A wireless charging circuit based on improved Z-source network

Abstract

The present invention discloses a wireless charging circuit based on an improved Z-source network, comprising a transmitting circuit and a receiving circuit, wherein the transmitting circuit comprises a primary-side rectifying and filtering circuit, an improved Z-source network circuit, a high-frequency inverter bridge circuit, and a primary-side LCC network circuit, and the receiving circuit comprises a secondary-side LCC network circuit and a secondary-side rectifying and filtering circuit; in view of the problem in the prior art that if high-power and long-distance wireless transmission of electric energy is to be achieved, its efficiency is inevitably reduced, and if high-efficiency wireless transmission of electric energy is to be achieved, its transmission distance and power level must be reduced, the present invention provides a wireless charging circuit based on an improved Z-source network, which can ensure high power and high efficiency when performing long-distance wireless charging.

Description

Technical Field

[0001] The present invention belongs to the field of wireless charging, and in particular relates to a wireless charging circuit based on an improved Z-source network. Background Art

[0002] With the depletion of traditional energy, the increasingly serious pollution problem and the rapid development of social economy and science and technology, electric energy, as an economic, practical, clean, easy to control and convertible energy form, plays an extremely important role in industry, transportation, life and other fields, and the acquisition methods are green and diverse (such as hydropower generation, nuclear power generation, wind power generation, solar power generation, etc.), becoming the energy that people rely on for survival. However, the traditional wire transmission method of electric energy has unavoidable shortcomings. Compared with wire transmission, wireless power transmission (Wireless Power Transfer, WPT) has incomparable advantages such as small footprint, safety and convenience, no mechanical wear, good corrosion and oxidation resistance, no spark electric shock danger, flexible application, and strong environmental adaptability. Nowadays, wireless power transmission technology is gradually applied to many fields, such as home appliances and consumer electronics, implantable medical devices, electric transportation, special applications, etc. However, it is worth noting that the current application scope of wireless charging is relatively small and there are few application occasions. At present, the most widely used application of wireless charging is the field of mobile phone wireless charging. This is because the power of mobile phone wireless charging is small and the distance is short, which makes it easy to realize the transmission of electric energy with high efficiency.

[0003] However, in the case of high-power and long-distance charging, wireless charging is rarely used in practice. Even in the field of electric vehicles, it is mostly at the stage of experimental verification and small-scale trial, and has not been promoted on a large scale. One very important reason is that the power, distance and efficiency of wireless charging cannot be achieved at the same time. Taking the traditional LCC wireless charging circuit in the prior art as an example, if high-power and long-distance wireless transmission of electric energy is to be achieved, its efficiency will inevitably decrease. If high-efficiency wireless transmission of electric energy is to be achieved, its transmission distance and power level can only be reduced. Therefore, in order to use high-power wireless charging technology with high efficiency, only several wireless charging devices with lower power levels can be connected in parallel, which not only increases the volume and makes the power density lower, but also greatly increases the cost. If the relationship between power, distance and efficiency can be met at the same time, it can lay a good foundation for the large-scale practical application of wireless charging. Summary of the invention

[0004] In view of the problem in the prior art that if high-power and long-distance wireless transmission of electric energy is to be achieved, its efficiency will inevitably be reduced, and if high-efficiency wireless transmission of electric energy is to be achieved, its transmission distance and power level must be reduced, the present invention provides a wireless charging circuit based on an improved Z-source network, which can ensure high power and high efficiency during long-distance wireless charging.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A wireless charging circuit based on an improved Z-source network, comprising a transmitting circuit and a receiving circuit;

[0007] The transmitting circuit includes a primary side rectifying and filtering circuit, an improved Z source network circuit, a high frequency inverter bridge circuit, and a primary side LCC network circuit; the receiving circuit includes a secondary side LCC network circuit and a secondary side rectifying and filtering circuit;

[0008] The primary side rectifying and filtering circuit is used to convert the input alternating current into direct current;

[0009] The improved Z-source network circuit is used to pump up the voltage of the direct current output by the primary side rectification and filtering circuit through the zero vector generated by the high-frequency inverter bridge circuit, and convert it into high voltage electricity;

[0010] The high-frequency inverter bridge circuit is used to convert the high-voltage electricity output by the improved Z-source network circuit into a high-frequency voltage;

[0011] The primary side LCC network circuit is used to convert the high-frequency voltage output by the high-frequency inverter bridge circuit into a resonant current;

[0012] A resonance is formed between the primary LCC network circuit and the secondary LCC network circuit, so as to transmit the resonant current to the secondary LCC network circuit in the form of electric energy;

[0013] The secondary side LCC network circuit is used to convert the electric energy received from the primary side LCC network circuit into a resonant current;

[0014] The secondary side rectifying and filtering circuit is used to convert the resonant current output by the secondary side LCC network circuit into a stable direct current.

[0015] Further improvement of the technical solution of the present invention, the primary side rectifier filter circuit is a single-phase rectifier filter circuit or a three-phase rectifier filter circuit, and the secondary side rectifier filter circuit is a single-phase rectifier filter circuit. The primary side rectifier filter circuit is a single-phase rectifier filter circuit or a three-phase rectifier filter circuit, which can convert the input single-phase city electricity or three-phase industrial electricity into direct current as the direct current input of the subsequent circuit.

[0016] Further improvement of the technical solution of the present invention, the primary side rectification and filtering circuit is a single-phase rectification and filtering circuit, including a diode D1, a diode D2, a diode D3, a diode D4 and a filter capacitor C0, wherein the diode D1, the diode D2, the diode D3 and the diode D4 are bridge-connected, and the output end is connected to the filter capacitor C0, wherein the diode D1 and the diode D2 constitute one bridge arm, and the diode D3 and the diode D4 constitute another bridge arm; the secondary side rectification and filtering circuit has the same structure as the primary side rectification and filtering circuit. Both the primary side rectification and filtering circuit and the secondary side rectification and filtering circuit are single-phase rectification and filtering circuits, which are composed of four diodes and a filter capacitor, and can convert the input single-phase mains power into direct current as the direct current input of the subsequent circuit.

[0017] A further improvement to the technical solution of the present invention is that the improved Z source network circuit comprises a coil L Z1 and coil L Z2 The transformer T Z1 、Inductance L Z3 、Diode D Z1 , capacitor C Z1 and capacitor C Z2 The inductor L Z3 One end is connected to the positive electrode of filter capacitor C0, and the other end is connected to capacitor C Z1 anode of the diode D Z1 One end is connected to the inductor L Z3 and capacitor C Z1 The other end is connected to the coil L Z1 The same end of the coil L Z1 The opposite end and the coil L Z2 The same-name ends of the coil L are connected Z1 The same name termination diode D Z1 The cathode of coil L Z2 The opposite end is connected to the input end of the high-frequency inverter bridge circuit and connected to the capacitor C Z1 The cathode of the capacitor C Z2 The anode and coil L Z1 and coil L Z2 The cathode is connected to the cathode of capacitor C0. The improved Z source network circuit can realize the pumping function of the DC output of the primary rectifier filter circuit and provide a higher voltage for the primary LCC network circuit. Z3 One end is connected to the positive electrode of filter capacitor C0, and the other end is connected to C Z1 The anode of the inverter is mainly used to connect the high frequency inverter bridge to the short circuit zero vector. Z1 Charging; diode D Z1 One end connected to L Z3 and C Z1 The other end is connected to the coil L Z1The same-name terminal, its main function is to block L when the high-frequency inverter bridge is inserted into the zero vector Z1 and C Z2 The generated high voltage flows back to the power supply; transformer T Z1 By coil L Z1 and L Z2 Composition, L Z1 Synonymous end and L Z2 The same-named ends of L Z1 The same name termination diode D Z1 The cathode, L Z2 The opposite end is connected to the input end of the high frequency inverter bridge and connected to C Z1 The cathode of Z1 The main function of the capacitor C is to generate a higher pump voltage. Z2 The anode and L Z1 With L Z2 The cathode is connected to the cathode of C0, and its main function is to filter and stabilize the voltage after the pump is stepped up.

[0018] A further improvement to the technical solution of the present invention is that the capacitor C Z1 and capacitor C Z2 It is composed of one capacitor or two or more capacitors connected in series.

[0019] A further improvement of the technical solution of the present invention is that the high-frequency inverter bridge circuit includes a semiconductor switch tube Q1, a semiconductor switch tube Q2, a semiconductor switch tube Q3 and a semiconductor switch tube Q4, wherein the semiconductor switch tube Q1, the semiconductor switch tube Q2, the semiconductor switch tube Q3 and the semiconductor switch tube Q4 are bridge-connected; the semiconductor switch tube Q1 and the semiconductor switch tube Q2 form a left bridge arm, the drain of the semiconductor switch tube Q1 is connected to the output end of the improved Z-source network circuit, the source of the semiconductor switch tube Q1 is connected to the drain of the semiconductor switch tube Q2, and the source of the semiconductor switch tube Q2 is connected to the C Z2 The semiconductor switch tube Q3 and the semiconductor switch tube Q4 constitute a right bridge arm, the drain of the semiconductor switch tube Q3 is connected to the output end of the improved Z source network circuit, the source of the semiconductor switch tube Q3 is connected to the drain of the semiconductor switch tube Q4, and the source of the semiconductor switch tube Q4 is connected to the capacitor C Z2 The high-frequency inverter bridge circuit has two functions. One is to generate a zero vector to make the improved Z source network circuit generate a pumping voltage, and the other is to generate a high-frequency voltage. Q1 and Q4 are a group of working tubes, and Q2 and Q3 are a group of working tubes. The two groups of working tubes are turned on alternately. At the same time, during the state conversion process, there will be a time when two groups of switch tubes are turned on at the same time. This time is the time of inserting the zero vector, and the improved Z source network circuit generates a voltage pump through this zero vector.

[0020] Further improvement of the technical solution of the present invention, the primary LCC network circuit includes an inductor L1, a capacitor C p , capacitor C1, transmission inductor L P One end of the inductor L1 is connected to the connection point of the semiconductor switch tube Q1 and the semiconductor switch tube Q2 in the high-frequency inverter bridge circuit, and the other end is connected to the capacitor C P and the connection point of capacitor C1, capacitor C P The other end of the transmission inductor L P One end of the capacitor C1 is connected to the transmission inductor L P The other end is connected to the connection point of the semiconductor switch tube Q2 and the semiconductor switch tube Q4 of the right bridge arm switch tube of the high-frequency inverter bridge circuit. The primary side LCC network circuit resonates with the secondary side LCC network circuit to ensure that the power of the primary side LCC network circuit is transmitted with the highest efficiency.

[0021] A further improvement of the technical solution of the present invention is that the secondary side LCC network circuit includes an inductor L2, a capacitor C s , capacitor C2, receiving inductor L S One end of the inductor L2 is connected to a bridge arm in the secondary side rectifier filter circuit, and the other end is connected to the capacitor C s and the connection point of capacitor C2, capacitor C s The other end of the receiving inductor L S One end of the capacitor C2 is connected to the receiving inductor L S The other end of the secondary side LCC network circuit is connected to the other bridge arm of the secondary side rectifier filter circuit. The secondary side LCC network circuit resonates with the primary side LCC network circuit to ensure that the secondary side LCC network circuit receives electrical energy with the highest efficiency.

[0022] Compared with the prior art, the technical effects of the present invention are:

[0023] The present invention provides a wireless charging circuit based on an improved Z-source network, which can ensure high power and high efficiency during long-distance wireless charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an overall structural diagram of an embodiment of the present invention.

[0025] Figure 2 It is a circuit principle diagram of the primary side rectification and filtering circuit of an embodiment of the present invention.

[0026] Figure 3 1 is a circuit schematic diagram of the transmitting circuit and the receiving circuit in the embodiment of the present invention. (The primary side rectification and filtering circuit and the secondary side rectification and filtering circuit are omitted)

[0027] Figure 4 This is the circuit diagram of the traditional LCC wireless charging circuit.

[0028] Figure 5 It is a relationship diagram between power and coupling factor of traditional LCC wireless charging circuit.

[0029] Figure 6 This is a graph showing the relationship between power and efficiency of a traditional LCC wireless charging circuit.

[0030] Figure 7 It is a comparison diagram of the relationship between the power and coupling factor of the charging circuit of the present invention and the traditional LCC wireless charging circuit.

[0031] Figure 8 It is a comparison diagram of the power and efficiency relationship between the charging circuit of the present invention and the traditional LCC wireless charging circuit. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0033] like Figure 1 As shown, a wireless charging circuit based on an improved Z source network provided in this embodiment includes a transmitting circuit and a receiving circuit; the transmitting circuit includes a primary side rectifying and filtering circuit, an improved Z source network circuit 1, a high frequency inverter bridge circuit 2, and a primary side LCC network circuit 3; the receiving circuit includes a secondary side LCC network circuit 4 and a secondary side rectifying and filtering circuit; the primary side rectifying and filtering circuit is used to convert the input alternating current into direct current; the improved Z source network circuit 1 is used to pump up the voltage of the direct current output by the primary side rectifying and filtering circuit through the zero vector generated by the high frequency inverter bridge circuit 2, and convert it into high voltage electricity; The bridge circuit 2 is used to convert the high voltage output by the improved Z-source network circuit 1 into a high-frequency voltage; the primary LCC network circuit 3 is used to convert the high-frequency voltage output by the high-frequency inverter bridge circuit 2 into a resonant current; resonance is formed between the primary LCC network circuit 3 and the secondary LCC network circuit 4, and is used to transmit the resonant current in the form of electric energy to the secondary LCC network circuit 4; the secondary LCC network circuit 4 is used to convert the electric energy received from the primary LCC network circuit 3 into a resonant current; the secondary rectifier and filter circuit is used to convert the resonant current output by the secondary LCC network circuit 4 into a stable direct current.

[0034] like Figure 2 As shown, the primary side rectification and filtering circuit is a single-phase rectification and filtering circuit, including a diode D1, a diode D2, a diode D3, a diode D4 and a filter capacitor C0, wherein the diode D1, the diode D2, the diode D3 and the diode D4 are bridge-connected, and the output end is connected to the filter capacitor C0, wherein the diode D1 and the diode D2 form one bridge arm, and the diode D3 and the diode D4 form another bridge arm;

[0035] In this embodiment, the input end of the primary side rectifying and filtering circuit is connected to the single-phase mains power, and the secondary side rectifying and filtering circuit has the same structure as the primary side rectifying and filtering circuit.

[0036] like Figure 3 As shown, the improved Z source network circuit 1 includes a coil L Z1 and coil L Z2 The transformer T Z1 、Inductance L Z3 、Diode D Z1 , capacitor C Z1 and capacitor C Z2 ;

[0037] Inductance L Z3 One end is connected to the positive electrode of filter capacitor C0, and the other end is connected to capacitor C Z1 Anode of diode D Z1 One end is connected to the inductor L Z3 and capacitor C Z1 The other end is connected to the coil L Z1 The eponymous end;

[0038] Coil L Z1 The opposite end and the coil L Z2 The same-name ends of the coil L are connected Z1 The same name termination diode D Z1 The cathode of coil L Z2 The opposite end is connected to the input end of the high-frequency inverter bridge circuit 2 and connected to the capacitor C Z1 The cathode of is connected;

[0039] Capacitor C Z2 The anode and coil L Z1 and coil L Z2 The cathode is connected to the cathode of the filter capacitor C0;

[0040] The high-frequency inverter bridge circuit 2 comprises a semiconductor switch tube Q1, a semiconductor switch tube Q2, a semiconductor switch tube Q3 and a semiconductor switch tube Q4, wherein the semiconductor switch tube Q1, the semiconductor switch tube Q2, the semiconductor switch tube Q3 and the semiconductor switch tube Q4 are connected in a bridge type;

[0041] The semiconductor switch tube Q1 and the semiconductor switch tube Q2 form a left bridge arm. The drain of the semiconductor switch tube Q1 is connected to the output end (bus positive pole) of the improved Z source network circuit 1. The source of the semiconductor switch tube Q1 is connected to the drain of the semiconductor switch tube Q2. The source of the semiconductor switch tube Q2 is connected to C Z2 The cathode (negative pole of busbar) is connected;

[0042] The semiconductor switch tube Q3 and the semiconductor switch tube Q4 form a right bridge arm. The drain of the semiconductor switch tube Q3 is connected to the output end (bus positive electrode) of the improved Z source network circuit 1. The source of the semiconductor switch tube Q3 is connected to the drain of the semiconductor switch tube Q4. The source of the semiconductor switch tube Q4 is connected to the capacitor C Z2 The cathode (negative pole of busbar) is connected;

[0043] The primary side LCC network circuit 3 includes an inductor L1 and a capacitor C p , capacitor C1, transmission inductor L P ;

[0044] One end of the inductor L1 is connected to the connection point of the semiconductor switch tube Q1 and the semiconductor switch tube Q2 in the high-frequency inverter bridge circuit 2, and the other end is connected to the capacitor C P and the connection point of capacitor C1, capacitor C P The other end of the transmission inductor L P One end of the capacitor C1 is connected to the transmission inductor L P The other end is connected to the high-frequency inverter bridge circuit 2, and is also connected to the connection point of the semiconductor switch tube Q2 and the semiconductor switch tube Q4 of the right bridge arm switch tube.

[0045] The secondary side LCC network circuit 4 includes an inductor L2 and a capacitor C s , capacitor C2, receiving inductor L S ;

[0046] One end of the inductor L2 is connected to a bridge arm in the secondary side rectifier filter circuit, and the other end is connected to the capacitor C s and the connection point of capacitor C2, capacitor C s The other end of the receiving inductor L S One end of the capacitor C2 is connected to the receiving inductor L S The other end is connected to the other end, and is also connected to the other bridge arm of the secondary side rectifier and filter circuit.

[0047] When the wireless charging circuit based on the improved Z-source network described in this embodiment is used, the transmitting circuit is set in a wireless charging device, the single-phase 220V AC mains power is connected to the primary side rectification and filtering circuit, and the receiving circuit is connected to the power input end of the electrical equipment that needs to be wirelessly charged, specifically connected to the output end of the secondary side rectification and filtering circuit, so that the wireless charging device can be used to wirelessly charge these electrical equipment.

[0048] In order to further illustrate the technical effect of the technical solution of the present invention, the wireless charging circuit based on the improved Z-source network described in the present invention is compared with the traditional LCC wireless charging circuit in the prior art mentioned in the background technology.

[0049] like Figure 4 As shown in the circuit diagram of the traditional LCC wireless charging circuit, the core circuit includes a high-frequency inverter bridge circuit and a bilateral LCC network, where Vi is the DC input voltage, Q1, Q2, Q3, and Q4 are four semiconductor switch tubes that form a high-frequency inverter bridge circuit; inductor L1, capacitor C1, capacitor C P and the transmitting coil L p The LCC network at the transmitter consists of inductor L2, capacitor C2, and capacitor C s and receiving coil L s It forms the LCC network at the receiving end.

[0050] For the traditional LCC wireless charging circuit, the power expression is:

[0051]

[0052] The efficiency expression is:

[0053]

[0054] Where A = 1 / (1-ω 2 L2C2), α=ω 2 L1C1, β=ω 2 L1 2 , Rp is the transmitting coil L P The internal resistance of the receiving coil L is Rs. S The internal resistance, R o For load.

[0055] like Figure 5 As shown in the figure, the relationship between the power and coupling factor of the traditional LCC wireless charging circuit, when the coupling factor is 0.2, its transmission power is only about 1300W, and its output power increases with the increase of the coupling factor. However, even if its coupling factor reaches 0.5, its output power is only about 9000W.

[0056] like Figure 6 As shown in the figure, the relationship between power and efficiency of the traditional LCC wireless charging circuit is Figure 6 It can be found that although the maximum efficiency of the traditional LCC wireless charging circuit can reach about 94%, its transmission power is very low at this time, only about 1200W, and as the transmission power increases, its efficiency decreases rapidly. When it reaches 30KW, it is only about 75%, and when it reaches 50KW, it is only about 60% to 65%.

[0057] It can be seen that although the traditional LCC wireless charging circuit can perform high-efficiency transmission, its transmission power is relatively small. In high-power situations, if high-power transmission is required, multiple devices need to be connected in parallel, which also increases the cost.

[0058] In summary, the traditional LCC wireless charging circuit has the following two disadvantages:

[0059] ① If high-power and long-distance wireless transmission of electrical energy is to be achieved, its efficiency will inevitably decrease.

[0060] ② If efficient wireless transmission of electrical energy is to be achieved, the transmission distance and power level must be reduced.

[0061] like Figure 3 As shown, for the present invention, the core circuit includes an improved Z source network circuit 1, a high frequency inverter bridge circuit 2, a primary side LCC network circuit 3 and a secondary side LCC network circuit 4.

[0062] The boost expression of the improved Z-source network circuit 1 is:

[0063]

[0064] Where V i is the given DC input voltage at the input end of the improved Z source network circuit 1, n is the L in the improved Z source network circuit 1 Z1 With L Z2 The turns ratio, D0 is the duty ratio of the through 0 vector, D1 is the duty ratio of the non-through vector (where D0+D1=1), V zo is the average output voltage of the improved Z source network circuit 1. It can be seen that the purpose of boosting can be achieved by changing the turns ratio and the value of the through zero vector.

[0065] The power expression of the wireless charging circuit based on the improved Z-source network described in the present invention is:

[0066]

[0067] The efficiency expression is:

[0068]

[0069] Where A = 1 / (1-ω 2 L2C2), α=ω 2 L1C1, β=ω 2 L1 2 , R zo =(V zo / V i ) 2 R o .

[0070] like Figure 7 As shown, P LCC Curve (k) is the relationship between the transmission power and coupling factor of the traditional LCC wireless charging circuit. Its input voltage is the voltage V after the mains is rectified.i =310V, P in the figure ZLCC5 (k) and P ZLCC6 Curve (k) is a curve showing the relationship between the transmission power and the coupling factor of a wireless charging circuit based on an improved Z source network according to the present invention. ZO is the pumped voltage after the mains is rectified and passed through the improved Z source network circuit 1, where P ZLCC5 (k) is V ZO =500V curve, P ZLCC6 (k) Curve is V ZO =600V, from which it can be seen that, for the same coupling factor, the transmission power of the wireless charging circuit based on the improved Z-source network described in the present invention is much higher than that of the traditional LCC wireless charging circuit.

[0071] When the coupling factor is 0.27, the power of the traditional LCC wireless charging circuit is only about 2500W, but the wireless charging circuit based on the improved Z-source network described in the present invention has a transmission power of 7500W when the pump-up voltage is 500V, and when the pump-up voltage is 600V, its transmission power is as high as 10KW.

[0072] When the coupling factor reaches 0.5, the power of the traditional LCC wireless charging circuit is only about 9000W, but the wireless charging circuit based on the improved Z source network described in the present invention has a transmission power of about 24KW when the pump-up voltage is 500V, and when the pump-up voltage is 600V, its transmission power is as high as about 35KW.

[0073] It can be seen that under the same coupling factor, the transmission power of the wireless charging circuit based on the improved Z source network described in the present invention can reach 3 to 4 times that of the traditional LCC wireless charging circuit. This also means that when the transmission distance is the same, the transmission power of the wireless charging circuit based on the improved Z source network described in the present invention can reach 3 to 4 times that of the traditional LCC wireless charging circuit.

[0074] At the same time, it can also be found that for the same power transmission, the coupling factor required by the wireless charging circuit based on the improved Z source network described in the present invention is much smaller than that of the traditional LCC wireless charging circuit. For example, when the transmission power is the same as 10KW, the coupling factor required by the traditional LCC wireless charging circuit is about 0.54, while the coupling factor required by the wireless charging circuit based on the improved Z source network described in the present invention when the pump-up voltage is 600V is only about 0.27, which is only 1 / 2 of the traditional LCC wireless charging circuit. This also means that when transmitting the same power, the transmission distance of the wireless charging circuit based on the improved Z source network described in the present invention can reach twice the distance of the traditional LCC wireless charging circuit.

[0075] like Figure 8 As shown, where η LCC The (P) curve is the relationship between the efficiency and transmission power of the traditional LCC wireless charging circuit. Its input voltage is the voltage V after the mains is rectified. i =310V, in the figure η ZLCC5 (P) and η ZLCC6 Curve (P) is a curve showing the relationship between the efficiency and transmission power of a wireless charging circuit based on an improved Z source network according to the present invention. ZO is the pumped voltage after the mains is rectified and passed through the improved Z source network circuit 1, where η ZLCC5 (P) is V ZO =500V curve, η ZLCC6 (P) curve is V ZO =600V, from which it can be seen that with the increase of power level, the transmission efficiency of the wireless charging circuit based on the improved Z source network described in the present invention is much higher than that of the traditional LCC wireless charging circuit.

[0076] from Figure 8 It can be seen that within 2500W, the transmission efficiency of the wireless charging circuit based on the improved Z source network described in the present invention is not significantly different from that of the traditional LCC wireless charging circuit, both of which are around 94%. However, as the power level increases, the disadvantages of the traditional LCC wireless charging circuit gradually become apparent.

[0077] When the power is 20KW, the efficiency of the traditional LCC wireless charging circuit quickly drops to about 82%, while the efficiency of the wireless charging circuit based on the improved Z source network described in the present invention is maintained above 90%, where V ZO = The efficiency at 600V is still around 93%.

[0078] When the power is 30KW, the efficiency of the wireless charging circuit based on the improved Z source network described in the present invention can still reach 90% (V ZO =600V), while the efficiency of traditional LCC wireless charging circuit is only about 74%.

[0079] When the power is 50KW, the efficiency of the wireless charging circuit based on the improved Z source network of the present invention can still reach 87% (V ZO =600V), while the efficiency of the traditional LCC wireless charging circuit is only about 61%.

[0080] From the above content, the following Table 1 shows the comparison between the wireless charging circuit based on the improved Z source network described in the present invention and the traditional LCC wireless charging circuit in terms of power and efficiency. It can be seen that the present invention provides a wireless charging circuit based on the improved Z source network, which can ensure high power and high efficiency during long-distance wireless charging, and has significant technical effects.

[0081]

Claims

1. A wireless charging circuit based on an improved Z-source network, characterized in that: including a transmitting circuit and a receiving circuit; The transmitting circuit comprises a primary side rectifying and filtering circuit, an improved Z source network circuit (1), a high frequency inverter bridge circuit (2), and a primary side LCC network circuit (3); the receiving circuit comprises a secondary side LCC network circuit (4) and a secondary side rectifying and filtering circuit; The primary side rectifying and filtering circuit is used to convert the input alternating current into direct current; The improved Z-source network circuit (1) is used to pump up the voltage of the direct current output by the primary-side rectifier filter circuit through the zero vector generated by the high-frequency inverter bridge circuit (2) to convert it into high-voltage electricity; The high-frequency inverter bridge circuit (2) is used to convert the high-voltage electricity output by the improved Z-source network circuit (1) into a high-frequency voltage; The primary-side LCC network circuit (3) is used to convert the high-frequency voltage output by the high-frequency inverter bridge circuit (2) into a resonant current; A resonance is formed between the primary LCC network circuit (3) and the secondary LCC network circuit (4), so as to transmit the resonant current in the form of electric energy to the secondary LCC network circuit (4); The secondary side LCC network circuit (4) is used to convert the electric energy received from the primary side LCC network circuit (3) into a resonant current; The secondary side rectification and filtering circuit is used to convert the resonant current output by the secondary side LCC network circuit (4) into a stable direct current; The primary side rectification and filtering circuit is a single-phase rectification and filtering circuit or a three-phase rectification and filtering circuit, and the secondary side rectification and filtering circuit is a single-phase rectification and filtering circuit; The primary side rectification and filtering circuit is a single-phase rectification and filtering circuit, comprising a diode D1, a diode D2, a diode D3, a diode D4 and a filter capacitor C0, wherein the diode D1, the diode D2, the diode D3 and the diode D4 are bridge-connected, and the output end is connected to the filter capacitor C0, wherein the diode D1 and the diode D2 constitute one bridge arm, and the diode D3 and the diode D4 constitute another bridge arm; The secondary side rectifying and filtering circuit has the same structure as the primary side rectifying and filtering circuit; The improved Z source network circuit (1) comprises a coil L Z1 and coil L Z2 The transformer T Z1 、Inductance L Z3 、Diode D Z1 , capacitor C Z1 and capacitor C Z2 ; The inductance L Z3 One end is connected to the positive electrode of filter capacitor C0, and the other end is connected to capacitor C Z1 anode of the diode D Z1 One end is connected to the inductor L Z3 and capacitor C Z1 The other end is connected to the coil L Z1 The eponymous end; The coil L Z1 The opposite end and the coil L Z2 The same-name ends of the coil L are connected Z1 The same name termination diode D Z1 The cathode of coil L Z2 The opposite end is connected to the input end of the high frequency inverter bridge circuit (2) and connected to the capacitor C Z1 The cathode of is connected; The capacitor C Z2 The anode and coil L Z1 and coil L Z2 The cathode is connected to the cathode of the filter capacitor C0; The capacitor C Z1 and capacitor C Z2 It is composed of one capacitor or two or more capacitors connected in series; The high-frequency inverter bridge circuit (2) comprises a semiconductor switch tube Q1, a semiconductor switch tube Q2, a semiconductor switch tube Q3 and a semiconductor switch tube Q4, wherein the semiconductor switch tube Q1, the semiconductor switch tube Q2, the semiconductor switch tube Q3 and the semiconductor switch tube Q4 are connected in a bridge type; The semiconductor switch tube Q1 and the semiconductor switch tube Q2 form a left bridge arm, the drain of the semiconductor switch tube Q1 is connected to the output end of the improved Z-source network circuit (1), the source of the semiconductor switch tube Q1 is connected to the drain of the semiconductor switch tube Q2, and the source of the semiconductor switch tube Q2 is connected to the C Z2 The cathode of is connected; The semiconductor switch tube Q3 and the semiconductor switch tube Q4 form a right bridge arm, the drain of the semiconductor switch tube Q3 is connected to the output end of the improved Z-source network circuit (1), the source of the semiconductor switch tube Q3 is connected to the drain of the semiconductor switch tube Q4, and the source of the semiconductor switch tube Q4 is connected to the capacitor C Z2 connected to the cathode.

2. The wireless charging circuit based on the improved Z-source network according to claim 1, characterized in that: The primary side LCC network circuit (3) comprises an inductor L1, a capacitor C p , capacitor C1, transmission inductor L P ; One end of the inductor L1 is connected to the connection point of the semiconductor switch tube Q1 and the semiconductor switch tube Q2 in the high-frequency inverter bridge circuit (2), and the other end is connected to the capacitor C P and the connection point of capacitor C1, capacitor C P The other end of the transmission inductor L P One end of the capacitor C1 is connected to the transmission inductor L P The other end is connected to the high frequency inverter bridge circuit (2), and is also connected to the connection point of the semiconductor switch tube Q2 and the semiconductor switch tube Q4 of the right bridge arm switch tube.

3. The wireless charging circuit based on the improved Z-source network according to claim 1, characterized in that: The secondary side LCC network circuit (4) comprises an inductor L2, a capacitor C s , capacitor C2, receiving inductor L S ; One end of the inductor L2 is connected to a bridge arm in the secondary side rectifier filter circuit, and the other end is connected to the capacitor C s and the connection of capacitor C2, capacitor C s The other end of the receiving inductor L S One end of the capacitor C2 is connected to the receiving inductor L S The other end is connected to the other end, and is also connected to the other bridge arm of the secondary side rectifier and filter circuit.

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