Configuration method for phase shift control of dual-active bridge circuit
By using the voltage feedback amount to generate an external phase shift angle in the dual active bridge circuit, the phase shift of the switching tube pulse signal is accurately controlled, and the problem of inaccurate phase shift control in the prior art is solved, and high-efficiency energy conversion and system stability are achieved.
Patent Information
- Application Number
- CN202510167817.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-17
- Publication Date
- 2025-05-06
AI Technical Summary
When faced with different working conditions, it is difficult to achieve accurate phase shift control, resulting in low energy conversion efficiency and system instability.
By utilizing the voltage feedback amount of the low-voltage side battery and the voltage feedback amount of the high-voltage side bus, an external phase shift angle is generated through the external phase shift signal configurator, so as to accurately control the phase shift of the pulse signal of the switch tube in the full bridge circuit, and automatically adjust the phase shift angle according to the charge and discharge state.
It realizes efficient energy conversion and power transmission, improves the working efficiency and stability of the system under different load conditions, and avoids instability in traditional control methods.
Smart Images
Figure CN119944826A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of power electronics, in particular to a configuration method for phase-shift control of a dual active bridge circuit. Background Art
[0002] In the application of dual active bridge circuits, precise control is required to ensure their efficient and stable operation under different working conditions.
[0003] In terms of phase shift control, the core lies in the reasonable allocation of internal and external phase shift angles according to the circuit operation requirements, so as to achieve accurate control of key performance indicators such as power flow and voltage conversion. The control means in the prior art mostly rely on a preset fixed phase shift mode to drive the power switch tubes on the high and low voltage sides according to the established phase shift angle combination. However, this method exposes significant defects: on the one hand, from the perspective of control accuracy, the fixed phase shift mode is difficult to dynamically adjust the phase shift angle according to real-time load changes, input voltage fluctuations and other working conditions, resulting in large deviations between the actual circuit operation state, ideal power transmission and voltage regulation targets, and ultimately leading to a significant reduction in energy conversion efficiency; on the other hand, in the face of complex and changeable working environments, such as sudden changes in grid voltage or sudden changes in load, due to the lack of adaptive internal and external phase shift adjustment strategies, the circuit system is very prone to instability, which seriously affects the normal operation of the equipment and the stability of surrounding electrical equipment. Summary of the invention
[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.
[0005] In view of the above problems and / or the problems existing in the existing dual active bridge circuit phase shift control technology, the present invention is proposed.
[0006] Therefore, the purpose of the present invention is to provide a configuration method for phase shift control of a dual active bridge circuit, which utilizes the voltage feedback of the low-voltage side battery and the voltage feedback of the high-voltage side bus to generate an external phase shift angle through an external phase shift signal configurator, thereby accurately controlling the phase shift between the corresponding switch tube ePWM pulse signals in the full-bridge circuits on both sides, and can automatically adjust the phase shift angle according to the charge and discharge status of the battery to achieve efficient energy conversion and power transmission.
[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a configuration method of dual active bridge circuit phase shift control, comprising the following steps: S1. configuring an enhanced pulse width modulation module ePWM in a digital signal processor DSP; S2, sampling the voltage feedback of the low-voltage side battery V batf and the voltage feedback of the high-voltage busbar V busf , the voltage feedback amount V batf and voltage feedback V busf The external phase shift signal configurator sent to the dual active bridge circuit forms a trigger signal, which triggers the phase shift between the corresponding switch tube ePWM pulse signals of the full bridge circuits on both sides of the dual active bridge circuit.
[0008] As a preferred solution of the configuration method of the dual active bridge circuit phase shift control in the present invention, wherein: in step S1, the configuration step is specifically as follows: Set the clock source and frequency of the ePWM module to match the operating frequency of the dual active bridge circuit; Configure the counter mode and select the appropriate counting direction and period value to meet the phase shift requirements; Enable configuration in the phase shift signal configurator, set the specific output comparison event A to enable, and configure the interrupt enable and interrupt selection according to the needs, and control the frequency of event triggering through the event trigger prescaler setting; ePWM phase enable, 0 means prohibiting phase shift, 1 means enabling phase shift, and the interrupt enable and trigger frequency can be adjusted as needed; Set the comparator function, set the comparison control register CMPCTL, determine that when the feedback signal of the dual active bridge circuit is equal to the preset reference value, a trigger signal is generated as a trigger event of the time base phase register TBPHS, and according to the cycle of the TBCTL time base control register, when the counter is in the rising or falling process, it compares with the value in the comparison control register CMPCTL and outputs a level signal; the output level signal of the comparator is sent to the dead zone generation module in the ePWM module, and the ePWM complementary signal is output and sent to the bridge arm switch tubes in the dual active bridge circuit respectively.
[0009] As a preferred solution of the configuration method of the dual active bridge circuit phase shift control in the present invention, wherein: in the external phase shift signal configurator, the error generated by comparing the feedback voltage of the dual active bridge circuit with the preset reference value, that is, the constant voltage charging reference voltage V of the low voltage side battery bat_ref The voltage feedback of the low voltage battery V batf The error generated after subtraction and the high-voltage bus reference voltage V bus_ref The high voltage side bus voltage feedback value V busf The error generated after subtraction is used to generate an external phase shift angle Φ of the corresponding switch tube drive signal in the full-bridge circuits on both sides of the dual active bridge circuit through the voltage regulator. The external phase shift angle Φ is sent to the phase shift register of the ePWM module of the DSP to form a trigger signal, which triggers the phase shift between the ePWM pulse signals of the corresponding switch tubes in the full-bridge circuits on both sides.
[0010] As a preferred scheme of the configuration method of the phase shift control of the dual active bridge circuit in the present invention, wherein: the external phase shift angle Φ is positive and negative according to the charging and discharging state, respectively. If the external phase shift angle Φ is a positive value, corresponding to the discharging state, the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to lag behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ; if the external phase shift angle Φ is a negative value, corresponding to the charging state, the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to lead the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ.
[0011] As a preferred solution of the configuration method of the phase shift control of the dual active bridge circuit in the present invention, step S1 also includes the following steps: configuring the internal phase shift angle D between the diagonal switch tubes of the two bridge arms in the dual active bridge circuit, the two bridge arms on the primary side adopt phase shift control, Q1 and Q2 constitute the primary leading bridge arm, Q3 and Q4 constitute the primary lagging bridge arm, and the phase shift angle between the primary leading bridge arm and the primary lagging bridge arm is D y1 The two bridge arms on the secondary side also adopt phase shift control. Q5 and Q6 form the leading bridge arm on the secondary side, and Q7 and Q8 form the lagging bridge arm on the secondary side. The phase shift angle between the leading bridge arm on the secondary side and the lagging bridge arm on the secondary side is D y2 .
[0012] As a preferred solution of the configuration method of the dual active bridge circuit phase shift control in the present invention, the configuration method of the internal phase shift angle D is as follows: The voltage gain K is obtained by multiplying the filtered bus voltage by the inverse of the turns ratio of the high-frequency isolation transformer and then dividing it by the filtered battery voltage value. If K=1, the internal phase shift function is shielded. If K<1, there is phase shift control on the low voltage side and no phase shift control on the high voltage side; it is divided into heavy load and light load conditions: when the absolute value of the external phase shift angle Φ is not less than the set first calculated value, it is heavy load, and the state parameter is set to 1; otherwise, it is light load, and the state parameter is set to 0; If K>1, there is phase shift control on the high voltage side and no phase shift control on the low voltage side; when the absolute value of the external phase shift angle Φ is not less than the set second calculated value, it is heavy load and the state parameter is set to 1; otherwise, it is light load and the state parameter is set to 0; The calculation formula of the internal phase shift angle D is: ; Calculate the feedforward amount F and add the feedforward amount F to the lag bridge in, N is the transformer turns ratio, V bat is the low voltage side battery voltage, V bus High voltage side bus voltage, T is the switching period of the dual active bridge.
[0013] As a preferred solution of the configuration method of the dual active bridge circuit phase shift control in the present invention, wherein: by superimposing the feedforward amount F related to the internal phase shift angle on the lagging bridge, the lagging bridge and the leading bridge are made to lag the desired external phase shift angle relative to the center point of the drive, and the calculation method of the feedforward amount is: When in the discharge state, that is, the driving signal of the switch tube in the high-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, ; In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high-voltage side. If F is a positive value, the high-voltage side will be shifted more by |F| angle; if F is a negative value, the high-voltage side will be shifted less by |F| angle. When in the charging state, that is, when the driving signal of the switch tube in the low-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the high-voltage side full-bridge circuit, ; In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high pressure side. If F is a positive value, the low pressure side will be shifted more by |F| angle; if F is a negative value, the low pressure side will be shifted less by |F| angle.
[0014] Compared with the prior art, the present invention has the following technical effects: 1. The voltage feedback of the low-voltage battery and the bus voltage feedback of the high-voltage bus are used to generate an external phase angle through an external phase shift signal configurator, thereby accurately controlling the phase shift between the corresponding switch tube ePWM pulse signals in the full-bridge circuits on both sides to achieve efficient energy conversion and power transmission.
[0015] 2. By introducing the voltage gain K to determine whether to turn on the internal phase shift function, and dividing it into heavy load and light load, the internal phase shift angle can be optimized according to the actual load conditions, which significantly improves the working efficiency of the dual active bridge circuit under different load conditions and makes up for the shortcomings of traditional internal phase shift control; 3. By superimposing the feedforward amount F related to the internal phase shift angle on the lag bridge, the phase shift angle on the high voltage side or the low voltage side can be flexibly adjusted according to the charge and discharge status, so that the circuit can maintain efficient and stable operation in different working modes.
[0016] In summary, the present invention can meet the phase shift control requirements of the dual active bridge circuit in different scenarios and the two-way flow of energy between the high voltage side and the low voltage side, thereby improving system performance and robustness. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them: Figure 1 A schematic diagram of a dual active bridge circuit and control components of the present invention; Figure 2 The schematic diagram of the external phase-shift signal configurator of the dual active bridge circuit of the present invention; Figure 3 It is a configuration flow chart of the inner phase shift D of the present invention; Figure 4 It is a flow chart of the inner phase shift center symmetric superposition compensation method of the present invention; Figure 5 It is a schematic diagram of the composition principle of an embodiment of the present invention; Figure 6 A timing diagram of a phase-shift pulse control signal for battery charging in an embodiment of the present invention; Figure 7 It is a timing diagram of a phase-shift pulse control signal for battery discharge in an embodiment of the present invention; Figure 8 The power switch tube driving waveform when the battery charging voltage gain K>1 in the embodiment of the present invention; Fig. 9 The power switch tube driving waveform when the battery charging voltage gain K<1 in the embodiment of the present invention; Fig.10 The power switch tube driving waveform when the battery discharge voltage gain K>1 in the embodiment of the present invention; Fig.11 1 is a driving waveform of the power switch tube when the battery discharge voltage gain K is less than 1 in an embodiment of the present invention.
[0018] in, Figure 1 The annotations for each letter symbol are as follows: .
[0019] Figure 2 The annotations for each letter symbol are as follows: . DETAILED DESCRIPTION
[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.
[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0023] Example 1 like Figure 1 As shown, the present invention also includes a hardware circuit, which includes a dual active bridge circuit 1, an external phase shift signal configurator 2 of the dual active bridge circuit and a drive circuit 3. The external phase shift signal configurator 2 of the dual active bridge circuit is implemented in the CPU through a program and ePWM configuration.
[0024] Reference Figure 1 and Figure 2 The embodiment of the present invention provides a configuration method for phase shift control of a dual active bridge circuit, comprising the following steps: S1. configuring an enhanced pulse width modulation module ePWM in a digital signal processor DSP; S2, sampling the voltage feedback of the low-voltage side battery V batf and the voltage feedback of the high-voltage busbar V busf , the voltage feedback amount V batf and voltage feedback V busf The external phase shift signal configurator sent to the dual active bridge circuit forms a trigger signal, which triggers the phase shift between the corresponding switch tube ePWM pulse signals of the full bridge circuits on both sides of the dual active bridge circuit.
[0025] In step S1, the configuration steps are specifically as follows: Set the clock source and frequency of the ePWM module to match the operating frequency of the dual active bridge circuit; Configure the counter mode and select the appropriate counting direction and period value to meet the phase shift requirements; Enable configuration in the phase shift signal configurator, set the specific output comparison event A to enable, and configure the interrupt enable and interrupt selection according to the needs, and control the frequency of event triggering through the event trigger prescaler setting; ePWM phase enable, 0 means prohibiting phase shift, 1 means enabling phase shift, and the interrupt enable and trigger frequency can be adjusted as needed; Set the comparator function, set the comparison control register CMPCTL, determine to generate a trigger signal as the trigger event of the time base phase register TBPHS when the feedback signal of the dual active bridge circuit is equal to the preset reference value, according to the period of the TBCTL time base control register, when the counter compares with the value in the comparison control register CMPCTL during the rising process, it will output a low level when the values are the same; when the counter compares with the value in the comparison control register CMPCTL during the falling process, it will output a high level when the values are the same; the output level signal of the comparator is sent to the dead zone generation module in the ePWM module, and the ePWM complementary signal is output, which is sent to the bridge arm switch tubes in the dual active bridge circuit respectively.
[0026] The configuration of key registers is shown in the following table.
[0027]
[0028] The configuration of the registers in the interrupt processing function in conjunction with the PWM wave pair is: when the counter value is equal to 0, the interrupt is triggered. In the interrupt processing, the TBPHS register is set to 0, and the PHSDIR register is set to 1. In this way, when the trigger signal arrives, the counter will start counting from 0 again, and the counting direction will remain upward. When the counter value reaches the period value, the interrupt will be triggered again. At this time, the TBPHS register is set to the period value, and the PHSDIR is set to 0. In this way, when the trigger signal arrives, the counter will start counting down from the period value again.
[0029] like Figure 2 As shown, the specific process of configuring the external phase shift signal of the external phase shift signal configurator 2 is as follows: The error generated by comparing the feedback voltage of the dual active bridge circuit with the preset reference value, that is, the constant voltage charging reference voltage V bat_ref The voltage feedback of the low voltage battery V batf The error generated after subtraction and the high-voltage bus reference voltage V bus_ref The high voltage side bus voltage feedback value V busf The error generated after subtraction is used to generate an external phase shift angle Φ of the corresponding switch tube drive signal in the full-bridge circuits on both sides of the dual active bridge circuit through the voltage regulator. The external phase shift angle Φ is sent to the phase shift register of the ePWM module of the DSP to form a trigger signal, which triggers the phase shift between the ePWM pulse signals of the corresponding switch tubes in the full-bridge circuits on both sides.
[0030] The external phase shift angle Φ is positive and negative according to the charging and discharging state. If the external phase shift angle Φ is positive, it corresponds to the discharging state, and the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to lag behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ; if the external phase shift angle Φ is negative, it corresponds to the charging state, and the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to advance the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ.
[0031] The present invention utilizes the voltage feedback of the low-voltage side battery and the voltage feedback of the high-voltage side busbar to generate an external phase shift angle through an external phase shift signal configurator, thereby accurately controlling the phase shift between the corresponding switch tube ePWM pulse signals in the full-bridge circuits on both sides, thereby achieving efficient energy conversion and power transmission.
[0032] Example 2 like Figure 3 and Figure 4 As shown, it is the first embodiment of the present invention. This embodiment provides a configuration method for phase shift control of a dual active bridge circuit. Step S1 also includes the following steps: configuring the internal phase shift angle D between the diagonal switch tubes of the two bridge arms in the dual active bridge circuit, the two bridge arms on the primary side adopt phase shift control, Q1 and Q2 constitute the primary leading bridge arm, Q3 and Q4 constitute the primary lagging bridge arm, and the phase shift angle between the primary leading bridge arm and the primary lagging bridge arm is D y1 The two bridge arms on the secondary side also adopt phase shift control. Q5 and Q6 form the leading bridge arm on the secondary side, and Q7 and Q8 form the lagging bridge arm on the secondary side. The phase shift angle between the leading bridge arm on the secondary side and the lagging bridge arm on the secondary side is D y2 .
[0033] The configuration method of the internal phase shift angle D is as follows: The voltage gain K is obtained by multiplying the filtered bus voltage by the inverse of the turns ratio of the high-frequency isolation transformer and then dividing it by the filtered battery voltage value. If K=1, the internal phase shift function is shielded. If K<1, there is phase shift control on the low voltage side and no phase shift control on the high voltage side; it is divided into heavy load and light load conditions: when the absolute value of the external phase shift angle Φ is not less than the set first calculated value, it is heavy load, and the state parameter is set to 1; otherwise, it is light load, and the state parameter is set to 0; If K>1, there is phase shift control on the high voltage side and no phase shift control on the low voltage side; when the absolute value of the external phase shift angle Φ is not less than the set second calculated value, it is heavy load and the state parameter is set to 1; otherwise, it is light load and the state parameter is set to 0; The calculation formula of the internal phase shift angle D is: ; Calculate the feedforward amount F, and add the feedforward amount F to the lag bridge; in, N is the transformer turns ratio,V bat is the low voltage side battery voltage, V bus High voltage side bus voltage, T is the switching period of the dual active bridge; By superimposing the feedforward amount F related to the internal phase shift angle on the lagging bridge, the lagging bridge and the leading bridge are made to lag the desired external phase shift angle relative to the center point of the drive. The calculation method of the feedforward amount is: When in the discharge state, that is, the driving signal of the switch tube in the high-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, ; In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high-voltage side. If F is a positive value, the high-voltage side will be shifted more by |F| angle; if F is a negative value, the high-voltage side will be shifted less by |F| angle. When in the charging state, that is, when the driving signal of the switch tube in the low-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the high-voltage side full-bridge circuit, ; In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high pressure side. If F is a positive value, the low pressure side will be shifted more by |F| angle; if F is a negative value, the low pressure side will be shifted less by |F| angle.
[0034] This embodiment introduces a voltage gain K to determine whether to turn on the internal phase shift function, and divides it into heavy load and light load, so that the internal phase shift angle can be optimized according to the actual load conditions, which significantly improves the working efficiency of the dual active bridge circuit under different load conditions and makes up for the shortcomings of traditional internal phase shift control; at the same time, by superimposing a feedforward amount F related to the internal phase shift angle on the lag bridge, the phase shift angle on the high voltage side or the low voltage side is flexibly adjusted according to the charge and discharge state, so that the circuit can maintain efficient and stable operation in different working modes.
[0035] Example 3 Reference Figure 5 to Figure 11 This embodiment proves the technical effect of the present invention through specific experiments.
[0036] like Figure 5 As shown, the high voltage side of the dual active bridge circuit 1 is connected to the bidirectional AC / DC converter 4 on the grid side, and then the bidirectional AC / DC converter 4 on the grid side is connected to the power grid, thus forming a bidirectional energy storage system.
[0037] Figure 3 The rated power of the bidirectional energy storage system is 5kW, where the battery voltage V connected to the low-voltage side of the dual active bridge circuit is bat The range is 42 V~60 V, the DC bus voltage V bus =400V, the maximum charge and discharge current is 100A; the rated value and frequency of the grid-side AC voltage are 230V / 50Hz; MOSFET field effect tubes are selected in the dual active bridge circuit 1, the low-voltage side switch tubes Q1~Q4 use Fairchild's N-channel MOSFET tubes, model FDA032N08 (rated voltage 75V, rated current 235A), the high-voltage side switch tubes Q5~Q8 use ON Semiconductor's N-channel MOSFET tubes, model FCH072N60 (rated voltage 600V, rated current 52A), the switching frequency is 100kHz, Figure 3 DQ1~DQ8 and CQ1~CQ8 are the body diodes and junction capacitances of the switch tubes Q1~Q8; the high-frequency transformer Tr uses the EE55 magnetic core, and the turns ratio between the low-voltage side winding and the high-voltage side winding is 1:4.
[0038] According to the switching frequency and the transmission power, the resonant inductor Ls=9 and the DC blocking capacitor Cs=45 can be calculated. The bidirectional AC / DC converter 4 on the grid side adopts a single-phase H4 full-bridge circuit. When the battery discharges through the dual active bridge circuit 1, the energy is transmitted to the DC bus to establish the DC bus voltage V bus , the energy of the DC bus is transmitted to the grid or local load through the bidirectional AC / DC converter 4 on the grid side; when the battery is charged through the independent input dual-channel-winding series dual active bridge circuit 1, the bus voltage Vbus on the high voltage side is provided by the bidirectional AC / DC converter 4 on the grid side. At this time, the bidirectional AC / DC converter 4 on the grid side absorbs energy from the grid, and the bidirectional AC / DC converter 4 on the grid side rectifies it into the DC bus voltage to transmit energy, thereby providing energy for the low voltage side battery of the dual active bridge circuit 1. Figure 5 The external phase shift signal configurator of the dual active bridge circuit is realized by the digital chip TMS320F28035 of TI Company; Figure 5The energy storage system shown is configured with an ePWM module according to the ePWM configuration method of DSP proposed in the present invention. The clock source and frequency of the ePWM module are set to match the operating frequency of the dual active bridge circuit, the counter mode is configured and the appropriate counting direction and cycle value are selected to meet the phase shift requirement; the comparator function is set to sample the voltage feedback amount Vbatf of the low-voltage side battery and the voltage feedback amount Vbusf of the high-voltage side busbar and send them to the external phase shift signal configurator of the dual active bridge circuit to form a trigger signal, thereby triggering the phase shift between the corresponding switch tube ePWM pulse signals in the full bridge circuits on both sides; wherein the ePWM port is configured as an asynchronous input, and the clock source of the input sampling is set as an asynchronous sampling clock, so that the clock source and frequency configuration match the operating frequency of the dual active bridge circuit; the counter mode is configured, and the counter mode is set to an increase and decrease counting mode, that is, the counter first increases and then decreases. The cycle value of the timer is set to a half cycle value of the switching cycle, and the initial phase of the timer is set to zero; the enable configuration sets a specific output comparison event A to be enabled, and the interrupt enable and interrupt selection can be configured according to requirements, and the frequency of event triggering is controlled by setting the event trigger prescaler; the configurations work together to enable the phase of ePWM, 0 means prohibiting phase shifting, 1 means allowing phase shifting, and the enable and trigger frequency of the interrupt can be adjusted as needed; the comparator function is set, the comparison control register CMPCTL is set, and it is determined that when the feedback signal of the dual active bridge circuit is equal to the preset reference value, a trigger signal is generated as a trigger event of the time base phase register TBPHS, and according to the cycle of the TBCTL time base control register, when the counter is in the rising (falling) process, it compares with the value in the comparison control register CMPCTL, and a low level (high level) is output when the values are the same; the output level signal of the comparator is sent to the dead zone generation module to output the complementary signal of ePWM, which is sent to the bridge arm switch tubes in the dual active bridge circuit respectively.
[0039] at the same time, Figure 5 The energy storage system shown in the figure adopts a digital control chip to implement the external phase shift signal configurator, internal phase shift angle D configuration process and internal phase shift center symmetric superposition compensation method of the dual active bridge circuit proposed in the present invention, that is, the control algorithm is implemented by software coding, thereby completing the phase shift control. The error generated by comparing the feedback voltage of the dual active bridge circuit with the preset reference value, that is, the constant voltage charging reference voltage V of the low voltage side battery bat_ref The voltage feedback of the low voltage battery V batf The error generated after subtraction and the high-voltage bus reference voltage V bus_ref The high voltage side bus voltage feedback value V busf The error generated after subtraction is used by the voltage regulator to generate the external phase shift angle Φ of the corresponding switch tube drive signal in the full-bridge circuit on both sides of the dual active bridge circuit. The external phase shift angle Φ is sent to the ePWM module phase shift register of the DSP to form a trigger signal. When the battery is charged, it generates Figure 6 The phase-shift pulse control signal shown is then passed through the drive circuit 3 to generate a drive signal for the corresponding switch tube. Figure 6 The phase-shift pulse control signal given is the on-off timing of the switch tube in the dual active bridge circuit 1. The phase-shift pulse control signal gives the control signal of the corresponding switch tube of the low-voltage side full bridge and the high-voltage side full bridge of the dual active bridge circuit 1. Figure 6 It is known that when the battery is charging, the on-off of the low-voltage side full-bridge circuit switch tube of the dual active bridge circuit 1 in the phase-shift pulse control signal lags behind the corresponding high-voltage side full-bridge switch tube Φ phase angle. When the battery is discharging, the following is generated: Figure 7 The phase-shift pulse control signal shown is then passed through the drive circuit 3 to generate a drive signal for the corresponding switch tube. Figure 7 The phase-shift pulse control signal given is the on-off timing of the switch tube in the dual active bridge circuit 1. The phase-shift pulse control signal gives the control signal of the corresponding switch tube of the low-voltage side full bridge and the high-voltage side full bridge of the dual active bridge circuit 1. Figure 7 It is known that when the battery is discharged, the on-off of the low-voltage side full-bridge circuit switch tube of the dual active bridge circuit 1 in the phase-shift pulse control signal leads the corresponding high-voltage side full-bridge switch tube by a phase angle Φ.
[0040] According to the configuration process of the internal phase shift angle D and the process of the internal phase shift center symmetric superposition compensation method. When the battery is charging, the power switch tube driving waveform is as follows when the voltage gain K>1 Figure 8 As shown; when the voltage gain K<1, the power switch tube drive waveform is as follows Fig. 9 When the battery is discharging, the power switch tube drive waveform is as follows when the voltage gain K>1 Fig.10 As shown; when the voltage gain K<1, the power switch tube drive waveform is as follows Fig.11 shown.
[0041] Figure 8-Figure 11 In each picture, the upper blue waveform is the driving waveform of the low-voltage side power switch tube Q1, and the red waveform is the driving waveform of the low-voltage side power switch tube Q4; the lower green waveform is the driving waveform of the high-voltage side power switch tube Q5, and the purple waveform is the driving waveform of the high-voltage side power switch tube Q8.
[0042] Figure 8 When the battery is charging, the full-bridge circuit on the high-voltage side is an advanced bridge, and the full-bridge circuit on the low-voltage side is a lagging bridge; K>1, there is an internal phase shift on the high-voltage side, and no internal phase shift on the low-voltage side.
[0043] Fig. 9 When the battery is charging, the full-bridge circuit on the high-voltage side is an advanced bridge, and the full-bridge circuit on the low-voltage side is a lagging bridge; K<1, there is no internal phase shift on the high-voltage side, and there is an internal phase shift on the low-voltage side.
[0044] Fig.10In the circuit, when the battery is discharged, the full-bridge circuit on the low-voltage side is an advanced bridge, and the full-bridge circuit on the high-voltage side is a lagging bridge; K>1, there is an internal phase shift on the high-voltage side, and there is no internal phase shift on the low-voltage side.
[0045] Fig.11 In the circuit, when the battery is discharged, the full-bridge circuit on the low-voltage side is an advanced bridge, and the full-bridge circuit on the high-voltage side is a lagging bridge; K<1, there is no internal phase shift on the high-voltage side, and there is an internal phase shift on the low-voltage side.
[0046] Depend on Figure 8-Figure 11 It can be seen that under the effect of the feedforward amount F superimposed on the lagging bridge, all working conditions can achieve the desired external shift phase angle Φ of the lagging bridge and the leading bridge relative to the center point they drive.
[0047] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
Claims
1. A configuration method for phase shift control of a dual active bridge circuit, characterized in that: The steps include: S1. configuring an enhanced pulse width modulation module ePWM in a digital signal processor DSP; S2, sampling the voltage feedback of the low-voltage side battery V batf and the voltage feedback of the high-voltage busbar V busf , the voltage feedback amount V batf and voltage feedback V busf The external phase shift signal configurator sent to the dual active bridge circuit forms a trigger signal, which triggers the phase shift between the corresponding switch tube ePWM pulse signals of the full bridge circuits on both sides of the dual active bridge circuit.
2. The configuration method of dual active bridge circuit phase shift control as claimed in claim 1, characterized in that: In step S1, the configuration steps are specifically as follows: Set the clock source and frequency of the ePWM module to match the operating frequency of the dual active bridge circuit; Configure the counter mode and select the appropriate counting direction and period value to meet the phase shift requirements; Enable configuration in the phase shift signal configurator, set the specific output comparison event A to enable, and configure the interrupt enable and interrupt selection according to the needs, and control the frequency of event triggering through the event trigger prescaler setting; ePWM phase enable, 0 means prohibiting phase shift, 1 means enabling phase shift, and the interrupt enable and trigger frequency can be adjusted as needed; Set the comparator function, set the comparison control register CMPCTL, determine that when the feedback signal of the dual active bridge circuit is equal to the preset reference value, a trigger signal is generated as a trigger event of the time base phase register TBPHS, and according to the cycle of the TBCTL time base control register, when the counter is in the process of rising or falling, it compares with the value in the comparison control register CMPCTL and outputs a level signal; The output level signal of the comparator is sent to the dead zone generation module in the ePWM module, and the ePWM complementary signal is output and sent to the bridge arm switch tubes in the dual active bridge circuit respectively.
3. The configuration method of dual active bridge circuit phase shift control as claimed in claim 1, characterized in that: In the external phase-shift signal configurator, the error generated by comparing the feedback voltage of the dual active bridge circuit with the preset reference value, that is, the constant voltage charging reference voltage V bat_ref The voltage feedback of the low voltage battery V batf The error generated after subtraction and the high-voltage bus reference voltage V bus_ref The high voltage side bus voltage feedback value V busf The error generated after subtraction is used to generate an external phase shift angle Φ of the corresponding switch tube drive signal in the full-bridge circuits on both sides of the dual active bridge circuit through the voltage regulator. The external phase shift angle Φ is sent to the phase shift register of the ePWM module of the DSP to form a trigger signal, which triggers the phase shift between the ePWM pulse signals of the corresponding switch tubes in the full-bridge circuits on both sides.
4. The configuration method of dual active bridge circuit phase shift control as claimed in claim 3, characterized in that: The external phase shift angle Φ is positive and negative according to the charging and discharging state. If the external phase shift angle Φ is positive, it corresponds to the discharging state, and the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to lag behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ; if the external phase shift angle Φ is negative, it corresponds to the charging state, and the driving signal of the switch tube in the high-voltage side full-bridge circuit is controlled to advance the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, and the phase shift angle is Φ.
5. The configuration method of dual active bridge circuit phase shift control according to any one of claims 1 to 4, characterized in that: Step S1 also The method comprises the following steps: configuring the internal phase shift angle D between the diagonal switch tubes of the two bridge arms in the dual active bridge circuit, adopting phase shift control for the two bridge arms on the primary side, Q1 and Q2 forming the primary leading bridge arm, Q3 and Q4 forming the primary lagging bridge arm, and the phase shift angle between the primary leading bridge arm and the primary lagging bridge arm is D y1 The two bridge arms on the secondary side also adopt phase shift control. Q5 and Q6 form the leading bridge arm on the secondary side, and Q7 and Q8 form the lagging bridge arm on the secondary side. The phase shift angle D between the leading bridge arm on the secondary side and the lagging bridge arm on the secondary side is y2 .
6. The configuration method of dual active bridge circuit phase shift control as claimed in claim 5, characterized in that: The configuration method of the internal phase shift angle D is as follows: The voltage gain K is obtained by multiplying the filtered bus voltage by the inverse of the turns ratio of the high-frequency isolation transformer and then dividing it by the filtered battery voltage value. If K=1, the internal phase shift function is shielded. If K<1, there is phase shift control on the low voltage side and no phase shift control on the high voltage side; it is divided into heavy load and light load conditions: when the absolute value of the external phase shift angle Φ is not less than the set first calculated value, it is heavy load, and the state parameter is set to 1; otherwise, it is light load, and the state parameter is set to 0; If K>1, there is phase shift control on the high voltage side and no phase shift control on the low voltage side; when the absolute value of the external phase shift angle Φ is not less than the set second calculated value, it is heavy load and the state parameter is set to 1; otherwise, it is light load and the state parameter is set to 0; The calculation formula of the internal phase shift angle D is: ; Calculate the feedforward amount F and add the feedforward amount F to the lag bridge in, N is the transformer turns ratio, V bat is the low voltage side battery voltage, V bus High voltage side bus voltage, T is the switching period of the dual active bridge.
7. The configuration method of dual active bridge circuit phase shift control as claimed in claim 6, characterized in that: By superimposing the feedforward amount F related to the internal phase shift angle on the lagging bridge, the lagging bridge and the leading bridge are made to lag the desired external phase shift angle relative to the center point of the drive. The calculation method of the feedforward amount is: When in the discharge state, that is, the driving signal of the switch tube in the high-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the low-voltage side full-bridge circuit, ； In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high-voltage side. If F is a positive value, the high-voltage side will be shifted more by |F| angle; if F is a negative value, the high-voltage side will be shifted less by |F| angle. When in the charging state, that is, when the driving signal of the switch tube in the low-voltage side full-bridge circuit lags behind the driving signal of the corresponding power switch tube in the high-voltage side full-bridge circuit, ； In the formula, D y1 is the internal phase shift angle on the low-pressure side, D y2 is the internal phase shift angle on the high pressure side. If F is a positive value, the low pressure side will be shifted more by |F| angle; if F is a negative value, the low pressure side will be shifted less by |F| angle.