CN117937930A - Bidirectional DC-DC converter control method based on linear active disturbance rejection - Google Patents
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Abstract
The invention belongs to the technical field of power electronics, and particularly relates to a control method of a bidirectional DC-DC converter based on linear active disturbance rejection. Firstly, establishing a linearization small signal model of a bidirectional DC-DC converter; then, according to a linearization small signal model of the bidirectional DC-DC converter, an improved linear active disturbance rejection controller is designed; and finally, the improved linear active disturbance rejection controller is used as an outer loop voltage loop and the PI controller is used as an inner loop current loop to be applied to the bidirectional DC-DC converter, so as to obtain the double closed loop linear active disturbance rejection control system of the bidirectional DC-DC converter. The method effectively improves the dynamic response speed of the DC bus voltage under the multi-source disturbance and the robustness of the system, and solves the stability problem of the DC bus voltage of the independent wind power system under the multi-source disturbance.
Description
Technical Field
The invention belongs to the technical field of power electronics, and particularly relates to a control method of a bidirectional DC-DC converter based on linear active disturbance rejection.
Background
With the development and utilization of new energy in the world, wind power and photovoltaic power generation technologies are taken as power generation technologies with wide development prospects, and have the advantages of abundant resources, safety, reliability, cleanliness, no pollution and the like, but also have the defects of large fluctuation, large influence by external conditions such as weather and the like, so that an energy storage device with a certain capacity needs to be configured in a new energy power generation system. The energy storage device has the function of peak clipping and valley filling, can well solve the problem of randomness and fluctuation of the output of the new energy power generation system, and achieves the aim of stable and efficient output of the new energy power generation system. The bidirectional DC-DC converter is used as a bridge between the direct current bus and the energy storage equipment, and the size and the direction of energy flow can be regulated through the control circuit, so that the redundant energy in the system can be reasonably distributed, the bidirectional DC-DC converter is optimally controlled, the dynamic performance of the system is improved, the influence of system parameters and external disturbance on the voltage stability of the direct current bus is reduced, and the bidirectional DC-DC converter becomes a focus of attention of researchers.
The bidirectional DC-DC converter generally adopts PI voltage and current double closed-loop control, and has the advantages of simplicity and easiness in implementation, however, the traditional PI controller is difficult to obtain an ideal control effect in the case of large disturbance of new energy and load, and meanwhile, the performance of the PI controller is limited due to uncertainty disturbance caused by temperature and device parameter perturbation. The institute Han Jing of science, china, clear researchers, on the basis of a PID controller, put forward a control strategy, namely, active Disturbance Rejection Control (ADRC). ADRC does not depend on an accurate mathematical model of a controlled object, ESO is used for observing state variables and interference amounts of a system, and the observation values are utilized for compensation in a feed-forward channel, so that the rapidity and accuracy of the system can be improved well. Due to the excessive parameters involved in conventional nonlinear ADRCs, tuning difficulties, american scholars Gao Zhijiang teach linearizing ADRCs and have proposed a linear active disturbance rejection control (ladc) technique. The method introduces the concept of bandwidth into ADRC, and relates the controller parameters with the bandwidths of the controller and the observer, so that the algorithm is simple and easy to apply, and the difficulty of parameter adjustment is reduced to a great extent. However, the traditional LADRC control disturbance estimation capability is not strong and is easy to be influenced by external interference, so that the dynamic performance and the robustness of the system are reduced.
Summarizing, improvements to traditional ladcs have become a concern for researchers.
Disclosure of Invention
The invention aims to solve the problem of direct current bus voltage stability of a wind power generation system under multi-source disturbance in the prior art, and provides a control method of a bidirectional DC-DC converter based on linear active disturbance rejection.
In order to achieve the technical purpose and the technical effect, the invention is realized by the following technical scheme:
the control method of the bidirectional DC-DC converter based on the linear active disturbance rejection is characterized by comprising the following steps of:
s1, establishing a linearization small signal model of a bidirectional DC-DC converter in two working states;
S2, constructing an improved linear active disturbance rejection controller according to a linear small signal model of the bidirectional DC-DC converter;
and S3, applying the improved linear active disturbance rejection controller serving as an outer loop voltage loop and the PI controller serving as an inner loop current loop to the bidirectional DC-DC converter to obtain the double closed loop linear active disturbance rejection control system of the bidirectional DC-DC converter.
Further, the step S1 specifically includes: based on the bi-directional DC-DC converter, mathematical models are built in Boost mode and Buck mode, respectively.
Further, when working in Boost mode, S 2 has two switching modes as the main switching tube; the state equation of the circuit under one switching period can be obtained according to the state space average method:
when working in the Buck mode, S 1 is used as a main switching tube and has two switching modes; the state equation of the circuit under one switching period can be obtained according to the state space average method:
In the formulas (1) and (2), U CH、UCL is direct current bus side supporting capacitor voltage and energy storage side filtering capacitor voltage respectively, U dc、Ub is direct current bus voltage and storage battery terminal voltage respectively, i L is inductance current, L is inductance value, C dc、Cb is direct current bus side supporting capacitor and energy storage side filtering capacitor respectively, R dc、Rb is direct current bus side equivalent internal resistance and energy storage side equivalent internal resistance respectively, and d Buck、dBoost is duty ratio in Buck and Boost modes respectively;
and respectively obtaining transfer functions from the inductive current to the direct current bus voltage and from the duty ratio to the inductive current according to state space average equations in the two modes.
Further, a small signal disturbance is introduced in one switching period, and the transfer function in the Boost mode of the following formula is obtained by simplifying the formula (1):
wherein, I L is the steady state value of the inductance current;
Transfer function in Buck mode is similarly available:
further, step S2 specifically includes: the LADRC defines the external disturbance and the parameter uncertainty as the total disturbance, and builds a LADRC differential equation.
Further, taking the Buck mode as an example, equation (4) is expressed as a first order integral with total perturbation:
In the method, in the process of the invention, Is the total disturbance;
Defining a state variable x 1＝Udc,x2 =f; then equation (5) can be described by a state space expression:
Where u=i L≈iL *, u is the control input and b 0 is the control gain.
Further, establishing a mathematical model of the linear expansion state observer; according to equation (6), LESO is established in combination with the Luenberger state observer design principle:
Wherein e 1 is an estimation error of the DC bus voltage, z 1,z2 is a state estimation value of the DC bus voltage and the total disturbance, and beta 1,β2 is an observer gain;
based on the total disturbance and LESO, introducing a bandwidth of a system observer, and selecting LESO parameters;
The characteristic equation of the LESO is:
λ(s)＝s2+β1s+β2 (8)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
Where ω 0 is observer bandwidth;
Further, a feedback control law is designed:
For the first-order LADRC, the feedback control law essence consists of two links of a proportional controller and disturbance compensation; the control law is designed as follows:
where k p is the proportional control gain, Is responsible for counteracting the overall disturbance;
if the LESO is able to estimate the system state well, substituting equation (10) into equation (6) one can derive the closed loop transfer function of the entire voltage control loop:
Thus, fast overshoot-free tracking of instructions can be achieved, where k p can also be denoted ω c, representing the controller bandwidth.
Further, in step S2, it is derived according to equation (7):
from the formula (6) and the formula (12):
let e 2＝z2-x2 and establish the improved LESO:
In the method, in the process of the invention, Is the estimated error of the total disturbance f.
Further, the characteristic equation of the modified LESO is:
λ(s)＝s2+(β1+β3)s+β1β3+β2 (15)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
Further, in step S3, the improved linear active disturbance rejection controller is used as an outer loop voltage loop, and the PI controller is used as an inner loop current loop; after the voltage given value and the actual value of the direct current bus are processed by the voltage outer ring, an inductance current given value is output, the error of the inductance current given value and the actual value is processed by the current inner ring to obtain a final control signal, and a PWM waveform generator is used for generating a modulation signal, so that the control of the bidirectional DC-DC converter is realized.
The beneficial effects of the invention are as follows:
1. According to the bidirectional DC-DC converter control method based on the linear active disturbance rejection, the disturbance observation capability and the disturbance rejection of the LADRC control method are improved through improvement of LESO.
2. According to the control method of the bidirectional DC-DC converter based on the linear active disturbance rejection, the improved LADRC control strategy is adopted by the voltage outer loop, so that disturbance observation capability and disturbance rejection of the system are effectively improved, the control capability on the voltage stability of the direct current bus is improved, and the problem of unstable voltage of the direct current bus caused by multi-source disturbance in the wind power energy storage system is solved.
Of course, it is not necessary for any one product to practice the invention to achieve all of the advantages set forth above at the same time.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a topology of a non-isolated half-bridge bi-directional converter according to the present invention;
FIG. 2 is a control block diagram of a bi-directional DC-DC converter according to the present invention;
FIG. 3 is a diagram of a conventional LESO structure;
FIG. 4 is a diagram of the improved LESO structure of the present invention;
FIG. 5 is a Bode plot of LESO versus disturbance estimation before and after improvement in accordance with the present invention;
FIG. 6 is a block diagram of an independent wind power system for which the present invention is applicable;
FIG. 7 is a graph showing the voltage waveforms of the DC bus during the start-up process under normal operating conditions in the present invention;
FIG. 8 is a graph showing a transient DC bus voltage waveform under a wind speed change in the present invention;
fig. 9 is a graph showing a transient dc bus voltage waveform under abrupt load change in the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The embodiment provides a control method of a bidirectional DC-DC converter based on linear active disturbance rejection, which adopts a non-isolated bidirectional DC-DC converter as shown in fig. 1. Firstly, a linearization small signal model of the bidirectional DC-DC converter in two working states is established, secondly, an improved linear active disturbance rejection controller is established according to the linearization small signal model, and finally, the improved linear active disturbance rejection controller is used as an outer loop voltage loop and the PI controller is used as an inner loop current loop to be applied to the bidirectional DC-DC converter, so that a double closed loop linear active disturbance rejection control system of the bidirectional DC-DC converter is obtained. The method specifically comprises the following steps:
in step one, based on the bidirectional DC-DC converter shown in fig. 1, mathematical models are built in Boost mode and Buck mode, respectively.
Operating in Boost mode, S 2 has two switching modes as the main switching tube. The state equation of the circuit under one switching period can be obtained according to the state space average method:
Operating in Buck mode, S 1 has two switching modes as the main switching tube. The state equation of the circuit under one switching period can be obtained according to the state space average method:
In the formulas (1) and (2), U CH、UCL is a dc bus side supporting capacitor voltage and an energy storage side filtering capacitor voltage, U dc、Ub is a dc bus voltage and a battery terminal voltage, i L is an inductance current, L is an inductance value, C dc、Cb is a dc bus side supporting capacitor and an energy storage side filtering capacitor, R dc、Rb is a dc bus side equivalent internal resistance and an energy storage side equivalent internal resistance, and d Buck、dBoost is a duty ratio in Buck and Boost modes, respectively.
And respectively obtaining transfer functions from the inductive current to the direct current bus voltage and from the duty ratio to the inductive current according to state space average equations in the two modes.
Introducing small signal disturbance in a switching period, and simplifying the formula (1) to obtain a transfer function in a Boost mode of the following formula:
Where I L is the steady state value of the inductor current.
Transfer function in Buck mode is similarly available:
In the second step, the LADRC defines the external disturbance and the parameter uncertainty as the total disturbance, and builds a LADRC differential equation.
Taking the Buck mode as an example, equation (4) is expressed as a first order integral with total perturbation:
In the formula (5), the amino acid sequence of the compound, Is the total disturbance.
A state variable x 1＝Udc,x2 =f is defined. Then equation (5) can be described by a state space expression:
Where u=i L≈iL *, u is the control input and b 0 is the control gain.
And establishing an extended state observer LESO mathematical model.
According to equation (6), LESO is established in combination with the Luenberger state observer design principle:
Where e 1 is the estimation error of the dc bus voltage, z 1,z2 is the state estimate of the LESO, and β 1,β2 is the observer gain. The state of x 1,x2 can be estimated in real time by tuning the appropriate observer gains β 1,β2,z1 and z 2, respectively.
Based on the total disturbance and the LESO, introducing a bandwidth of a system observer, and selecting LESO parameters.
The characteristic equation of the LESO is:
λ(s)＝s2+β1s+β2 (8)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
Where ω 0 is the observer bandwidth.
As can be seen from equation (7), the state estimation values z 1,z2 of the LESO are all adjusted by negative feedback with the estimation error e 1. This way of adjustment shows that the total disturbance of the dynamic estimation process is adjusted by the estimation error of another state variable. On this premise, there will be some hysteresis in the estimation of z 2 relative to z 1. Therefore, when selecting observer gain, β 2 is typically an order of magnitude greater than β 1 to compensate for the defect, but excessive gain reduces the immunity of the system. If the gain is set to a small value, the value can only accurately estimate the first state x 1, and the disturbance estimation performance of the lacc cannot reach a satisfactory state.
In order to solve the above problem, in this embodiment, when the LESO disturbance estimation is performed, a new error of z 2 and x 2 is additionally connected in parallel to serve as a link of adjusting the basis to adjust the derivative of z 2, so as to improve the accuracy of the disturbance estimation. The structure of the LESO before and after modification is shown in FIGS. 3 and 4.
From equation (7):
From the formula (6) and the formula (10):
let e 2＝z2-x2 and establish the improved LESO:
In the method, in the process of the invention, Is the estimated error of the total disturbance f.
The characteristic equation of the improved LESO is:
λ(s)＝s2+(β1+β3)s+β1β3+β2 (13)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
By applying Laplace transformation, the disturbance estimation transfer functions before and after LESO improvement are obtained respectively as follows And/>A bode plot is drawn for the same bandwidth condition as shown in fig. 5. It can be seen that the improved LESO has a higher amplitude gain, a stronger ability to estimate the disturbance, and a significantly improved phase lag.
A feedback control law is designed. For first-order LADRC, the feedback control law is composed of two links, namely a proportional controller and disturbance compensation. The former is responsible for amplifying the error feedback amount and improving the dynamic performance of the system, and the latter is used for compensating disturbance variables estimated by LESO.
According to fig. 2, the control law designed in this embodiment is:
where k p is the proportional control gain, Responsible for counteracting the overall disturbance.
If the LESO is able to estimate the system state well, substituting equation (15) into equation (6) can derive the closed loop transfer function of the entire voltage control loop in fig. 2:
Thus, fast overshoot-free tracking of instructions can be achieved, where k p can also be denoted ω c, representing the controller bandwidth.
And thirdly, constructing double closed-loop control by taking the improved linear active disturbance rejection system as a voltage outer loop and taking the PI controller as a current inner loop, applying the double closed-loop control to a bidirectional DC-DC converter to obtain a double closed-loop linear active disturbance rejection control method of the bidirectional DC-DC converter, and applying the double closed-loop linear active disturbance rejection control method to an independent wind power system. After the voltage given value and the actual value of the direct current bus are processed by the voltage outer ring, an inductance current given value is output, the error of the inductance current given value and the actual value is processed by the current inner ring to obtain a final control signal, and a PWM waveform generator is used for generating a modulation signal, so that the control of the bidirectional DC-DC converter is realized. The linear active disturbance rejection controller improves disturbance observation capability and disturbance rejection of the system, and realizes the stability of direct current bus voltage.
FIG. 6 is a block diagram of an independent wind power system applied in this embodiment, where when the power generated by the distributed power source is excessive, the energy storage system stores the power, and controls the bidirectional DC-DC converter to be in Buck mode, and the power flows from the DC bus to the energy storage system; when the electric energy generated by the distributed power supply is insufficient to meet the load, the energy storage system releases the electric energy to control the bidirectional DC-DC converter to be in a Boost mode, and the energy flows from the energy storage system to the DC bus. The energy storage system throughput energy is controlled to maintain the stability of the voltage of the direct current bus.
The design process of the bidirectional DC-DC converter control method based on the linear active disturbance rejection is verified through a Matlab/Simulink simulation platform. And (3) constructing an independent wind power system through simulation, and comparing the traditional PI, the traditional LADRC and the improved LADRC control method. The parameters of the model are: dc bus voltage U dc＝400V,Rdc＝200Ω,L＝1mH,Cdc＝220μF,Cb = 220 μf. In order to better analyze the tracking and robustness of the dc bus voltage in the two control strategies, the simulation is based on a stepwise analysis in three cases: (1) a start-up procedure under normal operating conditions; (2) transient processes under changes in wind speed; (3) transient process under abrupt load change.
Fig. 7 is a waveform diagram of the dc bus voltage during start-up under normal operating conditions. From fig. 7, it can be seen that the ladc reduces the 54V voltage overshoot, while shortening 0.06s into steady state, as opposed to the conventional PI. The improved LADRC used in this example reduced the voltage overshoot by 25V relative to the conventional LADRC and completed the transient 0.03s earlier. In addition, the improved LADRC has better tracking during start-up because the improved LESO is better able to estimate the high frequency disturbance and pass it on to the control law to compensate, with less noise impact at system steady state.
FIG. 8 is a transient DC bus voltage waveform diagram under the condition of wind speed change, wherein the wind speed is suddenly reduced at 0.5s and suddenly changed from 5m/s to 3m/s; the wind speed suddenly increased at 1s, changing from 3m/s to 5m/s. As can be seen from fig. 8, when the wind speed suddenly decreases, the voltage fluctuation range of the improved ladc is reduced by 12V compared to the conventional ladc; when the wind speed suddenly increases, the voltage fluctuation range of the improved LADRC is reduced by 18V compared with that of the traditional LADRC. Also, the voltage control system that improves the LADRC completes the transient process earlier than the traditional LADRC. LADRC is superior to conventional PI in terms of voltage fluctuation and recovery time. Therefore, the improved LADRC is more advantageous in terms of voltage fluctuation range and recovery time for disturbances caused by changes in external wind speed.
Fig. 9 is a graph of transient dc bus voltage waveforms for a load that is abrupt from 200Ω to 500Ω at 1.5s and from 500Ω to 200Ω at 2 s. As can be seen from fig. 9, the improved ladc is less affected by the sudden load increase, and the voltage fluctuation range of the improved ladc is reduced by 17.5V compared with that of the conventional ladc; the improved LADRC is reduced by 16.4V from the conventional LADRC voltage fluctuation range when the load is suddenly reduced. In addition, the recovery time of the conventional LADRC is 0.1s, while the recovery time of the modified LADRC is only 0.05s, which is 0.05s shorter than that of the conventional LADRC. LADRC is superior to conventional PI in terms of voltage fluctuation and recovery time. Thus, the improved LADRC performs better than conventional PI control and conventional LADRC for disturbances caused by abrupt load changes, both in voltage fluctuation range and recovery time.
The preferred embodiments of the invention disclosed above are intended only to assist in the explanation of the invention. The preferred embodiments are not exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand and utilize the invention. The invention is limited only by the claims and the full scope and equivalents thereof.
Claims (10)
1. The control method of the bidirectional DC-DC converter based on the linear active disturbance rejection is characterized by comprising the following steps of:
s1, establishing a linearization small signal model of a bidirectional DC-DC converter in two working states;
S2, constructing an improved linear active disturbance rejection controller according to a linear small signal model of the bidirectional DC-DC converter;
and S3, applying the improved linear active disturbance rejection controller serving as an outer loop voltage loop and the PI controller serving as an inner loop current loop to the bidirectional DC-DC converter to obtain the double closed loop linear active disturbance rejection control system of the bidirectional DC-DC converter.
2. The method for controlling a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 1, wherein step S1 specifically comprises: based on the bi-directional DC-DC converter, mathematical models are built in Boost mode and Buck mode, respectively.
3. The control method of a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 2, wherein the operation in Boost mode, S 2 as the main switching tube has two switching modes; the state equation of the circuit under one switching period can be obtained according to the state space average method:
when working in the Buck mode, S 1 is used as a main switching tube and has two switching modes; the state equation of the circuit under one switching period can be obtained according to the state space average method:
In the formulas (1) and (2), U CH、UCL is direct current bus side supporting capacitor voltage and energy storage side filtering capacitor voltage respectively, U dc、Ub is direct current bus voltage and storage battery terminal voltage respectively, i L is inductance current, L is inductance value, C dc、Cb is direct current bus side supporting capacitor and energy storage side filtering capacitor respectively, R dc、Rb is direct current bus side equivalent internal resistance and energy storage side equivalent internal resistance respectively, and d Buck、dBoost is duty ratio in Buck and Boost modes respectively;
and respectively obtaining transfer functions from the inductive current to the direct current bus voltage and from the duty ratio to the inductive current according to state space average equations in the two modes.
4. A control method of a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 3, wherein a small signal disturbance is introduced in a switching period, and the transfer function in Boost mode is obtained by simplifying the formula (1):
wherein, I L is the steady state value of the inductance current;
Transfer function in Buck mode is similarly available:
5. the method for controlling a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 4, wherein step S2 specifically comprises: the LADRC defines the external disturbance and the parameter uncertainty as the total disturbance, and builds a LADRC differential equation.
6. The method of claim 5, wherein, taking a Buck mode as an example, the equation (4) is expressed as a first-order integral form with total disturbance:
In the method, in the process of the invention, Is the total disturbance;
Defining a state variable x 1＝Udc,x2 =f; then equation (5) can be described by a state space expression:
Where u=i L≈iL *, u is the control input and b 0 is the control gain.
7. The method for controlling a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 6, wherein a mathematical model of a linear extended state observer is built; according to equation (6), LESO is established in combination with the Luenberger state observer design principle:
Wherein e 1 is an estimation error of the DC bus voltage, z 1,z2 is a state estimation value of the DC bus voltage and the total disturbance, and beta 1,β2 is an observer gain;
based on the total disturbance and LESO, introducing a bandwidth of a system observer, and selecting LESO parameters;
The characteristic equation of the LESO is:
λ(s)＝s2+β1s+β2 (8)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
Where ω 0 is observer bandwidth;
designing a feedback control law:
For the first-order LADRC, the feedback control law essence consists of two links of a proportional controller and disturbance compensation; the control law is designed as follows:
where k p is the proportional control gain, Is responsible for counteracting the overall disturbance;
if the LESO is able to estimate the system state well, substituting equation (10) into equation (6) one can derive the closed loop transfer function of the entire voltage control loop:
Thus, fast overshoot-free tracking of instructions can be achieved, where k p can also be denoted ω c, representing the controller bandwidth.
8. The method for controlling a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 7, wherein in step S2, the following is obtained according to formula (7):
from the formula (6) and the formula (12):
let e 2＝z2-x2 and establish the improved LESO:
In the method, in the process of the invention, Is the estimated error of the total disturbance f.
9. The method for controlling a bi-directional DC-DC converter based on linear active disturbance rejection according to claim 8, wherein the characteristic equation of the modified LESO is:
λ(s)＝s2+(β1+β3)s+β1β3+β2 (15)
Based on the pole allocation technology, an ideal characteristic equation lambda(s) = (s+ω 0)2 is selected:
10. The method for controlling a bidirectional DC-DC converter based on linear active disturbance rejection according to claim 9, wherein in step S3, the improved linear active disturbance rejection controller is used as an outer loop voltage loop and the PI controller is used as an inner loop current loop; after the voltage given value and the actual value of the direct current bus are processed by the voltage outer ring, an inductance current given value is output, the error of the inductance current given value and the actual value is processed by the current inner ring to obtain a final control signal, and a PWM waveform generator is used for generating a modulation signal, so that the control of the bidirectional DC-DC converter is realized.
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