An adaptive resonant network suitable for use in the transmitting end of a class E active rectifier

Abstract

The application provides an adaptive resonant network suitable for an E-class active rectifier transmitting end. The adaptive resonant network replaces the resonant capacitor of a traditional series resonant network with an adaptive equivalent adjustable capacitor composed of two branches. Each branch of the equivalent capacitor contains an additional inductor and capacitor. It is worth noting that one of the branches is connected in series with an additional AC auxiliary power supply. The auxiliary power supply can generate an auxiliary current in the coil. After the auxiliary current is superposed with the current generated by the main power supply, the phase difference between the total current flowing through the transmitting coil and the main power supply can be adjusted. Therefore, by reasonably adjusting the amplitude and phase of the auxiliary current, the phase difference between the main power supply of the transmitting end and the total current flowing through the transmitting coil can be kept at 0 when the equivalent reactance of the transmitting end changes, so that the power output capability is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of class E active rectifier, in particular to a kind of adaptive resonant network suitable for the emission end of class E active rectifier. BACKGROUND

[0002] Magnetic resonance type wireless power transmission technology utilizes the electromagnetic induction principle between receiving and transmitting coils, makes non-contact energy transmission with interval of several centimeters or even several meters become reality, can effectively overcome the defects such as line aging and poor sealing in physical connection power supply mode, has positive significance for improving the flexibility and safety of power supply system in high-power, high-temperature exposure, flood-prone and other application occasions.

[0003] However, due to the influence of the high uncertainty of the relative position between the coupling coils on the output power, the single resonant network cannot be directly applied to constant voltage, constant current or constant power output occasions, so additional power regulation circuit is required. The cascaded DC-DC converter for the passive rectifier circuit of the receiving end is one of the simplest power regulation strategies, but it has defects such as more additional components and low power density. Compared with the above, the active rectifier scheme that replaces the diodes of full-bridge and half-bridge rectifiers with active rectifier circuits such as MOSFET can make the rectifier circuit have the functions of rectification and power regulation, and has higher power density. However, this method uses a large number of active switches, the control circuit cost is high, and the output power can only be reduced. Therefore, the class E active rectifier using only one active switch further optimizes the power density of the main circuit, effectively reduces the cost of the control circuit, and in addition, due to the boost and buck functions of the circuit, it has more advantages in power adjustable range. However, the duty cycle of the switch will affect the equivalent reactance of the receiving end, thereby affecting the phase difference between the transmitting end coil current and the power supply, if the phase difference can be eliminated, the power regulation range of the class E active rectifier can be further improved. SUMMARY

[0004] The main purpose of the present application is to overcome the above-mentioned defects in the prior art, and to provide an adaptive resonant network suitable for the emission end of class E active rectifier. The network replaces the resonant capacitor in the traditional series resonant network with an equivalent adjustable capacitor containing an auxiliary voltage source. When the equivalent reactance of the transmitting end changes due to the duty cycle of the active rectifier, the transmitting end resonant network can always be kept in resonance by adjusting the equivalent adjustable capacitor value, which further improves the power transmission capability of the WPT system and enhances the adjustable range of the output power.

[0005] The present application adopts the following technical solutions:

[0006] An adaptive resonant network suitable for the transmitting end of a class-E active rectifier, the resonant network comprising: a DC voltage source v i1 for energizing; the DC voltage source v i1 is connected to the DC side of a half-bridge inverter circuit composed of a first switch S1 and a second switch S2 i1 is converted into a high-frequency AC voltage source v1; the DC side of the half-bridge inverter circuit composed of the first switch S1 and the second switch S2 is connected in series with a transmitting coil L1 and a first resonant capacitor, which is composed of a variable capacitor module;

[0007] The variable capacitor module is composed of two LC series branches and an auxiliary AC voltage source v2, which is composed of a large capacitor C i2 , a third switch S3 and a fourth switch S4 i2 connected to the DC side of a half-bridge inverter circuit composed of the third switch S3 and the fourth switch S4; in the variable capacitor module, one end of an LC branch composed of a third inductor L3 and a third capacitor C3 is connected to the high-level output end of the auxiliary AC voltage source v2, and the other end is connected to one end of an LC branch composed of a second inductor L2 and a second capacitor C2; the other end of the LC branch composed of the second inductor L2 and the second capacitor C2 is connected to the ground end of the auxiliary AC voltage source v2; in the transmitting end main circuit, one end of the transmitting coil L1 is connected to the high-level output end of the high-frequency AC voltage source v1, and the other end is connected to the intersection of the two LC branches in the variable capacitor module; the ground end of the high-frequency AC voltage source v1 is directly connected to the ground end of the auxiliary AC voltage source v2.

[0008] Specifically, the phase of the auxiliary AC voltage source v2 lags behind the high-frequency AC voltage source v1 by one quarter of a cycle.

[0009] Specifically, the inverter circuit composed of the first switch S1 and the second switch S2 or the third switch S3 and the fourth switch S4 adopts a full-bridge inverter circuit.

[0010] Specifically, the receiving end circuit of the class-E active rectifier comprises a series resonant network, which comprises a receiving coil L 11 and a second resonant capacitor C 11 , a first inductor Le and a receiving coil L 11 and a second resonant capacitor C 11 composing a resonant network directly in parallel; a diode D e and a fourth capacitor C e are connected in parallel; a load R O and a rectification capacitor C O are connected in parallel; the high-level end of C O is connected to the cathode of the fourth capacitor D e , and CO The low level end of the diode D is connected to one end of the series resonant network. e The anode of is connected to the other end of the series resonant network.

[0011] Specifically, the class E active rectifier receiving end circuit further includes a fifth capacitor C a The fifth switch tube S is connected in series a The auxiliary circuit formed: the fifth switch tube S a The drain of the diode D e The anode of the fifth switch tube S a The source and the fifth capacitor C a One end of the fifth capacitor C a The other end of the diode D e connected to the cathode.

[0012] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The present invention provides an adaptive resonant network suitable for the transmitter of a Class E active rectifier. The network replaces the resonant capacitor in a traditional series resonant network with a two-branch equivalent adjustable capacitor including an auxiliary voltage source. When the equivalent reactance of the transmitter changes due to the duty cycle of the active rectifier, the transmitter resonant network can be kept in a resonant state by adjusting the capacitance of the equivalent adjustable capacitor, that is, the transmitter is always kept operating in a zero-phase mode, further improving the power transmission capability of the WPT system and enhancing the adjustable range of the output power.

[0014] (2) The present invention provides an adaptive resonant network suitable for the transmitter end of a Class E active rectifier. The adjustable capacitor module can realize adaptive adjustment of the equivalent capacitance without the need for additional control links. The structure is simple and easy to use.

[0015] (3) The auxiliary voltage source required in the adjustable capacitor module can be constructed by itself using a large capacitor without the need to connect to an additional DC voltage source. By utilizing the characteristics of the device itself, the function can be realized while saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a WPT system using a Class E active rectifier and an adaptive resonant network suitable for the Class E active rectifier, provided in an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the principle of amplitude / phase adjustment of the transmitting coil current provided by an embodiment of the present invention;

[0018] Figure 3 The receiving end D provided in the embodiment of the present invention eWhen the on-time of the main AC power source v1 changes, the main AC power source v1 and the total coil iz1 ensure zero phase mode, and the phase of the auxiliary AC power source v2 relative to v1;

[0019] Figure 4 The adaptive resonant network provided by the embodiment of the present application has a comparison of output power with a traditional series resonant network;

[0020] The present application is further described below in combination with the drawings and specific embodiments. DETAILED DESCRIPTION

[0021] The present application is further described below in combination with the drawings and specific embodiments.

[0022] As shown in FIG. Figure 1 , in the transmitting end resonant network, a DC voltage source v i1 is used for energy supply, an inverter circuit composed of switching devices S1 and S2 can convert v i1 into a high-frequency AC voltage source v1, the transmitting coil L1 is used for energy transmission, and a variable capacitance module is used for self-adaptive capacitance adjustment. The variable capacitance module is composed of two LC series branches and an auxiliary AC voltage source v2, and v2 is provided by a half-bridge inverter circuit composed of a DC voltage source V i2 and S3 and S4. In physical connection, one end of an LC branch composed of an inductor L3 and a capacitor C3 in the variable capacitance module is connected to the high-level output end of v2, the other end is connected to one end of an LC branch composed of an inductor L2 and a capacitor C2, the other end of the LC branch composed of L2 and C2 is connected to the ground end of v2. In the transmitting end main circuit, one end of the coil L1 is connected to the high-level output end of v1, the other end is connected to the intersection of the two LC branches in the variable capacitance module, and the ground end of v1 is directly connected to the ground end of v2. It should be noted that the auxiliary power source V i2 in the variable capacitance can be constructed by using a large capacitor C i2 without connecting a complex external voltage source: C i2 can absorb energy from the main power source V i1 , thereby constructing a virtual voltage source V i2 with self-adaptive adjustment characteristics.

[0023] The receiving end includes a series resonant network for receiving energy and an E-class active rectifier for AC-DC conversion and power regulation. The series resonant network includes a receiving coil L 11 and a resonant capacitor C 11 ; in the E-class active rectifier, an inductor Le is directly connected in parallel with a resonant network composed of L 11 and C 11 ; a diode D e is connected in parallel with a capacitor C e ; and a load RO and the rectifier capacitor C O Parallel; C O The high level end and D e The cathode is connected to the low level and one end of the series resonant network, D e The anode of is connected to the other end of the series resonant network. Furthermore, the class E active rectifier also includes a capacitor C a Series switch tube S a Auxiliary circuit composed of: S a The drain and D e The anode of S a The source and C a One end is connected to C a The other end of D e connected to the cathode.

[0024] In a preferred embodiment, the switches S1, S2, S3, S4, S a The operating frequency is set to 200kHz; the receiving and transmitting coils L1 and L 11 The self-inductance is 110μH; the receiving end capacitance C 11 With L 11 Fully resonant, so it is set to 5.75nF; the inductor L e With capacitor C a They need to be large enough. In this example, they are set to 500μH and 3μF respectively. e The values ​​of inductors L2 and L3, and capacitors C2 and C3 in the variable capacitor module do not affect the module's adaptive regulation characteristics and are therefore not subject to specific limitations. In a preferred embodiment, L2 and L3 are set to 10μH and 100μH, respectively, and C2 and C3 are set to 2nF and 6nF, respectively. When the system is operating normally, the auxiliary AC voltage source v2 needs to lag behind v1 by a quarter of a cycle.

[0025] Since v2 and v1 can generate current i on the transmitting coil L1 respectively 11 with i 21 , after the attachment Figure 2 The current superposition principle shown in the figure is 11 with i 21 The total current of the synthetic transmitting coil i z1 Will always be able to maintain a zero phase relationship with v1. Figure 3 As shown, when the diode D in the class E active rectifier e When the on-time of the transmitter changes, the v1 and i z1When the zero-phase working state is achieved, the phase difference between v2 and v1 is always 90°. Therefore, in actual operation, the phase of v2 is set in advance, so that the transmitting end can achieve adaptive resonance without additional control links. As shown in Figure 4 The adaptive resonance network suitable for the class-E active rectifier can improve the power transmission capacity of the system by about 30%.

[0026] The above is only a specific embodiment of the present application, but the design concept of the present application is not limited thereto, and any non-essential modification of the present application using this concept shall be deemed to infringe the protection scope of the present application.

Claims

1. An adaptive resonant network suitable for a transmitter end of a Class E active rectifier, the resonant network comprising: DC voltage source v i1 Used for energy supply; the DC voltage source v i1 Connected to the DC side of the half-bridge inverter circuit composed of the first switch tube S1 and the second switch tube S2, the DC voltage source v i1 Converted into a high-frequency AC voltage source v1; the DC side of the half-bridge inverter circuit composed of the first switching tube S1 and the second switching tube S2 is connected in series with the transmitting coil L1 and the first resonant capacitor, characterized in that the first resonant capacitor is composed of a variable capacitance module; The variable capacitor module is composed of two LC series branches and an auxiliary AC voltage source v2, which is composed of a large capacitor C i2 , a third switch tube S3 and a fourth switch tube S4, the large capacitor C i2 The LC branch formed by the third inductor L3 and the third capacitor C3 in the variable capacitor module is connected to the DC side of the half-bridge inverter circuit formed by the third switching tube S3 and the fourth switching tube S4. In the variable capacitor module, one end of the LC branch formed by the third inductor L3 and the third capacitor C3 is connected to the high-level output terminal of the auxiliary AC voltage source v2, and the other end is connected to one end of the LC branch formed by the second inductor L2 and the second capacitor C2. The other end of the LC branch formed by the second inductor L2 and the second capacitor C2 is connected to the ground terminal of the auxiliary AC voltage source v2. In the transmitting end main circuit, one end of the transmitting coil L1 is connected to the high-level output terminal of the high-frequency AC voltage source v1, and the other end is connected to the intersection of the two LC branches in the variable capacitor module. The ground terminal of the high-frequency AC voltage source v1 is directly connected to the ground terminal of the auxiliary AC voltage source v2.

2. The adaptive resonant network suitable for a Class E active rectifier transmitter according to claim 1, characterized in that: The phase of the auxiliary AC voltage source v2 lags behind that of the high-frequency AC voltage source v1 by one quarter of a cycle.

3. The adaptive resonant network suitable for a Class E active rectifier transmitter according to claim 1, characterized in that: The inverter circuit formed by the first switch tube S1 and the second switch tube S2 or the third switch tube S3 and the fourth switch tube S4 adopts a full-bridge inverter circuit.

4. The adaptive resonant network suitable for a Class E active rectifier transmitter according to claim 1, characterized in that: The receiving end circuit of the class E active rectifier includes a series resonant network, and the series resonant network includes a receiving coil L 11 With the second resonant capacitor C 11 , the first inductor Le and the receiving coil L 11 With the second resonant capacitor C 11 The resonant network formed is directly connected in parallel; the diode D e and the fourth capacitor C e Parallel connection; load R O and the rectifier capacitor C O Parallel; C O The high level end and the fourth capacitor D e The cathode of O The low level end of the diode D is connected to one end of the series resonant network. e The anode of is connected to the other end of the series resonant network.

5. The adaptive resonant network suitable for a transmitting end of a class E active rectifier according to claim 4, characterized in that: The class E active rectifier receiving end circuit further includes a fifth capacitor C a The fifth switch tube S is connected in series a The auxiliary circuit formed: the fifth switch tube S a The drain of the diode D e The anode of the fifth switch tube S a The source and the fifth capacitor C a One end of the fifth capacitor C a The other end of the diode D e connected to the cathode.

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