A power supply system for a pulse load and a control method thereof
By employing voltage source and current source converter topologies in a pulse load power supply system, combined with open-loop judgment and closed-loop control of switching duty cycle and extended Kalman filtering algorithm, the problems of large bus voltage ripple and slow response speed in traditional power supply systems are solved, achieving rapid response to pulse loads and improving system stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-23
AI Technical Summary
In traditional pulse load power supply systems, the pulse power output response speed of the energy storage capacitor is limited, resulting in increased bus voltage ripple and insufficient load response speed, which affects the stability and reliability of the system.
A voltage source converter and a current source converter topology are adopted. By combining open-loop judgment and closed-loop control of the switching duty cycle, the extended Kalman filter algorithm is used to predict the pulse load current, and the switching control signal of the DC-DC converter is optimized by PI control to achieve fast response to pulse loads.
It effectively reduces DC bus voltage ripple, improves the response speed of pulse loads and the stability of the system, and enhances the reliability of the power supply system.
Smart Images
Figure CN122267702A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of DC microgrid technology, specifically relating to a power supply system and control method for pulse loads. Background Technology
[0002] In recent years, with the development of DC microgrid technology, high-power electrical loads have become increasingly diversified in fields such as new energy vehicles, all-electric aircraft, and ships. Among these, pulse loads in DC microgrids place higher demands on the load response speed, bus voltage accuracy, system stability, and reliability of the power supply system. Therefore, designing suitable power supply schemes for pulse loads, reducing bus voltage ripple caused by pulse loads, improving load response speed, and ensuring the reliability of system equipment are of great significance.
[0003] Traditional pulse load power supply systems employ a topology where a bidirectional DC-DC converter is connected in parallel with an energy storage capacitor on the DC bus. The pulse power output response speed of this system is limited by the control bandwidth of the bidirectional DC-DC converter. Furthermore, maintaining a dynamic voltage balance within the energy storage capacitor during pulse power output control further restricts the pulse power response speed. When the pulse power response speed is limited, the DC bus will provide a portion of the pulse power, leading to increased bus voltage ripple. Therefore, a pulse load power supply system that reduces bus voltage ripple is urgently needed. Summary of the Invention
[0004] To address the problems in the prior art, this invention provides a power supply system and control method for pulse loads.
[0005] The technical solution of the present invention is as follows:
[0006] In a first aspect, the present invention discloses a power supply system for a pulsed load, comprising a main power supply, a pulsed power supply, two DC-DC converters, and a DC bus; wherein the DC bus is connected to an external pulsed load, the main power supply is connected to the DC bus through a first DC-DC converter to provide the DC bus with a constant power current component required by the pulsed load, and the pulsed power supply is connected to the DC bus through a second DC-DC converter to provide the DC bus with a pulsed power current component required by the pulsed load;
[0007] At the beginning of each control cycle of the DC-DC converter, the output voltage of the first DC-DC converter, the inductor current value of each DC-DC converter, and the current of the pulse load are collected. The preset DC bus reference voltage is subtracted from the output voltage, and the first inductor current reference is obtained through PI control. Based on the first inductor current reference value and the inductor current value of the first DC-DC converter, the control signals of each switch in the first DC / DC converter are obtained and corresponding control is performed. At the same time, based on the current of the pulse load, the pulse load reference current, the upper limit value and the lower limit value of the pulse load reference current are obtained using extended Kalman filtering. Then, combined with the inductor current value of the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained and corresponding control is performed to realize the power supply to the pulse load.
[0008] Furthermore, the DC-DC converter includes an inductor, an inductor parasitic resistor, a first switch, a second switch, an output capacitor, and an output capacitor parasitic resistor. One end of the inductor is connected to the main power supply or the pulse power supply, and the other end of the inductor is connected to one end of the inductor parasitic resistor. The other end of the inductor parasitic resistor is connected to the input terminal of the first switch and the output terminal of the second switch, respectively. The input terminal of the second switch is connected to one end of the output capacitor parasitic resistor, and the other end of the output capacitor parasitic resistor is connected to one end of the output capacitor. The other end of the output capacitor is connected in parallel with the output terminal of the first switch and connected to the main power supply or the pulse power supply.
[0009] Further, obtaining the control signals for each switch in the first DC / DC converter includes:
[0010] Based on the difference between the first inductor current reference value and the inductor current value of the first DC-DC converter, the duty cycle of each switch in the first DC-DC converter is obtained through PI control. Then, based on the obtained duty cycle, the control signal of each switch in the first DC-DC converter is obtained through a control signal modulation method.
[0011] Further, obtaining the control signals for each switch in the second DC-DC converter includes:
[0012] First, the error between the pulse load reference current and the inductor current of the second DC-DC converter is calculated. Then, based on the relationship between this error and the upper and lower limits of the pulse load reference current, the duty cycle of the second switch of the second DC-DC converter is determined. Subsequently, the duty cycle of the first switch of the second DC-DC converter is determined based on the duty cycle of the second switch. Finally, based on the duty cycles of each switch in the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained through a control signal modulation method. The duty cycle of the first switch of the second DC / DC converter is 1 minus the duty cycle of the second switch of the second DC / DC converter.
[0013] Secondly, the present invention also discloses a control method utilizing the system, comprising the following steps:
[0014] At the beginning of each control cycle of the DC-DC converter, the output voltage of the first DC-DC converter, the inductor current value of each DC-DC converter, and the current of the pulse load are collected.
[0015] The difference between the preset DC bus reference voltage and the output voltage is calculated, and then the first inductor current reference value is obtained through PI control. The difference between the first inductor current reference value and the inductor current value of the first DC-DC converter is calculated, and then the control signals of each switch in the first DC / DC converter are obtained and corresponding control is performed.
[0016] Simultaneously, the pulse load current collected at the beginning of the k-th control cycle is used as the actual pulse load current observation value of the k-th control cycle. Then, based on the measurement-updated and corrected state estimate value of the (k-1)-th control cycle, the state prediction value of the current k-th control cycle based on the (k-1)-th control cycle is obtained. Then, based on the state prediction value and the actual pulse load current observation value, the measurement-updated and corrected state estimate value of the k-th control cycle is obtained. After that, based on the state vector corresponding to the measurement-updated and corrected state estimate value, the upper limit and lower limit values of the pulse reference current and pulse load reference current of the k-th control cycle are obtained. Then, combined with the inductor current value of the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained and corresponding control is performed to realize the power supply to the pulse load.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0018] 1. The present invention proposes a power supply system and control method for pulse loads, which adopts a topology of voltage source converter in parallel with current source converter to supply power to the pulse load. The current source converter adopts a combination of open-loop judgment of switch duty cycle and closed-loop control, which overcomes the problem of limited response speed and pulse load current coupling in the traditional current loop PI control method, thereby reducing the DC bus voltage ripple in complex power supply systems.
[0019] 2. This invention proposes a reference current generation algorithm based on extended Kalman filtering. The algorithm predicts and calculates the estimated value of the next cycle based on the extended Kalman filtering algorithm, which is used as the reference current for the pulse load. The input inductor current pulse control algorithm can further improve the response speed of the pulse power supply to the pulse load current and further reduce the DC bus voltage ripple in the pulse load power supply system. Attached Figure Description
[0020] Figure 1This is a structural block diagram of the power supply system for pulse loads according to the present invention.
[0021] Figure 2 This is a flowchart of the method for obtaining the duty cycle of each switch in the second DC-DC converter according to the present invention.
[0022] Figure 3 This is a flowchart of the method for obtaining the pulse load reference current, the upper limit value and the lower limit value of the pulse load reference current in this invention.
[0023] Figure 4 This is a waveform comparison diagram of the pulse load reference current and the inductor current value of the second DC-DC converter in this invention.
[0024] Figure 5 This is a waveform diagram showing the duty cycle of the second switch in the second DC / DC converter of the present invention.
[0025] Figure 6 This is a waveform diagram of the current output by the second DC-DC converter in this invention.
[0026] Figure 7 This is a waveform diagram of the current output by the first DC-DC converter in this invention. Detailed Implementation
[0027] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.
[0028] To reduce bus voltage ripple, this invention employs a topology that connects a voltage source converter in parallel with a current source converter to power the pulsed load. The conventional control method for this topology involves the voltage source converter using a dual-loop control of voltage and current to control the bus voltage, while the current source converter uses a single-loop control of inductor current to output the pulsed load. However, in this conventional control method, the pulse current output response speed of the current source converter is still limited by the control loop bandwidth; moreover, the pulse reference current of the current source converter typically filters the load current through a low-pass filter or similar means, failing to completely decouple the pulsed load, resulting in still relatively large bus voltage ripple.
[0029] To address the aforementioned problems, this invention proposes a pulse current control method that combines open-loop determination of the switch duty cycle with closed-loop control to improve the response speed of the current source converter to pulse loads. Furthermore, for periodic pulse load modeling, based on the extended Kalman filter algorithm, the pulse current component of the pulse load in the next control cycle is predicted and estimated, serving as the pulse load reference current I. refThis can further improve the response speed of the pulse power supply to the pulse current and effectively reduce the DC bus voltage ripple in the pulse load power supply system.
[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0031] like Figure 1 As shown, the power supply system for pulsed loads in this embodiment includes a main power supply, a pulsed power supply, and a first DC-DC converter connected to the main power supply (i.e., Figure 1 The DC-DC converter 1 in the middle, and the second DC-DC converter connected to the pulse power supply (i.e. Figure 1 The DC-DC converter 2) is connected in parallel with the first DC-DC converter and the DC bus. That is, the DC bus is connected to an external pulse load. The main power supply is connected to the DC bus through the first DC-DC converter to provide the DC bus with the constant power current component required by the pulse load; the pulse power supply is connected to the DC bus through the second DC-DC converter to provide the DC bus with the pulse power current component required by the pulse load.
[0032] The first and second DC-DC converters have the same structure. Each DC-DC converter includes an inductor, an inductor parasitic resistor, a first switch, a second switch, an output capacitor, and an output capacitor parasitic resistor. One end of the inductor is connected to the main power supply or pulse power supply, and the other end of the inductor is connected to one end of the inductor parasitic resistor. The other end of the inductor parasitic resistor is connected to the input terminal of the first switch and the output terminal of the second switch. The input terminal of the second switch is connected to one end of the output capacitor parasitic resistor, and the other end of the output capacitor parasitic resistor is connected to one end of the output capacitor. The other end of the output capacitor is connected in parallel with the output terminal of the first switch and connected to the main power supply or pulse power supply. Wherein, Figure 1 In the first DC-DC converter, the inductor is represented by L1, and the parasitic resistance of the inductor is represented by R. L1 This indicates that the first switch is represented by S1-1, the second switch by S1-2, and the parasitic resistance of the output capacitor is represented by R. C1 This indicates that the output capacitor is represented by C1. Figure 1 In the second DC-DC converter, the inductor is represented by L2, and the parasitic resistance of the inductor is represented by R. L2 This indicates that the first switch is represented by S2-1, the second switch by S2-2, and the parasitic resistance of the output capacitor is represented by R. C2 The output capacitor is represented by C2.
[0033] in, Figure 1 L in line1 and R line1L represents the parasitic inductance and parasitic resistance on the connection line between the first DC-DC converter and the DC bus. line2 and R line2 The parasitic inductance and parasitic resistance are on the connection line between the second DC-DC converter and the DC bus. Figure 1 C in Bus For DC bus capacitance, V bus This is the voltage of the DC bus capacitor.
[0034] The power supply system further includes control circuits for a first DC-DC converter and a second DC-DC converter; the control circuit for the first DC-DC converter includes a voltage controller, a current controller, and a first control signal modulator, and the control circuit for the second DC-DC converter includes a current reference value I. ref The system includes a generation unit, an inductor current pulse control algorithm unit, and a second control signal modulator.
[0035] At the beginning of each control cycle of the DC-DC converter, the output voltage v of the first DC-DC converter is acquired in real time. o1 The inductor current value i of the first DC-DC converter L1 The inductor current value i of the second DC-DC converter L2 and the current i of the pulse load Load Set the preset DC bus reference voltage V ref With output voltage v o1 The difference is calculated, and then input to the voltage controller for PI control to generate the inductor current reference value (i.e., the first inductor current reference value) of the first DC-DC converter. L1ref Then compare the inductor current reference value with the inductor current value i. L1 The difference is calculated, and then input into the current controller for PI control to obtain the duty cycle of each switch in the first DC-DC converter. Subsequently, based on the obtained duty cycle, the first control signal modulator generates control signals for each switch in the first DC-DC converter and performs corresponding control. The main purpose of the control circuit of the first DC-DC converter is to control the voltage V of the DC bus capacitor. bus Equal to the constant preset DC bus reference voltage V ref At the same time, it provides a constant power current component for the pulsed load.
[0036] Simultaneously, the current i of the pulse load... Load Input to the current reference value I based on the extended Kalman filter ref Generating unit, current reference value I ref The generator unit outputs a pulse load reference current I. ref Upper limit of pulse load reference current I ref-High The lower limit I of the pulse load reference currentref-Low The inductor current pulse control algorithm unit receives the inductor current value i from the second DC-DC converter. L2 Finally, the inductor current pulse control algorithm unit outputs the duty cycle of each switch in the second DC-DC converter. Based on the obtained duty cycle, the second control signal modulator generates control signals for each switch in the second DC-DC converter and performs corresponding control to complete the power supply to the pulse load. The main purpose of the control circuit of the second DC-DC converter is to output the pulse current portion of the pulse load through the inductor current pulse control algorithm, effectively improve the load output response speed, and effectively reduce the DC bus voltage ripple in the power supply system. In this embodiment, the flowchart of the method for generating control signals for each switch in the second DC-DC converter is as follows: Figure 2 As shown, the method includes:
[0037] 1) At the beginning of each control cycle of the DC-DC converter, the inductor current value i of the second DC-DC converter is acquired in real time. L2 and the current i of the pulse load Load .
[0038] 2) The current i of the pulse load Load Input to the current reference value I based on the extended Kalman filter ref Generating unit, current reference value I ref The generation unit generates a pulse load reference current I. ref Upper limit of pulse load reference current I ref-High The lower limit I of the pulse load reference current ref-Low And output it.
[0039] 3) The inductor current pulse control algorithm unit receives the pulse load reference current I. ref Upper limit of pulse load reference current I ref-High The lower limit of the pulse load reference current I ref-Low and the inductor current value i of the second DC-DC converter L2 Output the duty cycle of each switch in the second DC-DC converter.
[0040] Specifically: The inductor current pulse control algorithm unit first calculates the pulse load reference current I. ref The inductor current value i of the second DC-DC converter L2 Error value between :
[0041]
[0042] Then based on the pulse load reference current I refThe inductor current value i of the second DC-DC converter L2 and error value Determine the control mode:
[0043] Determine the pulse load reference current I ref Is it the upper limit value I? ref-High Lower limit value I ref-Low Or somewhere in between; if the pulse load reference current I ref Equal to the lower limit value I ref-Low If so, the control mode is fast discharge mode (Control_mode=0).
[0044] If the pulse load reference current I ref Equal to the upper limit value I ref-High And the inductor current value i of the second DC-DC converter L2 Less than 98% of the pulse load reference current I ref If so, the control mode is fast charging mode (Control_mode=2).
[0045] If the pulse load reference current I ref Equal to the upper limit value I ref-High And the inductor current value i of the second DC-DC converter L2 The pulse load reference current I is greater than or equal to 98%. ref If so, the control mode is constant current control mode (Control_mode=1).
[0046] If the pulse load reference current I ref At the upper limit value I ref-High With lower limit value I ref-Low Between, i.e., I ref-Low ref ref-High And error value Less than the upper limit of -10% I ref-High That is, Error < -10%I ref-High If so, the control mode is fast discharge mode (Control_mode=0).
[0047] If the pulse load reference current I ref At the upper limit value I ref-High With lower limit value I ref-Low Between, i.e., I ref-Low ref ref-High And error value The upper limit I is greater than 10%. ref-High That is, Error > 10% ref-High If so, the control mode is fast charging mode (Control_mode=2).
[0048] If the pulse load reference current I ref At the upper limit value I ref-High With lower limit value I ref-Low Between, i.e., I ref-Low ref ref-High And error value The upper limit I is greater than or equal to -10%. ref-High and less than or equal to the upper limit value I of 10% ref-High , that is -10%I ref-High ≤Error≤10%I ref-High If so, the control mode is constant current control mode (Control_mode=1).
[0049] Then, based on the control mode, set the duty cycle of the second switch of the second DC / DC converter. :
[0050]
[0051] in, This is the lower limit of the duty cycle, which is the preset value; This is the maximum allowable value for the duty cycle, which is the preset value; The proportional coefficient for the current controller using PI control; The integral coefficient for PI control is used for current control; The sampling frequency; This is the error value corresponding to the kth control cycle in the inductor current pulse control algorithm. This represents the sum of error values from the first control cycle to the kth control cycle.
[0052] Then, based on the duty cycle of the second switch of the second DC / DC converter Calculate the duty cycle of the first switch of the second DC / DC converter. Its duty cycle is: Finally, based on the obtained duty cycle, the control signals for each switch in the second DC / DC converter are generated by the second control signal modulator and controlled accordingly.
[0053] In this embodiment, the current reference value I of the present invention ref The algorithm flowchart for generating units is as follows: Figure 3 As shown, the algorithm flow includes:
[0054] In the first control cycle, initialization is performed first, that is, the posterior estimation error covariance matrix of the 0th control cycle is initialized. ; and set the state estimate after measurement update correction for the 0th control cycle. .
[0055] The state vector of the pulsed load current includes information such as the constant power current component, pulse amplitude, pulse phase, pulse frequency, and duty cycle modulation amplitude and phase. The pulsed load current state vector is modeled as follows:
[0056]
[0057] in, This is the state vector of the pulse load current during the kth control cycle; This represents the first component of the state vector of the pulse load current during the k-th control cycle. , This represents the constant power current component of the pulse load current during the k-th control cycle. This is the second component of the state vector of the pulse load current during the k-th control cycle. , The pulse current amplitude of the pulse load current during the k-th control cycle; This is the third component of the state vector of the pulse load current during the k-th control cycle. Let be the pulse phase of the pulse load current during the k-th control cycle. ; This is the fourth component of the state vector of the pulse load current during the k-th control cycle. , The pulse frequency of the pulse load current during the k-th control cycle; This is the fifth component of the state vector of the pulse load current during the k-th control cycle. Let be the duty cycle modulation amplitude of the pulse load current during the k-th control cycle. ; This is the sixth component of the state vector of the pulse load current during the k-th control cycle. The duty cycle modulation phase of the pulse load current during the k-th control cycle. .
[0058] Meanwhile, the pulse load reference current I is calculated for each control cycle. ref Upper limit of pulse load reference current I ref-High The lower limit I of the pulse load reference current ref-Low Previously, the pulse load current i was collected at the beginning of the k-th control cycle. Load The actual pulse load current observation value for the k-th control cycle is given by the equation for the actual pulse load current observation value:
[0059]
[0060]
[0061] in, This represents the actual pulse load current observation value during the k-th control cycle; State vector The observation function; It is a pulse function; To measure noise, it is a Gaussian function with mean 0 and covariance R, i.e. .
[0062] Calculate the pulse load reference current I in the k-th control cycle. ref Upper limit of pulse load reference current I ref-High The lower limit I of the pulse load reference current ref-Low First, calculate the state prediction value of the k-th control cycle based on the (k-1)-th control cycle. :
[0063]
[0064] in, The updated and corrected state estimate is the measurement value for the (k-1)th control cycle. This is the state transition function; Let Q be the process noise matrix. The process noise matrix is a Gaussian function with a mean of 0 and a covariance of Q, i.e. .
[0065] Then calculate the state transition Jacobian matrix for the kth control cycle. :
[0066]
[0067] in, Find the partial derivative of the state transition function with respect to the state vector.
[0068] Next, we calculate the prior estimation error covariance matrix obtained from the (k-1)th control cycle for the kth control cycle. :
[0069]
[0070] in, Q is the posterior estimation error covariance matrix for the (k-1)th control cycle; Q is the process noise covariance matrix. It is the transpose of the state transition Jacobian matrix for the k-th control cycle.
[0071] Then based on the state prediction value Calculate the predicted values for the k-th control period based on the observations of the (k-1)-th control period. :
[0072]
[0073] Based on the state prediction value Calculate the observation Jacobian matrix for the k-th control period. :
[0074]
[0075] in, For the observation function to the state vector Find the partial derivative.
[0076] Subsequently, based on actual pulse load current observations and observed predicted values Calculate the new information for the k-th control period :
[0077]
[0078] Then based on the observed Jacobian matrix and the prior estimation error covariance matrix Calculate the new information covariance for the kth control period. :
[0079]
[0080] in, To measure the noise covariance matrix; This is the transpose of the observation Jacobian matrix for the k-th control period.
[0081] Subsequently, based on the new information covariance Prior estimation error covariance matrix and the observed Jacobian matrix Calculate the Kalman gain in the kth control cycle. :
[0082]
[0083] in, It is the inverse of the information covariance matrix for the k-th control period.
[0084] Therefore, the state estimate after measurement update and correction in the k-th control cycle can be obtained. :
[0085]
[0086] Then, based on the prior estimation error covariance matrix Observation of the Jacobian matrix and Kalman gain Calculate the posterior estimation error covariance matrix for the k-th control cycle. :
[0087]
[0088] in, It is an identity matrix.
[0089] Finally, the state estimate is updated and corrected based on the measurement. get
[0090] The pulse reference current estimate for the kth control cycle :
[0091]
[0092] in, To measure the updated and corrected state estimate The second component of the corresponding state vector; To measure the updated and corrected state estimate The third component of the corresponding state vector; To measure the updated and corrected state estimate The fifth component of the corresponding state vector; To measure the updated and corrected state estimate The sixth component of the corresponding state vector.
[0093] Measure the updated and corrected state estimate The corresponding state vector is:
[0094]
[0095] in, The constant power current component of the state estimate after measurement update and correction in the k-th control cycle, i.e., the first component. ; The pulse current amplitude, i.e., the second component, is the state estimate updated and corrected by measurements over k control cycles. ; The pulse phase of the state estimate after measurement update and correction for k control cycles, i.e., the third component. ; The pulse frequency of the state estimate after measurement update correction for k control cycles, i.e., the fourth component. ; The duty cycle modulation amplitude of the state estimate after measurement update and correction for k control cycles, i.e., the fifth component. ; The duty cycle modulation phase of the state estimate after measurement update and correction for k control cycles, i.e., the sixth component. .
[0096] In summary, the pulse load reference current I in the kth control cycle ref Equal to the pulse reference current estimate The upper limit value I of the pulse load reference current in the kth control cycle ref-High Equal to the measured updated and corrected state estimate The second component of the corresponding state vector The lower limit of the pulse load reference current I ref-Low It equals the minimum value of the pulse load reference current, which is approximately 0.
[0097] In one embodiment of the present invention, the voltage of the pulse load is constant at V. bus The pulsed load current can be regarded as the superposition of the constant power current component and the pulsed power current component.
[0098] Based on the current reference value I ref The generation unit algorithm can obtain the pulse load reference current I. ref The waveform is as follows Figure 4 As shown, for periodic pulse load modeling, based on the extended Kalman filter algorithm, the pulse current component (i.e., pulse power current component) of the pulse load in the next control cycle is predicted and estimated, and used as the pulse load reference current I. ref The output can further improve the response speed of the pulse power supply to pulse current.
[0099] Based on the pulse load reference current I ref The inductor current value i of the second DC-DC converter L2 and error value In the logic that determines the duty cycle of each switch in the second DC-DC converter, when the pulse load reference current I... ref Upper limit value I ref-High And the inductor current value i of the second DC-DC converter L2 Less than 98% of the pulse load reference current I ref At that time, the duty cycle of the second switch of the second DC / DC converter is adjusted. The duty cycle is set to a preset upper limit, causing the inductor current to increase at its maximum rate of increase to near the upper limit of the pulse load reference current, thus achieving a fast response to the pulse load current; when the pulse load reference current I... ref Upper limit value I ref-HighAnd the inductor current value i of the second DC-DC converter L2 Greater than 98% of the pulse load reference current I ref At that time, the duty cycle of the second switch of the second DC / DC converter PI control enables output current with a small steady-state error; when the pulse load reference current I... ref Lower limit I ref-Low The duty cycle of the second switch of the second DC / DC converter The duty cycle is set to a preset lower limit, causing the inductor current to decrease at the maximum rate of decrease to near the lower limit of the pulse reference current; the duty cycle output by the inductor current pulse control algorithm unit... like Figure 5 As shown, the inductor current value i of the second DC-DC converter L2 like Figure 4 As shown.
[0100] In this embodiment, the pulse current control method combining open-loop judgment and closed-loop control can achieve rapid response to pulse loads, controlling the output current of the second DC-DC converter to be the pulse load current component, effectively reducing the bus voltage ripple caused by the pulse load, and the output current i of the second DC-DC converter... o2 like Figure 6 As shown, this represents the pulse current. The first DC-DC converter uses a dual-loop PI control for both voltage and current, maintaining a constant output voltage. Therefore, the output current is also the constant current component of the pulse load. The current i output by the first DC-DC converter is... o1 like Figure 7 As shown, this represents the constant current component of the pulsed load.
[0101] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.
Claims
1. A power supply system for pulsed loads, characterized in that, It includes a main power supply, a pulse power supply, two DC-DC converters, and a DC bus; wherein, the DC bus is connected to an external pulse load, the main power supply is connected to the DC bus through the first DC-DC converter to provide the DC bus with the constant power current component required by the pulse load; the pulse power supply is connected to the DC bus through the second DC-DC converter to provide the DC bus with the pulse power current component required by the pulse load. At the beginning of each control cycle of the DC-DC converter, the output voltage of the first DC-DC converter, the inductor current value of each DC-DC converter, and the current of the pulse load are collected. The preset DC bus reference voltage is subtracted from the output voltage, and the first inductor current reference is obtained through PI control. Based on the first inductor current reference value and the inductor current value of the first DC-DC converter, the control signals of each switch in the first DC / DC converter are obtained and corresponding control is performed. At the same time, based on the current of the pulse load, the pulse load reference current, the upper limit value and the lower limit value of the pulse load reference current are obtained using extended Kalman filtering. Then, combined with the inductor current value of the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained and corresponding control is performed to realize the power supply to the pulse load.
2. The power supply system according to claim 1, characterized in that, The DC-DC converter includes an inductor, an inductor parasitic resistor, a first switch, a second switch, an output capacitor, and an output capacitor parasitic resistor. One end of the inductor is connected to the main power supply or a pulse power supply, and the other end of the inductor is connected to one end of the inductor parasitic resistor. The other end of the inductor parasitic resistor is connected to the input terminal of the first switch and the output terminal of the second switch. The input terminal of the second switch is connected to one end of the output capacitor parasitic resistor, and the other end of the output capacitor parasitic resistor is connected to one end of the output capacitor. The other end of the output capacitor is connected in parallel with the output terminal of the first switch to the main power supply or the pulse power supply.
3. The power supply system for pulse loads according to claim 2, characterized in that, The process of obtaining control signals for each switch in the first DC / DC converter includes: Based on the difference between the first inductor current reference value and the inductor current value of the first DC-DC converter, the duty cycle of each switch in the first DC-DC converter is obtained through PI control. Then, based on the obtained duty cycle, the control signal of each switch in the first DC-DC converter is obtained through a control signal modulation method.
4. The power supply system according to claim 3, characterized in that, The process of obtaining control signals for each switch in the second DC-DC converter includes: First, the error between the pulse load reference current and the inductor current of the second DC-DC converter is calculated. Then, based on the relationship between this error and the upper and lower limits of the pulse load reference current, the duty cycle of the second switch of the second DC-DC converter is determined. Subsequently, the duty cycle of the first switch of the second DC-DC converter is determined based on the duty cycle of the second switch. Finally, based on the duty cycles of each switch in the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained through a control signal modulation method. The duty cycle of the first switch of the second DC / DC converter is 1 minus the duty cycle of the second switch of the second DC / DC converter.
5. The power supply system according to claim 4, characterized in that, Determining the duty cycle of the second switch of the second DC-DC converter includes: If the pulse load reference current is equal to the lower limit value, then the duty cycle of the second switch is the preset allowable lower limit value of the duty cycle; If the pulse load reference current is equal to the upper limit value, and the inductor current value of the second DC-DC converter is less than 98% of the pulse load reference current, then the duty cycle of the second switch is the preset upper limit value of the duty cycle. If the pulse load reference current is equal to the upper limit value, and the inductor current value of the second DC-DC converter is greater than or equal to 98% of the pulse load reference current, then the duty cycle of the second switch is: ； in, and These are the proportional and integral coefficients for the PI control of each switch duty cycle in the first DC-DC converter, respectively. This represents the error value corresponding to the current k-th control cycle. The sampling frequency; This is the sum of the error values from the first control cycle to the kth control cycle; If the pulse load reference current is between the upper limit and the lower limit, and the error value is less than the upper limit of -10%, then the duty cycle of the second switch is the preset allowable lower limit of the duty cycle. If the pulse load reference current is between the upper and lower limits, and the error value is greater than or equal to -10% of the upper limit and less than or equal to 10% of the upper limit, then the duty cycle of the second switch is: ; If the pulse load reference current is between the upper and lower limits and the error value is greater than the upper limit of 10%, then the duty cycle of the second switch is the preset upper limit of the duty cycle.
6. The power supply system according to claim 1, characterized in that, The process of obtaining the pulse load reference current and its upper and lower limits includes: 1) Based on the measurement-updated and corrected state estimate of the (k-1)th control period, obtain the state prediction value of the current k-th control period based on the (k-1)th control period, and then obtain the prior estimation error covariance matrix, the observation prediction value, and the observation Jacobian matrix of the k-th control period obtained based on the (k-1)th control period. 2) The pulse load current collected at the beginning of the kth control cycle is used as the actual pulse load current observation value of the kth control cycle, and then combined with the result of step 1) to obtain the measurement-updated and corrected state estimate value of the kth control cycle. 3) Based on the state vector corresponding to the state estimate value in step 2), obtain the pulse reference current estimate value for the kth control cycle. Use this pulse reference current estimate value as the pulse load reference current for the kth control cycle. Use the second component of the state vector corresponding to the state estimate value in step 2) as the upper limit value of the pulse load reference current for the kth control cycle. Finally, set the lower limit value of the pulse load reference current for the kth control cycle to 0.
7. The power supply system according to claim 6, characterized in that, In step 1), the state estimate value after measurement update correction in the 0th control cycle is the preset value; Obtaining the prior estimation error covariance matrix includes: firstly, obtaining the state transition Jacobian matrix for the k-th control cycle based on the state prediction value; then, obtaining the prior estimation error covariance matrix based on the state transition Jacobian matrix and the posterior estimation error covariance matrix for the (k-1)-th control cycle; wherein, the posterior estimation error covariance matrix for the 0-th control cycle is a preset value.
8. The power supply system according to claim 6, characterized in that, In step 2), the state estimate after measurement update and correction for the k-th control cycle is obtained, including: First, the pulse reference current estimate and the observation prediction value from step 1) are used to obtain the innovation for the k-th control cycle. Then, the innovation covariance for the k-th control cycle is calculated based on the observation Jacobian matrix and the prior estimation error covariance matrix from step 1). Next, the Kalman gain for the k-th control cycle is obtained based on the innovation covariance, the prior estimation error covariance matrix, and the observation Jacobian matrix. Finally, the state estimate after measurement update correction for the k-th control cycle is obtained based on the state prediction value, the Kalman gain, and the innovation. After obtaining the state estimate, the posterior estimation error covariance matrix for the kth control cycle is also obtained based on the prior estimation error covariance matrix, the observation Jacobian matrix, and the Kalman gain.
9. The power supply system for pulse loads according to claim 6, characterized in that, In step 3), the state vector corresponding to the measured updated and corrected state estimate in the k-th control cycle is: ； in, The constant power current component of the state estimate after measurement update and correction for the k-th control cycle; The pulse current amplitude, i.e., the second component, is the state estimate updated and corrected by measurements over k control cycles. The pulse phase of the state estimate after measurement update correction for k control cycles; The pulse frequency of the measured state estimate after correction for k control cycles; The duty cycle modulation amplitude is the state estimate value updated and corrected for k control cycles. The duty cycle modulation phase is used to update the corrected state estimate for k control cycles. The estimated pulse reference current value for the k-th control cycle is: ； in, It is an impulse function.
10. A control method using the system according to any one of claims 1-9, characterized in that, Includes the following steps: At the beginning of each control cycle of the DC-DC converter, the output voltage of the first DC-DC converter, the inductor current value of each DC-DC converter, and the current of the pulse load are collected. The difference between the preset DC bus reference voltage and the output voltage is calculated, and then the first inductor current reference value is obtained through PI control. The difference between the first inductor current reference value and the inductor current value of the first DC-DC converter is calculated, and then the control signals of each switch in the first DC / DC converter are obtained and corresponding control is performed. Simultaneously, the pulse load current collected at the beginning of the k-th control cycle is used as the actual pulse load current observation value of the k-th control cycle. Then, based on the measurement-updated and corrected state estimate value of the (k-1)-th control cycle, the state prediction value of the current k-th control cycle based on the (k-1)-th control cycle is obtained. Then, based on the state prediction value and the actual pulse load current observation value, the measurement-updated and corrected state estimate value of the k-th control cycle is obtained. After that, based on the state vector corresponding to the measurement-updated and corrected state estimate value, the upper limit and lower limit values of the pulse reference current and pulse load reference current of the k-th control cycle are obtained. Then, combined with the inductor current value of the second DC-DC converter, the control signals of each switch in the second DC-DC converter are obtained and corresponding control is performed to realize the power supply to the pulse load.