A dual-bus AC / DC hybrid energy routing system and its control method

Abstract

The present invention provides a dual-bus AC / DC hybrid energy routing system and a control method thereof, which relate to the fields of high-power power electronics technology and grid-connected control technology. The system comprises a three-phase PWM bidirectional DC / AC conversion unit, a buck-boost conversion unit 1, a buck-boost conversion unit 2, a bidirectional buck-boost conversion unit, a non-isolated high-gain DC / DC conversion unit, a three-phase PWM rectifier unit, a single-phase PWM inverter unit, a three-phase PWM inverter unit, a full-bridge DAB conversion unit, a full-bridge CLLC bidirectional DC / DC conversion unit, a photovoltaic panel, a diesel generator, a battery, a DC load 1, a DC load 2, a single-phase AC load, a three-phase AC load, a high-voltage side DC bus, a low-voltage side DC bus, and a three-phase AC power grid. The system can be connected to a variety of distributed energy resources and a three-phase AC power grid, providing AC ports and DC ports of different voltage levels for various loads. The system can adjust the operating mode of the energy router according to the generated power of the distributed energy resources and the power of each load, and can perform high-efficiency regulation during grid-connected operation control.

Description

Technical Field

[0001] The present invention relates to the fields of high-power power electronics technology and grid-connected control technology, and in particular to a dual-bus AC / DC hybrid energy routing system and a control method thereof. Background Art

[0002] With the diversification of energy utilization, traditional power system equipment is unable to meet the requirements of diverse power supply forms, flexible energy flow, and intelligent power transmission control. This has led to the concept of the Energy Internet. The Energy Internet aims to achieve the comprehensive utilization of distributed energy resources and maximize their benefits. Energy routers are a key component of the Energy Internet, addressing issues related to energy access, energy control, and energy transmission, enabling interconnection, energy transmission, and power control between energy networks.

[0003] Currently, mainstream DC / DC boost converters include Boost converters, Buck-Boost converters with boost function, bidirectional Buck-Boost converters, and DAB converters. DAB converters and bidirectional Buck-Boost converters are not suitable for unidirectional energy transmission. However, the boost gain range of Boost converters and Buck-Boost converters is relatively small. When distributed energy outputs low-voltage DC and uses them to supply energy routers, the DC / DC conversion voltage may not reach the DC bus voltage level. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a dual-bus AC / DC hybrid energy routing system and a control method thereof.

[0005] On the one hand, a dual-bus AC / DC hybrid energy routing system includes a three-phase PWM bidirectional DC / AC conversion unit, a buck-boost conversion unit 1, a buck-boost conversion unit 2, a bidirectional buck-boost conversion unit, a non-isolated high-gain DC / DC conversion unit, a three-phase PWM rectifier unit, a single-phase PWM inverter unit, a three-phase PWM inverter unit, a full-bridge DAB conversion unit, a full-bridge CLLC bidirectional DC / DC conversion unit, a photovoltaic panel, a diesel generator, a battery, a DC load 1, a DC load 2, a single-phase AC load, a three-phase AC load, a high-voltage side DC bus, a low-voltage side DC bus, and a three-phase AC power grid;

[0006] The AC input side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the three-phase AC power grid, and the DC output side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the high-voltage side DC bus; the output end of the BUCK-BOOST conversion unit 1 is connected to the DC load 1, and the input end of the BUCK-BOOST conversion unit 1 is connected to the high-voltage side DC bus; the low-voltage input end of the bidirectional BUCK-BOOST conversion unit is connected to the battery;

[0007] The high-voltage output end of the bidirectional BUCK-BOOST conversion unit is connected to the low-voltage side DC bus; the low-voltage input end of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel, and the high-voltage output end of the non-isolated high-gain DC / DC conversion unit is connected to the low-voltage side DC bus; the input end of the three-phase PWM rectifier unit is connected to the diesel generator, and the output end of the three-phase PWM rectifier unit is connected to the high-voltage side DC bus; the input end of the single-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the single-phase PWM inverter unit is connected to the single-phase AC load; the input end of the three-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the three-phase PWM inverter unit is connected to the three-phase AC load; the output end of the BUCK-BOOST conversion unit 2 is connected to the DC Load 2, the input end of the BUCK-BOOST conversion unit 2 is connected to the low-voltage side DC bus; the high-voltage side positive pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the positive pole of the high-voltage side DC bus, the high-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the high-voltage side positive pole of the full-bridge DAB conversion unit, and the high-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the high-voltage side DC bus; the low-voltage side positive pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the negative pole of the low-voltage side DC bus; the low-voltage side positive pole of the full-bridge DAB conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the low-voltage side DC bus.

[0008] The non-isolated high-gain DC / DC conversion unit is a unidirectional transmission boost converter, specifically including power diodes D0, D1, D2, D3, D4, D5, D6, D7, inductors L1, L2, L3, capacitors C, C0, and IGBT switch tube VT; the low-voltage side of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel;

[0009] The positive pole of the photovoltaic panel is respectively connected to one end of the inductor L1 and the anode of the power diode D2, the other end of L1 is connected to the anode of D1, the cathode of D1 is connected to the cathode of D2, one end of the inductor L2 is connected to the anode of the power diode D5, the other end of the inductor L2 is connected to the anode of D4, the cathode of D4 is connected to the cathode of D5, L2, D4, and D5 are connected to form a charge and discharge unit; the anode of D5 is connected to the cathode of D2 and D1, the anode of D3 is connected to the anode of D1, the cathode of D3 is connected to the anode of D4, one end of the inductor L3 is connected to the cathodes of D4 and D5, and the anode of the power diode D6 is connected to the cathode of D3 , the cathode of D6 is connected to the other end of L3, the anode of D7 is connected to the cathode of D5, one end of the capacitor C is connected to the cathode of D7, the other end of C is connected to the cathode of D6, and the cathode of D6 is connected to the collector of the IGBT switch tube VT; the anode of D0 is connected to the cathode of D7, one end of the capacitor C0 is connected to the cathode of D0, and the other end of C0 is connected to the emitter of VT. The low-voltage side DC bus is connected to both ends of C0, which is the high-voltage side of the unidirectional transmission boost converter. The high-voltage side of the unidirectional transmission boost converter is the output end of the converter and is connected to the low-voltage side DC bus; the negative end of the low-voltage side DC bus and the emitter of VT are connected to the negative end of the photovoltaic panel;

[0010] On the other hand, a dual-bus AC / DC hybrid energy routing control method is implemented based on the aforementioned dual-bus AC / DC hybrid energy routing system, specifically comprising the following steps:

[0011] Step 1: Sample the voltage and current of the photovoltaic panels, diesel generators, batteries, three-phase AC grid, and all loads in the energy router;

[0012] Step 2: Establish a power balance equation that satisfies the operating state of the dual-bus AC / DC hybrid energy router and discretize the equation;

[0013] The power balance equation at any time t is:

[0014] P G (t)+P C (t)-P F (t)+F J (t)P J (t)+F X (t)P X (t) = 0

[0015] P G (t), P C (t), P F (t), P J (t), P X (t) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power; FJ (k) is the grid-side switching function, which inputs power from the AC grid side and has a value of 1, and outputs power to the AC grid side and has a value of -1; F X (k) is the energy storage switch function, which inputs power from the battery side and has a value of 1, and outputs power to the battery side and has a value of -1;

[0016] The power balance equation in the kth sampling period is as follows:

[0017] P G (k)+P C (k)-P F (k)+F J (k)P J (k)+F X (k)P X (k) = 0

[0018] Where k represents the kth sampling period of the energy router; P G (k), P C (k), P F (k), P J (k), P X (k) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power in the kth sampling period;

[0019] The specific expression of the sum of the load power of each port of the dual busbar of the energy router is as follows:

[0020] P G (k)=U G (k)I G (k)

[0021] P C (k)=U C (k)I C (k)

[0022] P J (k)=U J (k)I J (k)

[0023] P X (k)=U X (k)I X (k)

[0024] P F (k)=U H (k)I HF (k)+U L (k)I LF (k)

[0025] Among them U G (k), I G (k), U C (k), I C (k), U HF (k), I HF (k), U LF (k), I LF (k), U x (k), I X (k) are respectively the sum of the PV side voltage sampling value, PV side current sampling value, diesel generator side voltage sampling value, diesel generator side current sampling value, high-voltage side load voltage sampling value, high-voltage side load current sampling value, low-voltage side load voltage sampling value, low-voltage side load low-voltage side DC bus side current sampling value, AC grid high-voltage side DC bus side voltage sampling value, AC grid high-voltage side DC bus side input current sampling value, battery side voltage sampling value, and battery side current sampling value;

[0026] Step 3: The three-phase PWM bidirectional DC / AC conversion unit is in the conduction mode. An average switching dynamic equation is established for the three-phase PWM bidirectional DC / AC conversion unit. The average switching dynamic equation is as follows:

[0027]

[0028]

[0029]

[0030] in and V IC-DC 、i IC-abc and v ICO-abc Average switching dynamic value; V IC-DC : DC side voltage of three-phase PWM bidirectional DC / AC conversion unit; i IC-abc : filter inductor current vector of the three-phase PWM bidirectional DC / AC conversion unit; v ICO-abc : AC side filter voltage phasor of three-phase PWM bidirectional DC / AC conversion unit; i IC-DC : DC side current of three-phase PWM bidirectional DC / AC conversion unit; u abc-ave : average switching voltage vector of the three-phase PWM bidirectional DC / AC conversion unit; L IC-AC 、R IC-AC 、C IC-AC 、C IC-DC They represent the filter inductor, filter resistor, filter capacitor and DC link capacitor of the three-phase PWM bidirectional DC / AC conversion unit respectively; i ICO-abc : AC output current vector of the three-phase PWM bidirectional DC / AC conversion unit;

[0031] Step 4: Discretize the average switching dynamic equation of the three-phase PWM bidirectional DC / AC conversion unit and establish a periodic sampling function. The periodic sampling function is shown in the following formula:

[0032] v iCO-abc (k+1)=f1(v ICO-abc (k),…,v iCO-abc (kd y1 ),u abc-abe (k),…,u abc-ave (kd u ))

[0033] V IC-DC (k+1)=f2(V IC-DC (k)…, V IC-DC (kd y2 )u abc-ave (k),…,u abc-ave (kd u ))

[0034]

[0035] u abc_ave =[u a_ave ,u b_ave ,u c_ave ] T

[0036] where d y1 d y2 d u is the model order, f1 and f2 represent the parameter-driven nonlinear function; is the three-phase voltage of a, b, c; u a_ave， u b_ave， u c_ave is the average switching state of the three-phase voltages a, b, and c;

[0037] Step 5: Check the remaining battery power; when the battery is fully charged, the battery enters sleep mode;

[0038] When the battery is not fully charged, it is determined whether the remaining battery power is greater than 0.5. If so, the battery is charged in constant voltage control mode, otherwise the battery module is charged in constant current control mode;

[0039] Step 6: Based on the DC side control voltage level and the AC side control AC frequency, establish the per-unit active power transfer function of the double droop control;

[0040] According to the different working modes of the battery, the droop coefficient of the three-phase PWM bidirectional DC / AC conversion unit of the energy router is updated as shown in the following formula:

[0041]

[0042]

[0043] in, t k When the double sag curve is consistent value; t k+1 AC angular frequency; t k+1 When DC droop voltage; is the angular frequency change value within k+1 sampling period, k ac and k dc is the droop coefficient of the AC side and the DC side;

[0044] Generate a power instruction and establish a power instruction function connecting the AC grid and the energy router, as shown in the following formula:

[0045]

[0046] Where ΔP Lac is the change value of the AC side load power; ΔP Lac is the change value of DC side load power; is the power command value of the kth sampling period;

[0047] Step 7: Design an observation device to estimate the observation coefficient matrix Φ(k), and obtain the observation device and its corresponding self-matching update function, as shown in the following formula:

[0048]

[0049] in for estimated value; Transpose the observation coefficient vector of column i;

[0050] V i (k) is the i-th vector of the DC side voltage dynamic change matrix in the k-th cycle; ||ΔU(k)|| is the norm of the AC side voltage dynamic change matrix within the stable step length L;

[0051] Step 8: Given the control input linearization length L, when ||ΔU(k)|| is not equal to 0, define the real variable parameter matrix Φ(l) of the pseudo-block linear matrix. Based on the per-unit values ​​of the reference voltage and reference frequency, an equivalent partial format dynamic fitting parameter model is obtained based on the parameter-driven partial format dynamic fitting method, as shown in the following equation:

[0052] ΔV(k+1)=Φ(k)ΔU(k)

[0053] AU(k)=[ΔuT (k),…,Δu T (k-L+1)] T =U(k)-U(k-1)

[0054] ΔV(k+1)=V(k+1)-V(k)

[0055] Δu(k-i+1)=u(k-i+1)-u(ki), i=1,...,L,

[0056]

[0057] Where L is the linearization step size of the partial format; AV(k+1) is the DC side voltage dynamic change matrix; ΔU(k) ​​is the AC side voltage dynamic change matrix within the stable step size L; Φ(k) is the observation coefficient matrix;

[0058] Step 10: Design a parameter-driven dynamic fitting voltage controller for the three-phase PWM bidirectional DC / AC conversion unit, estimate the parameter values ​​of the pseudo-block linear matrix Φ(k), and establish the parameter-driven voltage control equation for the three-phase PWM bidirectional DC / AC conversion unit:

[0059] When ||ΔU(k)||≤δ,

[0060]

[0061] in is the estimated value of the DC side voltage matrix in the k+1th cycle;

[0062] When ||ΔU(k)||>δ,

[0063] u(k)=u(k-1)+δ·sign(ΔU(k))

[0064] Where V * (k) is the reference trajectory, the diagonal matrix α = diag(α1, α2, α3, α4); α i is the stability coefficient of the i-th vector; δ is the linearization step threshold; sign() is the sign function;

[0065] Step 11: Perform an inverse z-transform on the parameter drive voltage control equation of the three-phase PWM bidirectional DC / AC conversion unit, perform PWM modulation, and control the DC bus voltage on the high-voltage side of the DC end of the three-phase PWM bidirectional DC / AC conversion unit of the energy router to complete the power transmission of the energy router.

[0066] The beneficial effects of adopting the above technical solution are:

[0067] The present invention proposes a dual-bus AC / DC hybrid multi-port mutual assistance energy router device and its control strategy, which has the following advantages:

[0068] 1. The dual-bus AC / DC hybrid multi-port energy router uses a non-isolated high-gain DC / DC converter unit to connect the photovoltaic units, significantly improving the voltage gain and eliminating the need to connect more photovoltaic units in series to increase the output voltage on the photovoltaic unit side.

[0069] 2. A parameter-driven power control method is used to control the three-phase PWM bidirectional DC / AC conversion unit. This method does not require the mathematical model of the controlled object and its structure, order, time delay, and other information. Only the measured I / O parameters are required for connection control with the AC power grid, thereby improving power control efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a block diagram of the overall structure of the present invention.

[0071] Figure 2 Schematic diagram of the energy router topology of the present invention.

[0072] Figure 3 This is a structural diagram of a non-isolated high-gain DC / DC conversion unit.

[0073] Figure 4 It is the overall operation flow chart of the present invention.

[0074] Figure 5 This is a flow chart of the grid-connected control method. DETAILED DESCRIPTION

[0075] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0076] On the one hand, a dual-bus AC / DC hybrid energy routing system, e.g. Figure 1 、 Figure 2 As shown, it includes a three-phase PWM bidirectional DC / AC conversion unit, a BUCK-BOOST conversion unit 1, a BUCK-BOOST conversion unit 2, a bidirectional BUCK-BOOST conversion unit, a non-isolated high-gain DC / DC conversion unit, a three-phase PWM rectifier unit, a single-phase PWM inverter unit, a three-phase PWM inverter unit, a full-bridge DAB conversion unit, a full-bridge CLLC bidirectional DC / DC conversion unit, a photovoltaic panel, a diesel generator, a battery, a DC load 1, a DC load 2, a single-phase AC load, a three-phase AC load, a high-voltage side DC bus, a low-voltage side DC bus, and a three-phase AC power grid;

[0077] The AC input side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the three-phase AC power grid, and the DC output side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the high-voltage side DC bus; the output end of the BUCK-BOOST conversion unit 1 is connected to the DC load 1, and the input end of the BUCK-BOOST conversion unit 1 is connected to the high-voltage side DC bus; the low-voltage input end of the bidirectional BUCK-BOOST conversion unit is connected to the battery;

[0078] The high-voltage output end of the bidirectional BUCK-BOOST conversion unit is connected to the low-voltage side DC bus; the low-voltage input end of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel, and the high-voltage output end of the non-isolated high-gain DC / DC conversion unit is connected to the low-voltage side DC bus; the input end of the three-phase PWM rectifier unit is connected to the diesel generator, and the output end of the three-phase PWM rectifier unit is connected to the high-voltage side DC bus; the input end of the single-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the single-phase PWM inverter unit is connected to the single-phase AC load; the input end of the three-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the three-phase PWM inverter unit is connected to the three-phase AC load; the output end of the BUCK-BOOST conversion unit 2 is connected to the DC Load 2, the input end of the BUCK-BOOST conversion unit 2 is connected to the low-voltage side DC bus; the high-voltage side positive pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the positive pole of the high-voltage side DC bus, the high-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the high-voltage side positive pole of the full-bridge DAB conversion unit, and the high-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the high-voltage side DC bus; the low-voltage side positive pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the negative pole of the low-voltage side DC bus; the low-voltage side positive pole of the full-bridge DAB conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the low-voltage side DC bus.

[0079] The non-isolated high-gain DC / DC conversion unit is as follows: Figure 3 As shown, it is a unidirectional transmission boost converter, which specifically includes power diodes D0, D1, D2, D3, D4, D5, D6, D7, inductors L1, L2, L3, capacitors C, C0, and the controlled IGBT switch tube VT; the low-voltage side of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel;

[0080] The positive pole of the photovoltaic panel is respectively connected to one end of the inductor L1 and the anode of the power diode D2, which is the high level side of the DC input end. The other end of L1 is connected to the anode of D1, and the cathode of D1 is connected to the cathode of D2. L1, D1, and D2 are connected to form a charge and discharge unit; one end of the inductor L2 is connected to the anode of the power diode D5, and the other end of the inductor L2 is connected to the anode of D4, and the cathode of D4 is connected to the cathode of D5. L2, D4, and D5 are connected to form a charge and discharge unit; the anode of D5 is connected to the cathode of D2 and D1, the anode of D3 is connected to the anode of D1, and the cathode of D3 is connected to the anode of D4, and the two charge and discharge units are connected; one end of the inductor L3 is connected to D4, D 5, the anode of the power diode D6 is connected to the cathode of D3, the cathode of D6 is connected to the other end of L3, the anode of D7 is connected to the cathode of D5, one end of the capacitor C is connected to the cathode of D7, the other end of C is connected to the cathode of D6, and the cathode of D6 is connected to the collector of the IGBT switch tube VT; the anode of D0 is connected to the cathode of D7, one end of the capacitor C0 is connected to the cathode of D0, and the other end of C0 is connected to the emitter of VT, the low-voltage side DC bus is connected to both ends of C0, which is the high-voltage side of the unidirectional transmission boost converter. The high-voltage side of the unidirectional transmission boost converter is the converter output end, which is connected to the low-voltage side DC bus; the negative end of the low-voltage side DC bus and the emitter of VT are connected to the negative end of the photovoltaic panel;

[0081] In this embodiment, the non-isolated, high-gain DC / DC converter unit controls the voltage regulation range by controlling VT. When switch VT is turned on, power diodes D2, D3, D5, D6, and D7 are forward biased, and inductors L1, L2, and L3 are connected in parallel. Inductors L1, L2, and L3, along with the capacitor, are simultaneously charged to full voltage. Simultaneously, diodes D1, D4, and D0 are reverse biased, and C0 supplies power to the load. In this topology, the DC power supply forms a circuit with L1-D3-D6-VT, D2-L2-D6-VT, D2-D5-L3-VT, and D2-D5-DT-C-VT, respectively. The DC load side forms a discharge circuit with C0. When switch VT is turned off, power diodes D1, D4, and D0 are forward biased, and inductors L1, L2, and L3 are connected in series. The energy stored in inductors L1, L2, and L3 is discharged to the load along capacitor C, charging capacitor C0. At the same time, diodes D2, D3, D5, D6, and D7 are reverse biased, forming a single loop L1-D1-L2-D4-L3-C-D0-(C0 / DC load) in the topology.

[0082] The energy router device is divided into different working modes according to the energy flow status of each module port, including:

[0083] The three-phase PWM bidirectional DC / AC conversion unit is divided into non-conduction mode, rectification conduction mode, and inverter conduction mode;

[0084] The bidirectional BUCK-BOOST conversion unit is divided into non-conduction mode, input mode, and output mode; corresponding to the battery's sleep mode, discharge mode, and charge mode;

[0085] The charging mode is switched according to the amount of electrical energy stored in the battery.

[0086] On the other hand, a dual-bus AC / DC hybrid energy routing control method is implemented based on the aforementioned dual-bus AC / DC hybrid energy routing system, such as Figure 4 、 Figure 5 As shown, the specific steps include:

[0087] Step 1: Sample the voltage and current of the photovoltaic panels, diesel generators, batteries, three-phase AC grid, and all loads in the energy router;

[0088] Step 2: Establish a power balance equation that satisfies the operating state of the dual-bus AC / DC hybrid energy router and discretize the equation;

[0089] The power balance equation at any time t is:

[0090] P G (t)+P C (t)-P F (t)+F J (t)P J (t)+F X (t)P X (t) = 0

[0091] P G (t), P C (t), P F (t), P J (t), P X (t) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power; F J (k) is the grid-side switching function, which inputs power from the AC grid side and has a value of 1, and outputs power to the AC grid side and has a value of -1; F X (k) is the energy storage switch function, which inputs power from the battery side and has a value of 1, and outputs power to the battery side and has a value of -1;

[0092] The power balance equation in the kth sampling period is as follows:

[0093] P G (k)+P C (k)-P F (k)+F J (k)P J (k)+FX (k)P X (k) = 0

[0094] Where k represents the kth sampling period of the energy router; P G (k), P C (k), P F (k), P J (k), P X (k) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power in the kth sampling period;

[0095] The specific expression of the sum of the load power of each port of the dual busbar of the energy router is as follows:

[0096] P G (k)=U c (k)I c (k)

[0097] P C (k)=U C (k)I C (k)

[0098] P J (k)=U J (k)I J (k)

[0099] P X (k)=U X (k)I X (k)

[0100] P F (k)=U H (k)I HF (k)+U L (k)I LF (k)

[0101] Among them U G (k), I G (k), U C (k), I C (k), U HF (k), I HF (k), U LF (k), I LF (k), U X (k), I X(k) are respectively the sum of the PV side voltage sampling value, PV side current sampling value, diesel generator side voltage sampling value, diesel generator side current sampling value, high-voltage side load voltage sampling value, high-voltage side load current sampling value, low-voltage side load voltage sampling value, low-voltage side load low-voltage side DC bus side current sampling value, AC grid high-voltage side DC bus side voltage sampling value, AC grid high-voltage side DC bus side input current sampling value, battery side voltage sampling value, and battery side current sampling value;

[0102] Step 3: The three-phase PWM bidirectional DC / AC conversion unit is in the conduction mode. An average switching dynamic equation is established for the three-phase PWM bidirectional DC / AC conversion unit. The average switching dynamic equation is as follows:

[0103]

[0104]

[0105]

[0106] in and V IC-DC 、i IC-ab c and v ICO-abc Average switching dynamic value; V IC-DC : DC side voltage of three-phase PWM bidirectional DC / AC conversion unit; i IC-abc : filter inductor current vector of the three-phase PWM bidirectional DC / AC conversion unit; v ICO-abc : AC side filter voltage phasor of three-phase PWM bidirectional DC / AC conversion unit; i Ic-DC : DC side current of three-phase PWM bidirectional DC / AC conversion unit; u abc-ave : average switching voltage vector of the three-phase PWM bidirectional DC / AC conversion unit; L IC-AC 、R IC-AC 、C IC-AC 、C IC-DC They represent the filter inductor, filter resistor, filter capacitor and DC link capacitor of the three-phase PWM bidirectional DC / AC conversion unit respectively; i ICO-abc : AC output current vector of the three-phase PWM bidirectional DC / AC conversion unit;

[0107] Step 4: Discretize the average switching dynamic equation of the three-phase PWM bidirectional DC / AC conversion unit and establish a periodic sampling function. The periodic sampling function is shown in the following formula:

[0108] v ICO-abc (k+1)=f1(v ICO - abc (k),…,vICO-abc (kd y1 ),u abc-abe (k),…,u abc-ave (kd u ))

[0109] V IC-DC (k+1)=f2(V IC-DC (k)…, V IC-DC (kd y2 )u abc-ave (k),…,u abc-ave (kd u ))

[0110]

[0111] u abc_ave =[u a_ave ,u b_ave ,u c_abe ] T

[0112] where d y1 d y2 d u is the model order, f1 and f2 represent the parameter-driven nonlinear function; is the three-phase voltage of a, b, c; u a_ave， u b_ave， u c_ave is the average switching state of the three-phase voltages a, b, and c;

[0113] Step 5: Check the remaining battery power; when the battery is fully charged, the battery enters sleep mode;

[0114] When the battery is not fully charged, it is determined whether the remaining battery power is greater than 0.5. If so, the battery is charged in constant voltage control mode, otherwise the battery module is charged in constant current control mode;

[0115] Step 6: Establish the per-unit transfer function of the active power of the double droop control based on the DC side control voltage level and the AC side control AC frequency;

[0116] According to the different working modes of the battery, the droop coefficient of the three-phase PWM bidirectional DC / AC conversion unit of the energy router is updated as shown in the following formula:

[0117]

[0118]

[0119] in, t k When the double sag curve is consistent value; t k+1 AC angular frequency; t k+1 When DC droop voltage; is the angular frequency change value within k+1 sampling period, k ac and k dc is the droop coefficient of the AC side and the DC side;

[0120] Generate a power instruction and establish a power instruction function connecting the AC grid and the energy router, as shown in the following formula:

[0121]

[0122] Where ΔP Lac is the change value of the AC side load power; ΔP Lac is the change value of DC side load power; is the power command value of the kth sampling period;

[0123] Step 7: Design an observation device to estimate the observation coefficient matrix Φ(k), and obtain the observation device and its corresponding self-matching update function, as shown in the following formula:

[0124]

[0125] in for estimated value; Transpose the observation coefficient vector of column i;

[0126] V i (k) is the i-th vector of the DC side voltage dynamic change matrix in the k-th cycle; ||ΔU(k)|| is the norm of the AC side voltage dynamic change matrix within the stable step length L;

[0127] Step 8: Given the control input linearization length L, when ||ΔU(k)|| is not equal to 0, define the real variable parameter matrix Φ(l) of the pseudo-block linear matrix. Based on the per-unit values ​​of the reference voltage and reference frequency, an equivalent partial format dynamic fitting parameter model is obtained based on the parameter-driven partial format dynamic fitting method, as shown in the following equation:

[0128] ΔV(k+1)=Φ(k)ΔU(k)

[0129] ΔU(k)=[Δu T (k),…,Δu T (k-L+1)] T =U(k)-U(k-1)

[0130] ΔV(k+1)=V(k+1)-V(k)

[0131] Δu(k-i+1)=u(k-i+1)-u(ki), i=1,...,L,

[0132]

[0133] Where L is the linearization step size of the partial format; ΔV(k+1) is the DC side voltage dynamic change matrix; ΔU(k) ​​is the AC side voltage dynamic change matrix within the stable step size L; Φ(k) is the observation coefficient matrix;

[0134] Step 10: Design a parameter-driven dynamic fitting voltage controller for the three-phase PWM bidirectional DC / AC conversion unit, estimate the parameter values ​​of the pseudo-block linear matrix Ф(k), and establish the parameter-driven voltage control equation for the three-phase PWM bidirectional DC / AC conversion unit:

[0135] When ||ΔU(k)||≤δ,

[0136]

[0137] in is the estimated value of the DC side voltage matrix in the k+1th cycle;

[0138] When ||ΔU(k)||>δ,

[0139] u(k)=u(k-1)+δ·sign(ΔU(k))

[0140] Where V * (k) is the reference trajectory, the diagonal matrix α = diag(α1, α2, α3, α4); α i is the stability coefficient of the i-th vector; δ is the linearization step threshold; sign() is the sign function;

[0141] Step 11: Perform an inverse z-transform on the parameter drive voltage control equation of the three-phase PWM bidirectional DC / AC conversion unit, perform PWM modulation, and control the DC bus voltage on the high-voltage side of the DC end of the three-phase PWM bidirectional DC / AC conversion unit of the energy router to complete the power transmission of the energy router.

[0142] The above description is merely a preferred embodiment of the present disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also encompass other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned inventive concept. For example, a technical solution formed by mutually replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A dual-bus AC / DC hybrid energy routing system, characterized in that: It includes a three-phase PWM bidirectional DC / AC conversion unit, a BUCK-BOOST conversion unit 1, a BUCK-BOOST conversion unit 2, a bidirectional BUCK-BOOST conversion unit, a non-isolated high-gain DC / DC conversion unit, a three-phase PWM rectifier unit, a single-phase PWM inverter unit, a three-phase PWM inverter unit, a full-bridge DAB conversion unit, a full-bridge CLLC bidirectional DC / DC conversion unit, a photovoltaic panel, a diesel generator, a battery, a DC load 1, a DC load 2, a single-phase AC load, a three-phase AC load, a high-voltage side DC bus, a low-voltage side DC bus, and a three-phase AC power grid; The AC input side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the three-phase AC power grid, and the DC output side of the three-phase PWM bidirectional DC / AC conversion unit is connected to the high-voltage side DC bus; the output end of the BUCK-BOOST conversion unit 1 is connected to the DC load 1, and the input end of the BUCK-BOOST conversion unit 1 is connected to the high-voltage side DC bus; the low-voltage input end of the bidirectional BUCK-BOOST conversion unit is connected to the battery; the high-voltage output end of the bidirectional BUCK-BOOST conversion unit is connected to the low-voltage side DC bus; the low-voltage input end of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel, and the high-voltage output end of the non-isolated high-gain DC / DC conversion unit is connected to the low-voltage side DC bus; The input end of the three-phase PWM rectifier unit is connected to the diesel generator, and the output end of the three-phase PWM rectifier unit is connected to the high-voltage side DC bus; the input end of the single-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the single-phase PWM inverter unit is connected to the single-phase AC load; the input end of the three-phase PWM inverter unit is connected to the low-voltage side DC bus, and the output end of the three-phase PWM inverter unit is connected to the three-phase AC load; the output end of the BUCK-BOOST conversion unit 2 is connected to the DC load 2, and the input end of the BUCK-BOOST conversion unit 2 is connected to the low-voltage side DC bus; the full-bridge CLLC bidirectional DC / DC The high-voltage side positive pole of the conversion unit is connected to the positive pole of the high-voltage side DC bus, the high-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the high-voltage side positive pole of the full-bridge DAB conversion unit, and the high-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the high-voltage side DC bus; the low-voltage side positive pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge CLLC bidirectional DC / DC conversion unit is connected to the negative pole of the low-voltage side DC bus; the low-voltage side positive pole of the full-bridge DAB conversion unit is connected to the positive pole of the low-voltage side DC bus, and the low-voltage side negative pole of the full-bridge DAB conversion unit is connected to the negative pole of the low-voltage side DC bus.

2. A dual-bus AC / DC hybrid energy routing system according to claim 1, characterized in that: The non-isolated high-gain DC / DC conversion unit is a unidirectional transmission boost converter, specifically including power diodes D0, D1, D2, D3, D4, D5, D6, D7, inductors L1, L2, L3, capacitors C, C0, and IGBT switch tube VT; the low-voltage side of the non-isolated high-gain DC / DC conversion unit is connected to the photovoltaic panel; the positive electrode of the photovoltaic panel is respectively connected to one end of the inductor L1 and the anode of the power diode D2, the other end of L1 is connected to the anode of D1, and the cathode of D1 is connected to the cathode of D2, one end of the inductor L2 is connected to the anode of the power diode D5, the other end of the inductor L2 is connected to the anode of D4, and the cathode of D4 is connected to the cathode of D5, L2, D4, and D5 are connected to form a charging and discharging unit; the anode of D5 is connected to the cathodes of D2 and D1, and the anode of D3 is connected to the cathode of D2. The anode of D1 is connected, the cathode of D3 is connected to the anode of D4, one end of the inductor L3 is connected to the cathodes of D4 and D5, the anode of the power diode D6 is connected to the cathode of D3, the cathode of D6 is connected to the other end of L3, the anode of D7 is connected to the cathode of D5, one end of the capacitor C is connected to the cathode of D7, the other end of C is connected to the cathode of D6, and the cathode of D6 is connected to the collector of the IGBT switch tube VT; the anode of D0 is connected to the cathode of D7, one end of the capacitor C0 is connected to the cathode of D0, and the other end of C0 is connected to the emitter of VT. The low-voltage side DC bus is connected to both ends of C0, which is the high-voltage side of the unidirectional transmission boost converter. The high-voltage side of the unidirectional transmission boost converter is the converter output end, which is connected to the low-voltage side DC bus; the negative end of the low-voltage side DC bus and the emitter of VT are connected to the negative end of the photovoltaic panel.

3. A dual-bus AC / DC hybrid energy routing control method, implemented based on the dual-bus AC / DC hybrid energy routing system according to claim 1, characterized in that: The following steps are involved: Step 1: Sample the voltage and current of the photovoltaic panels, diesel generators, batteries, three-phase AC grid, and all loads in the energy router; Step 2: Based on the power balance equation at any time t, establish the power balance equation that satisfies the operating state of the dual-bus AC / DC hybrid energy router and discretize the equation; Step 3: The three-phase PWM bidirectional DC / AC conversion unit is in the conduction mode, and an average switching dynamic equation is established for the three-phase PWM bidirectional DC / AC conversion unit; Step 4: Discretize the average switching dynamic equation of the three-phase PWM bidirectional DC / AC conversion unit and establish a periodic sampling function; Step 5: Check the remaining battery power; when the battery is fully charged, the battery enters sleep mode; When the battery is not fully charged, it is determined whether the remaining battery power is greater than 0.

5. If so, the battery is charged in constant voltage control mode, otherwise the battery module is charged in constant current control mode; Step 6: Based on the DC side control voltage level and the AC side control AC frequency, establish the per-unit active power transfer function of the dual droop control; update the droop coefficient of the energy router's three-phase PWM bidirectional DC / AC conversion unit according to the different operating modes of the battery; Step 7: Design an observation device to estimate the observation coefficient matrix Φ(k), and obtain the observation device and its corresponding self-matching update function; Step 8: Given the control input linearization length L, when ‖ΔU(k)‖ is not equal to 0, define the real variable parameter matrix Φ(l) of the pseudo-block linear matrix. Based on the per-unit values ​​of the reference voltage and reference frequency, an equivalent partial format dynamic fitting parameter model is obtained based on the parameter-driven partial format dynamic fitting method. Step 9: Design a parameter-driven dynamic fitting voltage controller for the three-phase PWM bidirectional DC / AC conversion unit, estimate the parameter values ​​of the pseudo-block linear matrix Φ(k), and establish the parameter-driven voltage control equation for the three-phase PWM bidirectional DC / AC conversion unit: Step 10: Perform an inverse z-transform on the parameter drive voltage control equation of the three-phase PWM bidirectional DC / AC conversion unit, perform PWM modulation, and control the DC bus voltage on the high-voltage side of the DC end of the three-phase PWM bidirectional DC / AC conversion unit of the energy router to complete the power transmission of the energy router.

4. A dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The power balance equation at any time t described in step 2 is: P G (t)+P C (t)-P F (t)+F J (t)P J (t)+F X (t)P X (t)=0 P G (t), P C (t), P F (t), P J (t), P X (t) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power; F J (k) is the grid-side switching function, which inputs power from the AC grid side and has a value of 1, and outputs power to the AC grid side and has a value of -1; F X (k) is the energy storage switch function, which inputs power from the battery side and has a value of 1, and outputs power to the battery side and has a value of -1; The power balance equation in the kth sampling period is as follows: P G (k)+P C (k)-P F (k)+F J (k)P J (k)+F X (k)P X (k)=0 Where k represents the kth sampling period of the energy router; P G (k), P C (k), P F (k), P J (k), P X (k) is the input power of the photovoltaic unit side, the input power of the diesel generator side, the total load power, the AC grid side power and the battery side power in the kth sampling period; The specific expression of the sum of the load power of each port of the dual busbar of the energy router is as follows: P G (k)=U G (k)I G (k) P C (k)=U C (k)I C (k) P J (k)=U J (k)I J (k) P X (k)=U X (k)I X (k) P F (k)=U H (k)I HF (k)+U L (k)I LF (k) Among them U G (k), I G (k), U C (k), I C (k), U HF (k), I HF (k), U LF (k), I LF (k), U X (k), I X (k) are respectively the PV side voltage sampling value, PV side current sampling value, diesel generator side voltage sampling value, diesel generator side current sampling value, high-voltage side load voltage sampling value, high-voltage side load current sampling value, low-voltage side load voltage sampling value, the sum of the low-voltage side load low-voltage side DC bus side current sampling value, AC grid high-voltage side DC bus side voltage sampling value, AC grid high-voltage side DC bus side input current sampling value, battery side voltage sampling value, and battery side current sampling value.

5. A dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The average switching dynamic equation described in step 3 is as follows: in and V IC-DC 、i IC-abc and v ICO-abc Average switching dynamic value; V IC-DC : DC side voltage of three-phase PWM bidirectional DC / AC conversion unit; i IC-abc : filter inductor current vector of the three-phase PWM bidirectional DC / AC conversion unit; v ICO-abc : AC side filter voltage phasor of three-phase PWM bidirectional DC / AC conversion unit; i IC-DC : DC side current of three-phase PWM bidirectional DC / AC conversion unit; u abc-ave : average switching voltage vector of the three-phase PWM bidirectional DC / AC conversion unit; L IC-AC 、R IC-AC 、C IC-AC 、C IC-DC They represent the filter inductor, filter resistor, filter capacitor and DC link capacitor of the three-phase PWM bidirectional DC / AC conversion unit respectively; i ICO-abc : AC output current vector of the three-phase PWM bidirectional DC / AC conversion unit.

6. A dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The periodic sampling function described in step 4 is shown below: v ICO-abc (k+1)=f1(v ICO-abc (k),…,v ICO-abc (k-d y1 ),u abc-ave (k),…,u abc-ave (k-d u )) In IC-DC (k+1)=f2(V IC-DC (k)…,V IC-DC (when y2 )u abc-ave (k),…,u abc-ave (when u )) in abc-ave =[in a-ave ,in b-ave ,in c-ave ] T where d y1 d y2 d u is the model order, f1 and f2 represent the parameter-driven nonlinear function; is the three-phase voltage of a, b, c; u a-ave ,u b-ave ,u c-ave is the average switching state of the three-phase voltage a, b, and c.

7. A dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The droop coefficient described in step 6 is as follows: in, t k When the double sag curve is consistent value; t k+1 AC angular frequency; t k+1 When DC droop voltage; is the angular frequency change value within k+1 sampling period, k ac and k dc is the droop coefficient of the AC side and the DC side; Generate a power instruction and establish a power instruction function connecting the AC grid and the energy router, as shown in the following formula: Where ΔP Lac is the change value of the AC side load power; ΔP Lac is the change value of DC side load power; is the power command value of the kth sampling period.

8. The dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The self-matching update function in step 7 is as follows: in for estimated value; Transpose the observation coefficient vector of column i; V i (k) is the i-th vector of the DC side voltage dynamic change matrix in the k-th cycle; ||ΔU(k)|| is the norm of the AC side voltage dynamic change matrix within the stable step length L.

9. The dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The partial format dynamic fitting parameter model described in step 8 is shown as follows: ΔV(k+1)=Φ(k)ΔU(k) ΔU(k)=[Δu T (k),…,Δu T (k-L+1)] T =U(k)-U(k-1) ΔV(k+1)=V(k+1)-V(k) Δu(k-i+1)=u(k-i+1)-u(ki),i=1,…,L, Where L is the linearization step size of the partial format; ΔV(k+1) is the dynamic change matrix of the DC side voltage; ΔU(k) ​​is the dynamic change matrix of the AC side voltage within the stable step size L; Φ(k) is the observation coefficient matrix.

10. A dual-bus AC / DC hybrid energy routing control method according to claim 3, characterized in that: The parameter drive voltage control equation of the three-phase PWM bidirectional DC / AC conversion unit in step 9 is: When ||ΔU(k)||≤δ, in is the estimated value of the DC side voltage matrix in the k+1th cycle; When ||ΔU(k)||>δ, u(k)=u(k-1)+δ·sign(ΔU(k)) Where the diagonal matrix α=diag(α1,α2,α3,α4); i is the stability coefficient of the i-th vector; δ is the linearization step threshold; sign() is the sign function.

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