Direct power decoupling control method for pulse load power supply

Abstract

The invention belongs to the technical field of power supplies, and particularly relates to a direct power decoupling control method for a pulse load power supply. A pulse load power supply is a two-stage power supply, a front-stage converter is a dual-active-bridge converter, a rear-stage converter is a two-phase interleaved parallel synchronous rectification BUCK converter, an intermediate decoupling capacitor is connected in parallel between the two-stage converters, only average power is provided by controlling the front-stage DAB converter, pulse power is provided by the rear-stage BUCK converter through the intermediate decoupling capacitor, and the pulse load power supply is realized. The pulse load power and the average power are completely decoupled; meanwhile, the provided control method can adapt to the wide input voltage range of the direct-current bus, and input current fluctuation is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of power supplies, and particularly relates to a direct power decoupling control method for a pulse load power supply. Background Art

[0002] With the continuous development of spacecraft, there are more and more pulse load devices, such as phased array radars, synthetic aperture radars, electromagnetic pulse weapons, etc. As Figure 1 shown, the power of the pulse load consists of average power and pulsating power, and has the characteristics of high peak-to-average ratio and rapid change. Directly connecting to the spacecraft DC bus will cause bus voltage fluctuations, reduce the power quality of the power supply system, and even endanger the safe and stable operation of the spacecraft.

[0003] To reduce the impact of the strong pulse characteristics of the pulse load on the DC bus, a pulse load power supply is usually used as an interface converter, and passive devices in the pulse load power supply, such as supercapacitors, are used to provide pulsating power, and the DC bus provides average power to suppress DC bus voltage fluctuations and improve system stability.

[0004] However, the current control strategy of the pulse load power supply is difficult to adapt to the wide input voltage range of the spacecraft power DC bus and the strong pulse characteristics of the load. If the DC bus voltage fluctuates violently, the existing decoupling control strategy is difficult to maintain the output voltage stable and suppress the input current fluctuation. Summary of the Invention

[0005] In view of the above problems, the present invention proposes a two-stage power supply suitable for medium and high frequency pulse loads, and its topological structure is as Figure 2 shown. In order to adapt to the wide voltage range change of the DC bus and the strong pulse characteristics of the load, the front-stage isolated DC / DC converter adopts a dual active bridge (DAB) converter, and the rear-stage DC / DC converter adopts a two-phase interleaved parallel synchronous rectification BUCK converter. The present invention proposes a direct power decoupling control strategy for the DAB+BUCK two-stage converter to adapt to the wide voltage range change of the DC bus and the strong pulse load characteristics of the load.

[0006] The technical solution of the present invention is as follows:

[0007] A direct power decoupling control method for a pulse load power supply, characterized in that the pulse load power supply is a two-stage power supply, the front-stage converter is a dual active bridge converter, the rear-stage converter is a two-phase interleaved parallel synchronous rectification BUCK converter, and an intermediate decoupling capacitor is connected in parallel between the two-stage converters. The control method specifically includes:

[0008] Control of the front-stage converter:

[0009] Sample the voltage V of the intermediate decoupling capacitor d , and compare it with the first given voltage Vdref Make a comparison to obtain the first error err_vd;

[0010] Input the first error err_vd into the PI controller to obtain the real-time transmission power Meanwhile, utilize V d and the input voltage V of the pre-stage converter in Calculate the voltage gain M through calculation;

[0011] Based on the transmission power and the voltage gain M, obtain the real-time phase shift ratio D through the single-phase-shift modulation strategy 0 , through D 0 Control the pre-stage converter so that after the pre-stage converter enters the steady state, it only transmits the average power;

[0012] Control of the post-stage converter:

[0013] Sample the output voltage V of the post-stage converter o , the output current i o and the inductor current i L , compare the output voltage V o with the second given voltage V oref to obtain the second error err_vo;

[0014] Input the second error err_vo into the voltage-loop PI controller to obtain the first current given value I o_ref ;

[0015] Add the first current given value I o_ref to the output current i of the post-stage converter o , and then subtract the inductor current i of the post-stage converter L to obtain the second current given value;

[0016] Input the second current given value into the current-loop PI controller to obtain the duty cycle D of the post-stage converter B , and achieve the control of the post-stage converter to make the post-stage converter provide pulsed power.

[0017] Furthermore, the calculation method of the voltage gain M is:

[0018] M = nV d / V in

[0019] where n is the turns ratio of the transformer in the pre-stage converter.

[0020] Furthermore, the calculation method of the real-time phase shift ratio D 0 is:

[0021]

[0022] The beneficial effects of the present invention are as follows: By controlling the front-stage DAB converter to only provide the average power and the rear-stage BUCK converter to provide the pulsed power through the intermediate decoupling capacitor, the pulsed load power and the average power are completely decoupled; meanwhile, the proposed control method can adapt to a wide input voltage range of the DC bus and greatly reduce the input current fluctuation. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the composition of the pulsed load power.

[0024] Figure 2 It is a schematic diagram of the two-stage topology structure.

[0025] Figure 3 It is a schematic diagram of the structure of the DAB+BUCK two-stage converter.

[0026] Figure 4 It is a schematic diagram of the direct power decoupling control strategy. Detailed Embodiment

[0027] The technical solution of the present invention will be described in detail below with reference to the drawings.

[0028] The present invention aims to reliably supply power to the pulsed load under a wide input voltage and improve the stability of the power supply system. Based on the Figure 3 DAB+BUCK two-stage converter, a direct power decoupling control method for a pulsed load power supply applicable to a wide voltage range is proposed. In order to adapt to the wide voltage range change of the DC bus and the strong pulsed characteristics of the load, the front-stage isolated DC / DC converter adopts a dual active bridge (DAB) converter, and the rear-stage DC / DC converter adopts a two-phase interleaved parallel synchronous rectification BUCK converter. The specific structure of the two-stage converter is as shown in Figure 3 . For the DAB+BUCK two-stage converter, the present invention proposes a direct power decoupling control strategy to adapt to the wide voltage range change of the DC bus and the strong pulsed load characteristics.

[0029] The topology of the DAB+BUCK two-stage pulsed load power supply is as shown in Figure 3 , where V in is the input voltage of the DC bus, i in is the input current at the DC bus end, L in is the input filter inductor of the two-stage converter, C in is the input filter capacitor, i L1 is the inductor current of the DAB converter, L 1 is the inductor of the DAB converter, T is the isolation transformer of the DAB converter, and its turns ratio is n:1. S 1 -S 8 are the switching tubes of the front-stage DAB converter, Q1 -Q 4 is the switching transistor of the post-stage BUCK converter, L 2 and L 3 are the inductors of the BUCK converter, i L2 and i L3 are the inductor currents of L 2 and L 3 respectively, C o is the output capacitor of the BUCK converter, V o and i o are the output voltage and output current respectively.

[0030] Based on the DAB+BUCK two-stage converter, the proposed direct power decoupling control method is as Figure 4 shown. The front-stage DAB converter adopts a direct power control strategy, and the post-stage BUCK converter adopts a voltage-current double-loop control strategy. The specific control method is as follows: First, sample the intermediate decoupling capacitor voltage V d . On the one hand, compare V d with the given intermediate decoupling capacitor voltage V dref to obtain the error err_vd. The error is input into the PI controller, and the PI controller directly outputs the real-time transfer power . On the other hand, calculate the voltage gain M by comparing V d with the sampled input voltage V in . Then, the real-time transfer power and the voltage gain M are simultaneously input into the single-phase-shift modulation strategy, and the real-time phase-shift ratio D 0 is calculated through formula (1):

[0031]

[0032] When the DAB converter enters the steady-state operation, the error err_vd approaches 0, and the real-time transfer power P 0 * output by the PI controller tends to be stable. At this time, the input current i in will also tend to be stable, and the DAB converter only transfers the average power, realizing the decoupling of the pulse load power and the average power. For the two-phase interleaved parallel BUCK converter, compare the sampled output voltage V o with the given output voltage V oref to obtain the error err_vo. The error is input into the voltage-loop PI controller, and the voltage-loop PI controller outputs the given value I o_ref of the current. In order to make the inductor current i L track the output current i o , make I o_ref add to the output current i o and then subtract the inductor current iL As the given value of the current-loop PI controller, finally, the current-loop PI controller outputs the duty cycle D of the two-phase interleaved parallel BUCK converter. B 。

[0033] Based on the DAB+BUCK two-stage converter, the present invention proposes a direct power decoupling control method for a pulse load power supply applicable to a wide voltage range, enabling it to still have a good pulse power suppression effect under extreme working conditions, thereby improving the system stability.

[0034] A simulation platform for a two-stage pulse load power supply with a dual-active-bridge converter in the front stage and a BUCK converter in the rear stage is built based on Matlab / Simulink, and simulation experiments are carried out within the input voltage range of 150V to 450V. The simulation parameters of the platform are shown in Table 1:

[0035] Table 1 Parameters of the DAB+BUCK two-stage pulse load power supply simulation platform

[0036]

[0037] Among them, D p is the duty cycle of the pulse load, and P peak is the peak power of the pulse load.

[0038] To verify the effectiveness of the proposed control method, the steady-state performance of the pulse load power supply is simulated and tested under the conditions of V 1 =150V, V 1 =270V, V 1 =450V. The data in Table 2 are the simulation results using the direct decoupling control strategy. It can be easily obtained from the simulation results that the control method proposed by the present invention can greatly reduce the input current ripple and improve the power supply reliability under wide input voltage working conditions.

[0039] Table 2 Simulation experiment results

[0040]

[0041]

Claims

1. A direct power decoupling control method for a pulse load power supply, characterized in that: The pulse load power supply is a two-stage power supply, the front-stage converter is a dual active bridge converter, the rear-stage converter is a two-phase staggered parallel synchronous rectification BUCK converter, and an intermediate decoupling capacitor is connected in parallel between the two-stage converters. The control method specifically includes: Control of the pre-converter: Sample the intermediate decoupling capacitor voltage V d and with the first given voltage V dref Make a comparison and get the first error err_vd; Input the first error err_vd into the PI controller to obtain the real-time transmission power At the same time, using V d and the previous converter input voltage V in The voltage gain M is obtained by calculation; Based on transmission power The voltage gain M is obtained by using a single phase shift modulation strategy to obtain a real-time phase shift value D0. The previous converter is controlled by D0 so that the previous converter only transmits average power after entering a steady state. Control of the subsequent converter: Sample the output voltage V of the post-stage converter o , output current i o and the inductor current i L , with output voltage V o With the second given voltage V oref Make a comparison and get the second error err_vo; The second error err_vo is input into the voltage loop PI controller to obtain the first current given value I o_ref ; The first current given value I o_ref The output current i of the subsequent converter o Add, then subtract the inductor current i of the subsequent converter L , thereby obtaining a second current given value; The second current given value is input into the current loop PI controller to obtain the duty cycle D of the subsequent converter. B , realizing the control of the subsequent converter so that the subsequent converter provides pulse power.

2. A direct power decoupling control method for a pulse load power supply according to claim 1, characterized in that: The voltage gain M is calculated as: M=nV d / V in Where n is the turns ratio of the transformer in the previous converter.

3. A direct power decoupling control method for a pulse load power supply according to claim 1, characterized in that: The calculation method of real-time shift phase D0 is:

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