Power synthesis circuit of multi-path high-frequency power supply

Abstract

The invention discloses a power synthesis circuit of a multi-path high-frequency power supply. Power synthesis is carried out on n paths of input power supplies through n groups of first-stage CV / CC networks and one group of second-stage CC / CV networks; specifically, when two-stage CV / CC and CC / CV networks are designed, the load impedance can be linearly changed to the equivalent input impedance of each power supply according to actual requirements, and the conversion can ensure that the power supply with high load sensitivity can be subjected to power synthesis, so that the method has good flexibility and can adapt to the power supply requirements under a high-frequency circuit.

Description

Technical Field

[0001] The invention belongs to the technical field of power synthesis, and more specifically, relates to a power synthesis circuit of multiple high-frequency power supplies. Background Art

[0002] At present, the output capacity of a single power supply is limited, and it is difficult to meet the required output under certain circumstances. For example, the output of a commonly used high-frequency power inverter is limited by the voltage and current withstand capabilities of the switching device. The output power of a single inverter is low, so a multi-channel power synthesis method is usually used to achieve a higher output power.

[0003] At present, power synthesis still has the following problems: 1. The operating states of each power supply are coupled after the power synthesis network; 2. The equivalent load impedance changes; 3. The design method is complex and lacks universality. Taking high-frequency power inverters as an example, since high-frequency inverters are more sensitive to load changes, existing designs mostly use fixed load impedance or complex phase control, but the actual application loads are mostly flexible and changeable, and the state after the power synthesis network is more complicated, which limits its application in high-power power supplies. Therefore, when designing a power synthesis network, impedance compression is usually also considered to make it as close as possible to the optimal load point of the inverter design to avoid hard switching, which causes loss and heat, or even damage to the device. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a power synthesis circuit for multiple high-frequency power supplies. The power synthesis circuit is designed by a two-stage passive two-port network to achieve linear impedance conversion and power synthesis functions.

[0005] To achieve the above-mentioned purpose, the present invention provides a power synthesis circuit for multiple high-frequency power supplies, characterized in that it comprises: multiple input power supplies V1 to V n , a first-stage constant voltage / constant current two-port network and a second-stage constant voltage / constant current two-port network;

[0006] The multi-channel input power supply comprises n channels of input voltage, wherein n is a positive integer greater than 2, which are respectively used to supply power to the first-stage constant voltage / constant current two-port network;

[0007] The first-stage constant voltage / constant current two-port network includes n groups, and the n groups of constant voltage / constant current are connected in parallel. Each group is connected in series with a voltage source, which is used to convert n input voltages into n currents, and then connected in parallel at the output side to the input side of the second-stage constant current / constant voltage two-port network;

[0008] The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into one-channel voltage output to obtain the output of the power synthesis circuit.

[0009] The object of the invention of the present invention is achieved in this way:

[0010] The present invention discloses a power synthesis circuit for multiple high-frequency power supplies, which performs power synthesis on n input power supplies through n groups of first-stage CV / CC networks and one group of second-stage CC / CV networks. Specifically, when designing two-stage CV / CC and CC / CV networks, the load impedance can be linearly changed to the equivalent input impedance of each power supply according to actual requirements. Such transformation can ensure that power supplies with high load sensitivity can also be power synthesized. Therefore, the circuit has good flexibility and can adapt to the power supply requirements under high-frequency circuits.

[0011] At the same time, the power synthesis circuit of a multi-channel high-frequency power supply of the present invention also has the following beneficial effects:

[0012] (1) By using CV / CC and CC / CV networks, power synthesis of multiple power supplies is achieved, breaking through the current situation of limited output of a single high-frequency power supply.

[0013] (2) The power synthesis network uses CV / CC and CC / CV networks, which are more flexible than the synthesis network similar to the Chireix synthesizer used by Liu M et al. of Princeton University. The two-stage CV / CC and CC / CV networks are not affected by the load, and the output voltage is linearly related to the input voltage, which is more flexible in actual high-frequency applications.

[0014] (3) The CV / CC and CC / CV networks can also perform linear transformation of impedance while synthesizing power. Compared with the power synthesis network designed by Surakitbovorn K et al. of Stanford University, the equivalent impedance of the power supply can be clearly given. When designing a load-sensitive power supply, it can be well matched to the load range of normal operation of the power supply, and the actual application range is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a power synthesis circuit architecture diagram of a multi-channel high-frequency power supply of the present invention;

[0016] Figure 2 These are three structural diagrams of CV / CC and CC / CV networks;

[0017] Figure 3 This is the LTspice simulation model diagram of the four-way power synthesis;

[0018] Figure 4 It is the simulation waveform under ideal conditions;

[0019] Figure 5 It is the simulation waveform of class-E input voltage of 9.5V, 10V, 10.5V and 20V respectively;

[0020] Figure 6 It is the simulation waveform of class-E output phases of -5°, 0°, 5° and 10° respectively;

[0021] Figure 7 This is the simulation result diagram when the network inductance value is +10%;

[0022] Figure 8 This is the simulation result diagram when the network inductance value is -10%. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0024] Example

[0025] Figure 1 This is a power synthesis circuit architecture diagram of a multi-channel high-frequency power supply of the present invention.

[0026] In this embodiment, if Figure 1 As shown, the present invention is a power synthesis circuit of multiple high-frequency power supplies, comprising: multiple input power supplies V1 to V n , a first-stage constant voltage / constant current (CV / CC) two-port network and a second-stage constant current / constant voltage (CC / CV) two-port network;

[0027] In this embodiment, the number of first-stage CV / CC two-port networks is determined by the number of power supplies, the number of second-stage CC / CV two-port networks is 1, and the first-stage CV / CC two-port networks are connected in parallel to the second-stage CC / CV two-port network for power synthesis.

[0028] The multi-input power supply includes n input voltages, where n is a positive integer greater than 2, which are respectively used to power a first-stage constant voltage / constant current two-port network;

[0029] The first-stage constant voltage / constant current two-port network includes n groups, and the n groups of constant voltage / constant current are connected in parallel. Each group is connected in series with a voltage source to convert n input voltages into n currents, and then connected in parallel at the output side to the input side of the second-stage constant current / constant voltage two-port network;

[0030] The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into one-channel voltage output to obtain the output of the power synthesis circuit.

[0031] In this embodiment, both the first-stage constant voltage / constant current two-port network and the second-stage constant current / constant voltage two-port network adopt passive lossless two-port networks composed of inductors and capacitors, including three network structures: L-type, T-type and Π-type; but the input ports and output ports of the three network structures of the second-stage constant current / constant voltage two-port network are swapped with those of the three network structures of the first-stage constant voltage / constant current two-port network.

[0032] In this embodiment, the three network structures of L type, T type and Π type are as follows: Figure 2 As shown, Figure 2 (a) is the L-type network structure, Figure 2 (b) is a T-type network structure. Figure 2 (c) is a Π-type network structure;

[0033] In the three network structure diagrams, X represents reactance, that is, X is composed of capacitance, inductance or a combination of the two. Generally, the series reactance is inductance or inductive, and the parallel reactance is capacitance or capacitive;

[0034] Assume that the transmission matrix of the L-type network structure is:

[0035]

[0036] Assume that the transmission matrix of the T-type network structure is:

[0037]

[0038] Assume that the transmission matrix of the Π-type network structure is

[0039]

[0040] In the formula, X1, X2, and X3 all represent reactance.

[0041] If the three structural transfer matrices are all represented by A, the voltage and current relationship between the two ports is:

[0042]

[0043] Where a, b, c, d are the transmission parameters of the two-port network, and the specific values ​​are determined by the structure of the two-port network.

[0044] The output port of the two-port network is connected to a load impedance, which is called the output impedance Z0. The impedance seen by the two-port network is called the input impedance Z i , the relationship between them is If a=0, the output current Only with input voltage It is related to the load, but not to other factors, so it is called a load-independent constant voltage / constant current (CC / CV) network. and output current The relationship is:

[0045]

[0046] For three passive lossless two-port networks, Figure 2 Take the L-type network shown in (a) as an example. For input port, connect power supply, It is the output port, connected to the next level network, when X1=-X2=X p , the output current flowing through the L-type network is only related to the input voltage, so it is called a constant voltage / constant current (CV / CC) network; Figure 2 In the T-type network shown in (b), X1=-X3=X p , Figure 2 The Π-type network shown in (c) needs to satisfy X2=-X3=-X p , all three structures can form CV / CC networks, and the corresponding transmission parameter matrix A p for:

[0047]

[0048] Among them, d p Determined by the network structure and parameters.

[0049] The specific parameter design of CV / CC network is shown in Table 1;

[0050] Network structure Type formation conditions <![CDATA[d p ]]> L-type <![CDATA[X1=-X2=X p ]]> <![CDATA[d p =1]]> T-Type <![CDATA[X1=-X3=X p ]]> <![CDATA[d p =1-X2 / X p ]]> Π type <![CDATA[X2=-X3=-X p ]]> <![CDATA[d p =1+X p / X1]]>

[0051] Table 1

[0052] The passive lossless two-port network satisfies the reciprocity theorem. When the input and output ports are swapped, if the second row and second column element d of the transmission parameter matrix is ​​0, then its output voltage Only with input current The relationship is:

[0053]

[0054] In this case, it is called a CC / CV network. For the three network structures of CC / CV network, the L-type network needs to satisfy X1=-X2=X s ,T-type network needs to satisfy X2=-X3=X s , the Π-type network needs to satisfy X1=-X3=-X s Both can form CV / CC networks, and the corresponding transmission parameter matrix A s for:

[0055]

[0056] where a s Determined by the network structure and parameters.

[0057] The specific parameter design of CV / CC network is shown in Table 2;

[0058]

[0059]

[0060] Table 2

[0061] In summary, the power synthesis circuit of the present invention is connected in parallel through the same CV / CC network and then provides power to the load through the CC / CV network. Assuming that the amplitude and phase difference of the output voltage of each power supply are small enough, the output voltage of each power supply can be regarded as completely the same, and the output current of each inverter through the CV / CC network is Therefore, the total output current after parallel connection is And this current has nothing to do with the impedance of the next stage. After the parallel connection, the current passes through the CC / CV network and the voltage obtained by the load is Again it is independent of the load but depends on the power combining network parameters and the input voltage.

[0062] In addition, the power synthesis circuit provided by the present invention can perform linear transformation on the load network. From the impedance relationship of the two-port network, it can be concluded that the equivalent impedance seen by the single-channel power supply after power synthesis is:

[0063]

[0064] The imaginary part of the denominator is na s X s +d p X p = 0 can satisfy the linear change from load impedance to power supply equivalent impedance. The equivalent input impedance of the single-channel power supply after the change is The load impedance Z L Equivalent impedance Z with single power supply eq The ratio is called the impedance scaling factor and is denoted by Z eq / Z L =λ. The linear load conversion relationship provides a simple method to transfer the actual load impedance area to the target load area. The designer can directly express the impedance area before and after the power synthesis network transformation in the load impedance plane, which is helpful for us to control some power supplies with high load sensitivity to achieve normal output.

[0065] Figure 3 LTspice simulation model diagram of four-way power synthesis.

[0066] The input power adopts high-frequency inverter (including but not limited to Class D, Class E, The input DC is 10V, and the power synthesis network adopts the equal impedance synthesis network of Π-Π type structure. The number of synthesis paths is designed to be 4, so |X p / X s |=2, in order to achieve better high-frequency filtering effect, the series reactance X3 of the two π-type networks is taken as the inductance, that is, X p and X s are all positive. s Take it as 20Ω, then X p The inductance of the CV / CC and CC / CV networks is 469.5nH and 234.7nH respectively, and the capacitance is 293.4pF and 586.9pF respectively at the operating frequency of 13.56MHz. Under ideal conditions, the output voltage deviation, phase deviation and network parameter deviation of each class-E are simulated respectively. Figure 4 is the ideal simulation waveform. Figure 5 This is the simulated waveform of the class-E input voltage of 9.5V, 10V, 10.5V and 20V. Figure 6 This is the simulation waveform of the class-E output phases of -5°, 0°, 5° and 10° respectively. Figure 7 This is the simulation result when the network inductance value is +10%. Figure 8 is the simulation result when the network inductance value is -10%. The simulation results show that the inverter can operate normally after being synthesized by the Π-Π type equal impedance power synthesis network, and the working states of each class-E are exactly the same, which reflects the equal impedance nature of the power synthesis network. In addition, although the operating states of different class-E power supplies are very different, the current waveforms after synthesis are basically the same. This result shows that the slight imbalance between the inverters (including the DC voltage amplitude and the drive signal phase) has little effect on the operating state of each inverter, and they can still maintain the expected zero voltage switching state (ZVS) operation; finally, the impact caused by the network parameter deviation is also small. However, under some loads close to the edge of the ZVS load area, it may be offset outside the boundary, causing the inverter to be in a slight hard switching state under these loads. Therefore, when designing power synthesis circuits for some power supplies (such as inverters) that are highly sensitive to loads, a certain tolerance should be left between the load area where the power supply operates normally and the target operating area. At the same time, it should be ensured that there will be no large deviations in the network parameters, and the resonance relationship between the reactances of different properties of the network should be guaranteed to minimize the impact of parameter deviations.

[0067] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A power synthesis circuit for multiple high-frequency power supplies, characterized in that: include: Multiple input power supplies V1~V n , a first-stage constant voltage / constant current two-port network and a second-stage constant voltage / constant current two-port network; The multi-channel input power supply comprises n channels of input voltage, wherein n is a positive integer greater than 2, which are respectively used to supply power to the first-stage constant voltage / constant current two-port network; The first-stage constant voltage / constant current two-port network includes n groups, and the n groups of constant voltage / constant current are connected in parallel. Each group is connected in series with a voltage source, which is used to convert n input voltages into n currents, and then connected in parallel at the output side to the input side of the second-stage constant current / constant voltage two-port network; The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into one-channel voltage output to obtain the output of the power synthesis circuit.

2. The power synthesis circuit of a multi-channel high-frequency power supply according to claim 1, characterized in that: The multi-channel input power supplies adopt the same model to ensure that the voltage amplitudes and phases of the n-channel input voltages are the same.

3. The power synthesis circuit of a multi-channel high-frequency power supply according to claim 1, characterized in that: The first-stage constant voltage / constant current two-port network adopts a passive lossless two-port network composed of inductors and capacitors, including three network structures: L-type, T-type and Π-type.

4. The power synthesis circuit of a multi-channel high-frequency power supply according to claim 1, characterized in that: The structure of the second-stage constant current / constant voltage two-port network is similar to that of the first-stage constant voltage / constant current two-port network, and also adopts a passive lossless two-port network composed of inductors and capacitors, including three network structures: L-type, T-type and Π-type. However, the input ports and output ports of the three network structures of the second-stage constant current / constant voltage two-port network are swapped with those of the three network structures of the first-stage constant voltage / constant current two-port network.

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