Impedance adapter for multi-voltage DC power supply and distribution system

Abstract

The embodiment of the present invention discloses an impedance adapter device for a multi-voltage level DC power supply and distribution system, which relates to the technical field of DC power supply and distribution. The harmonic disturbance generation module in this solution includes a full-bridge inverter circuit and a filter circuit; the matching access module includes an isolation transformer, a DC blocking capacitor, a segmented current limiting circuit and a fault protection circuit. The isolation transformer and the segmented current limiting circuit are used to ensure the smooth startup of the device, and the fault protection circuit is used to reversely drive the segmented current limiting circuit when a short-circuit fault occurs in the DC blocking capacitor, thereby limiting the short-circuit current and protecting the impedance adapter device. After being connected to the DC power supply and distribution system, the impedance distribution characteristics of the system can be changed to achieve the suppression of system resonance; and through the introduction of an adaptive impedance control strategy, the impedance adapter device of the present invention has the ability to adapt to multiple working conditions. It can reshape the impedance distribution of the DC power supply and distribution system, achieve the suppression of broadband oscillations, and thus greatly improve the ability of the DC power supply and distribution system to operate stably.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current (DC) power supply and distribution, and in particular to an impedance adapter for a multi-voltage level DC power supply and distribution system. Background Art

[0002] A DC power supply and distribution system is a subsystem designed for use with a power supply or similar power supply system. As a key enabler for the integrated consumption of renewable energy, efficient integration of electric vehicles, AC distribution network upgrades and capacity expansion, and integrated energy systems, DC power supply and distribution systems have become a key development direction for future power grids and even the Energy Internet. However, DC power supply and distribution systems exhibit low inertia, weak damping, and strong system coupling. Time-varying nonlinear loads, intermittent renewable energy sources, and device parameter migration can easily excite system dynamics. This makes random source-grid-load excitation and the resulting wideband multi-resonance issues a critical factor in the safe and high-quality operation of DC power supply and distribution systems. Regarding the resonance suppression issue in DC power supply and distribution systems, current solutions propose impedance reshaping: first, suppressing system resonances by adjusting the converter's port impedance characteristics through active damping, and second, suppressing system resonances by modifying passive components within the system. This approach, exemplified by the addition of active damping control to the interface converter, essentially adds a damping branch by injecting a compensation signal into the control loop, achieving active suppression of internal resonances or active control of input (or output) impedance. However, active damping control not only reduces the dynamic characteristics of the converter, but is also constrained by the controller bandwidth. Directly replacing passive components in the system is inflexible. Therefore, power electronic devices can be added to the system to simulate different passive components to suppress system resonance. Compared with passive damping, this method does not change the steady-state operating point of the system and is more applicable. However, as the voltage and power levels of DC systems increase, the stress on the switching devices in existing devices increases, making it difficult to ensure device reliability. Furthermore, due to the wide resonant frequency band of DC power supply and distribution systems, the control bandwidth and impedance simulation frequency band of the impedance adapter device need to be designed in conjunction with the resonant frequency band of the system to meet the requirements of broadband oscillation suppression. Existing devices are not designed for this purpose.

[0003] Therefore, it is necessary to improve and design an impedance adaptation device that can simultaneously meet the impedance simulation requirements of multiple voltage levels and multiple operating conditions, so as to achieve the purpose of suppressing the broadband oscillation of the DC power supply and distribution system, so as to ensure the safe and stable operation of the system. Summary of the Invention

[0004] An embodiment of the present invention provides an impedance adaptation device for a multi-voltage level DC power supply and distribution system, which can suppress broadband oscillations of the DC power supply and distribution system, thereby ensuring safe and stable operation of the system.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] An impedance adaptation device for a multi-voltage DC power supply and distribution system, wherein a harmonic disturbance generation module is connected as a system to be adapted via a matching access module;

[0007] The harmonic disturbance generating module includes: a full-bridge inverter circuit and a filter circuit, the filter circuit is connected to the full-bridge inverter circuit, and the filter circuit is used to filter out switching harmonics and improve the output quality of the harmonic disturbance;

[0008] The matching access module includes: a segmented current limiting circuit and a fault protection circuit. The matching access module is used as an intermediate link to connect the harmonic disturbance generating module and the DC bus of the system to be adapted. The type of the system to be adapted is a DC power supply and distribution system.

[0009] In the harmonic disturbance generating module, the full-bridge inverter circuit includes: a first MOS tube Q 1 to the fourth MOS tube Q 4. DC side capacitor C d connected in parallel to the input side of the full-bridge inverter circuit; the filter circuit is connected to the output side of the full-bridge inverter circuit, and the pre-stage filter inductor L f and filter capacitors C f The filtering circuit is formed.

[0010] In the matching access module, including: isolation transformer T r , post-stage filter inductor L s , DC blocking capacitors C s and circuit breaker 2 S h ; Isolation transformer T r The primary side passes through the circuit breaker S c Connected to the filter branch, isolation transformer T r The secondary side is connected in series with the post-stage filter inductor of the matching access module L s and DC blocking capacitors C s A circuit breaker is provided between the segmented current limiting circuit and the DC bus of the system to be adapted. S h ;

[0011] Specifically, the components constituting the segmented current limiting circuit include: first to second current limiting resistors R s1 andR s2 , the first to third trigger resistors R g1 to R g3 , the first to second trigger capacitors C g1 and C g2 , the first to second Zener diodes D g1 and D g2 , and the first to second trigger MOS tubes Q g1 and Q g2 ; R s1 and R s2 In passing C s During the charging process, the MOS tubes are triggered in turn Q g1 and Q g2 Cut off, thereby suppressing the current impact during the charging process in segments. R g1 to R g3 To trigger Q g1 and Q g2 The conduction provides a stable gate voltage; the trigger resistor R g1 ~ R g3 By using the basic principle of series voltage division, the MOS tube is triggered Q g1 and Q g2 The conduction provides a stable gate voltage; the trigger capacitor C g1 and C g2 With trigger resistor R g1 and R g2 Jointly determine the current limiting resistor R s1 and R s2 The time of being cut off; Zener diode D g1 and D g2 Used to ensure triggering of MOS tube Q g1 andQ g2 Gate voltage stabilization.

[0012] The fault protection circuit includes: an optical coupler, an operational amplifier and a voltage stabilizing diode; when C s When a short circuit occurs, the secondary side of the optocoupler outputs a low level to the operational amplifier, which then outputs a low level and triggers Q g2 Shut down, at this time R s2 The matching circuit is put into use to suppress the short-circuit impact current, thereby protecting the impedance adapter. T r The segmented current limiting circuit is used to ensure smooth startup of the device. The fault protection circuit is used to reversely drive the segmented current limiting circuit when a short circuit fault occurs in the DC blocking capacitor, thereby limiting the short circuit current and protecting the impedance adapter.

[0013] Furthermore, the adaptation process of the impedance adaptation device for the multi-voltage level DC power supply and distribution system includes:

[0014] The output port of the matching access module is connected in parallel to the DC bus of the system to be adapted. S c With circuit breaker 2 S h All are in disconnected state;

[0015] Close circuit breaker 2 S h , and wait for the DC blocking capacitor C s Charge to bus voltage;

[0016] Start the harmonic disturbance generation module and select the adaptation mode, then close the circuit breaker. S c , the impedance adaptation device starts to run, and the adaptation modes include: fixed impedance simulation and adaptive impedance simulation.

[0017] In the impedance simulation control loop, the bandpass filter BPF1 is used to control the bus voltage. v bus Extract the oscillation harmonic component as the signal reference of the inner loop current command value; directly multiply the oscillation harmonic component by the conductance reference value G ref Get the current command value of the resistance simulation i z_ref ; Or, multiply the oscillation harmonic component by the capacitance reference value after the differential link C ref get iz_ref ; i z_ref Input inner loop quasi-PR regulator. i z_ref Through the inner loop quasi-PR regulator G i ( s ) so that the impedance adapter simulates resistance or capacitance at the system resonance frequency, thereby suppressing system resonance.

[0018] In the capacitor voltage self-maintaining control loop, the DC side capacitor C d The command value v Cd_ref and actual value v Cd The difference between the two passes through the PI regulator of the voltage outer loop G v ( s ) to obtain the inner loop current command value i v_ref The signal reference is multiplied by the harmonic component outside the impedance simulation frequency to obtain the inner loop current command value of the capacitor voltage self-maintaining control i v_ref Inner loop current command value i v_ref Through the inner loop quasi-PR regulator G r ( s ) tracking, so that the impedance adapter simulates negative resistance outside the system resonant frequency, sends energy to the system to maintain the DC side capacitance C d The voltage is stable.

[0019] The embodiment of the present invention provides an impedance adaptation device for a multi-voltage level DC power supply and distribution system, a harmonic disturbance generating module, including a full-bridge inverter circuit and a filter circuit, the filter circuit is connected to the full-bridge inverter circuit, and is used to filter out switching harmonics and improve the quality of harmonic disturbance output; a matching access module, including an isolation transformer, a DC blocking capacitor, a segmented current limiting circuit and a fault protection circuit, which serves as an intermediate link to connect the harmonic disturbance generating module and the busbar of the system to be adapted. Among them, the isolation transformer and the segmented current limiting circuit are used to ensure the smooth start-up of the device, and the fault protection circuit is used to reversely drive the segmented current limiting circuit when a short-circuit fault occurs in the DC blocking capacitor, thereby limiting the short-circuit current and protecting the impedance adaptation device. The impedance adaptation device of the present invention has a wide-band port impedance simulation capability, and after being connected to the DC power supply and distribution system, it can change the impedance distribution characteristics of the system to suppress the resonance of the system; and through the introduction of an adaptive impedance control strategy, the impedance adaptation device of the present invention has the capability of multi-working condition adaptation. This impedance adapter can adapt to DC power supply and distribution systems with different voltage levels and different operating conditions. It has the ability to simulate the port's wide-band impedance, can reshape the impedance distribution of the DC power supply and distribution system, and suppress wide-band oscillations, thereby greatly improving the DC power supply and distribution system's ability to operate stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of the circuit structure of the impedance matching device provided by the present invention; Figure 1 middle, v Cd Indicates the DC side capacitor voltage, v inv Represents the bridge arm output voltage, i Lf Represents the pre-stage filter inductor current, i o Indicates the device output port current, V cc Indicates the optocoupler supply voltage for the fault protection circuit, V ref Represents the input reference voltage of the operational amplifier in the fault protection circuit.

[0022] Figure 2 This is a block diagram of the basic control strategy for impedance adaptation provided by the present invention; Figure 2 middle, v busIndicates the DC bus voltage of the system to be adapted, BPF1 represents a bandpass filter, which is used to extract the oscillation harmonic components, BPF2 represents a bandpass filter, which is used to extract the available harmonic components outside the impedance simulation frequency, and HPF represents a high-pass filter, which is used to simulate the differential link. G ref represents the conductivity reference value, C ref Indicates the capacitance reference value, i v_ref Indicates the current command value used to maintain the stability of the DC side capacitor voltage. i z_ref Indicates the current command value for impedance simulation, v Cd_ref Indicates the DC side capacitor reference voltage, cos(ω v t ) represents the time domain expression of the available harmonic components outside the impedance simulation frequency, ω v represents the angular frequency of the available harmonic components, t Indicates time, G i ( s ) represents a quasi-PR regulator, G v ( s ) represents the PI regulator, G r ( s ) represents a quasi-PR regulator, K pwm represents the modulation gain, s represents a complex frequency domain variable, T s Indicates control delay, v Cf Indicates filter capacitor C f The voltage across the terminals, L f Indicates the inductance value of the pre-stage filter, i p Indicates the primary current of the isolation transformer, i Cf Indicates filter capacitor C f On current, Z p (s) represents the equivalent parallel impedance of the primary side of the isolation transformer, n Indicates the primary-to-secondary turns ratio of the isolation transformer, Z s (s) represents the equivalent series impedance of the secondary side of the isolation transformer.

[0023] Figure 3This is a block diagram of the adaptive impedance control considering DC bus voltage distortion provided by the present invention. Figure 3 In the example, RMS represents the root mean square value extraction step. V rms Indicates the RMS value of the busbar harmonic voltage, V lim Indicates the upper limit of busbar harmonic voltage distortion value, G R ( s ) represents the PI regulator, G C ( s ) represents the PI regulator, G x represents the adaptive conductance value, C x Indicates the adaptive adaptation capacitance value, i R_ref Indicates the current command value of the resistance simulation, i C_ref Indicates the current command value of capacitor simulation, Δ V rms Indicates the rate of change of the RMS value of the busbar harmonic voltage, Δ V lim Indicates the reference value of the busbar harmonic voltage RMS change rate, I max Indicates the upper limit of the RMS output current of the adapter device. I rms Indicates the RMS value of the impedance simulation current command value. ≥1 indicates an OR operation, and & indicates an AND operation. DETAILED DESCRIPTION

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention will be described in detail below, with examples of the embodiments illustrated in the accompanying drawings. Throughout, identical or similar reference numerals represent identical or similar elements or elements having identical or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and intended only to explain the present invention and are not to be construed as limiting the present invention. Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" as used in the description of the present invention refers to the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or intervening elements may be present. Furthermore, "connected" or "coupled" as used herein may include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and unless defined as such, will not be interpreted in an idealized or overly formal sense.

[0025] In this embodiment, a main circuit of an impedance adapter device applicable to a multi-voltage DC power supply and distribution system and having adaptive impedance simulation capability is provided, such as Figure 1 As shown, the device includes: a harmonic disturbance generating module, including a DC side capacitor C d , MOS tube Q 1~ Q 4. Pre-stage filter inductor L f , filter capacitor C f And circuit breaker S c .

[0026] Matching access modules, including isolation transformers T r , post-stage filter inductor L s , DC blocking capacitors C s , current limiting resistorR s1 and R s2 , trigger resistor R g1 ~ R g3 , trigger capacitor C g1 and C g2 , Zener diode D g1 and D g2 , trigger MOS tube Q g1 and Q g2 and circuit breaker 2 S h .

[0027] In the impedance adaptation device provided in this embodiment, the MOS tube Q 1~ Q 4 form a full-bridge inverter circuit, DC side capacitor C d Connected in parallel to the input side of the full-bridge inverter circuit. L f , filter capacitor C f It forms the pre-stage filter circuit and is connected to the output side of the full-bridge inverter circuit; the isolation transformer T r The primary side passes through the circuit breaker S c Connected to the filter branch, the secondary side is directly connected in series with the post-stage filter inductor L s With DC blocking capacitor C s .

[0028] In the impedance matching device provided in this embodiment, the pre-stage filter inductor L f , filter capacitor C f , isolation transformer and post-stage filter inductor L s The LCL filter circuit is composed to ensure the waveform quality of the output current of the device. When the device is connected to the system, the post-filter inductor L s With current limiting resistor R s1 、 R s2 and DC blocking capacitors C sThe RLC second-order segmented snubber circuit can fully suppress the current impact while taking into account the charging efficiency of the DC blocking capacitor.

[0029] In the impedance adaptation device provided in this embodiment, the current limiting resistor R s1 and R s2 , trigger resistor R g1 ~ R g3 , trigger capacitor C g1 and C g2 , Zener diode D g1 and D g2 , and trigger MOS tube Q g1 and Q g2 Composed of segmented current limiting circuit, current limiting resistor R s1 and R s2 In the DC blocking capacitor C s During the charging process, the MOS tubes are triggered in sequence Q g1 and Q g2 Cut off, segmented suppression of current shock during charging; trigger resistor R g1 ~ R g3 By using the basic principle of series voltage division, the MOS tube is triggered Q g1 and Q g2 The conduction provides a stable gate voltage; the trigger capacitor C g1 and C g2 With trigger resistor R g1 and R g2 Jointly determine the current limiting resistor R s1 and R s2 The time of being cut off; Zener diode D g1 and D g2 Used to ensure triggering of MOS tube Q g1 and Q g2Gate voltage stabilization.

[0030] In the impedance adaptation device provided in this embodiment, the fault protection circuit is composed of an optical coupler, an operational amplifier and a voltage regulator diode. C s When a short circuit occurs, the secondary side of the optocoupler outputs a low level to the operational amplifier, which then outputs a low level to trigger the MOS tube. Q g2 Shutdown, current limiting resistor R s2 A matching circuit is added to suppress short-circuit surge current and protect the device.

[0031] In this embodiment, a basic control strategy principle block diagram of the impedance adaptation device is provided, such as Figure 2 As shown, the basic control loop of impedance adaptation includes: impedance simulation control loop, which is responsible for impedance simulation of the device port; and capacitor voltage self-maintaining control loop, which is responsible for maintaining the DC side capacitor C d The voltage is stable.

[0032] In the impedance simulation control loop provided by this embodiment, the bandpass filter BPF1 is derived from the system bus voltage. v bus Extract the oscillation harmonic component as the inner loop current command value i z_ref The signal reference is then multiplied by the conductance reference value G ref Get the current command value of the resistance simulation i z_ref , or multiplied by the capacitance reference value after the differential link C ref Get the current command value of capacitor simulation i z_ref Current command value i z_ref Through the inner loop quasi-PR regulator G i ( s ) so that the impedance adapter simulates resistance or capacitance at the system resonance frequency, thereby suppressing system resonance.

[0033] In the capacitor voltage self-maintaining control loop provided by this embodiment, the DC side capacitor C d The command value v Cd_ref and actual value v Cd The difference between the two passes through the PI regulator of the voltage outer loop G v ( s ) to obtain the inner loop current command valuei v_ref The signal reference is then multiplied by the harmonic components outside the impedance simulation frequency to obtain the inner loop current command value of the capacitor voltage self-maintaining control i v_ref Inner loop current command value i v_ref Through the inner loop quasi-PR regulator G r ( s ) tracking, so that the impedance adapter simulates negative resistance outside the system resonant frequency, sends energy to the system to maintain the DC side capacitance C d The voltage is stable.

[0034] In this embodiment, an adaptive impedance control block diagram considering DC bus voltage distortion is provided, such as Figure 3 System bus voltage v bus The AC harmonic component obtained by the bandpass filter BPF1 is used as the reference signal of the resistance-capacitance simulation and sent to the RMS value extraction link to obtain the system harmonic RMS value. V rms ;Will V rms The upper limit of busbar harmonic voltage distortion is specified V lim After making the difference, it is sent to the PI regulator G R ( s )and G C ( s ), thus obtaining the conductivity reference value G x and capacitance reference value C x The above reference value is multiplied to obtain the current command value i R_ref and i C_ref , the final current command value of the impedance simulation i z_ref Determined by the adaptive switching judgment link. Considering the power demand of the device, capacitor simulation is given priority, that is, the command value i z_ref Pick i C_ref Then, the two comparators detect the rate of change of the RMS value of the busbar harmonic voltage and the impedance simulation current command value. When any of the values does not meet the requirements, the capacitance simulation is switched to the resistance simulation, that is, the command value i z_ref Switch to i R_ref , while the PI regulatorG R ( s ) output is initialized; Similarly, if the resistance simulation still cannot meet the adaptation requirements, the command value i z_ref By setting the command value i z_ref The output is sent to the impedance simulation control loop to achieve adaptive impedance control of the impedance adapter.

[0035] The following describes the impedance matching process of the embodiment:

[0036] 1. Connect the output port of the matching access module to the DC bus of the system to be adapted. S c With circuit breaker 2 S h All are in disconnected state.

[0037] 2. Close circuit breaker 2 S h , waiting for the DC blocking capacitor C s Charge to bus voltage.

[0038] 3. Start the harmonic disturbance generation module and select the adaptation mode according to actual needs, then close the circuit breaker. S c , the device starts running.

[0039] The impedance adapter device for a multi-voltage DC power supply and distribution system provided by an embodiment of the present invention solves the problem of high device stress in existing impedance adapter devices through reasonable design of the topology; through reasonable design of the control strategy, the device can fully suppress the broadband oscillation of the DC power supply and distribution system while meeting the adaptation requirements of various complex working conditions. Among them, the harmonic disturbance generation module, composed of a DC side capacitor, a full-bridge inverter circuit and a filter circuit, is responsible for generating high-quality harmonic currents and ensuring the accuracy of the device port impedance simulation; the matching access module, composed of an isolation transformer, a DC blocking capacitor, a segmented current limiting circuit and a fault protection circuit, is responsible for balancing the voltage and current stress of the switching devices in the device, achieving electrical isolation between the device and the system to be adapted, and at the same time solving the overcurrent problem when the device is connected to the system and the DC blocking capacitor fails, ultimately achieving the suppression of broadband oscillations of the DC power supply and distribution system, thereby ensuring the safe and stable operation of the system.

[0040] In practice, this impedance adapter employs a basic dual-loop control strategy, consisting of an impedance simulation control loop and a DC capacitor voltage self-maintaining control loop. Building on this basic control strategy, an adaptive impedance control strategy is implemented that takes DC bus voltage distortion into account. By detecting the distortion of the system bus voltage and continuously adjusting the impedance simulation value, the system automatically suppresses broadband oscillations.

[0041] Specifically, the solution of this embodiment has the following advantages: 1. Through a modular main circuit topology design, the voltage and current stresses of the device's switching components during operation are significantly reduced, while also enabling the device to be compatible with multiple voltage levels. 2. The introduction of a segmented current limiting circuit resolves overcurrent issues when the device is connected to the system; the introduction of a fault protection circuit ensures the safe and stable operation of the device. 3. Through the effective design of the control strategy, the device is capable of wide-band adaptive impedance simulation, meeting the requirements of multi-operational conditions.

[0042] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An impedance adapter for a multi-voltage DC power supply and distribution system, characterized in that: The harmonic disturbance generation module is connected to the system to be adapted through the matching access module; The harmonic disturbance generating module includes: a full-bridge inverter circuit and a filter circuit, the filter circuit is connected to the full-bridge inverter circuit, and the filter circuit is used to filter out switching harmonics; The matching access module includes: a segmented current limiting circuit and a fault protection circuit. The matching access module is used as an intermediate link to connect the harmonic disturbance generating module and the DC bus of the system to be adapted. The type of the system to be adapted is a DC power supply and distribution system; The adaptation process of the impedance matching device includes: The output port of the matching access module is connected in parallel to the DC bus of the system to be adapted. S c With circuit breaker 2 S h All are in disconnected state; Close circuit breaker 2 S h , and wait for the DC blocking capacitor C s Charge to bus voltage; Start the harmonic disturbance generation module and select the adaptation mode, then close the circuit breaker. S c , the impedance adaptation device starts to operate, and the adaptation modes include: fixed impedance simulation and adaptive impedance simulation; Wherein, in the matching access module, it includes: an isolation transformer T r , post-stage filter inductor L s , DC blocking capacitors C s and circuit breaker 2 S h ; Isolation transformer T r The primary side passes through the circuit breaker S c Connected to the filter branch, isolation transformer T r The secondary side is connected in series with the post-stage filter inductor of the matching access module L s and DC blocking capacitors C s A circuit breaker is provided between the segmented current limiting circuit and the DC bus of the system to be adapted. S h .

2. The impedance adapter device for a multi-voltage DC power supply and distribution system according to claim 1, characterized in that: In the harmonic disturbance generating module, the full-bridge inverter circuit includes: a first MOS tube Q 1 to the fourth MOS tube Q 4. DC side capacitor C d Connected in parallel to the input side of the full-bridge inverter circuit; The filter circuit is connected to the output side of the full-bridge inverter circuit, and the front-stage filter inductor L f and filter capacitors C f The filtering circuit is formed.

3. The impedance adapter for a multi-voltage DC power supply and distribution system according to claim 1, characterized in that: The components constituting the segmented current limiting circuit include: first to second current limiting resistors R s1 and R s2 , the first to third trigger resistors R g1 to R g3 , the first to second trigger capacitors C g1 and C g2 , the first to second Zener diodes D g1 and D g2 , and the first to second trigger MOS tubes Q g1 and Q g2 ; R s1 and R s2 In passing C s During the charging process, the MOS tubes are triggered in turn Q g1 and Q g2 Cut off, thereby suppressing the current impact during the charging process in segments.

4. The impedance adapter for a multi-voltage DC power supply and distribution system according to claim 3, characterized in that: The fault protection circuit includes: an optocoupler, an operational amplifier and a voltage stabilizing diode; when C s When a short circuit occurs, the secondary side of the optocoupler outputs a low level to the operational amplifier, which then outputs a low level and triggers Q g2 Shut down, at this time R s2 A matching circuit is put into use to suppress the short-circuit surge current.

5. The impedance adapter for a multi-voltage DC power supply and distribution system according to claim 4, characterized in that: In the impedance simulation control loop, the bandpass filter BPF1 is used to filter the bus voltage v bus Extracting the oscillation harmonic component as the signal reference of the inner loop current command value; Directly multiply the oscillation harmonic component by the conductance reference value G ref Get the current command value of the resistance simulation i z_ref ; Or, multiply the oscillation harmonic component by C ref get i z_ref ; i z_ref Input inner loop quasi-PR regulator.

6. The impedance adapter for a multi-voltage DC power supply and distribution system according to claim 5, characterized in that: In the capacitor voltage self-maintaining control loop, the DC side capacitor C d The command value v Cd_ref and actual value v Cd The difference between the two passes through the PI regulator of the voltage outer loop G v ( s ) to obtain the inner loop current command value i v_ref The signal reference; The signal reference is multiplied by the harmonic components outside the impedance simulation frequency to obtain the inner loop current command value of the capacitor voltage self-maintaining control i v_ref。

Images