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.
① has advantages compared with resistance load, because its working mode is to use power electronic conversion technology to complete the test power experiment, the output energy of the device to be tested is fed back to the electric network, saving energy, on the other hand not generating a large amount of heat, avoiding the problem of the rise of the environmental temperature of the test place, ② has small volume and light weight, because the electronic load does not change the tested power into heat, it is unnecessary to use a large-volume resistance box and cooling equipment, thus saving installation space, ③ the simulated power is continuously adjustable, as is well known, the resistance load has to adopt step adjustment when the power is high, and is greatly limited when in use, the user can set the required power (or power output current) -time change curve through the computer interface when in specific use, the load size of the device can be strictly set, ④ adopts energy feedback mode, therefore, the power test place is not equipped with large capacity, and the existing single electronic load function is difficult to develop.
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 controllerS123、PWMO123The 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.
Said input side conversion sheetThe unit all includes with three-phase contravariant structure and public direct current bus electric capacity that exchange three-phase connection with output side transform unit, and wherein every looks contravariant structure all includes: 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 unitDC;
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<kp1<100、0.1<ki1<10、1<kp2<100、0.1<ki2<10、1<kp3<100、0.1<ki3<10, measuring the output side AC voltage uoAC current ioAnd from this, the output side AC voltage amplitude U is obtainedsOutput side AC current amplitude Id、IqAnd a power angle theta of the output side alternating voltage and the alternating current;
② setting given DC voltage value UDCrefMeasuring the DC voltage UDCWill set a given value U of DC voltageDCrefAnd the measured DC voltage UDCThe difference between the two values is controlled by the 1 st proportional-integral deviced0Comprises the following steps:
ud0=kp1*(UDCref-UDC)+ki1*∫(UDCref-UDC)dt
wherein, UDCrefThe 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 USAnd current IdObtaining the active power control quantity u of the inversion unit by the 2 nd proportional integratordThe concrete formula is as follows:
ud=kp2*(ud0-Id)+ki2*∫(ud0-Id)dt+US
④ measured output side AC current IqObtaining the reactive power control quantity u of the inversion unit through a 3 rd proportional integratorqThe concrete formula is as follows:
uq=kp3*Iq+ki3*∫Iqdt;
⑤ according to the reactive power control quantity uqActive power control quantity udAnd 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<kp4<100、0.1<ki4<10、1<kp5<100、0.1<ki5<10、1<kp6<100、0.1<ki6<10、1<kp7<100、0.1<ki7<10, measuring the input-side AC voltage usAC current isAnd from this, the input-side AC voltage amplitude U is obtainedS1Input side alternating current amplitude Id1、Iq1And the power angle theta of the input side AC voltage and the AC current2Calculating active power P ═ US1×Id1Reactive power Q ═ US1×Iq1;
② setting active power given value PrefA 1 is to PrefAnd 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 formulad20:
ud20=kp4*(Pref-P)+ki4*∫(Pref-P)dt
③ according to the intermediate control quantity u output from the 4 th proportional-integral deviced20Combined with measured input-side AC voltage US1And current Id1Obtaining the control quantity u of the inversion unit by the following formulad2:
ud2=kp5*(ud20-Id1)+ki5*∫(ud20-Id1)dt+US1
④ setting reactive power set value QrefIs mixing Q withrefThe 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 formulaq20:
uq20=kp6*(Qref-Q)+ki6*∫(Qref-Q)dt
⑤ according to the output value of the 6 th proportional integrator, combined with the measured input side alternating current Iq1And calculating the control quantity u of the inversion unit according to the following formula through 7 th proportional-integral controlq2:
uq2=kp7*(uq20-Iq1)+ki7*∫(uq20-Iq1)dt
⑥ according to the control quantity ud2、uq2And 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 IdrefIn the above step, ud20=Idref;
Step 3, constant resistance control:
under the control of selecting constant resistance, the constant resistance is controlled as follows: given resistance reference value RrefIn the above step 1, ud20=Us1/Idref。
The energy feedback optimization model function of the energy feedback optimization method is as follows:
wherein,is UDCAverage 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 2S123、PWMO123The 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.
The invention relates to an AC/DC energy feedback type electronic simulation load deviceIn the system, the input side conversion unit and the output side conversion unit comprise a three-phase inversion structure and a common 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 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, the collector of the first IGBT is connected with the 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, signals of the control ends of the first IGBT and the second IGBT are opposite, a collector of the second IGBT is an alternating current output end of the inversion unit, direct current input ends of the inversion unit are arranged at two ends of the common direct current bus capacitor, and voltage of the common direct current bus capacitor is direct current voltage U of the inversion unitDC。
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:
the control parameters 1 of the 1 st proportional-integral control PI1, the 2 nd proportional-integral controller PI2 and the 3 rd proportional-integral controller PI3 are given<kp1<100、0.1<ki1<10、1<kp2<100、0.1<ki2<10、1<kp3<100、0.1<ki3<10, measuring the output side AC voltage uoAC current ioAnd from this, the output side AC voltage amplitude U is obtainedsOutput side AC current amplitude Id、IqAnd the power angle theta of the output side alternating voltage and the alternating current.
Setting a given value U of DC voltageDCrefMeasuring the DC voltage UDCWill set a given value U of DC voltageDCrefAnd the measured DC voltage UDCThe difference is subjected to the 1 st proportional-integral control (PI1) to obtain an intermediate control amount ud0The calculation formula is as follows:
ud0=kp1*(UDCref-UDC)+ki1*∫(UDCref-UDC)dt
wherein, UDCrefThe 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 USAnd current IdObtaining the control quantity u of the inversion unit through the following formula containing a 2 nd proportional integrator PI2dThe concrete formula is as follows:
ud=kp2*(ud0-Id)+ki2*∫(ud0-Id)dt+US
measured output side alternating current IqObtaining the control quantity u of the inversion unit through a 3 rd proportional integrator PI3qThe concrete formula is as follows:
uq=kp3*Iq+ki3*∫Iqdt
according to the reactive power control quantity u obtained in the above stepsqActive power control quantity udAnd after dq-abc park inverse transformation, a Pulse Width Modulation (PWM) signal of the three-phase inversion unit is obtained, and the output voltage of the output side transformation unit is adjusted.
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<kp4<100、0.1<ki4<10、1<kp5<100、0.1<ki5<10、1<kp6<100、0.1<ki6<10、1<kp7<100、0.1<ki7<10, measuring the input-side AC voltage usAC current isAnd from this, the input-side AC voltage amplitude U is obtainedS1Input side alternating current amplitude Id1、Iq1And the power angle theta of the input side AC voltage and the AC current2Calculating active power P ═ US1×Id1And reactive power Q ═ US1×Iq1。
Setting constant power control, active power given value PrefA 1 is to PrefAnd performing proportional integral control PI4 to obtain intermediate control amount ud20The calculation formula is
ud20=kp4*(Pref-P)+ki4*∫(Pref-P)dt
The output value of the 4 th proportional integrator PI4 is combined with the measured input side alternating voltage US1And current Id1Obtaining the control quantity u of the inversion unit by the following formulad2The concrete formula is as follows:
ud2=kp5*(ud20-Id1)+ki5*∫(ud20-Id1)dt+US1
setting a given value of reactive power QrefIs mixing Q withrefAnd performing 6 th proportional-integral control PI6 on the difference between the calculated reactive power Q to obtain an intermediate control quantity uq20The calculation formula is
uq20=kp6*(Qref-Q)+ki6*∫(Qref-Q)dt
The output value of the 6 th proportional integrator PI6 is combined with the measured input side alternating current Iq1Obtaining the control quantity u of the inversion unit through the 7 th proportional-integral control PI7q2The concrete formula is as follows:
uq2=kp7*(uq20-Iq1)+ki7*∫(uq20-Iq1)dt
the control quantity u obtained according to the stepsd2、uq2And 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 IdrefIn the above step, ud20=Idref。
Step 3, constant resistance control:
given resistance reference value RrefIn the above step 1, ud20=Us1/Idref。
The energy feedback optimization method of the invention comprises
Energy feedback optimization model function:
wherein,is UDCAverage 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.