CN105656318A - Alternating current/direct current energy reclaiming type electronic simulation loading device and control method thereof - Google Patents

Abstract

The invention relates to an alternating current/direct current energy reclaiming type electronic simulation loading device and a control method of the alternating current/direct current energy reclaiming type electronic simulation loading device. The alternating current/direct current energy reclaiming type electronic simulation loading device is composed of a controller, an input side transform unit, an input side H-bridge inversion unit, an isolation high-frequency transformer, an output side H-bridge rectifying unit, an output side conversion unit, a display unit, an input voltage mutual inductor, an input current mutual inductor, an output voltage mutual inductor, an output current mutual inductor, a direct current voltage mutual inductor, an input alternating current terminal, an output alternating current terminal and an output direct current terminal. The alternating current/direct current energy reclaiming type electronic simulation loading device is an energy feedback electronic simulation loading device, and can output feedback to an alternating current or direct current power supply, and the input side can simulate three modes of constant power, constant current and constant impedance; and besides, the alternating current/direct current energy reclaiming type electronic simulation loading device can simulate various load characteristic curves and has adjustable power factor, and the device can be set by a display unit panel or by an upper computer through communication. The loading testing study is remarkably advantageous in electricity saving, and has the characteristics of flexibly simulating various loading characteristics and realizing alternating current/direct current feedback.

Description

Alternating current/direct current energy feedback type electronic simulation load device and control method thereof

Technical Field

The invention relates to the technical field of power electronics, in particular to an alternating current/direct current energy feedback type electronic simulation load device and a control method thereof.

Background

With the increasingly wide application of power electronic devices, new products and new technologies are increasing. At present, various power electronic devices are subjected to factory experiments and reliability experiments (mainly aging experiments) before use, which are physical experiments generally by adopting a resistance energy consumption discharge method, and other load characteristics are difficult to test and experiment. To overcome this problem, tests are required to be performed with electronic analog power loads. The device is designed and realized by utilizing a power electronic technology, a computer control technology and an electric power system automation technology and is used for carrying out examination tests on various direct-current power supplies.

On one hand, the maximum amount of electric energy absorbed by the tested power supply can be recycled for the tested power supply, and the loss of the electric energy is only the switching loss and the line loss of the PWM converter, so that the energy is saved to the maximum extent; on the other hand, the adopted PWM converter works in a switching state, so that the requirement of high-power application is easily met compared with the common electronic load working in an amplifying state, and the PWM converter has a wider application field.

The invention is used for replacing the traditional resistance type power load to carry out related power experiments, can also be applied to the test experiments of instrument equipment, and meets the IEEE-519 standard. Compared with a resistance type load, the invention has the advantages that firstly, because the working mode of the invention is to utilize the power electronic transformation technology to feed back the output energy of the equipment to be tested to the power grid on the premise of completing the test power experiment, the energy is saved, and on the other hand, a large amount of heat is not generated, thereby avoiding the problem of the rise of the environmental temperature of the test place; ② small volume and light weight. Because the electronic load does not change the tested power into heat, a resistor box and cooling equipment which are bulky do not need to be used, and the installation space is saved; and the simulated power is continuously adjustable. As is known, the resistive load has to be adjusted in steps when the power is high, and is greatly limited when in use, a user can set a required power (or power output current) -time change curve through a computer interface when in specific use, and the load of the device is strictly operated according to the setting after the device is started; and fourthly, because an energy feedback mode is adopted, a large power supply capacity does not need to be equipped in a test site. The existing electronic feedback load has a single function and is difficult to meet the technical requirements of power electronics which are developed at a high speed.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an ac/dc energy feedback type electronic simulation load device and a control method thereof, which have the advantages of obvious power saving advantages in load test and research, and the characteristics of flexibly simulating various load characteristics and ac/dc feedback.

The technical solution of the invention is as follows:

an AC/DC energy feedback type electronic simulation load device is characterized by comprising: a controller, an input side conversion unit, an input side H bridge inversion unit, an isolation high-frequency transformer, an output side H bridge rectification unit, an output side conversion unit, an input voltage transformer, an input current transformer, an output voltage transformer, an output current transformer, a direct current voltage transformer, an input alternating current terminal, an output direct current terminal and a display unit,

the input end of the input side conversion unit is connected with the input alternating current terminal, the output end of the input side conversion unit is connected with the input end of the input side H-bridge inversion unit, the output end of the input side H-bridge inversion unit is connected with the input end of the isolation high-frequency transformer, the output end of the isolation high-frequency transformer is connected with the input end of the output side H-bridge rectification unit, the output end of the output side H-bridge rectification unit is connected with the input end of the output side conversion unit, and the output end of the output side conversion unit is connected with the output alternating current terminal; the output direct current terminal is connected with the output end of the output side H bridge rectifying unit; the input side of the direct-current voltage sensor is connected with the output end of the output side H bridge rectifying unit;

the input side of the input voltage transformer is connected with the main circuit of the input end of the input side conversion unit, and the voltage signal output end of the input voltage transformer is connected with the input voltage signal input end corresponding to the controller; the input current transformer is connected in series in a circuit between the input side conversion unit and the input alternating current terminal, and an alternating current signal output end of the input current transformer is connected with an alternating current input current signal input end of the controller;

the input side of the output voltage transformer is connected with the main circuit of the output end of the output side conversion unit, and the voltage signal output end of the output voltage transformer is connected with the input port of the controller for outputting an alternating current voltage signal; the output current transformer is connected in series in a circuit of the output end of the output side conversion unit, and a current signal output end of the output current transformer is connected with an output current signal input end of the controller; the voltage signal output end of the direct-current voltage sensor is connected with the direct-current voltage signal input port of the controller;

the output PWM signal of the controller_S123、PWM_O123The port is respectively connected with the PWM control signal end of the input side conversion unit and the PWM control signal end of the output side conversion unit; the local communication port of the controller is connected with the communication port of the display unit, and the remote communication port of the controller is connected with the upper computer in a communication way.

The input side conversion unit and the output side conversion unit both comprise a three-phase inversion structure and a public direct-current bus capacitor, wherein the three-phase inversion structure is connected with alternating current three phases, and each phase of inversion structure comprises: the inverter comprises a first insulated gate bipolar transistor (IGBT for short) and a second IGBT, wherein the emitter of the first IGBT is connected with the collector of the second IGBT, the collector of the first IGBT is connected with the emitter of the second IGBT through a common direct current bus capacitor, and the control ends of the first IGBT and the second IGBT are used as the control ends of an inverter unitThe two ends of the public direct current bus capacitor are direct current input ends of the inversion unit, and the voltage of the public direct current bus capacitor is the direct current voltage U of the inversion unit_DC；

Because the control signals of the control end of the first IGBT and the control end of the second IGBT are opposite, the inversion unit PWM signal output by the inversion unit PWM signal output end of the control unit can generate an opposite inversion unit PWM signal through an external phase inverter or the control unit, and then the inversion unit PWM signal and the opposite inversion unit PWM signal are correspondingly input into the control end of the first IGBT and the control end of the second IGBT.

Input side H bridge inverter unit and output side H bridge inverter unit all include: the emitter of the first IGBT is connected with the collector of the third IGBT, and the collector of the first IGBT is connected with the emitter of the third IGBT through a common direct current bus capacitor; the emitter of the second IGBT is connected with the collector of the fourth IGBT, and the collector of the second IGBT is connected with the emitter of the fourth IGBT through the common direct current bus capacitor;

the control signals of the control end of the first IGBT and the control end of the third IGBT are opposite, and the control signals of the control end of the second IGBT and the control end of the fourth IGBT are opposite; the control signals of the control end of the first IGBT and the control end of the fourth IGBT are the same, the control signals of the control end of the second IGBT and the control end of the third IGBT are the same, and the control signals are locally generated and are signals with 10 k-50 kHz frequency and 50% duty ratio.

The control method of the alternating current-direct current energy feedback type electronic simulation load device is characterized by comprising an output side conversion unit control method, an input side conversion unit control method and an energy feedback optimization method.

The method for controlling the output side conversion unit includes the following steps:

① control parameter 1 for 1 st, 2 nd and 3 rd proportional integrators<k_p1<100、0.1<k_i1<10、1<k_p2<100、0.1<k_i2<10、1<k_p3<100、0.1<k_i3<10, measuring the output side AC voltage u_oAC current i_oAnd from this, the output side AC voltage amplitude U is obtained_sOutput side AC current amplitude I_d、I_qAnd a power angle theta of the output side alternating voltage and the alternating current;

② setting given DC voltage value U_DCrefMeasuring the DC voltage U_DCWill set a given value U of DC voltage_DCrefAnd the measured DC voltage U_DCThe difference between the two values is controlled by the 1 st proportional-integral device_d0Comprises the following steps:

u_d0＝k_p1*(U_DCref-U_DC)+k_i1*∫(U_DCref-U_DC)dt

wherein, U_DCrefThe voltage is a given value of direct current voltage, and the per unit value is 1-1.2;

③ combining the output value of the 1 st proportional integrator with the measured output side AC voltage U_SAnd current I_dObtaining the active power control quantity u of the inversion unit by the 2 nd proportional integrator_dThe concrete formula is as follows:

u_d＝k_p2*(u_d0-I_d)+k_i2*∫(u_d0-I_d)dt+U_S

④ measured output side AC current I_qObtaining the reactive power control quantity u of the inversion unit through a 3 rd proportional integrator_qThe concrete formula is as follows:

u_q＝k_p3*I_q+k_i3*∫I_qdt；

⑤ according to the reactive power control quantity u_qActive power control quantity u_dAnd after dq-abc park inverse transformation, obtaining a three-phase inversion unit Pulse Width Modulation (PWM) signal:

the output voltage of the output side conversion unit is adjusted.

The input side conversion unit control method comprises the following steps:

step 1, constant power control:

and selecting the constant power control, wherein the constant power control is as follows:

① control parameter 1 of 4 th proportional integrator, 5 th proportional integrator and 6 th proportional integrator<k_p4<100、0.1<k_i4<10、1<k_p5<100、0.1<k_i5<10、1<k_p6<100、0.1<k_i6<10、1<k_p7<100、0.1<k_i7<10, measuring the input-side AC voltage u_sAC current i_sAnd from this, the input-side AC voltage amplitude U is obtained_S1Input side alternating current amplitude I_d1、I_q1And the power angle theta of the input side AC voltage and the AC current₂Calculating active power P ═ U_S1×I_d1Reactive power Q ═ U_S1×I_q1；

② setting active power given value P_refA 1 is to P_refAnd the difference between the calculated P and the P is subjected to the 4 th proportional-integral control, and the intermediate control amount u is calculated according to the following formula_d20：

u_d20＝k_p4*(P_ref-P)+k_i4*∫(P_ref-P)dt

③ according to the 4 th proportional productIntermediate control quantity u of divider output_d20Combined with measured input-side AC voltage U_S1And current I_d1Obtaining the control quantity u of the inversion unit by the following formula_d2：

u_d2＝k_p5*(u_d20-I_d1)+k_i5*∫(u_d20-I_d1)dt+U_S1

④ setting reactive power set value Q_refIs mixing Q with_refThe difference between the calculated reactive power Q and the calculated reactive power Q is controlled by a 6 th proportional integrator, and an intermediate control quantity u is calculated according to the following formula_q20：

u_q20＝k_p6*(Q_ref-Q)+k_i6*∫(Q_ref-Q)dt

⑤ according to the output value of the 6 th proportional integrator, combined with the measured input side alternating current I_q1And calculating the control quantity u of the inversion unit according to the following formula through 7 th proportional-integral control_q2：

u_q2＝k_p7*(u_q20-I_q1)+k_i7*∫(u_q20-I_q1)dt

⑥ according to the control quantity u_d2、u_q2And after dq-abc park inverse transformation, obtaining a three-phase inversion unit Pulse Width Modulation (PWM) signal:

the output voltage of the input-side conversion unit is adjusted.

Step 2, constant current control:

under the constant current control, the constant current control is selected as follows: giving the value of the active current I_drefIn the above step, u_d20＝I_dref；

Step 3, constant resistance control:

under the control of selecting constant resistance, the constant resistance is controlled as follows: given resistance reference value R_refIn the above step 1, u_d20＝U_s1/I_dref。

The energy feedback optimization model function of the energy feedback optimization method is as follows:

$\&lsqb;P_{loss}\&rsqb;=MinObjects({\left(u_{d2}-u_d\right)}^2+{\left(u_{q2}-u_q\right)}^2+{\left(U_{DC}-{\stackrel{\&OverBar;}{U}}_{DC}\right)}^2)$

wherein,is U_DCAverage value of (a).

The invention has the following characteristics:

1. the invention relates to an electronic simulation load with energy feedback, which carries out energy feedback through an alternating current or direct current power supply.

2. The invention can simulate three modes of constant power, constant current and constant impedance, and the power factor is adjustable.

3. The invention can simulate various load characteristic curves and is set through the display unit panel, and also can be set through the upper computer through communication.

4. The load test of the invention has obvious power saving advantage.

Drawings

Fig. 1 is a schematic structural diagram of an ac/dc energy feedback type electronic analog load device according to the present invention.

Fig. 2 is a schematic diagram of an input/output side conversion unit topology of the present invention.

FIG. 3 is a schematic diagram of an I/O side H-bridge inverter unit according to the present invention.

Fig. 4 is a control block diagram of the output side conversion unit of the present invention.

Fig. 5 is a control block diagram of an input side conversion unit of the present invention.

Detailed Description

The present invention will be further described with reference to the following examples and drawings, but the scope of the present invention should not be limited thereto.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an ac/dc energy feedback type electronic analog load device according to the present invention. It can be seen from the figure that the ac/dc energy feedback type electronic simulation load device of the present invention comprises: the high-frequency isolation transformer comprises a controller 2, an input side conversion unit 3, an input side H bridge inverter unit 4, an isolation high-frequency transformer 5, an output side H bridge rectifier unit 6, an output side conversion unit 7, a display unit 16, an input voltage transformer 8, an input current transformer 9, an output voltage transformer 10, an output current transformer 11, a direct current voltage transformer 12, an input alternating current terminal 13, an output alternating current terminal 14 and an output direct current terminal 15.

The input end of the input side conversion unit 3 is connected with the input alternating current terminal 13, and the output end of the input side conversion unit 3 is connected with the input end of the input side H-bridge inverter unit 4; the output end of the input side H bridge inverter unit 4 is connected with the input end of the isolation high-frequency transformer 5; the output end of the isolation high-frequency transformer 5 is connected with the input end of the output side H bridge rectifying unit 6; the output end of the output side H bridge rectifying unit 6 is connected with the input end of the output side converting unit 7; the output end of the output side conversion unit 7 is connected with the output alternating current terminal 14; the output direct current terminal 15 is connected with the output end of the output side H bridge rectifying unit 6;

the input side of the input voltage transformer 8 is connected with the input end main circuit of the input side conversion unit 3, and the voltage signal output end of the input voltage transformer 8 is connected with the input voltage signal input port corresponding to the controller 2; the input current transformer 9 is connected in series in the input main circuit of the input side conversion unit 3, and the current signal output end of the input current transformer 9 is connected with the input current signal input port corresponding to the controller 2;

the input side of the output voltage transformer 10 is connected with the main circuit of the output end of the output side transformation unit 7, and the voltage signal output end of the output voltage transformer 10 is connected with the output voltage signal input port corresponding to the controller 2; the output current transformer 11 is connected in series in the output main circuit of the output side conversion unit 7, and the current signal output end of the output current transformer is connected with the output current signal input port corresponding to the controller 2;

the input side of the direct-current voltage sensor 12 is connected with the output direct-current end circuit of the output side H-bridge rectifying unit 6, and the voltage signal output end of the direct-current voltage sensor 12 is connected with the direct-current voltage signal input port corresponding to the controller 2;

the output pulse width modulation signal PWM of the controller 2_S123、PWM_O123The port is respectively connected with the PWM control signal end of the input side conversion unit 3 and the PWM control signal end of the output side conversion unit 7; the local communication port of the controller 2 is connected with the communication port of the display unit 16, and the remote communication port of the controller 2 is connected with the upper computer in a communication way.

In the ac/dc energy feedback type electronic analog load device system of the present invention, the input side conversion unit and the output side conversion unit include a three-phase inversion structure connected to an ac three-phase and a common dc bus capacitor, wherein each phase inversion structure includes: the power supply comprises a first Insulated Gate Bipolar Transistor (IGBT) and a second IGBT, wherein an emitter of the first IGBT is connected with a collector of the second IGBT, a collector of the first IGBT is connected with an emitter of the second IGBT through a common direct current bus capacitor, control ends of the first IGBT and the second IGBT serving as control ends of an inversion unit are connected with an inversion unit PWM signal output end of the control unit corresponding to a phase inversion unit PWM signal, and control ends of the first IGBT and the second IGBT are connected with an inversion unit PWM signal output end of the control unit corresponding to the phase inversion unit PWM signalThe signals are opposite, the collector of the second IGBT is the alternating current output end of the inversion unit, the two ends of the common direct current bus capacitor are the direct current input ends of the inversion unit, and the voltage of the common direct current bus capacitor is the direct current voltage U of the inversion unit_DC。

In the above scheme, since the control end of the first IGBT and the control end of the second IGBT have opposite signals, the inversion unit PWM signal output by the inversion unit PWM signal output end of the control unit may generate an opposite inversion unit PWM signal through the external inverter or from the inside of the control unit, and then the inversion unit PWM signal and the opposite inversion unit PWM signal are correspondingly input to the control end of the first IGBT and the control end of the second IGBT.

In the ac/dc energy feedback type electronic analog load device system of the present invention, the input side H-bridge inverter unit and the output side H-bridge inverter unit (see fig. 3) have the following structure: the IGBT comprises a first IGBT, a second IGBT, a third IGBT and a fourth IGBT, wherein the emitter of the first IGBT is connected with the collector of the third IGBT, and the collector of the first IGBT is connected with the emitter of the third IGBT through the common direct current bus capacitor; and the emitter of the second IGBT is connected with the collector of the fourth IGBT, and the collector of the second IGBT is connected with the emitter of the fourth IGBT through the common direct current bus capacitor.

The control signals of the control end of the first IGBT and the control end of the third IGBT are opposite, and the control signals of the control end of the second IGBT and the control end of the fourth IGBT are opposite; the control signals of the control end of the first IGBT and the control end of the fourth IGBT are the same, and the control signals of the control end of the second IGBT and the control end of the third IGBT are the same. The control signal is generated locally and is a signal with the frequency of 10 k-50 kHz and the duty ratio of 50%.

The invention also provides an alternating current and direct current energy-feedback type electronic simulation load control method,

referring to fig. 4, the method for controlling the output side conversion unit includes the steps of:

given the 1 st proportional-integral control PI1, the 2 nd proportional-integral PI2, and the 3 rd proportional-integral PControl parameter 1 of I3<k_p1<100、0.1<k_i1<10、1<k_p2<100、0.1<k_i2<10、1<k_p3<100、0.1<k_i3<10, measuring the output side AC voltage u_oAC current i_oAnd from this, the output side AC voltage amplitude U is obtained_sOutput side AC current amplitude I_d、I_qAnd the power angle theta of the output side alternating voltage and the alternating current.

Setting a given value U of DC voltage_DCrefMeasuring the DC voltage U_DCWill set a given value U of DC voltage_DCrefAnd the measured DC voltage U_DCThe difference is subjected to the 1 st proportional-integral control (PI1) to obtain an intermediate control amount u_d0The calculation formula is as follows:

u_d0＝k_p1*(U_DCref-U_DC)+k_i1*∫(U_DCref-U_DC)dt

wherein, U_DCrefThe voltage is a given value of direct current voltage, and the per unit value is 1-1.2.

The output value of the 1 st proportional integrator PI1 is combined with the measured output side alternating voltage U_SAnd current I_dObtaining the control quantity u of the inversion unit through the following formula containing a 2 nd proportional integrator PI2_dThe concrete formula is as follows:

u_d＝k_p2*(u_d0-I_d)+k_i2*∫(u_d0-I_d)dt+U_S

measured output side alternating current I_qObtaining the control quantity u of the inversion unit through a 3 rd proportional integrator PI3_qThe concrete formula is as follows:

u_q＝k_p3*I_q+k_i3*∫I_qdt

according to the reactive power control quantity u obtained in the above steps_qActive power control quantity u_dThrough dq-abAnd c, after park inverse transformation, obtaining a Pulse Width Modulation (PWM) signal of the three-phase inversion unit, and adjusting the output voltage of the output side transformation unit.

The input-side conversion unit control method, see fig. 5, includes

Step 1, constant power control:

the control parameter 1 of the 4 th proportional integrator PI4, the 5 th proportional integrator PI5, the 6 th proportional integrator PI6 and the 7 th proportional integrator PI7 is given<k_p4<100、0.1<k_i4<10、1<k_p5<100、0.1<k_i5<10、1<k_p6<100、0.1<k_i6<10、1<k_p7<100、0.1<k_i7<10, measuring the input-side AC voltage u_sAC current i_sAnd from this, the input-side AC voltage amplitude U is obtained_S1Input side alternating current amplitude I_d1、I_q1And the power angle theta of the input side AC voltage and the AC current₂Calculating active power P ═ U_S1×I_d1And reactive power Q ═ U_S1×I_q1。

Setting constant power control, active power given value P_refA 1 is to P_refAnd performing proportional integral control PI4 to obtain intermediate control amount u_d20The calculation formula is

u_d20＝k_p4*(P_ref-P)+k_i4*∫(P_ref-P)dt

The output value of the 4 th proportional integrator PI4 is combined with the measured input side alternating voltage U_S1And current I_d1Obtaining the control quantity u of the inversion unit by the following formula_d2The concrete formula is as follows:

u_d2＝k_p5*(u_d20-I_d1)+k_i5*∫(u_d20-I_d1)dt+U_S1

setting a given value of reactive power Q_refIs mixing Q with_refAnd performing 6 th proportional-integral control PI6 on the difference between the calculated reactive power Q to obtain an intermediate control quantity u_q20The calculation formula is

u_q20＝k_p6*(Q_ref-Q)+k_i6*∫(Q_ref-Q)dt

The output value of the 6 th proportional integrator PI6 is combined with the measured input side alternating current I_q1Obtaining the control quantity u of the inversion unit through the 7 th proportional-integral control PI7_q2The concrete formula is as follows:

u_q2＝k_p7*(u_q20-I_q1)+k_i7*∫(u_q20-I_q1)dt

the control quantity u obtained according to the steps_d2、u_q2And after dq-abc park inverse transformation, a three-phase inversion unit Pulse Width Modulation (PWM) signal is obtained, and the output voltage of the input side transformation unit is adjusted.

Step 2, constant current control:

giving the value of the active current I_drefIn the above step, u_d20＝I_dref。

Step 3, constant resistance control:

given resistance reference value R_refIn the above step 1, u_d20＝U_s1/I_dref。

The energy feedback optimization method of the invention comprises

Energy feedback optimization model function:

$\&lsqb;P_{loss}\&rsqb;=MinObjects({\left(u_{d2}-u_d\right)}^2+{\left(u_{q2}-u_q\right)}^2+{\left(U_{DC}-{\stackrel{\&OverBar;}{U}}_{DC}\right)}^2)$

wherein,is U_DCAverage value of (a).

The invention relates to an alternating current/direct current energy feedback type electronic simulation load device, which is an electronic simulation load with energy feedback and outputs feedback to an alternating current or direct current power supply. The input side can simulate three modes of constant power, constant current and constant impedance, in addition, various load characteristic curves can be simulated, the power factor is adjustable, the setting is carried out through a display unit panel, and the setting can also be carried out through an upper computer through communication. The invention has obvious power saving advantages in load test and research, and has the characteristics of flexibly simulating various load characteristics and AC/DC feedback.

Claims (7)

1. An AC/DC energy feedback type electronic simulation load device is characterized by comprising: a controller (2), an input side conversion unit (3), an input side H bridge inversion unit (4), an isolation high-frequency transformer (5), an output side H bridge rectification unit (6), an output side conversion unit (7), an input voltage transformer (8), an input current transformer (9), an output voltage transformer (10), an output current transformer (11), a direct current voltage transformer (12), an input alternating current terminal (13), an output alternating current terminal (14), an output direct current terminal (15) and a display unit (16),

said input side conversionThe input end of the unit (3) is connected with the input alternating current terminal (13), the output end of the input side conversion unit (3) is connected with the input end of the input side H bridge inversion unit (4), the output end of the input side H bridge inversion unit (4) is connected with the input end of the isolation high-frequency transformer (5), the output end of the isolation high-frequency transformer (5) is connected with the input end of the output side H bridge rectification unit (6), the output end of the output side H bridge rectification unit (6) is connected with the input end of the output side conversion unit (7), and the output end of the output side conversion unit (7) is connected with the output alternating current terminal (14); the output direct current terminal (15) is connected with the output end of the output side H bridge rectifying unit (6); the input side of the direct-current voltage sensor (12) is connected with the output end of the output side H-bridge rectifying unit (6), and the voltage signal output end of the direct-current voltage sensor (12) is connected with a direct-current voltage signal input port (U) corresponding to the controller (2)_DC) Connecting;

the input side of the input voltage transformer (8) is connected with a main circuit at the input end of the input side conversion unit (3), and the voltage signal output end of the input voltage transformer (8) is connected with an input voltage signal input port (Us) corresponding to the controller (2); the input current transformer (9) Is connected in series in a circuit between the input side conversion unit (3) and the input alternating current terminal (13), and an alternating current signal output end of the input current transformer (9) Is connected with an alternating current input current signal input port (Is) of the controller (2);

the input side of the output voltage transformer (10) is connected with a main circuit of the output end of the output side conversion unit (7), and the voltage signal output end of the output voltage transformer (10) is connected with an input port (UO) of the controller (2) for outputting an alternating voltage signal; the output current transformer (11) is connected in series in a circuit of the output end of the output side conversion unit (7), and a current signal output end of the output current transformer (11) is connected with an output current signal input port (Io) of the controller (2); the voltage signal output end of the direct-current voltage sensor (12) is connected with the direct-current voltage signal input port of the controller (2);

the output pulse width modulation signal PWM of the controller (2)_S123、PWM_O123The port is respectively connected with the PWM control signal end of the input side conversion unit (3) and the PWM control signal end of the output side conversion unit (7); the local communication port of the controller (2) is connected with the communication port of the display unit (16), and the far-end communication port of the controller (2) is connected with an upper computer in a communication way.

2. The ac/dc energy feedback type electronic analog load device according to claim 1, wherein the input side conversion unit (3) and the output side conversion unit (7) each comprise a three-phase inversion structure connected to three phases of ac and a common dc bus capacitor (C), wherein each phase inversion structure comprises: the IGBT device comprises a first insulated gate bipolar transistor (IGBT for short) and a second IGBT, wherein an emitter of the first IGBT is connected with a collector of the second IGBT, the collector of the first IGBT is connected with the emitter of the second IGBT through a common direct current bus capacitor, the emitter of the first IGBT is used as a control end of an inversion unit, the control end of the first IGBT and the control end of the second IGBT are connected with an inversion unit PWM signal output end of the control unit corresponding to a corresponding phase inversion unit PWM signal, the control ends of the first IGBT and the second IGBT have opposite signals, the collector of the second IGBT is an alternating current output end of the inversion unit, two ends of the common direct current bus capacitor are direct current input ends of the inversion unit, and the voltage of the common direct current bus capacitor is the direct current voltage U of the inversion unit_DC；

Because the control signals of the control end of the first IGBT and the control end of the second IGBT are opposite, the inversion unit PWM signal output by the inversion unit PWM signal output end of the control unit can generate an opposite inversion unit PWM signal through an external phase inverter or the control unit, and then the inversion unit PWM signal and the opposite inversion unit PWM signal are correspondingly input into the control end of the first IGBT and the control end of the second IGBT.

3. The ac/dc energy feedback type electronic analog load device according to claim 1, wherein the input side H-bridge inverter unit (4) and the output side H-bridge inverter unit (6) each comprise: the IGBT comprises a first IGBT, a second IGBT, a third IGBT and a fourth IGBT, wherein the emitter of the first IGBT is connected with the collector of the third IGBT, and the collector of the first IGBT is connected with the emitter of the third IGBT through a common direct current bus capacitor (C); the emitter of the second IGBT is connected with the collector of the fourth IGBT, and the collector of the second IGBT is connected with the emitter of the fourth IGBT through the common direct current bus capacitor (C);

the control signals of the control end of the first IGBT and the control end of the third IGBT are opposite, and the control signals of the control end of the second IGBT and the control end of the fourth IGBT are opposite; the control signals of the control end of the first IGBT and the control end of the fourth IGBT are the same, the control signals of the control end of the second IGBT and the control end of the third IGBT are the same, and the control signals are locally generated and are signals with 10 k-50 kHz frequency and 50% duty ratio.

4. The method for controlling the ac/dc energy feedback type electronic analog load device according to claim 1, wherein the method comprises an output side converter unit control method, an input side converter unit control method, and an energy feedback optimization method.

5. The control method according to claim 4, wherein the output-side conversion unit control method comprises the steps of:

① control parameters 1 for 1 st proportional integrator (PI1), 2 nd proportional integrator (PI2) and 3 rd proportional integrator (PI3)<k_p1<100、0.1<k_i1<10、1<k_p2<100、0.1<k_i2<10、1<k_p3<100、0.1<k_i3<10, measuring the output side AC voltage u_oAC current i_oAnd from this, the output side AC voltage amplitude U is obtained_sOutput side AC current amplitude I_d、I_qAnd a power angle theta of the output side alternating voltage and the alternating current;

② is provided withFixed DC voltage given value U_DCrefMeasuring the DC voltage U_DCWill set a given value U of DC voltage_DCrefAnd the measured DC voltage U_DCThe difference between the two is controlled by the 1 st proportional-integrator (PI1)_d0Comprises the following steps:

u_d0＝k_p1*(U_DCref-U_DC)+k_i1*∫(U_DCref-U_DC)dt

wherein, U_DCrefThe voltage is a given value of direct current voltage, and the per unit value is 1-1.2;

③ the output value of the 1 st proportional integrator (PI1) is combined with the measured output side AC voltage US and current Id, and the 2 nd proportional integrator (PI2) is used to obtain the active power control quantity u of the inverter unit_dThe concrete formula is as follows:

u_d＝k_p2*(u_d0-I_d)+k_i2*∫(u_d0-I_d)dt+U_S

④ measured output side AC current I_qThe reactive power control quantity u of the inverter unit is obtained through a 3 rd proportional integrator (PI3)_qThe concrete formula is as follows:

u_q＝k_p3*I_q+k_i3*∫I_qdt；

⑤ according to the reactive power control quantity u_qActive power control quantity u_dAnd after dq-abc park inverse transformation, obtaining a three-phase inversion unit Pulse Width Modulation (PWM) signal:

the output voltage of the output side conversion unit is adjusted.

6. The control method according to claim 4, wherein the input-side conversion unit control method comprises the steps of:

step 1, constant power control:

and selecting the constant power control, wherein the constant power control is as follows:

① control parameters 1 for 4 th proportional integrator (PI4), 5 th proportional integrator (PI5) and 6 th proportional integrator (PI6)<k_p4<100、0.1<k_i4<10、1<k_p5<100、0.1<k_i5<10、1<k_p6<100、0.1<k_i6<10、1<k_p7<100、0.1<k_i7<10, measuring the input-side AC voltage u_sAC current i_sAnd from this, the input-side AC voltage amplitude U is obtained_S1Input side alternating current amplitude I_d1、I_q1And the power angle theta of the input side AC voltage and the AC current₂Calculating active power P ═ U_S1×I_d1Reactive power Q ═ U_S1×I_q1；

② setting active power given value P_refA 1 is to P_refThe difference from P is controlled by a 4 th proportional-integral unit (PI4), and an intermediate control amount u is calculated by the following formula_d20：

u_d20＝k_p4*(P_ref-P)+k_i4*∫(P_ref-P)dt

③ according to the intermediate control quantity u outputted from the 4 th proportional-integral device (PI4)_d20Combined with measured input-side AC voltage U_S1And current I_d1Obtaining the control quantity u of the inversion unit by the following formula_d2：

u_d2＝k_p5*(u_d20-I_d1)+k_i5*∫(u_d20-I_d1)dt+U_S1

④ setting reactive power set value Q_refIs mixing Q with_refThe difference between the calculated reactive power Q and the calculated reactive power Q is controlled by a 6 th proportional integrator (PI6), and an intermediate control quantity u is calculated according to the following formula_q20：

u_q20＝k_p6*(Q_ref-Q)+k_i6*∫(Q_ref-Q)dt

⑤ according to the output value of the 6 th proportional integrator (PI6), combined with the measured input side AC current I_q1After the 7 th proportional-integral control (PI7), the inversion is calculated according to the following formulaUnit control quantity u_q2：

u_q2＝k_p7*(u_q20-I_q1)+k_i7*∫(u_q20-I_q1)dt

⑥ according to the control quantity u_d2、u_q2And after dq-abc park inverse transformation, obtaining a three-phase inversion unit Pulse Width Modulation (PWM) signal:

adjusting an output voltage of the input side conversion unit;

step 2, selecting constant current control, wherein the constant current control is as follows: giving the value of the active current I_drefIn the above step, u_d20＝I_dref；

And 3, selecting constant resistance control, wherein the constant resistance control comprises the following steps: given resistance reference value R_refIn the above step 1, u_d20＝U_s1/I_dref。

7. The control method of claim 4, wherein the energy feedback optimization model function of the energy feedback optimization method is:

$\&lsqb;P_{loss}\&rsqb;=MinObjects({\left(u_{d2}-u_d\right)}^2+{\left(u_{q2}-u_q\right)}^2+{\left(U_{DC}-{\stackrel{\&OverBar;}{U}}_{DC}\right)}^2)$

wherein,is U_DCAverage value of (a).