DC / DC converter can be equivalent to a high-frequency alternating square wave voltage source with amplitudes of the input and the transformer ratio multiple of the output voltage connected to the two sides of the inductor.

[0028] The direction of the inductor current and the switching state of the power tubes determine the converter current flow path. Taking the dual-active bridge DC / DC circuit 1 as an example, when the inductor current is positive, the power tubes S1 and S4, or D2 and D3, Q1 and Q4, or M2 and M3 are turned on. When the inductor current is negative, the power tubes S2 and S3, or D1 and D4, Q2 and Q3, or M1 and M4 are turned on. Since the converter operating state is positive and negative symmetrical in the previous and next half switching cycles, according to the volt-second balance principle, the change in the converter inductor current within a switching cycle is ultimately zero. By analyzing the inductor current expression and considering that the inductor current values ​​of half switching cycles are reciprocal, the transmission power of the dual-active bridge DC / DC converter i can be derived as:

[0029]

[0030] where N i is the high-frequency transformer ratio, U ini is the input side voltage, U oi is the output side voltage, d i is the bridge displacement ratio, f i is the converter switching frequency, L i is the inductance value.

[0031] When designing the converter operating range, since the back-end circuit of the fast charging pile module has a parallel input and series output structure, the average output current of each dual-active bridge DC / DC converter is equal. According to the transmission power expression of the dual-active bridge DC / DC converter, the control quantity and frequency of the two converters in the same module should meet the following constraints:

[0032]

[0033] The signal modulation and transmission method of the present invention is as follows.

[0034] This invention combines power electronics with communications technology. Building on traditional power electronics and control techniques, this invention applies relevant data communications technologies to develop a synchronous power / signal transmission strategy suitable for electric vehicle charging station systems. Unlike traditional power line carrier communications, this synchronous power / signal transmission strategy requires no additional harmonic coupling equipment. Instead, it leverages the signal processing potential of phase-shift modulation to embed information within the power tube switching signal carrier. This allows both the input and output switching ripple of the main circuit to contain data information, allowing data to be transmitted using the corresponding frequency harmonics generated.

[0035] like Figure 3As shown, the signal generating system 1 and the signal generating system 2 are identical in structure, the signal generating system 1 comprises a signal generator 1 and a frequency selector 1, and the frequency selector 1 is connected to the signal generator 1, a triangular carrier generator 1 and a triangular carrier generator 2 respectively.

[0036] The driving system 1 and the driving system 2 are identical in structure, the driving system 1 comprises a driving subsystem 1 and a driving subsystem 2, the driving subsystem 1 and the driving subsystem 2 are identical in structure, the driving subsystem 1 comprises a triangular carrier generator 1, a control quantity adjuster 1, a phase shift calculator 1, a phase shift calculator 2, a phase shift calculator 3, a phase shift calculator 4, a comparator 1, a comparator 2, a comparator 3, a comparator 4, a NOT gate 1, a NOT gate 2, a NOT gate 3 and a NOT gate 4, the control quantity adjuster output is connected to the four phase shift calculators, the phase shift calculator outputs are compared with the triangular carrier generator outputs respectively to generate the driving signals of the switch tubes S1, S3, Q1, Q3, S5, S7, Q5 and Q7, and the comparator outputs are connected to the NOT gates respectively to generate the driving signals of the switch tubes S2, S4, Q2, Q4, S6, S8, Q6 and Q8.

[0037] The signal modulation and transmission principles of each module are identical, the core is a double active bridge DC / DC converter circuit in the later stage, based on a phase shift modulation mode, through a certain signal modulation criterion, combined with a frequency shift keying modulation method, data is modulated into a specific pulse sequence to correspond to a corresponding switching frequency, on this basis, the double active bridge converter is controlled to operate at different switching frequencies, and the variable frequency ripple signals of the two converters are jointly embodied on the module output load side, and the signals are embedded in the output voltage ripple and shared in the transmission channel.

[0038] For the periodic switching of the power switch in the double active bridge DC / DC converter, different switching frequencies will induce corresponding double-frequency ripple signals on the output side, and the structure characteristics of the input parallel and output series structure in the module cause the superimposed ripple signals of the output voltages of the two converters on the module output side.

[0039] The ripple signals on the output side of the double active bridge DC / DC converter i under different switching frequencies can be expressed as:

[0040]

[0041] Therefore, two different frequency ripples are required for a converter to send "0" and "1" signals, and since there are two double active bridge DC / DC converters in a module, and bidirectional signal transmission needs to be achieved in the two modules, a total of 8 different frequency ripple signals are required, that is, the double active bridge DC / DC converter 1 transmits signals by using the switching frequencies f 1a , f 1b , the double active bridge DC / DC converter 2 transmits signals by using the switching frequencies f 2a , f2b The switching frequency of the converter 3 is f 3a 、f 3b The switching frequency of the converter 4 is f 4a 、f 4b The switching frequency transmission signal is connected to the control pulse selector using a signal generator to select triangular carriers of different frequencies to generate a ripple signal of corresponding frequency on the load.

[0042] The key to achieving data communication based on synchronous power / signal transmission is bus ripple modulation and information extraction. The amplitude of the switching ripple signal is related to factors such as circuit topology, input voltage, output voltage, and load. Injected ripple signals will affect the stability and reliability of the module. To ensure the quality of power transmission and the stability of communication signals, the focus of ripple composite modulation is to control the amplitude, frequency, and phase of the bus ripple. The theoretical calculation of the corresponding relationship between the output ripple and modulation parameters of the dual active bridge DC / DC converter in this invention is as follows.

[0043] According to the output side voltage and current analysis of the dual active bridge DC / DC converter, k is defined i =N i U oi / U ini , then the corresponding ripple expression generated at the output side of the single phase shift modulation converter i is:

[0044]

[0045] where Δu oi is the output ripple amplitude of the dual active bridge DC / DC converter, R i is the equivalent load of converter i.

[0046] The present invention uses the bus harmonics induced by the power switch as the data carrier signal. If the ripple amplitude is too small, it will affect the transmission distance, while if it is too large, it will affect the power quality. The above ripple analysis studies the coupling relationship between the ripple signal, the load, and the input voltage, which can provide a reference for the design of the converter's operating range.

[0047] The power / signal synchronous transmission strategy uses the harmonic transmission signal generated by the switching action, which has certain requirements for the harmonic amplitude. Using the Fourier analysis method, the output side voltage second harmonic amplitude of the dual active bridge DC / DC converter i under single phase shift modulation can be calculated as:

[0048]

[0049] The signal demodulation method of the present invention is as follows.

[0050] like Figure 4As shown, the signal demodulation system 1 and the signal demodulation system 2 are of the same structure, the signal demodulation system 1 comprises a sampling module 1, a band-pass filter 1, an FFT demodulation module 1 and a threshold value determinator 1, the sampling module 1 is connected with the band-pass filter 1, the band-pass filter 1 is connected with the FFT demodulation module 1, the FFT demodulation module 1 is connected with the threshold value determinator 1, and the threshold value determinator 1 demodulates the signal 2 emitted by the signal generation system 2.

[0051] In the signal demodulation system 1, the collected voltage signal is first input into the band-pass filter to filter out irrelevant frequency signals in the power bus, the filtered signal is subjected to FFT transformation, and the original signal emitted by the signal generation system 2 can be obtained after the modulus operation, so as to restore the original data. Similarly, in the signal demodulation system 2, the collected voltage signal is first input into the band-pass filter, and the relevant frequency signal generated by the signal generation system 1 is extracted, and then the same algorithm is adopted to demodulate the original signal emitted by the signal generation system 1 and restore it. This algorithm can be realized by a digital processor such as DSP.

[0052] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and range of equivalent elements of the claims are intended to be embraced in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0053] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A power / signal synchronous transmission system and method for electric vehicle charging piles, characterized in that: The charging pile system is composed of a plurality of module stacks, taking a double module as an example, including input parallel, output parallel charging pile module circuit 1 and charging pile module circuit 2, signal generation system 1, drive system 1, signal demodulation system 1, signal generation system 2, drive system 2 and signal demodulation system 2; the charging pile module circuit 1 includes three-phase full-bridge rectifier circuit 1, input parallel, output series double active bridge DC / DC circuit 1 and double active bridge DC / DC circuit 2, and the charging pile module circuit 2 includes three-phase full-bridge rectifier circuit 2, input parallel, output series double active bridge DC / DC circuit 3 and double active bridge DC / DC circuit 4; the double active bridge DC / DC circuit 1-4 adopts phase shift modulation method, taking the charging pile module circuit 1 under single phase shift modulation as an example, wherein the control quantity and frequency of the double active bridge DC / DC circuit 1, 2 should satisfy the following constraints: where N1 and N2 are the transformer turns ratio of the dual active bridge DC / DC circuits 1, 2, U o1 and U o2 are the output voltage of the dual active bridge DC / DC circuits 1, 2, d1 and d2 are the phase shift ratio of the dual active bridge DC / DC circuits 1, 2, f1 and f2 are the carrier frequency of the dual active bridge DC / DC circuits 1, 2, and L1 and L2 are the inductance of the dual active bridge DC / DC circuits 1, 2.

2. The power / signal synchronous transmission system and method for electric vehicle charging piles according to claim 1, characterized in that: The signal generation system 1 connects the charging pile module circuit 1 through the drive system 1, and the charging pile module circuit 1 also connects the signal demodulation system 1 and the charging pile module circuit 2; the signal generation system 2 connects the charging pile module circuit 2 through the drive system 2, and the charging pile module circuit 2 also connects the signal demodulation system 2; the signal generation system 1 and the signal generation system 2 have the same structure, the signal generation system 1 includes a signal generator 1 and a frequency selector 1 based on the frequency shift keying method, the frequency selector 1 is connected with the signal generator 1, a triangular carrier generator 1 and a triangular carrier generator 2 respectively, and the carrier frequencies f1 and f2 of the double active bridge DC / DC circuit 1, 2 are switched for double-frequency parallel transmission, which is used to increase the signal transmission rate and noise immunity of the charging pile module circuit. 3.The electric energy / signal synchronous transmission system and method for electric vehicle charging pile according to claim 2, characterized in that: The drive system 1 and the drive system 2 have the same structure, the drive system 1 includes a drive subsystem 1 and a drive subsystem 2, the drive subsystem 1 and the drive subsystem 2 have the same structure, the drive subsystem 1 includes a triangular carrier generator 1, a control quantity regulator 1, a phase shift calculator 1, a phase shift calculator 2, a phase shift calculator 3, a phase shift calculator 4, a comparator 1, a comparator 2, a comparator 3, a comparator 4, a NOT gate 1, a NOT gate 2, a NOT gate 3 and a NOT gate 4, the control quantity regulator output end is connected with the four phase shift calculators, the phase shift calculator outputs are compared with the triangular carrier generator outputs respectively, the drive signals of the switch tubes S1, S3, Q1, Q3, S5, S7, Q5 and Q7 are generated, and the comparator output ends are connected with the NOT gates respectively, the drive signals of the switch tubes S2, S4, Q2, Q4, S6, S8, Q6 and Q8 are generated.

4. The power / signal synchronous transmission system and method for electric vehicle charging piles according to claim 3, characterized in that: The charging pile module circuit 1 and the charging pile module circuit 2 are structurally identical, the charging pile module circuit 1 and the charging pile module circuit 2 are connected in parallel in input and output, the charging pile module circuit 1 comprises a three-phase full-bridge rectifier circuit 1, a dual active bridge DC / DC circuit 1 and a dual active bridge DC / DC circuit 2, the dual active bridge DC / DC circuit 1 and the dual active bridge DC / DC circuit 2 are structurally identical and are connected in a parallel input and series output mode, the dual active bridge DC / DC circuit 1 comprises a primary side full-bridge circuit, an inductor L1, a high-frequency transformer T1, a secondary side full-bridge circuit and a capacitor C1, the primary side full-bridge circuit is connected with the three-phase rectifier circuit and the inductor L1, the high-frequency transformer is connected with the inductor L1 and the secondary side full-bridge circuit, and the gate electrodes of the switching tubes in the primary side full-bridge circuit and the secondary side full-bridge circuit are connected with the driving subsystem 1.

5. The power / signal synchronous transmission system and method for electric vehicle charging piles according to claim 4, characterized in that: The signal demodulation system 1 and the signal demodulation system 2 are structurally identical, the signal demodulation system 1 comprises a sampling module 1, a band-pass filter 1, an FFT demodulation module 1 and a threshold value determinator 1, the sampling module 1 is connected with the band-pass filter 1 in output, the band-pass filter 1 is connected with the FFT demodulation module 1 in output, the FFT demodulation module 1 is connected with the threshold value determinator 1 in output, and the threshold value determinator 1 demodulates the signal 2 emitted by the signal demodulation output signal generation system 2.

6. An electric energy / signal synchronous transmission system and method for an electric vehicle charging pile, characterized in that: The power / signal synchronous transmission system and method for the electric vehicle charging pile according to any one of claims 1-5 are used, and the specific method is as follows: the signal generation system 1 and the signal generation system 2 are used to generate signals to be sent, a frequency shift keying modulation mode is combined, the driving system 1 controls the power switches of the dual active bridge DC / DC circuit 1 and the dual active bridge DC / DC circuit 2 by sending trigger pulses 1 and 2 with different frequencies, respectively, generates voltage ripples containing two specific frequency components on the load and supplies power to the load, the driving system 2 controls the power switches of the dual active bridge DC / DC circuit 3 and the dual active bridge DC / DC circuit 4 by sending trigger pulses 3 and 4 with different frequencies, respectively, and the frequencies are different from those of the trigger pulses 1 and 2, generates voltage ripples containing two specific frequency components on the load and supplies power to the load.

7. The power / signal synchronous transmission system and method for electric vehicle charging piles according to claim 6, characterized in that: The signal demodulation system 1 and the signal demodulation system 2 demodulate the signals by extracting the different frequency components of the ripple signals on the load, restore the original signals, and realize bidirectional transmission of the signals.

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