Vehicle-mounted multi-path DC-DC output system and method for new energy vehicle

Abstract

The invention discloses a vehicle-mounted multi-path DC-DC output system for a new energy vehicle. The vehicle-mounted multi-path DC-DC output system comprises a phase-shifted full-bridge converter; an LCC resonant network; a wireless energy coupler; the series resonance network is connected with the wireless energy coupler; a positive and negative half-wave rectifier formed by a bidirectional switch, wherein the positive and negative half-wave rectifier formed by the bidirectional switch is connected with the wireless energy coupler and the series resonance network; and the synchronous rectifier bridge is connected with the positive and negative half-wave rectifier formed by the bidirectional switch, and the positive and negative half-wave rectifier formed by the bidirectional switch and the synchronous rectifier bridge form a channel # A, a channel # B and a channel # C. According to the invention, the two half-wave rectifiers are integrated on one branch through the two power tube devices which are reversely connected in series, so that the space is saved for a receiving side, and the performance of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of on-board DC-DC technology for new energy vehicles and the field of wireless power transmission, and in particular to an on-board multi-channel DC-DC output system and method for new energy vehicles. Background Art

[0002] In recent years, the new energy vehicle market has been in a high growth trend, and the penetration rate of new energy vehicles has exceeded 50%. In addition to requiring efficient transmission and simple control, the on-board DC-DC system has different requirements for different applications. Including input and output isolation, realizing multiple types of power supply forms to power the load, and realizing flexibility in power use. With the development of magnetically coupled wireless power transfer (MC-WPT) technology and the requirements of different application scenarios, its research and application have also gradually shifted from the initial single-load wireless power supply mode to the multi-load wireless power supply mode. Compared with single-load MC-WPT technology, multi-load MC-WPT technology has the advantages of higher power density, higher excitation source utilization, and freer spatial location of the receiving load, and the system compatibility is further improved.

[0003] In order to achieve multiple outputs, one method is to increase the number of transmission paths by using a Multi-Input-and-Multi-Output (MIMO) system. This means that multiple transmitters and multiple receivers are needed to achieve multi-path transmission and output, which will undoubtedly increase the size of the system and is not conducive to cost control.

[0004] In order to save costs, simplify the structure, and reduce the cross-coupling phenomenon caused by the MIMO system, the single-input-and-multi-output (SIMO) WPT system is currently more popular. One of the implementation methods is to use a single-T or double-T resonant circuit to configure passive devices such as inductors and capacitors to achieve voltage or current conversion. However, this passive topology makes it difficult to adjust the output voltage or current during the charging process. Summary of the invention

[0005] The present invention provides an on-board multi-channel DC-DC output system and method for new energy vehicles. The present invention integrates two half-wave rectifiers into one branch through two reverse-series power tube devices, thereby saving space for the receiving side and improving the performance of the system.

[0006] The technical solutions to the above problems are as follows:

[0007] An on-board multi-channel DC-DC output system for new energy vehicles includes a primary-side inverter and a secondary-side synchronous rectifier, wherein the primary-side inverter includes:

[0008] Phase-shifted full-bridge converter;

[0009] An LCC resonant network, wherein the LCC resonant network comprises a first compensation coil, a first compensation capacitor, and a second compensation capacitor, wherein one end of the first compensation coil is electrically connected to the phase-shifted full-bridge converter, and one end of the first compensation capacitor is connected to the other end of the first compensation coil;

[0010] A wireless energy coupler, the wireless energy coupler comprises a transmitting coil and a receiving coil, one end of the transmitting coil is connected to the other end of the first compensation coil, the other end of the transmitting coil is connected to one end of the second compensation capacitor, and the other ends of the first compensation capacitor and the second compensation capacitor are connected to a phase-shifted full-bridge converter;

[0011] The secondary side synchronous rectifier comprises:

[0012] A series resonant network, the series resonant network is connected to the wireless energy coupler;

[0013] A positive and negative half-wave rectifier formed by a bidirectional switch, wherein the positive and negative half-wave rectifier formed by the bidirectional switch is connected to the wireless energy coupler and the series resonant network;

[0014] A synchronous rectifier bridge is connected to a positive and negative half-wave rectifier formed by a bidirectional switch. The positive and negative half-wave rectifier formed by the bidirectional switch and the synchronous rectifier bridge form channel #A, channel #B, and channel #C.

[0015] The vehicle-mounted multi-channel DC-DC output method for new energy vehicles includes the vehicle-mounted multi-channel DC-DC output system for new energy vehicles, and the process is as follows:

[0016] The primary controller includes a voltage and current double closed loop and a feedforward control link and a receiving loop current I S Polarity detection link: two links respectively perform phase shift voltage regulation control on the primary inverter and synchronous rectification control on channel #A:

[0017] A secondary controller is used to adjust the voltage of channel #B and channel #C.

[0018] The circuit structure of the present invention is theoretically deduced, and it can be concluded that: resonance is achieved through the LCC-S type compensation topology, the system zero phase angle input is guaranteed, the reactive power of the primary loop is eliminated, the soft switching conditions are created, and resonant wireless energy transmission is realized; secondly, for multiple different outputs, a control structure including two feedback PI controllers is proposed to achieve independent control of the output voltage control, and the system does not require additional communication equipment, simplifying the complexity of system control; in order to overcome the input disturbance, a feedforward control strategy is introduced to achieve compensation for the input disturbance. Finally, a simulation experiment platform was built, and the system showed excellent stability and robustness, verifying the feasibility of the method proposed in the present invention. The present invention can not only realize multi-channel positive and negative DC power output with input and output isolation, but also each DC power output can be independently controlled. The system not only has good regulation ability for load mutations, but also has a good inhibitory effect on input disturbances.

[0019] The present invention is a SIMO-WPT system based on different types of rectifiers, including a synchronous rectifier to achieve positive DC output, and a bidirectional switch to form a half-wave rectifier to achieve positive / negative DC power output, wherein two half-wave rectifiers are integrated into one branch through two reverse series power tube devices, saving space for the receiving side. Two sets of adjustable receiving loops were successfully built to achieve scene applications under multiple different output power requirements, and the system does not require additional detection circuits and communication equipment, thereby realizing a cost-effective system. In summary, the present invention has the following two innovations:

[0020] (1) Different from the traditional single-input multiple-output, the present invention combines a full-wave rectifier with a half-wave rectifier at the same time, and considers two groups of output channels as a whole (channel #A, channel #B, channel #C, where channel #B and channel #C constitute a group of half-wave rectifiers, group B works to output positive power, and group C works to output negative power). Specifically, channel #A is equipped with a synchronous rectifier, while channel #B and channel #C are equipped with half-wave rectifiers using the positive half-cycle and negative half-cycle of the AC voltage source respectively, and the switching of the two half-wave rectifiers can be achieved without multiple groups of loops.

[0021] (2) In terms of control strategy: For channel #A and channel #B, the PI control plus feedforward control of the present invention forms a composite control strategy to perform output constant voltage control. In particular, channel #A adopts voltage and current dual closed-loop PI control + feedforward compensation to achieve output constant voltage, and reduces losses through synchronous rectification; for channel #B and channel #C, by detecting the current flowing through the receiving coil, the opening and closing of the two reverse-series switching tubes are controlled based on the PI voltage closed-loop controller, which can enable the system to have efficient and stable output and meet the requirements of different output circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a structural diagram of the vehicle-mounted multi-channel DC-DC output system of the present invention;

[0023] Figure 2a is the equivalent circuit diagram of channel #B;

[0024] Figure 2b is the equivalent circuit diagram of channel #C;

[0025] Figure 3 A flow chart of the overall control strategy of the vehicle-mounted multi-channel DC-DC output method;

[0026] Figure 4 It is the inverter output voltage and current waveform;

[0027] Figure 5a It is the logic diagram of the switch tube conduction in the phase-shifted full-bridge converter;

[0028] Figure 5b The logic diagram of the switch tube conduction in the positive and negative half-wave rectifier composed of a bidirectional switch;

[0029] Figure 6a is the rectified output voltage of channel #A;

[0030] Figure 6b is the rectified output voltage of channel #B (channel #C);

[0031] Figure 7a This is the output voltage waveform of channel #A under load changes;

[0032] Figure 7b This is the output voltage waveform of channel #B under load changes;

[0033] Figure 8 This is the output channel voltage waveform when the input voltage changes;

[0034] Fig. 9 Output voltage of channels #B and #C. DETAILED DESCRIPTION

[0035] like Figure 1 As shown, the vehicle-mounted multi-channel DC-DC output system for new energy vehicles of the present invention includes a primary-side inverter and a secondary-side synchronous rectifier. The primary-side inverter includes: a phase-shifted full-bridge converter, an LCC resonant network, and a wireless energy coupler. The secondary-side synchronous rectifier includes a series resonant network, a positive and negative half-wave rectifier composed of a bidirectional switch, and a synchronous rectifier bridge. The following describes in detail the various parts and the relationship between them.

[0036] The phase-shifted full-bridge converter includes an inverter body, which includes a first power tube Q1, a second power tube Q2, a third power tube Q3, and a fourth power tube Q4. The first power tube Q1 is connected to the second power tube Q2, the third power tube Q3 is connected to the first power tube Q1 and the fourth power tube Q4 respectively, and the fourth power tube Q4 is also connected to the second power tube Q2. In this embodiment, the first power tube Q1 to the fourth power tube Q4 are all IGBT switch tubes.

[0037] The LCC resonant network includes a first compensation coil L T , the first compensation capacitor C T , the second compensation capacitor C P , the first compensation coil L T One end of the first compensation capacitor C is electrically connected to the phase-shifted full-bridge converter. T One end of the first compensation coil L T The other end of the connection.

[0038] The wireless energy coupler includes a transmitting coil L P , receiving coil L S , transmitting coil L P One end of the first compensation coil L T The other end is connected to the transmitting coil L P The other end of the second compensation capacitor C P One end of the first compensation capacitor C T and the second compensation capacitor C P The other end is connected to the phase-shifted full-bridge converter.

[0039] The series resonant network is connected to the wireless energy coupler, and the series resonant network includes a third compensation capacitor C S , the third compensation capacitor C S One end of the receiving coil L S Connect the third compensation capacitor C S The other end is connected to the positive and negative half-wave rectifier composed of a bidirectional switch.

[0040] The positive and negative half-wave rectifiers formed by the bidirectional switch are connected to the wireless energy coupler and the series resonant network, and the positive and negative half-wave rectifiers formed by the bidirectional switch include a first power switch tube Q b , the second power switch tube Q c , the first output capacitor C BC , the first power switch tube Q b , the second power switch tube Q c All are IGBT switch tubes, the first power switch tube Q b With the second power switch tube Q c The first output capacitor C BC With the second power switch tube Qc connect.

[0041] The synchronous rectifier bridge is connected to the positive and negative half-wave rectifiers formed by the bidirectional switch, and the positive and negative half-wave rectifiers formed by the bidirectional switch and the synchronous rectifier bridge constitute channel #A, channel #B, and channel #C. The synchronous rectifier bridge includes the fifth power tube Q5, the sixth power tube Q6, the seventh power tube Q7, the eighth power tube Q8, and the second output capacitor C A The fifth power tube Q5 is connected to the sixth power tube Q6, the seventh power tube Q7 is connected to the fifth power tube Q5 and the eighth power tube Q8 respectively, the eighth power tube Q8 is also connected to the sixth power tube Q6, and the second output capacitor C A One end of the second output capacitor C is connected to the seventh power tube Q7. A The other end of the transistor is connected to the eighth power tube Q8. The fifth power tube Q5 to the eighth power tube Q8 are all IGBT switch tubes.

[0042] For a synchronous rectifier bridge, the switching sequence is usually required to be synchronized with the current direction, that is, when the rectified current I S When the rectifier current I S When the rectifier current I S When it is positive, the output voltage can be controlled. For the negative half-wave rectifier (i.e. channel #C), when the rectified current I S When negative, the output voltage can be controlled.

[0043] For the LCC-S type compensation network, the compensation component parameters satisfy the following relationship:

[0044] C T = ( ω 2 L T) - 1 ,C P =[ω 2 (L P -L T )]-1,C S = ( ω 2 L S) - 1 (1)

[0045] Among them, C T is the first compensation capacitor, C P is the second compensation capacitor, C S is the third compensation capacitor, L Tis the first compensation coil, L P is the transmitting coil, L S is the receiving coil, ω is the operating angular frequency of the inverter, satisfying ω=2πf.

[0046] By setting the LCC-S type compensation topology, most of the high-order harmonics are filtered out. In order to simplify the analysis, the present invention adopts the fundamental wave approximation method for theoretical derivation. The inverter is controlled by phase-shifted modulation (PSM), and the fundamental wave component of the inverter output voltage can be written in phasor form as:

[0047]

[0048] Where: U in is the output voltage of the inverter body, V dc is a DC voltage source, and δ is the conduction angle.

[0049] Kirchhoff voltage and current loop equations are written for the proposed circuit topology. Their phasor form can be expressed as:

[0050]

[0051] R eq =R eqa / / R eqb / / R eqc

[0052] is the phasor of the output voltage of the inverter body, R T is the parasitic resistance of the first compensation coil, is the phasor of the primary inverter input current, is the phasor of the transmitting coil current, is the phasor of the rectified current, is the phase of the secondary AC bus voltage, R S is the parasitic resistance of the receiving coil, R eq is the secondary AC equivalent resistance, R eqa is the equivalent resistance of channel #A, R eqb is the equivalent resistance of channel #B, R eqc is the equivalent resistance of channel #C, the following results can be obtained:

[0053]

[0054] Where R a is the equivalent resistance of channel #A, R b is the equivalent resistance of channel #B, R c is the equivalent resistance of channel #C, U S is the secondary AC bus voltage, Vb is the output voltage of channel #B, V c is the output voltage of channel #C.

[0055] Substituting equations (1) and (2) into equation (3), we can obtain U S , I T The phasor expression of is:

[0056]

[0057] X M =ωMR eq , X CT =1 / ωC T , M is the mutual inductance between the transmitting coil and the receiving coil, R P is the parasitic resistance of the transmitting coil.

[0058] For channel #A, according to the relationship between the input and output voltages of the synchronous rectifier bridge, the rectified voltage V a It can be expressed as follows:

[0059]

[0060] Figure 2a The equivalent circuit of output channel #B is given, Figure 2b The equivalent circuit of output channel #C is given, where U S is the secondary side AC bus voltage.

[0061] from Figure 2a and Figure 2b It can be seen that the SIMO-WPT proposed in the present invention integrates the output channels #B and #C into one loop, which undoubtedly reduces the additional devices and the volume occupied, and only needs to control the opening and closing of two reverse-connected series switches to achieve the switching between the positive half-wave rectifier (channel #B) and the negative half-wave rectifier (channel #C). The specific control strategy will be described in detail later.

[0062] Channel #B (positive half-wave rectifier) ​​output voltage V b It can be expressed as follows:

[0063]

[0064] Where D Qb is the duty cycle of the pulse width modulation in the positive half cycle of channel #B.

[0065] Similarly, the output voltage V of channel #C (negative half-wave rectifier) c It can be expressed as follows:

[0066]

[0067] Where: D Qc is the duty cycle of the pulse width modulation in the negative half cycle of channel #C.

[0068] The input impedance of the system is Z in It can be given by the following formula:

[0069]

[0070] By calculating equations (4), (7) and (8), we can obtain the following R eq :

[0071]

[0072] From (9) and (10), we can see that due to R eq It is purely resistive, Z in It is also purely resistive, which means that the entire system can achieve input zero phase angle (ZPA).

[0073] like Figure 3 As shown, the vehicle-mounted multi-channel DC-DC output method for new energy vehicles of the present invention is characterized in that it includes the vehicle-mounted multi-channel DC-DC output system for new energy vehicles according to any one of claims 1 to 5, and the process is as follows:

[0074] The primary controller includes a voltage and current double closed loop and a feedforward control link and a receiving loop current I S Polarity detection link: two links respectively perform phase shift voltage regulation control on the primary inverter and synchronous rectification control on channel #A:

[0075] A secondary controller is used to adjust the voltage of channel #B and channel #C.

[0076] The process of phase-shift voltage regulation control is:

[0077] 1) Use the A / D module of the DSP controller to sample the rectified voltage V of channel #A a With the rectified current I a , and then the collected signal is fed back to the primary controller based on PI control of voltage and current dual closed-loop controller.

[0078] 2) The controller picks up the rectified voltage V a With the rectified current I a signal, the rectified voltage V a With reference output voltage V aref The error generated is sent to the PI controller, and after the voltage outer loop control, the input signal is compared with the reference output current I aref For comparison, the error signal is sent to the inner loop PI controller.

[0079] 3) To perform feedforward control, first obtain an approximate model of the controlled system. The closer this model is to the real system, the more obvious the control effect will be. Assume that the frequency domain model of a controlled object is:

[0080]

[0081] Among them, A and B are system constants, and S is a complex frequency domain variable.

[0082] The feedforward controller is the inverse of the controlled object, so the input and output expressions of the feedforward controller are derived as follows:

[0083]

[0084] Among them, U f (t) is the output expression of the feedforward controller, and x(t) is the time domain expression of the controlled object. By discretizing it, we can get the output formula of the feedforward controller we want to achieve. The input of the feedforward controller is the set value, which is expressed as follows:

[0085]

[0086] T is the cycle of the controlled object, k is the current time sampling point, x(k), x(k-1), and x(k-2) are the expressions of the controlled object corresponding to the k, k-1, and k-2 sampling points respectively, and U f (k) is the output expression of the feedforward controller at sampling point k. According to the actual system requirements, the corresponding feedforward control parameters can be set; the rectified voltage V is obtained according to the following formula a and a DC voltage source V dc And the relationship between the phase shift angle:

[0087]

[0088] Get the rectified voltage V a and a DC voltage source V dc The relationship between the phase shift angle is:

[0089]

[0090] U s is the secondary side AC bus voltage, C T is the compensation capacitor, M is the mutual inductance between the transmitting coil and the receiving coil, U in is the output voltage of the phase-shifted full-bridge converter, V dc is the DC voltage source, σ is the phase shift angle, and ω is the operating angular frequency of the inverter.

[0091] The phase shift angle in equation (15) can be changed through feedforward control, thereby speeding up the response speed of the DC-DC system.

[0092] 4) The input signal after voltage and current dual closed-loop control and feedforward control is used to generate two pairs of complementary PWM pulse waves through a PWM generator to control the opening and closing of the upper and lower tubes of the front and rear bridge arms of the primary-side inverter respectively.

[0093] The specific control process of the synchronous rectification of channel #A is as follows:

[0094] 1) Use the DSP controller A / D conversion module to sample the receiving coil current and determine the rectifier current I S polarity.

[0095] 2) According to I S The different polarities of the rectified current I S >0, the fifth power tube Q5 and the eighth power tube Q8 in the synchronous rectifier bridge are turned on; when the rectifier current I S <0, the sixth power tube Q6 and the seventh power tube Q7 of the synchronous rectifier bridge are turned on.

[0096] Through the above logical judgment, synchronous rectification of channel #A is achieved.

[0097] The process of the secondary controller regulating the voltage of channel #B and channel #C is as follows:

[0098] (1) First, set the rectifier current I S <0, channel #B is turned on, when the rectifier current I S When >0, channel #C is turned on.

[0099] (2) The secondary controller uses the A / D module of the DSP controller to sample the output voltage V of channel #B b and the output voltage V of channel #C c , the output preset voltage is subtracted from the sampled output voltage, and the error information is sent to the PI controller. Qb and D Qc Adjust the voltage V b and V c ;

[0100] In the above, D Qb is the duty cycle of the pulse width modulation in the positive half cycle of channel #B, D Qc is the duty cycle of the pulse width modulation in the negative half cycle of channel #C.

[0101] For the above scheme, in order to verify the feasibility of the proposed SIMO-WPT system, the simulation model was built using Matlab / Simulink simulation software and the results were analyzed. The system simulation parameters are shown in Table 1, which gives examples of the units and values ​​of the parameters used in the above formulas.

[0102] Table 1 System simulation parameters

[0103]

[0104] The simulation data given in Table 1 can provide a good reference basis for subsequent experimental verification.

[0105] ZPA Verification

[0106] From equations (9) and (10), it can be seen that the input impedance of the system designed by the present invention presents a pure resistive load as a whole, that is, the system realizes zero phase angle input. In order to verify the theory, a simulation model is built and the results are as follows: Figure 4 shown.

[0107] from Figure 4 It can be seen that after inversion, the output voltage and current basically maintain the same phase, indicating that the input impedance of the system eliminates the imaginary part, presents a pure resistive load property, and realizes ZPA.

[0108] Control strategy verification

[0109] The present invention sets up two controllers, primary and secondary, which respectively control the inverter to perform phase shift voltage regulation control, achieve synchronous rectification of channel #A and control the switching of channels #B and #C, and enable the output voltage of the two groups of channels to quickly stabilize to the reference voltage. The output pulse waveform of the phase shift voltage regulation switch tube and the output pulse waveform of the channel #B and #C switch tubes are as follows: Figure 6a and Figure 6b shown.

[0110] Figure 5a The PWM output pulse under voltage and current double closed-loop control and feedforward control is shown. The first power tube Q1 and the second power tube Q2 are the switch tubes of the front and rear upper bridge arms respectively. After passing through the voltage outer loop and current inner loop control links and the feedforward control link, the input signal is sent to the PWM generator, which performs phase shifting and voltage regulation according to the difference in the signal, so that the system can respond quickly and control the conduction and shutdown of the switch tubes from the first power tube Q1 to the fourth power tube Q4.

[0111] Figure 5b The PWM output pulses of control channels #B and #C are shown. The first power switch tube Q b And the second power switch tube Q c They are forward and reverse switch tubes respectively. The conduction and shutdown of the two reverse series switch tubes are controlled by detecting the polarity of the receiving coil current.

[0112] The rectified output voltages of channel #A, channel #B (#C) are shown in FIG6 . Figure 6a is the rectified output voltage of channel #A, Figure 6bRectified output voltage of channel #B(#C).

[0113] In Figure 6, the output reference voltage of channel #A is set to 100 V, and the output reference voltage of channel #B (#C) is set to 50 V. As can be seen from the above figure, after being controlled by the control strategy proposed in the present invention, the two groups of output voltage channels of the circuit can respond quickly and reach the ideal voltage value, which verifies the feasibility of the proposed method and can meet the increasing needs of different power usage scenarios.

[0114] Dynamic response verification

[0115] (a) Output power independent regulation verification

[0116] Dynamic adjustment capability is a key factor in measuring system stability. Figure 7a , Figure 7b The inverter output voltage and current waveforms and the output voltage waveforms on the rectifier side of the two loops are given respectively when the channel #A and channel #B loads fluctuate.

[0117] exist Figure 7a In the example, the rectifier output voltage of channel #A is set to 120V, and the load is switched from 10Ω to 20Ω. The rectifier output voltage of channel #B is set to 40V, and its load remains unchanged at 10Ω. Figure 7a It can be seen that when a load jump occurs in channel #A, its rectifier output voltage fluctuates slightly at the load switching point and then immediately remains unchanged at 120V, while the rectifier output voltage of channel #B remains unchanged at 40V. At this time, the primary controller also controls the phase shift angle to change and performs phase shift voltage regulation.

[0118] exist Figure 7b In the example, the rectifier output voltage of channel #B is set to 60V, and the load is switched from 5Ω to 10Ω. The rectifier output voltage of channel #A is set to 100V, and its load remains unchanged at 20Ω. Figure 7b It can be seen that when a load jump occurs in channel #B, its rectified output voltage remains unchanged at 60V, while the rectified output voltage of channel #A remains unaffected at 100V. Similarly, the primary controller also performs phase-shift voltage regulation control.

[0119] The above results show that, through the circuit topology and control strategy proposed in the present invention, different output loops can independently adjust their output power according to demand without being affected by other loops.

[0120] (b) Output constant voltage verification under input voltage fluctuation

[0121] In actual application scenarios, due to reasons such as unbalanced grid voltage, the input voltage may fluctuate, resulting in unstable output of the entire system. Therefore, it is necessary to control it. Figure 8It shows the voltage waveforms of the two output channels #A and #B when the input voltage fluctuates.

[0122] exist Figure 8 In the example, the input voltage is set to switch from 120V to 100V, the rectified output voltage of channel #A is 100V, and the rectified output voltage of channel #B is 60V. Figure 8 It can be seen that when the input voltage changes, the output voltage of the two channels is not affected and remains constant, which proves that the proposed system has good anti-interference ability and can adapt to more extreme power usage scenarios.

[0123] (c) Verification of multiple positive / negative DC power outputs

[0124] In the present invention, channel #B is set as positive power rectifier output, and channel #C is set as negative power rectifier output. Fig. 9 The output waveforms of channels #B and #C are shown.

[0125] Depend on Fig. 9 As shown, the rectifier output of channel #A is set to 100V, the positive voltage output value of #B is 60V, and the negative voltage output of #C is -60V. It can be seen from the above figure that when the #B and #C channels are switched, the output voltage of channel #A fluctuates slightly when the #B and #C voltages are switched, but in practice it is within the specified error range. The outputs of channels #B and #C can respond quickly and reach the set output voltage. The system responds quickly and has good dynamic adjustment capabilities.

[0126] Summarize

[0127] The on-board multi-channel DC-DC output system of the new energy vehicle provided by the present invention first successfully builds two groups of adjustable output channels, and comprehensively considers different types of rectifiers, including a group of synchronous rectifiers to realize one DC output and a group of half-wave rectifiers to realize positive / negative DC power output. Then, the LCC-S type compensation topology is adopted to realize resonance, and the conditions for the system to realize ZPA are theoretically derived, and a feedforward-feedback composite control strategy is proposed. The control strategy consists of two controllers, primary and secondary, which can enable the system to respond quickly and achieve stable output under load and input disturbances. Finally, by building a simulation model, it is verified that the circuit topology and control strategy proposed in the present invention can realize the effectiveness of multi-channel output regulation.

[0128] The above embodiments are part of the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but cannot be simply understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

Claims

1. An on-board multi-channel DC-DC output system for new energy vehicles, characterized in that: The invention comprises a primary-side inverter and a secondary-side synchronous rectifier, wherein the primary-side inverter comprises: Phase-shifted full-bridge converter; The LCC resonant network includes a first compensation coil (L T ), the first compensation capacitor (C T ), the second compensation capacitor (C P ), the first compensation coil (L T ) is electrically connected to the phase-shifted full-bridge converter, and the first compensation capacitor (C T ) and the first compensation coil (L T )’s other end; Wireless energy coupler, the wireless energy coupler includes a transmitting coil (L P )、Receiving coil (L S ), transmitting coil (L P ) and the first compensation coil (L T ) is connected to the other end of the transmitting coil (L P ) and the other end of the second compensation capacitor (C P ) is connected to one end of the first compensation capacitor (C T ) and the second compensation capacitor (C P ) is connected to the phase-shifted full-bridge converter; The secondary side synchronous rectifier comprises: A series resonant network, the series resonant network is connected to the wireless energy coupler; A positive and negative half-wave rectifier formed by a bidirectional switch, wherein the positive and negative half-wave rectifier formed by the bidirectional switch is connected to the wireless energy coupler and the series resonant network; A synchronous rectifier bridge is connected to a positive and negative half-wave rectifier formed by a bidirectional switch. The positive and negative half-wave rectifier formed by the bidirectional switch and the synchronous rectifier bridge form channel #A, channel #B, and channel #C.

2. The vehicle-mounted multi-channel DC-DC output system for new energy vehicles according to claim 1, characterized in that: The phase-shifted full-bridge converter comprises an inverter body, which comprises a first power tube (Q1), a second power tube (Q2), a third power tube (Q3), and a fourth power tube (Q4). The first power tube (Q1) is connected to the second power tube (Q2), the third power tube (Q3) is connected to the first power tube (Q1) and the fourth power tube (Q4) respectively, and the fourth power tube (Q4) is also connected to the second power tube (Q2).

3. The vehicle-mounted multi-channel DC-DC output system for new energy vehicles according to claim 1, characterized in that: The series resonant network includes a third compensation capacitor (C S ), the third compensation capacitor (C S ) and the receiving coil (L S ) connection, the third compensation capacitor (C S ) is connected to the positive and negative half-wave rectifier composed of a bidirectional switch.

4. The vehicle-mounted multi-channel DC-DC output system for new energy vehicles according to claim 1, characterized in that: The positive and negative half-wave rectifier formed by the bidirectional switch includes a first power switch tube (Q b ), the second power switch tube (Q c ), the first output capacitor (C BC ), the first power switch tube (Q b ) and the second power switch tube (Q c ) in reverse series, the first output capacitor (C BC ) and the second power switch tube (Q c )connect.

5. The vehicle-mounted multi-channel DC-DC output system for new energy vehicles according to claim 1, characterized in that: The synchronous rectifier bridge includes a fifth power tube (Q5), a sixth power tube (Q6), a seventh power tube (Q7), an eighth power tube (Q8), a second output capacitor (C A ), the fifth power tube (Q5) is connected to the sixth power tube (Q6), the seventh power tube (Q7) is connected to the fifth power tube (Q5) and the eighth power tube (Q8) respectively, the eighth power tube (Q8) is also connected to the sixth power tube (Q6), and the second output capacitor (C A ) is connected to the seventh power tube (Q7), and the second output capacitor (C A ) is connected to the eighth power tube (Q8).

6. A vehicle-mounted multi-channel DC-DC output method for new energy vehicles, characterized in that: The vehicle-mounted multi-channel DC-DC output system for new energy vehicles comprising any one of claims 1 to 5, wherein the process is as follows: The primary controller includes a voltage and current double closed loop and a feedforward control link and a receiving loop current I S Polarity detection link: two links respectively perform phase shift voltage regulation control on the primary inverter and synchronous rectification control on channel #A: A secondary controller is used to adjust the voltage of channel #B and channel #C.

7. The vehicle-mounted multi-channel DC-DC output method for new energy vehicles according to claim 6, characterized in that: The process of phase-shift voltage regulation control is: 1) Use the A / D module of the DSP controller to sample the rectified voltage V of channel #A a With the rectified current I a ,Then the collected signal is fed back to the primary controller, which is a voltage and current dual closed-loop controller based on PI control; 2) The controller picks up V a , I a signal, the rectified voltage V a With reference output voltage V aref The error generated is sent to the PI controller, and after the voltage outer loop control, the input signal is compared with the reference output current I aref For comparison, the error signal is sent to the inner loop PI controller; 3) To perform feedforward control, first obtain an approximate model of the controlled system. Assume that the frequency domain model of a controlled object is: Among them, A and B are system constants, and S is a complex frequency domain variable; The feedforward controller is the inverse of the controlled object, so the input and output expressions of the feedforward controller are derived as follows: Among them, U f (t) is the output expression of the feedforward controller, and x(t) is the time domain expression of the controlled object. By discretizing it, we can get the output formula of the feedforward controller we want to achieve. The input of the feedforward controller is the set value, which is expressed as follows: T is the cycle of the controlled object, k is the current time sampling point, x(k), x(k-1), and x(k-2) are the expressions of the controlled object corresponding to the k, k-1, and k-2 sampling points respectively, and U f (k) is the output expression of the feedforward controller at sampling point k; According to the actual system requirements, set the corresponding feedforward control parameters; according to the following formula, V a and V dc And the relationship between the phase shift angle: U s is the secondary side AC bus voltage, C T is the compensation capacitor, M is the mutual inductance between the transmitting coil and the receiving coil, U in is the output voltage of the phase-shifted full-bridge converter, V dc is the DC voltage source, σ is the phase shift angle, ω is the operating angular frequency of the inverter; 4) The input signal after voltage and current dual closed-loop control and feedforward control is used to generate two pairs of complementary PWM pulse waves through a PWM generator to control the opening and closing of the upper and lower tubes of the front and rear bridge arms of the primary-side inverter respectively.

8. The vehicle-mounted multi-channel DC-DC output method for new energy vehicles according to claim 6, characterized in that: The specific control process of channel #A synchronous rectification is as follows: 1) Use the DSP controller A / D conversion module to sample the receiving coil current and determine the rectifier current I S Polarity; 2) According to I S The different polarities of the rectified current I S >0, the fifth power tube (Q5) and the eighth power tube (Q8) in the synchronous rectifier bridge are turned on; When the rectified current I S <0, the sixth power tube (Q6) and the seventh power tube (Q7) of the synchronous rectifier bridge are turned on; Through the above logical judgment, synchronous rectification of channel #A is achieved.

9. The vehicle-mounted multi-channel DC-DC output method for new energy vehicles according to claim 6, characterized in that: The process of the secondary controller regulating the voltage of channel #B and channel #C is as follows: (1) First, when the rectified current I S <0, channel #B is turned on, when the rectifier current I S >0, channel #C is turned on; (2) The secondary controller uses the A / D module of the DSP controller to sample the output voltage V of channel #B b and the output voltage V of channel #C c , the output preset voltage is subtracted from the sampled output voltage, and the error information is sent to the PI controller. Qb and D Qc Adjust the voltage V b and V c ; In the above, D Qb is the duty cycle of the pulse width modulation in the positive half cycle of channel #B, D Qc is the duty cycle of the pulse width modulation in the negative half cycle of channel #C.

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