Circuit that can be used to improve high-current inductance in power line communications

Abstract

The present application provides a circuit for high-current inductance that can be used to improve power line communications. To improve power line communications, an isolator can be used to separate the power line into a power consumption side and a transmission side to prevent the time-varying noise and impedance of the power consumption side in the communication frequency band from affecting the communication effect, and this isolator often requires the use of an inductor with a larger inductance value. If the isolator is located on a path where a larger alternating current passes (such as the entrance of an electric meter), the inductor made by traditional processes and known technologies requires a large magnetic core to avoid magnetic saturation, which is not only expensive but also large in size and not conducive to installation. The present invention uses a special circuit that maintains a small inductance value when a low-frequency alternating current passes through the inductor, but presents a large inductance value in the communication frequency band, and a small magnetic core can be used to meet the high inductance value requirements of the communication frequency band.

Description

Technical Field

[0001] The present invention relates to a key component required for improving Power Line Communication (PLC). Background Art

[0002] Power line communication has been widely used in many fields since the late 1990s, such as the HomePlug AV standard developed by the HPA (HomePlug Powerline Alliance), G3-PLC (Generation 3th Power Line Communication), HPLC (High speed PLC), etc. Because the power grid usually has problems such as high noise and low impedance that change over time, the communication quality is generally poor. These problems can be solved by setting a low-pass filter (or isolator) before the power unit (power side) (including the modem itself), such as Figure 1A As shown in the figure, the low-pass 3dB frequency turning point of this low-pass filter is much lower than the communication signal, which can block the communication signal but does not affect the power supply and separate the power line into two sections, one is the transmission side and the other is the power consumption side. The communication signal of the modem communication module (communication unit) bypasses this low-pass filter through a coupler and enters the transmission side of the power line. In this way, for the frequency band used by the communication signal of the communication module, the time-varying noise and the time-varying low impedance are isolated on the power consumption side, and the transmission side becomes a transmission medium with stable impedance and low noise, which can greatly improve the communication effect.

[0003] However, large currents generally flow through the wires on the transmission side. In order to pass high currents, the inductor (used in the isolator) must have a large magnetic core, which is expensive, large in size and difficult to install. Figure 1B This is a schematic diagram of a second-order low-pass filter, which is the simplest type of isolator. The larger the inductance value, the better the isolation effect. However, it also means that the larger the inductance volume, the higher the cost. Summary of the invention

[0004] The present invention provides a circuit for improving a high current inductor of power line communication, comprising: using a coupler to sense the voltage across a main inductor, coupling a related voltage (aV, a is a coupling coefficient, usually a constant, if a large capacitor or even a short circuit is used for coupling, a is equal to 1) to a current generator, and coupling the current of the current generator back to the main inductor; the purpose of the current generator is to copy one or more related currents (with a phase close to the current actually flowing through the inductor), allowing this current to flow into the main inductor to suppress the current driven by the signal itself. In this way, the inductance value of the main inductor is amplified, and the effect of a large inductor can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] [ Figure 1A ]Shows techniques previously used to improve PLC communications.

[0006] [ Figure 1B ]shows a commonly used second-order low-pass filter circuit.

[0007] [ Figure 2A to Figure 2D ]Shows schematic diagrams of several embodiments of the present invention.

[0008] [ Figure 3A~Figure 3B ]shows a schematic diagram of an embodiment of the present invention.

[0009] [ Figure 4A~Figure 4B ]Shows a schematic diagram of reducing the input current by replicating the current flowing into the transformer.

[0010] [ Figure 5A ] shows a circuit that uses a differential inverting linear driver plus a 1:1 transformer to generate a large inductor in the signal frequency band.

[0011] [ Figure 5B ]for Figure 2D A schematic diagram of another embodiment of the current generator 202 is shown.

[0012] [ Figure 6 ] shows a circuit that uses a differential inverting linear driver plus a 1:M transformer to generate a large inductor in the signal frequency band.

[0013] [ Figure 7 ]shows a method of combining a previous invention with the circuit of the present invention to achieve a stable and mass-producible method of increasing the inductance by 100 times.

[0014] [ Figure 8 ]shows a method of combining two transformers to achieve a stable and mass-producible 100-fold inductance.

[0015] [ Fig.9A ]is a schematic diagram showing another embodiment of the current generator 202 mentioned above.

[0016] [ Fig. 9B ] is a schematic diagram showing a circuit of the present invention in one embodiment.

[0017]

Explanation of symbols

[0018] 200A, 200B, 200C, 200D, 300A, 300B, 500A, 500B, 600, 700, 800, 900: Circuit

[0019] V: Voltage across the main inductor

[0020] 201, 201_1, 201_2: Coupler

[0021] 202, 202_1, 202_2: current generator

[0022] 202A: Analog-to-Digital Converter

[0023] 202B: Digital Inductor Current Calculator

[0024] 202C: Current Digital-to-Analog Converter

[0025] 203: Isolator

[0026] L P 1. L P 1_1, L P 1_2: Main inductance

[0027] L, L S2 :inductance

[0028] L S , L S1 , L S1 _1, L S1 _2: Secondary inductance

[0029] V in : Isolator or filter input voltage

[0030] Vc: Change in magnetic flux at inductance L S The voltage generated on

[0031] V L1 :Inductance L S2 Voltage

[0032] I0: The current value generated by the signal source flowing into the main inductor or main transformer coil

[0033] I in : The current flowing into the main inductor generated by the signal source

[0034] I + , I - : The current generated by the current generator

[0035] Ic: The current value generated by the current generator

[0036] L0, L2: Main inductor inductance

[0037] L1: Inductance value of the current generator reference inductor

[0038] I L1 : Flowing through inductor L S2 Current

[0039] C. C X , C Y , CR : Capacitor

[0040] Z, KZ: Impedance

[0041] M, M1, M2, N, K, a: constants

[0042] ω: angular frequency

[0043] 1, 2: Input terminal

[0044] Q1~Q4: output terminal

[0045] LNA: Linear Amplifier

[0046] T2, T3: Transformer

[0047] 204: Low pass filter DETAILED DESCRIPTION

[0048] The present invention discloses a component with low inductance at low frequencies for transmitting large currents, but high inductance at high-frequency communication signal bands, which can meet the needs of an isolator without requiring a large magnetic core. Figure 2A As shown in the schematic diagram, Figure 2A A circuit 200A is shown which can be used to improve a high current inductor for power line communication. The circuit 200A includes a main inductor L P , a coupler 201, and a current generator 202. The first current I related to the communication signal in Flowing through the main inductor L P And generate a voltage V related to the communication signal, the main inductor L P Located on a power supply line, the main inductor L P At the same time, alternating current (usually 50 or 60 Hz) or direct current flows.

[0049] Main inductance L P has two ends and a first current I in The current value I0 flows through the main inductor L P The coupler 201 is used to sense the main inductance L P The voltage V across the two ends or the main inductance L P A voltage of a preset ratio between the two ends is generated, and a coupling voltage aV is generated. In this embodiment, a is a coupling coefficient. The current generator 202 is coupled to the coupler 201. The current generator 202 receives the coupling voltage aV according to the coupler 201 or another coupler to generate a second current I + , and the current generator 202 couples the second current I with the same coupler 201 or another coupler + Flow to the main inductor L P , and finally the second current I -The current flows back to the coupler 201 and then returns to the current generator 202. The output impedance of the current generator 202 must be high impedance.

[0050] The purpose of the current generator 202 is to replicate the first current I in The second current I + , the second current I + The phase and magnitude of the current flowing through the main inductor L P The first current I in , let this second current I + Flowing into the main inductor L P , that is, with the second current I + Replace the first current I in 0.8 to 0.95 times of the first current I driven by the communication signal of the circuit 200A. in The first current I in It is generated by the communication signal source and flows into the main inductor L P The current value is I0.

[0051] In other words, the circuit 200A uses a coupler 201 to sense the main inductance L P The voltage V at both ends couples a related voltage aV to the current generator 202. The current generated by the current generator 202 returns to the main inductor L. P The coupler 201 generally has a high-pass filter function. Its main purpose is to filter out low-frequency power waves. The simplest way to achieve this is to connect a capacitor in series. The purpose of the current generator 202 is to replicate one or more currents that are similar to the first current I in The related second current I + , that is, the second current I + The phase and magnitude are close to the actual current flowing through the main inductor L P The first current I in , let this second current I + Flowing into the main inductor L P , which can suppress the first current I driven by the signal itself in .

[0052] In addition, Figure 2B and Figure 2C As shown in the schematic diagram, the circuits 200B and 200C can also allow the second current I + Flows into another set of inductor L coils, which are connected to the main inductor L P The coils are connected in series and wound on the same magnetic core, and the inductor L is connected in parallel to the coupler 202 and the main inductor L P , the transmission side, the inductor L can produce a magnetic flux change in the magnetic core to suppress the flow through the original inductor (the low-frequency power supply current only flows through the main inductor L P , and the main inductance LP Used to provide a first current I related to the communication signal in With AC signal, the main inductance L P Wrapped wires are wires with larger wire diameters; however Figure 2B and Figure 2C The newly wound inductor L in the schematic diagram will only flow through the first current I in The second current I + , so the inductance L is compared with the main inductance L P The coil can be wound with a wire of smaller diameter. In other words, only the current of the communication signal will flow through the inductor L coil, so the wire diameter of the inductor L coil is smaller than the main inductor L. P Coil wire diameter. By changing the winding wire of inductor L, the value of input current can be changed, for example Figure 2B The second current I + (Suppressing the first current I in The inhibition current) ratio Figure 2A The second current I + The same suppression of the first current I can be achieved with a smaller in In this embodiment, the coil of the inductor L is coupled to the main inductor L P The preset position in the coil, that is, the coil of the inductor L is coupled to the main inductor L P The position of the coil is not the main inductance L P For the communication signal source, the first current I in The decrease is equivalent to the increase of the main inductance value, that is, through the second current I + The resulting change in magnetic flux in the magnetic core can achieve the effect of increasing the inductance value. In this embodiment, the coupler 201 is used to sense the main inductance L P The voltage V' of a preset ratio at both ends is generated to generate a coupling voltage aV'. The simplest coupling circuit only needs two capacitors C, such as Figure 2D As shown, since low-voltage capacitors are relatively cheap, this type of circuit is suitable for low-voltage circuits.

[0053] like Figure 3A As shown in the schematic diagram, the secondary side inductor L of the circuit 300A S Coil and main inductance L P The coils are separated, wherein the communication signal related first current I in Flowing through the main inductor L P And generate a voltage V related to the communication signal, the main inductor L P Located on a power supply line, the main inductor L P AC current (usually 50 or 60 Hz) or DC current flows through the secondary side. S coupled to the coupler 201, that is, the circuit 300A can also allow the second current I+ Flows into another group or multiple groups wound around the original main inductor L P The coils of the magnetic core are connected to the main inductor L P The coils are separated (equivalent to a transformer). As long as a magnetic flux change is generated in the magnetic core to suppress the flow through the main inductor L P The first current I in In this embodiment, the main inductor L P Coil and secondary inductance L S The ratio of coil turns is 1:M, and M is a constant; the secondary inductance L S According to the main inductance L P The voltage across the main inductance L P A voltage of a preset ratio between the two ends generates a voltage MV. The coupler 201 senses the secondary inductance L S The voltage across the two terminals or the secondary inductance L S The voltage of a preset ratio between the two ends is used to generate a coupling voltage aMV; the current generator 202 receives the coupling voltage aMV according to the coupler 201 or another coupler to generate a current I + , the current generator 202 couples the current I using the same coupler 202 or another coupler + , so that the main inductor L P The purpose of the current generator 202 is to generate a second current I + Used to copy the first current I in The main inductor L P The magnetic field generated by the magnetic core is used to suppress the first current I driven by the communication signal of the circuit 300A itself. in In other words, the second current I + Flowing into the secondary side inductor L S Instead of the main inductor L P To suppress the flow through the main inductor L P The first current I in , and the main inductance L P The transformer formed by the secondary inductor L is used to isolate the high voltage on the transmission side from entering the coupler 201. For the AC power grid, the 50 / 60Hz voltage of the current generator 202 is relatively high, possibly higher than 300 volts. In this case, the transformer is used to isolate the high voltage from entering the coupler 201, which is less expensive. Figure 3B As shown in the schematic diagram, the simplest coupler 201 in the circuit 300B is a capacitor C. The impedance of this capacitor C in the communication frequency band can be ignored, and it can filter out low-frequency AC signals. If the voltage drop of low-frequency AC in the main coil is very small, then even this capacitor can be omitted.

[0054] like Figure 4A As shown in the schematic diagram, Figure 4A show Figure 3A Schematic diagram of a transformer in an embodiment. In this embodiment, a 1:1 transformer is used. When the current generator 202 does not generate current (the second current I generated by the current generator 202 is + The current value I c =0), the main inductance L on the transmission side P The coil is a pure inductor, the main inductance L P The voltage drop on both sides will be reflected at the other end of the transformer. Figure 4B As shown in the schematic diagram, a transformer is used to suppress the first current I input from the transmission side. in The main concept is to use the second current I of the current generator 202 + , to generate a magnetic field in the transformer, so that the change in magnetic flux is in the secondary side inductance L S The voltage Vc generated on the main inductor L is close to P The voltage Vc should not be greater than the voltage Vc, otherwise it will cause oscillation. P This produces an equivalent effect of a higher inductance. Since the current generator 202 does not generate current flowing into the secondary inductor L in the low frequency AC band (50 / 60Hz) of this circuit, S The coil (coupler 201 filters out low frequency signals), and the output impedance of the current generator 202 is relatively high, and the current generator 202 is equivalent to an open circuit. Therefore, at low frequencies, the transformer (main inductor L P and the secondary inductance L S ) is a small inductor (when selecting an inductor, it is necessary to ensure that magnetic saturation will not occur when the maximum AC current passes through it). In this way, a component with high inductance only at high frequencies (communication frequency bands) can be produced. When the second current I generated by the current generator 202 + Induction in the main inductor L P When the reverse voltage on the in close to zero, that is, with the second current I + Replace the first current I in The effect is 0.8~0.95 times.

[0055] The above concept can be implemented using a variety of different known circuits, and several examples are given below. Figure 5A As shown in the schematic diagram, in the circuit 500A, the main inductor L P The inductance value is L0, the main inductance L P and the secondary inductance L S1 The circuit 500A can use the transformer to extract the isolator main inductance L P The voltage V across the two ends. In this embodiment, the current generator 202 of the circuit 500A is implemented by a differential linear driver, which drives another reference inductor L at its load end.S2 , whose inductance is L1, flows through the reference inductor L S2 The current is I L1 , and L1 / L0=N, the main inductance L P With the secondary side inductance L S1 The number of winding coils is the same (i.e. the main inductance L P and the secondary inductance L S1 To become a 1:1 transformer), the current generator 202 only needs to copy the current I + The current value I=N×I L1 In an ideal state, the first current I on the transmission side is in In this embodiment, the differential linear driver has a first input terminal 1 and a second input terminal 2, and the first input terminal 1 and the second input terminal 2 are respectively coupled to the secondary side inductor L S1 The differential linear driver has a first output terminal Q1, a second output terminal Q2, a third output terminal Q3, and a fourth output terminal Q4, wherein the first output terminal Q1 and the fourth output terminal Q4 are connected in series with an inductor L as a load terminal. S2 ; The first input terminal 1 and the third output terminal Q3 are coupled in parallel with the coupler 201 (capacitor C in this embodiment), the second output terminal Q2 is coupled in parallel with the second input terminal 2, and there is a matching electrical group Z between the first input terminal 1 and the coupler 201; there is a matching electrical group Z between the second input terminal 2 and the second output terminal Q2; the first input terminal 1 and the first output terminal Q1 are matched with impedance Z in parallel; the second input terminal 2 and the fourth output terminal Q4 are matched with impedance Z in parallel. In this embodiment, the impedance value of the matching impedance Z is much larger than ωL0 or ωL1 in the communication frequency band. In order to avoid the generation of DC (from the incomplete balance of the circuit itself) or 50 / 60Hz low-frequency current of the differential linear driver, the reference inductor L S2 A large capacitor C can be connected in series R ,like Figure 5A As shown in the schematic diagram.

[0056] Please note that the current generator 202 may include one or more amplifiers and a reference inductor L S2 The current replica circuit is used as a current replica circuit. The current replica circuit is a reference inductor L S2 The voltage V given at both ends L1 , reference inductance L S2 Voltage across the terminals V L1 With the main inductance L P The voltage V across the two ends has a proportional relationship, so the reference inductor L S2 A current I will flow in L1 , generated by the current replication circuit and the reference inductor L S2 The current I L1There is a proportional relationship between the current I + Output.

[0057] Similarly, Figure 5B The circuit 500B in FIG. Figure 2D Schematic diagram of another embodiment of the current generator 202, the current generator 202 is also implemented by a differential linear driver, the differential linear driver drives another reference inductor L at its load end S2 The principle is the same as described above and will not be elaborated on here.

[0058] Figure 6 As shown in the schematic diagram, in the circuit 600, in order to reduce the power loss of the linear driver, if the supply voltage V CC (Not shown) If the voltage of the signal source is large, the number of turns of the winding inductor can be adjusted to M times. At this time, if the feedback impedance of the linear driver is K times the input impedance (K is a constant), then L1 / L0=M 2 ×N×K, the linear driver replicates the current I flowing into the secondary inductor or transformer + The current value I=N×I L1 In an ideal state, the signal source generates a current flowing into the main inductor L P The current value I0 will approach zero.

[0059] Taking into account the actual conditions, including temperature changes, time delays, or inaccuracies in component accuracy, it is difficult to achieve a high multiple of the equivalent inductance value while facilitating mass production in order to avoid circuit oscillation. Figure 7 As shown in the schematic diagram, the circuit 700 further includes a linear amplifier LNA, which is arranged between the power transmission side and the power consumption side. The linear amplifier LNA is coupled to transformers T2 and T3 at the power transmission side and the power consumption side respectively. The input end of the linear amplifier LNA is coupled to the two ends of the secondary coil of the transformer T2, and the input end of the linear amplifier LNA and the two ends of the secondary coil of the transformer T2 are respectively coupled to the input impedance M1Z. The output end of the linear amplifier LNA is coupled to the two ends of the main coil of the transformer T3, and the output end and the input end of the linear amplifier LNA are respectively connected in parallel with the output impedance 0.9M2Z. The circuit 700 uses a linear amplifier LNA to make the main inductor L P The voltage on the other side becomes 0.9M2V in ( Figure 7 For example, the turns ratio of the coupling transformer T2 is 1:M1 (M1 is a constant), then the ratio of the input impedance to the output impedance is M1:0.9M2), the main inductor L P A low-pass filter 204 is connected to filter out the noise on the power consumption side. If the capacitance impedance (1 / ωC) of the low-pass filter 204 in the communication frequency band is much smaller than the inductance impedance (ωLf ), then the main inductance L P The inductance value L0, the main inductance L P The cross voltage is 0.1V in , the inductor L in the low-pass filter 204 f The cross voltage is 0.9V in , at this time, the current flowing through the main inductor L P The first current I in The current value I0 is only 0.1 times of the original value, which is equivalent to the main inductance L P The inductance value L0 is increased by 10 times. Then the current generator 202 outputs the current I + The resulting magnetic flux change, current I + The current value I c It is also equal to 0.9 times the original isolation inductance (based on Figure 6 For example, I + =0.9×N×I L1 ), then this circuit can increase the average inductance by 100 times, the actual value is about 50 to 200 times, and the loop is stable without oscillation.

[0060] like Figure 8 As shown in the schematic diagram, another embodiment of the circuit 800 is to use two main inductors L P _1 and L P _2 (or transformer), two main inductors L P _1 and L P _2 (or transformer) respectively has a corresponding secondary side inductance L S1 _1 and L S1 _2, couplers 201_1, 201_2, and corresponding current generators 202_1 and 202_2, main inductor L P _1 and L P The inductance values ​​of _2 are L0 and L2 respectively, and the main inductance L P _1 has a corresponding coupler 201_1 and a current generator 202_1, a main inductor L P The transformer _2 has a corresponding coupler 201_2 and a current generator 202_2, and the coupler 201_2 has two current generators I2 + The positive output terminal of the coupler 201_2 is coupled to the current I2 of the coupler 201_1. + The positive output terminal of the coupler 201_2 is coupled to the secondary side inductor L S1 _2 input terminal; please note that the secondary side inductor L S1 The output terminal of _1 is coupled to the secondary side inductor L S1 _2 input terminal to ensure that the coupler 201_2 is coupled to the secondary side inductor LS1 The input end of _1 and the coupler 201_2 are coupled to the secondary side inductor L S1 _2 output terminal, the voltage across the two will be V in ; and a filter capacitor C is connected in parallel on the power side behind the circuit 800. If the impedance of the filter capacitor C in the communication frequency band is much smaller than the main inductor L P _1 and L P _2 group impedance, the input voltage V in Equivalent to the main inductance L P 1_1 and L P 1_2 The sum of the voltage drops, the output current is divided into I1 + With I2 + Two groups, one of which outputs current I2 + larger, coupled to the power consumption side, in other words, the second current output by the current generators 202_1 and 202_2 is based on the main inductance L in the two transformers. P _1 and L P _2 The voltage drop ratio is divided into two groups, and the maximum output current I2 in the two groups + is coupled to the power consumption side, and the reference voltage of the current generator 202_1 and 202_2 is two sets of secondary side inductors L S1 _1 and L S1 _2 cross voltage (if the coupling coefficient a=1), and the reference voltage of the current generator 202_1 comes from the secondary side inductor L S1 The key to this design is that the circuit 800 can maintain a tolerance of 5% for component errors instead of 1% or less, and can achieve a 100-fold increase in inductance. For example, the error of the current generator 202_2 makes the main inductor L P _2 becomes 0.95Vin, then the current generator 202_1 will generate I1 with a cross voltage of 0.05Vin. + , so the accuracy requirement is still maintained at 5%. P _1 and L P _2 In the case of the same inductance value, if the main inductance L P _2 The voltage on V in When the current value is I0, the current generator (input voltage is Vin) generates I2 + ~0.89I0; I1 + ~0.09I0, then this circuit 800 can also increase the average inductance value by 100 times, and the actual value is about 50~200 times, and the loop is stable and will not oscillate. The main reason is that the voltage drop of the two sections is generated. The voltage drop near the signal end (transmission side) is only 0.1 times the original voltage (i.e. 0.1V in), and 90% of the current is coupled from the current generator 202_1, so the signal source itself only needs to bear 1% of the current, which is like the inductance is increased 100 times.

[0061] The above circuit using two inductors (or transformers) can be extended to a circuit with multiple inductors in a similar manner to generate multiple sets of currents to increase the inductance value.

[0062] Please refer to Fig.9A and Fig. 9B , Fig.9A A schematic diagram showing another embodiment of the current generator 202 is shown. Fig. 9B The schematic diagram of the circuit of the present invention in one embodiment is shown. In this embodiment, the current generator 202 is mainly composed of an analog-to-digital converter 202A, a digital inductor current calculator 202B, and a current digital-to-analog converter 202C; wherein the digital inductor current calculator 202B is a digital circuit, and the analog-to-digital converter 202A performs digitization according to the coupling voltage and transmits it to the digital inductor current calculator 202B to calculate the first inductor L S1 The digital information of the output current is sent to the current digital-to-analog converter 202C to generate the actual current I + .

[0063] Therefore, in addition to using the coupling voltage to add to an actual reference inductor to replicate the main inductor current, the coupling voltage can also be digitized by an analog-to-digital converter, and then the inductor current is predicted by digital calculation, and the digitized information is then output to a current digital-to-analog converter to generate the actual current and send it back to the coupler, such as Fig. 9B This method does not require the aforementioned reference inductor, but the operation clock of the computing circuit must be relatively high speed to avoid too much delay and affect the current suppression effect of high-frequency signals.

Claims

1. A circuit for improving high current inductance of power line communication, characterized in that: The circuit comprises: a main inductor, a first current related to a communication signal flows through the main inductor and generates a voltage related to the communication signal, and the main inductor is located on a power supply line, and an alternating current or a direct current flows through the main inductor; A coupler, used for sensing the voltage across the main inductor and generating a coupling voltage; as well as a current generator, receiving the coupling voltage through the coupler to generate a second current, the current generator uses the coupler to couple the second current to flow to the main inductor, and the second current flows back to the coupler and then returns to the current generator; The purpose of the current generator is to generate 0.8 to 0.95 times the first current to generate the second current, and the phase of the second current is close to the first current flowing through the main inductor; The second current flows into the main inductor to suppress the first current driven by the communication signal of the circuit itself.

2. The circuit according to claim 1, characterized in that The current generator receives the coupling voltage from the coupler to generate the second current, and the second current flows to the coil of the main inductor wound around the same magnetic core.

3. The circuit according to claim 1, characterized in that The circuit comprises: a first inductor connected in parallel between the coupler and the main inductor, and the first inductor and the main inductor are connected in series and wound on the same magnetic core; The coil wire diameter of the first inductor is smaller than the coil wire diameter of the main inductor, and only the current of the communication signal flows through the coil of the first inductor.

4. A circuit for improving high current inductance of power line communication, characterized in that: The circuit comprises: a main inductor, a first current related to a communication signal flows through the main inductor and generates a voltage related to the communication signal, the main inductor is located on a power supply line, and an alternating current or a direct current flows through the main inductor; a first inductor, generating another voltage according to the voltage across the main inductor; A coupler, used for sensing the voltage across the first inductor and generating a coupling voltage; as well as a current generator, receiving the coupling voltage by the coupler to generate a second current, wherein the current generator couples the second current by the coupler to cause the main inductor to generate a resistive electromotive force; The purpose of the current generator is to generate the second current to generate a magnetic field 0.8 to 0.95 times that generated by the first current in the magnetic core of the main inductor, so as to suppress the first current driven by the communication signal of the circuit itself.

5. The circuit according to claim 4, characterized in that The first inductor is coupled to the coupler, and the first inductor and the main inductor are wound on the same magnetic core, and the first inductor and the main inductor form a first transformer; The second current flows into the first inductor instead of the main inductor to suppress the first current flowing through the main inductor, and the first transformer is used to isolate a high voltage on the transmission side from entering the coupler.

6. The circuit according to claim 1 or 4, characterized in that: The current generator has one or more amplifiers and a reference inductor used as a current replication circuit. The current replication circuit is a voltage given by the amplifier at both ends of the reference inductor. The voltage at both ends of the reference inductor is proportional to the voltage at both ends of the main inductor. Therefore, current flows into the reference inductor, and the second current output is generated by the current replication circuit in a proportional relationship with the current on the reference inductor.

7. The circuit according to claim 1 or 4, characterized in that: The current generator is mainly composed of an analog-to-digital converter, a digital inductor current calculator, and a current digital-to-analog converter; wherein the digital inductor current calculator is a digital circuit, and the analog-to-digital converter digitizes the coupling voltage and transmits the digital information of the current output by the first inductor to the digital inductor current calculator to calculate the digital information, and transmits the information to the current digital-to-analog converter to generate the actual second current.

8. The circuit according to claim 4, characterized in that The circuit has a transformer formed by the first inductor and the main inductor, and the current generator is a differential linear driver, and the differential linear driver includes: a first input terminal; a second input terminal; a first output terminal; a second output terminal; a third output terminal; a fourth output terminal; Among them, the first input end and the second input end are coupled to the input end and the output end of the first inductor respectively, and the first output end and the fourth output end are connected in series with a second inductor as load ends; the first input end and the third output end are coupled to the coupler in parallel, the second output end is coupled to the second input end in parallel, and there is a first matching resistor between the first input end and the coupler; there is a second matching resistor between the second input end and the second output end; a third matching impedance is connected in parallel between the first input end and the first output end; and a fourth matching impedance is connected in parallel between the second input end and the fourth output end.

9. The circuit according to claim 8, characterized in that The impedance value of the differential linear driver matching impedance Z is greater than ωL0 or ωL1, where ω is the angular frequency of the communication frequency band, L0 is the inductance value of the main inductor, and L1 is the inductance value of the second inductor.

10. The circuit according to claim 5, characterized in that The circuit includes a linear amplifier, which is arranged between the power transmission side and the power consumption side. The linear amplifier is coupled to a second transformer and a third transformer on the power transmission side and the power consumption side respectively; the input end of the linear amplifier is coupled to the two ends of the secondary coil of the second transformer, and the input end of the linear amplifier and the two ends of the secondary coil of the first transformer are respectively coupled to a first input impedance, the output end of the linear amplifier is coupled to the two ends of the main coil of the third transformer, and a second output impedance is connected in parallel between the output end and the input end of the linear amplifier.

11. The circuit according to claim 5, characterized in that The circuit has a second inductor and another main inductor to form a second transformer, and the first transformer has a corresponding first coupler and a first current generator, the second transformer has a corresponding second coupler and a second current generator, and the second coupler has two positive output ends of the second current, one of which is coupled to the positive output end of the second current of the first coupler, and the other is coupled to the input end of the second inductor; wherein, a filter capacitor is connected in parallel to the power consumption side of the circuit, and the impedance of the filter capacitor in the communication frequency band is much smaller than the impedance of the main inductor, then the input voltage of the transmission side is equivalent to the sum of the voltage drops of the main inductors, and the second current output by the current generator is divided into two groups according to the ratio of the voltage drops of the main inductors in the first transformer and the second transformer, and the largest second current in the two groups is coupled to the power consumption side.

12. The circuit according to claim 11, characterized in that When the coupling coefficient between the first coupler and the second coupler is 1, the reference voltages of the first current generator and the second current generator are respectively the sum of the voltages across the first inductor and the second inductor, and the reference voltage of the first current generator is from the voltage across the first inductor.

13. The circuit according to claim 4, characterized in that When the circuit is in the low-frequency AC band, the current generator will not generate the second current to flow into the coil of the first inductor because the output impedance of the current generator is relatively high, so the current generator is effectively disconnected.

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