Electronic load device and electronic load circuit

Abstract

The present invention belongs to the field of testing technology, and provides an electronic load device and an electronic load circuit. The embodiment of the present invention provides an electronic load circuit including a first waveform control conversion unit, a high-frequency isolation bidirectional power converter, and a second waveform control conversion unit that are electrically connected in sequence, so that the first waveform control conversion unit is electrically connected to a device under test and a control unit, the high-frequency isolation bidirectional power converter is electrically connected to the control unit, and the second waveform control conversion unit is electrically connected to a power grid and the control unit, so that bidirectional power flow and active power and reactive power control of the device under test can be realized under the control of the control unit, which has a small size, low cost, high efficiency, and can meet the test requirements of the device under test that needs to work in four quadrants.

Description

Technical Field

[0001] The present invention belongs to the field of testing technology, and in particular relates to an electronic load device and an electronic load circuit. Background Art

[0002] UPS (Uninterrupted Power Supply), frequency converters, photovoltaic inverters, energy storage converters, electric vehicle drives and other equipment usually undergo aging tests before leaving the factory. Traditional aging test systems generally include motors that are suitable for the power level of the device under test. The electric energy output by the device under test is consumed by the motor, which is large in size, high in cost, and has low feedback efficiency. Different devices under test require different motors to be equipped, which places high demands on testers, is prone to errors and causes accidents, and has low work efficiency. There are also aging test systems based on power frequency transformers. The use of power frequency transformers limits the space for improving the size, cost and feedback efficiency of the aging test system. There are also aging test systems based on isolated AC (Alternating Current) / DC (Direct Current) converters and inverter cascades, which cannot meet the testing requirements of devices under test that require four-quadrant operation. Summary of the invention

[0003] The object of the present invention is to provide an electronic load device and an electronic load circuit, which are small in size, low in cost, high in efficiency and can meet the test requirements of a device under test that requires four-quadrant operation.

[0004] A first aspect of an embodiment of the present invention provides an electronic load circuit, comprising a first waveform control conversion unit, a high-frequency isolated bidirectional power converter, and a second waveform control conversion unit electrically connected in sequence;

[0005] The first waveform control conversion unit is used to be electrically connected to the device under test and the control unit, filter the first AC signal output by the device under test, change the current waveform of the first AC signal and the angle between the voltage waveform and the current waveform of the first AC signal under the control of the control unit, convert the first AC signal into a first DC signal and output it to the high-frequency isolated bidirectional power converter;

[0006] The high-frequency isolated bidirectional power converter is used to be electrically connected to the control unit, and under the control of the control unit, the voltage of the first DC signal is changed and output to the second waveform control conversion unit;

[0007] The second waveform control conversion unit is used to be electrically connected to the power grid and the control unit, and under the control of the control unit, convert the first DC signal into a second AC signal, and filter the second AC signal before outputting it to the power grid; it is also used to filter the third AC signal output by the power grid, and under the control of the control unit, convert the third AC signal into a second DC signal before outputting it to the high-frequency isolated bidirectional power converter, so as to realize bidirectional power flow;

[0008] The high-frequency isolated bidirectional power converter is also used to change the voltage of the second DC signal under the control of the control unit and output it to the first waveform control conversion unit;

[0009] The first waveform control conversion unit is also used to convert the second DC signal into a fourth AC signal under the control of the control unit, change the current waveform of the fourth AC signal and the angle between the voltage waveform and the current waveform of the fourth AC signal, filter the fourth AC signal and output it to the device under test, so as to realize bidirectional power flow and control of the active power and reactive power of the device under test.

[0010] In one embodiment, the first waveform control conversion unit includes a first filter network and a first totem pole network;

[0011] The first filter network is electrically connected to the first totem pole network, and the first totem pole network is electrically connected to the high-frequency isolated bidirectional power converter;

[0012] The first filter network is used to be electrically connected to the device under test, and to filter the first AC signal output by the device under test and then output it to the first totem pole network;

[0013] The first totem pole network is used to be electrically connected to the control unit, and under the control of the control unit, change the current waveform of the first alternating current signal and the angle between the voltage waveform and the current waveform of the first alternating current signal, convert the first alternating current signal into a first direct current signal and output it to the high-frequency isolated bidirectional power converter; and is also used to, under the control of the control unit, convert the second direct current signal into a fourth alternating current signal, change the current waveform of the fourth alternating current signal and the angle between the voltage waveform and the current waveform of the fourth alternating current signal, and output it to the first filtering network;

[0014] The first filtering network is further used to filter the fourth alternating current signal and then output it to the device under test.

[0015] In one embodiment, the first filter network includes a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, a sixth inductor, a first capacitor, a second capacitor, and a third capacitor;

[0016] One end of the first inductor, the second inductor and the third inductor is respectively used to be electrically connected to the device under test; the other ends of the first inductor, the second inductor and the third inductor are respectively electrically connected to one end of the fourth inductor to the sixth inductor in a one-to-one correspondence;

[0017] The other ends of the fourth inductor, the fifth inductor and the sixth inductor respectively constitute the first connection end, the second connection end and the third connection end of the first filter network, and are respectively electrically connected to the first connection end, the second connection end and the third connection end of the first totem pole network in a one-to-one correspondence;

[0018] One end of the first capacitor is electrically connected to the other end of the first inductor and one end of the fourth inductor, and the other end of the first capacitor is electrically connected to the other end of the second inductor and one end of the fifth inductor;

[0019] One end of the second capacitor is electrically connected to the other end of the third inductor and one end of the fifth inductor, and the other end of the second capacitor is electrically connected to the other end of the third inductor and one end of the sixth inductor;

[0020] One end of the third capacitor is electrically connected to the other end of the first inductor and one end of the fourth inductor, and the other end of the third capacitor is electrically connected to the other end of the third inductor and one end of the sixth inductor.

[0021] In one embodiment, the first totem pole network includes a first electronic switch tube, a second electronic switch tube, a third electronic switch tube, a fourth electronic switch tube, a fifth electronic switch tube and a sixth electronic switch tube;

[0022] The output end of the first electronic switch tube and the input end of the second electronic switch tube are electrically connected to form a first connection end of the first totem pole network, which is used to be electrically connected to the first connection end of the first filter network;

[0023] The output end of the third electronic switch tube and the input end of the fourth electronic switch tube are electrically connected to form a second connection end of the first totem pole network, which is used to be electrically connected to the second connection end of the first filter network;

[0024] The output end of the fifth electronic switch tube and the input end of the sixth electronic switch tube are electrically connected to form a third connection end of the first totem pole network, which is used to be electrically connected to the third connection end of the first filter network;

[0025] The input ends of the first electronic switch tube, the third electronic switch tube and the fifth electronic switch tube are electrically connected to form a first connection end of the first waveform control conversion unit, which is used to be electrically connected to the first connection end of the high-frequency isolation bidirectional power converter;

[0026] The output ends of the second electronic switch tube, the fourth electronic switch tube and the sixth electronic switch tube are electrically connected to form the second connection end of the first waveform control conversion unit, which is used to be electrically connected to the second connection end of the high-frequency isolation bidirectional power converter.

[0027] In one embodiment, the high-frequency isolated bidirectional power converter includes a first conversion circuit, a second conversion circuit and a high-frequency transformer;

[0028] The first conversion circuit is electrically connected to the first waveform control conversion unit and the primary side of the high-frequency transformer, and the second conversion circuit is electrically connected to the secondary side of the high-frequency transformer and the second waveform control conversion unit;

[0029] The first conversion circuit is used to be electrically connected to the control unit, and to chop the first DC signal and then output it to the primary side of the high-frequency transformer;

[0030] The high-frequency transformer is used to change the voltage of the first direct current signal and output it to the second conversion circuit;

[0031] The second conversion circuit is used to be electrically connected to the control unit, chop the first DC signal and output it to the second waveform control conversion unit; and is also used to chop the second DC signal and output it to the secondary side of the high-frequency transformer;

[0032] The high-frequency transformer is also used to change the voltage of the second DC signal and output it to the first conversion circuit;

[0033] The first conversion circuit is further used for chopping the second DC signal and outputting the signal to the first waveform control conversion unit.

[0034] In one embodiment, the first conversion circuit and the second conversion circuit are full-bridge circuits, half-bridge circuits, push-pull circuits or flyback circuits.

[0035] In one embodiment, the second waveform control conversion unit includes a second filter network and a second totem pole network;

[0036] The second filter network is electrically connected to the second totem pole network, and the second totem pole network is electrically connected to the high frequency isolated bidirectional power converter;

[0037] The second totem pole network is used to be electrically connected to the control unit, and under the control of the control unit, convert the first DC signal into a second AC signal and output it to the second filter network;

[0038] The second filter network is used to be electrically connected to the power grid, filter the second AC power signal and output it to the power grid; and is also used to filter the third AC power signal output by the power grid and output it to the second totem pole network;

[0039] The second totem pole network is also used to convert the third AC power signal into a second DC power signal under the control of the control unit and output the second DC power signal to the high-frequency isolated bidirectional power converter.

[0040] In one embodiment, the second filtering network includes a seventh inductor, an eighth inductor, a ninth inductor, a sixth capacitor, a seventh capacitor, and an eighth capacitor;

[0041] One end of the seventh inductor, the eighth inductor and the ninth inductor is respectively used to be electrically connected to the power grid;

[0042] The other ends of the seventh inductor, the eighth inductor and the ninth inductor respectively constitute the first connection end, the second connection end and the third connection end of the second filtering network, and are used to be electrically connected to the first connection end, the second connection end and the third connection end of the second totem pole network in a one-to-one correspondence;

[0043] The sixth capacitor is electrically connected between one end of the seventh inductor and one end of the eighth inductor;

[0044] The seventh capacitor is electrically connected between one end of the eighth inductor and one end of the ninth inductor;

[0045] The eighth capacitor is electrically connected between one end of the seventh inductor and one end of the ninth inductor.

[0046] In one embodiment, the second totem pole network includes a fifteenth electronic switch tube, a sixteenth electronic switch tube, a seventeenth electronic switch tube, an eighteenth electronic switch tube, a nineteenth electronic switch tube and a twentieth electronic switch tube;

[0047] The output end of the nineteenth electronic switch tube and the input end of the twentieth electronic switch tube are electrically connected to form a first connection end of the second totem pole network, which is used to be electrically connected to the first connection end of the second filter network;

[0048] The output end of the seventeenth electronic switch tube and the input end of the eighteenth electronic switch tube are electrically connected to form a second connection end of the second totem pole network, which is used to be electrically connected to the second connection end of the second filter network;

[0049] The output end of the fifteenth electronic switch tube and the input end of the sixteenth electronic switch tube are electrically connected to form a third connection end of the second totem pole network, which is used to be electrically connected to the third connection end of the second filter network;

[0050] The input ends of the fifteenth electronic switch tube, the seventeenth electronic switch tube and the nineteenth electronic switch tube are electrically connected to form a first connection end of the second waveform control conversion unit, which is used to be electrically connected to the third connection end of the high-frequency isolation bidirectional power converter;

[0051] The output ends of the sixteenth electronic switch tube, the eighteenth electronic switch tube and the twentieth electronic switch tube are electrically connected to form the second connection end of the second waveform control conversion unit, which is used to be electrically connected to the fourth connection end of the high-frequency isolation bidirectional power converter.

[0052] A second aspect of the embodiments of the present invention provides an electronic load device, including a control unit and the electronic load circuit as described in the first aspect of the embodiments of the present invention, for testing a device under test.

[0053] The embodiment of the present invention provides an electronic load circuit including a first waveform control conversion unit, a high-frequency isolated bidirectional power converter and a second waveform control conversion unit which are electrically connected in sequence, so that the first waveform control conversion unit is electrically connected to the device under test and the control unit, the high-frequency isolated bidirectional power converter is electrically connected to the control unit, and the second waveform control conversion unit is electrically connected to the power grid and the control unit. Under the control of the control unit, bidirectional power flow and active power and reactive power control of the device under test can be achieved. The circuit has small size, low cost, high efficiency and can meet the testing requirements of the device under test that needs to work in four quadrants. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a first structure of an electronic load circuit provided by an embodiment of the present invention;

[0055] Figure 2 A second structural schematic diagram of an electronic load circuit provided in an embodiment of the present invention;

[0056] Figure 3 A third structural schematic diagram of the electronic load circuit provided by an embodiment of the present invention;

[0057] Figure 4 A schematic diagram of the structure of a dual-active converter provided in an embodiment of the present invention;

[0058] Figure 5 A schematic diagram of the structure of a bidirectional series resonant converter provided by an embodiment of the present invention;

[0059] Figure 6 A schematic diagram of a first structure of a bidirectional LLC resonant converter provided by an embodiment of the present invention;

[0060] Figure 7 A second structural schematic diagram of a bidirectional LLC resonant converter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0063] like Figure 1 As shown, an embodiment of the present invention provides an electronic load circuit 100, comprising a first waveform control conversion unit 1, a high-frequency isolated bidirectional power converter 2, and a second waveform control conversion unit 3 which are electrically connected in sequence;

[0064] The first waveform control conversion unit 1 is used to be electrically connected to the device under test 200 and the control unit 300, filter the first AC signal output by the device under test 200, change the current waveform of the first AC signal and the angle between the voltage waveform and the current waveform of the first AC signal under the control of the control unit 300, convert the first AC signal into a first DC signal and output it to the high-frequency isolation bidirectional power converter 2;

[0065] The high-frequency isolated bidirectional power converter 2 is used to be electrically connected to the control unit 300, and changes the voltage of the first DC signal under the control of the control unit 300 and outputs it to the second waveform control conversion unit 3;

[0066] The second waveform control conversion unit 3 is used to be electrically connected to the power grid 400 and the control unit 300, and under the control of the control unit 300, convert the first DC signal into a second AC signal, and filter the second AC signal before outputting it to the power grid 400; it is also used to filter the third AC signal output by the power grid 400, and under the control of the control unit 300, convert the third AC signal into a second DC signal before outputting it to the high-frequency isolation bidirectional power converter 2, so as to realize bidirectional power flow;

[0067] The high-frequency isolated bidirectional power converter 2 is also used to change the voltage of the second DC signal under the control of the control unit 300 and output it to the first waveform control conversion unit 1;

[0068] The first waveform control conversion unit 1 is also used to convert the second DC signal into a fourth AC signal under the control of the control unit 300, change the current waveform of the fourth AC signal and the angle between the voltage waveform and the current waveform of the fourth AC signal, filter the fourth AC signal and output it to the device under test 200, so as to realize bidirectional power flow and control of the active power and reactive power of the device under test 200.

[0069] In the application, the device under test can be a UPS, frequency converter, photovoltaic inverter, energy storage converter, electric vehicle drive, etc. The power grid can be a mains power grid or a power frequency grid. The working power supply of the device under test and the frequency and voltage amplitude of the power grid can be set according to actual needs. The electronic load circuit can adapt to the device under test and power grid of any frequency and voltage amplitude.

[0070] In application, the control unit has voltage sampling, current sampling and logic operation functions, and can be an integrated circuit, chip or device formed by integrating a voltage sampling circuit, a current sampling circuit and a logic operation circuit. The control unit can be a central processing unit (CPU), or other general processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general processor can be a microprocessor or the processor can also be any conventional processor, etc. The control unit can adaptively adjust the frequency and voltage amplitude of the second AC signal and the fourth AC signal output by the electronic load circuit according to the actual needs of the frequency and voltage amplitude of the device under test and the power grid.

[0071] In application, the first waveform control conversion unit, the high-frequency isolated bidirectional power converter and the second waveform control conversion unit can be implemented by selecting circuits, chips or devices with corresponding functions according to actual needs.

[0072] like Figure 2 As shown, in one embodiment, the first waveform control conversion unit 1 includes a first filter network 11 and a first totem pole network 12;

[0073] The first filter network 11 is electrically connected to the first totem pole network 12, and the first totem pole network 12 is electrically connected to the high-frequency isolation bidirectional power converter 2;

[0074] The first filter network 11 is used to be electrically connected to the device under test 200, and to filter the first alternating current signal output by the device under test 200 and then output it to the first totem pole network 12;

[0075] The first totem pole network 12 is used to be electrically connected to the control unit 300, and to change the current waveform of the first AC signal and the angle between the voltage waveform and the current waveform of the first AC signal under the control of the control unit 300, convert the first AC signal into a first DC signal and output it to the high-frequency isolated bidirectional power converter 2; and is also used to convert the second DC signal into a fourth AC signal under the control of the control unit 300, change the current waveform of the fourth AC signal and the angle between the voltage waveform and the current waveform of the fourth AC signal, and output it to the first filter network 11;

[0076] The first filter network 11 is further used to filter the fourth alternating current signal and output the signal to the device under test 200 .

[0077] In applications, the first filtering network can be implemented by selecting a filtering network, chip or device with corresponding functions according to actual needs, for example, an LC filtering network, a CLC filtering network, an LCL filtering network, etc.

[0078] like Figure 3 As shown, in one embodiment, the first filter network 11 includes a first inductor L1, a second inductor L2, a third inductor L3, a fourth inductor L4, a fifth inductor L5, a sixth inductor L6, a first capacitor C1, a second capacitor C2 and a third capacitor C3;

[0079] One end of the first inductor L1, the second inductor L2 and the third inductor L3 is respectively used to be electrically connected to the device under test 200; the other ends of the first inductor L1, the second inductor L2 and the third inductor L3 are respectively electrically connected to one end of the fourth inductor L4 to the sixth inductor L6 in a one-to-one correspondence;

[0080] The other ends of the fourth inductor L4, the fifth inductor L5 and the sixth inductor L6 respectively constitute the first connection end, the second connection end and the third connection end of the first filter network 11, and are respectively electrically connected to the first connection end, the second connection end and the third connection end of the first totem pole network 12 in a one-to-one correspondence;

[0081] One end of the first capacitor C1 is electrically connected to the other end of the first inductor L1 and one end of the fourth inductor L4, and the other end of the first capacitor C1 is electrically connected to the other end of the second inductor L2 and one end of the fifth inductor L5;

[0082] One end of the second capacitor C2 is electrically connected to the other end of the third inductor L3 and one end of the fifth inductor L5, and the other end of the second capacitor C2 is electrically connected to the other end of the third inductor L3 and one end of the sixth inductor L6;

[0083] One end of the third capacitor C3 is electrically connected to the other end of the first inductor L1 and one end of the fourth inductor L4 , and the other end of the third capacitor C3 is electrically connected to the other end of the third inductor L3 and one end of the sixth inductor L6 .

[0084] In applications, each inductor in the first filter network can be implemented by a high-frequency inductor or at least two high-frequency inductors connected in series. Each capacitor in the first filter network is a non-polar capacitor.

[0085] In applications, the first totem pole network can be implemented by selecting circuits, chips or devices with corresponding functions according to actual needs.

[0086] like Figure 3 As shown, in one embodiment, the first totem pole network 12 includes a first electronic switch tube Q1, a second electronic switch tube Q2, a third electronic switch tube Q3, a fourth electronic switch tube Q4, a fifth electronic switch tube Q5 and a sixth electronic switch tube Q6;

[0087] The output end of the first electronic switch tube Q1 and the input end of the second electronic switch tube Q2 are electrically connected to form a first connection end of the first totem pole network 12, which is used to be electrically connected to the first connection end of the first filter network 11;

[0088] The output end of the third electronic switch tube Q3 and the input end of the fourth electronic switch tube Q4 are electrically connected to form a second connection end of the first totem pole network 12, which is used to be electrically connected to the second connection end of the first filter network 11;

[0089] The output end of the fifth electronic switch tube Q5 and the input end of the sixth electronic switch tube Q6 are electrically connected to form a third connection end of the first totem pole network 12, which is used to be electrically connected to the third connection end of the first filter network 11;

[0090] The input ends of the first electronic switch tube Q1, the third electronic switch tube Q3 and the fifth electronic switch tube Q5 are electrically connected to form a first connection end of the first waveform control conversion unit 1, which is used to be electrically connected to the first connection end of the high-frequency isolation bidirectional power converter 2;

[0091] The output ends of the second electronic switch tube Q2 , the fourth electronic switch tube Q4 and the sixth electronic switch tube Q6 are electrically connected to form the second connection end of the first waveform control conversion unit 1 , which is used to be electrically connected to the second connection end of the high-frequency isolation bidirectional power converter 2 .

[0092] In application, each electronic switch tube in the first totem pole network can be implemented by selecting a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) according to actual needs, and the channel type of the electronic switch tube can be selected according to actual needs.

[0093] like Figure 3 As shown, it is exemplarily shown that the first electronic switch tube Q1, the second electronic switch tube Q2, the third electronic switch tube Q3, the fourth electronic switch tube Q4, the fifth electronic switch tube Q5 and the sixth electronic switch tube Q6 are all P-channel enhancement MOSFETs; wherein the drain of the first electronic switch tube Q1, the second electronic switch tube Q2, the third electronic switch tube Q3, the fourth electronic switch tube Q4, the fifth electronic switch tube Q5 and the sixth electronic switch tube Q6 serves as the input end and the source serves as the output end.

[0094] like Figure 2 As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 includes a first conversion circuit 21, a second conversion circuit 22 and a high-frequency transformer 23 (in Figure 3 to Figure 7 Indicated as T1);

[0095] The first conversion circuit 21 is electrically connected to the first waveform control conversion unit 1 and the primary side of the high-frequency transformer 23, and the second conversion circuit 22 is electrically connected to the secondary side of the high-frequency transformer 23 and the second waveform control conversion unit 3;

[0096] The first conversion circuit 21 is used to be electrically connected to the control unit 300, and to chop the first DC signal and then output it to the primary side of the high-frequency transformer 23;

[0097] The high frequency transformer 23 is used to change the voltage of the first DC signal and output it to the second conversion circuit 22;

[0098] The second conversion circuit 22 is used to be electrically connected to the control unit 300, and to chop the first DC signal and output it to the second waveform control conversion unit 3; and is also used to chop the second DC signal and output it to the secondary side of the high-frequency transformer 23;

[0099] The high frequency transformer 23 is also used to change the voltage of the second DC signal and output it to the first conversion circuit 21;

[0100] The first conversion circuit 21 is further used for chopping the second DC signal and outputting the signal to the first waveform control conversion unit 1 .

[0101] In application, the first conversion circuit and the second conversion circuit can be implemented by selecting circuits, chips or devices with corresponding functions according to actual needs. The ratio of the primary DC bus voltage to the secondary DC bus voltage of the high-frequency transformer is equal to the ratio of the number of turns of the primary winding to the number of turns of the secondary winding of the high-frequency transformer.

[0102] In one embodiment, the first conversion circuit and the second conversion circuit are full-bridge circuits, half-bridge circuits, push-pull circuits or flyback circuits.

[0103] like Figure 3 to Figure 7 As shown in any of the drawings, the structures of the first conversion circuit 21 and the second conversion circuit 22 are exemplarily shown when the first conversion circuit 21 and the second conversion circuit 22 are full-bridge circuits;

[0104] The first conversion circuit 21 includes a seventh electronic switch tube Q7, an eighth electronic switch tube Q8, a ninth electronic switch tube Q9, a tenth electronic switch tube Q10 and a fourth capacitor C4, and the second conversion circuit 22 includes an eleventh electronic switch tube Q11, a twelfth electronic switch tube Q12, a thirteenth electronic switch tube Q13, a fourteenth electronic switch tube Q14 and a fifth capacitor C5;

[0105] The output ends of the seventh electronic switch tube Q7 and the eighth electronic switch tube Q8 are electrically connected to form a first connection end of the first conversion circuit 21, which is used to be electrically connected to one end of the primary side of the high-frequency transformer T1;

[0106] The output ends of the ninth electronic switch tube Q9 and the tenth electronic switch tube Q10 are electrically connected to form a second connection end of the first conversion circuit 21, which is used to be electrically connected to the other end of the primary side of the high-frequency transformer T1;

[0107] The input end of the seventh electronic switch tube Q7, the input end of the ninth electronic switch tube Q9 and one end of the fourth capacitor C4 are electrically connected to form a first connection end of the high-frequency isolation bidirectional power converter 2, which is used to be electrically connected to the first connection end of the first waveform control conversion unit 1;

[0108] The output end of the eighth electronic switch tube Q8, the output end of the ninth electronic switch tube Q9 and the other end of the fourth capacitor C4 are electrically connected to form a second connection end of the high-frequency isolation bidirectional power converter 2, which is used to be electrically connected to the second connection end of the first waveform control conversion unit 1;

[0109] The output ends of the eleventh electronic switch tube Q11 and the twelfth electronic switch tube Q12 are electrically connected to form a first connection end of the second conversion circuit 22, which is used to be electrically connected to one end of the secondary side of the high-frequency transformer T1;

[0110] The output ends of the thirteenth electronic switch tube Q13 and the fourteenth electronic switch tube Q14 are electrically connected to form a second connection end of the second conversion circuit 22, which is used to be electrically connected to the other end of the secondary side of the high-frequency transformer T1;

[0111] The input end of the eleventh electronic switch tube Q11, the input end of the thirteenth electronic switch tube Q13 and one end of the fifth capacitor C5 are electrically connected to form a third connection end of the high-frequency isolation bidirectional power converter 2, which is used to be electrically connected to the first connection end of the second waveform control conversion unit 3;

[0112] The output end of the twelfth electronic switch tube Q12, the output end of the fourteenth electronic switch tube Q14 and the other end of the fifth capacitor C5 are electrically connected to form the fourth connection end of the high-frequency isolation bidirectional power converter 2, which is used to be electrically connected to the second connection end of the second waveform control conversion unit 3.

[0113] In application, each electronic switch tube in the first conversion circuit and the second conversion circuit can be implemented by selecting a metal-oxide semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-EffectTransistor, MOSFET) or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) according to actual needs, and the channel type of the electronic switch tube can be selected according to actual needs.

[0114] like Figure 3 to Figure 7 As shown in any of the accompanying drawings, it is exemplified that the seventh electronic switch tube Q7, the eighth electronic switch tube Q8, the ninth electronic switch tube Q9, the tenth electronic switch tube Q10, the eleventh electronic switch tube Q11, the twelfth electronic switch tube Q12, the thirteenth electronic switch tube Q13 and the fourteenth electronic switch tube Q14 are all P-channel enhancement type MOSFETs; wherein the drain of the seventh electronic switch tube Q7, the eighth electronic switch tube Q8, the ninth electronic switch tube Q9, the tenth electronic switch tube Q10, the eleventh electronic switch tube Q11, the twelfth electronic switch tube Q12, the thirteenth electronic switch tube Q13 and the fourteenth electronic switch tube Q14 is used as the input end and the source is used as the output end.

[0115] In application, the high-frequency isolated bidirectional power converter can adopt a high-frequency isolated CLLC converter. When the first conversion circuit and the second conversion circuit are full-bridge circuits or half-bridge circuits, the high-frequency isolated bidirectional power converter can also adopt a dual-active converter, a series resonant converter, an LLC resonant converter, other equivalent circuits with corresponding functions, or deformation circuits of these circuits. According to the power level requirements of the converter, these basic circuits can also be cascaded or at least two high-frequency transformers can be connected in series and / or in parallel.

[0116] like Figure 3 As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 is a high-frequency isolated CLLC converter, and the high-frequency isolated bidirectional power converter 2 also includes a first high-frequency inductor Lr1, a second high-frequency inductor Lr2, a first high-frequency capacitor Cr1 and a second high-frequency capacitor Cr2, the first high-frequency inductor Lr1 is electrically connected between the first connection end of the first conversion circuit 21 and one end of the first high-frequency capacitor Cr1, the other end of the first high-frequency capacitor Cr1 is electrically connected to one end of the primary side of the high-frequency transformer T1, the second high-frequency capacitor Cr2 is electrically connected between one end of the secondary side of the high-frequency transformer and one end of the second high-frequency inductor Lr2, and the other end of the second high-frequency inductor Lr2 is electrically connected to the first connection end of the second conversion circuit 22.

[0117] In application, the resonant frequency formed by the first high-frequency inductor and the first high-frequency capacitor is equal to the resonant frequency formed by the second high-frequency inductor and the second high-frequency capacitor.

[0118] like Figure 4 As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 is a dual-active converter, and the high-frequency isolated bidirectional power converter 2 also includes a first high-frequency inductor Lr1, which is electrically connected between the first connection end of the first conversion circuit 21 and one end of the primary side of the high-frequency transformer T1.

[0119] like Figure 5 As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 is a bidirectional series resonant converter, and the high-frequency isolated bidirectional power converter 2 also includes a first high-frequency inductor Lr1 and a first high-frequency capacitor Cr1. The first high-frequency inductor Lr1 is electrically connected between the first connection end of the first conversion circuit 21 and one end of the first high-frequency capacitor Cr1, and the other end of the first high-frequency capacitor Cr1 is electrically connected to one end of the primary side of the high-frequency transformer T1.

[0120] like Figure 6 As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 is a bidirectional LLC resonant converter, and the high-frequency isolated bidirectional power converter 2 also includes a first high-frequency inductor Lr1, a second high-frequency inductor Lr2 and a first high-frequency capacitor Cr1, the first high-frequency inductor Lr1 is electrically connected between the first connection end of the first conversion circuit 21 and one end of the first high-frequency capacitor Cr1, the other end of the first high-frequency capacitor Cr1 is electrically connected to one end of the primary side of the high-frequency transformer T1, and the second high-frequency inductor Lr2 is electrically connected to both ends of the primary side of the high-frequency transformer T1.

[0121] like Figure 7As shown, in one embodiment, the high-frequency isolated bidirectional power converter 2 is a bidirectional LLC resonant converter, and the high-frequency isolated bidirectional power converter 2 also includes a first high-frequency inductor Lr1, a second high-frequency inductor Lr2, a first high-frequency capacitor Cr1 and a second high-frequency capacitor Cr2. The first high-frequency inductor Lr1 is electrically connected between the first connection end of the first conversion circuit 21 and one end of the first high-frequency capacitor Cr1, the other end of the first high-frequency capacitor Cr1 is electrically connected to one end of the primary side of the high-frequency transformer T1, the second high-frequency inductor Lr2 is electrically connected to both ends of the primary side of the high-frequency transformer T1, and the second high-frequency capacitor Cr2 is electrically connected between one end of the secondary side of the high-frequency transformer and the first connection end of the second conversion circuit 22.

[0122] In the application, each capacitor in the high frequency isolated bidirectional power converter is a non-polarized capacitor.

[0123] like Figure 2 As shown, in one embodiment, the second waveform control conversion unit 3 includes a second filter network 31 and a second totem pole network 32;

[0124] The second filter network 31 is electrically connected to the second totem pole network 32, and the second totem pole network 32 is electrically connected to the high-frequency isolation bidirectional power converter 2;

[0125] The second totem pole network 32 is used to be electrically connected to the control unit 300, and under the control of the control unit 300, convert the first DC signal into a second AC signal and output it to the second filter network 31;

[0126] The second filter network 31 is used to be electrically connected to the power grid 400, filter the second AC signal and output it to the power grid 400; and filter the third AC signal output by the power grid 400 and output it to the second totem pole network 32;

[0127] The second totem pole network 32 is further used to convert the third AC power signal into a second DC power signal under the control of the control unit 300 and output the second DC power signal to the high-frequency isolation bidirectional power converter 2 .

[0128] In applications, the second filtering network can be implemented by selecting a filtering network, chip or device with corresponding functions according to actual needs, for example, an LC filtering network, a CLC filtering network, an LCL filtering network, etc.

[0129] like Figure 3 As shown, in one embodiment, the second filtering network 31 includes a seventh inductor L7, an eighth inductor L8, a ninth inductor L9, a sixth capacitor C6, a seventh capacitor C7 and an eighth capacitor C8;

[0130] One end of the seventh inductor L7, the eighth inductor L8 and the ninth inductor L9 is respectively used to be electrically connected to the power grid 400; the other ends of the seventh inductor L7, the eighth inductor L8 and the ninth inductor L9 respectively constitute the first connection end, the second connection end and the third connection end of the second filter network 31, and are used to be electrically connected to the first connection end, the second connection end and the third connection end of the second totem pole network 32 in a one-to-one correspondence;

[0131] The sixth capacitor C6 is electrically connected between one end of the seventh inductor L7 and one end of the eighth inductor L8;

[0132] The seventh capacitor C7 is electrically connected between one end of the eighth inductor L8 and one end of the ninth inductor L9;

[0133] The eighth capacitor C8 is electrically connected between one end of the seventh inductor L7 and one end of the ninth inductor L9.

[0134] In applications, each inductor in the second filter network can be implemented by a high-frequency inductor or at least two high-frequency inductors connected in series. Each capacitor in the first filter network is a non-polar capacitor.

[0135] In applications, the second totem pole network can be implemented by selecting circuits, chips or devices with corresponding functions according to actual needs.

[0136] like Figure 3 As shown, in one embodiment, the second totem pole network 32 includes a fifteenth electronic switch tube Q15, a sixteenth electronic switch tube Q16, a seventeenth electronic switch tube Q17, an eighteenth electronic switch tube Q18, a nineteenth electronic switch tube Q19 and a twentieth electronic switch tube Q20;

[0137] The output end of the nineteenth electronic switch tube Q19 and the input end of the twentieth electronic switch tube Q20 are electrically connected to form a first connection end of the second totem pole network 32, which is used to be electrically connected to the first connection end of the second filter network 31;

[0138] The output end of the seventeenth electronic switch tube Q17 and the input end of the eighteenth electronic switch tube Q18 are electrically connected to form a second connection end of the second totem pole network 32, which is used to be electrically connected to the second connection end of the second filter network 31;

[0139] The output end of the fifteenth electronic switch tube Q15 and the input end of the sixteenth electronic switch tube Q16 are electrically connected to form a third connection end of the second totem pole network 32, which is used to be electrically connected to the third connection end of the second filter network 31;

[0140] The input ends of the fifteenth electronic switch tube Q15, the seventeenth electronic switch tube Q17 and the nineteenth electronic switch tube Q19 are electrically connected to form a first connection end of the second waveform control conversion unit 3, which is used to be electrically connected to the third connection end of the high-frequency isolation bidirectional power converter 2;

[0141] The output ends of the sixteenth electronic switch tube Q16 , the eighteenth electronic switch tube Q18 and the twentieth electronic switch tube Q20 are electrically connected to form a second connection end of the second waveform control conversion unit 3 , which is used to be electrically connected to the fourth connection end of the high-frequency isolation bidirectional power converter 2 .

[0142] In application, each electronic switch tube in the second totem pole network can be implemented by selecting a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) according to actual needs, and the channel type of the electronic switch tube can be selected according to actual needs.

[0143] like Figure 3 As shown, it is exemplified that the fifteenth electronic switch tube Q15, the sixteenth electronic switch tube Q16, the seventeenth electronic switch tube Q17, the eighteenth electronic switch tube Q18, the nineteenth electronic switch tube Q19 and the twentieth electronic switch tube Q20 are all P-channel enhancement type MOSFETs; wherein the drain of the fifteenth electronic switch tube Q15, the sixteenth electronic switch tube Q16, the seventeenth electronic switch tube Q17, the eighteenth electronic switch tube Q18, the nineteenth electronic switch tube Q19 and the twentieth electronic switch tube Q20 serves as the input end and the source serves as the output end.

[0144] The embodiment of the present invention provides an electronic load circuit including a first waveform control conversion unit, a high-frequency isolated bidirectional power converter and a second waveform control conversion unit which are electrically connected in sequence, so that the first waveform control conversion unit is electrically connected to the device under test and the control unit, the high-frequency isolated bidirectional power converter is electrically connected to the control unit, and the second waveform control conversion unit is electrically connected to the power grid and the control unit. Under the control of the control unit, bidirectional power flow and active power and reactive power control of the device under test can be realized. The circuit has small size, low cost, high efficiency and can meet the test requirements of the device under test that needs to work in four quadrants.

[0145] The electronic load circuit provided by the embodiment of the present invention is implemented based on the principle of electronic transformer, so that the device under test can feed back electric energy to the power grid, saving energy and electricity; a high-frequency transformer and a high-frequency switching device are used to form a high-frequency isolated bidirectional power converter, which replaces the industrial frequency transformer, and has a small size, low cost, high efficiency and is easy to use; the high-frequency transformer and the conversion circuits on both sides thereof operate in a full resonance state, and have high conversion efficiency; the input end of the high-frequency isolated bidirectional power converter is connected to the first waveform control conversion unit, and a full master control switching device is used, which can effectively control the current waveform and active and reactive power, expand the adaptability of the electronic load circuit, and meet the requirements of different switching frequencies, different voltage frequencies and voltage amplitudes of the device under test; bidirectional power transmission meets the test requirements of new power electronic equipment such as electric vehicle drivers and energy storage converters.

[0146] An embodiment of the present invention further provides an electronic load device, including a control unit and an electronic load circuit, for testing a device under test.

[0147] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An electronic load circuit, It is characterized in that It includes a first waveform control conversion unit, a high-frequency isolation bidirectional power converter, and a second waveform control conversion unit which are electrically connected in sequence; The first waveform control conversion unit is used to be electrically connected to the device under test and the control unit, filter the first AC signal output by the device under test, change the current waveform of the first AC signal and the angle between the voltage waveform and the current waveform of the first AC signal under the control of the control unit, convert the first AC signal into a first DC signal and output it to the high-frequency isolated bidirectional power converter; The high-frequency isolated bidirectional power converter is used to be electrically connected to the control unit, and under the control of the control unit, the voltage of the first DC signal is changed and output to the second waveform control conversion unit; The second waveform control conversion unit is used to be electrically connected to the power grid and the control unit, and under the control of the control unit, convert the first DC signal into a second AC signal, and filter the second AC signal before outputting it to the power grid; it is also used to filter the third AC signal output by the power grid, and under the control of the control unit, convert the third AC signal into a second DC signal before outputting it to the high-frequency isolated bidirectional power converter, so as to realize bidirectional power flow; The high-frequency isolated bidirectional power converter is also used to change the voltage of the second DC signal under the control of the control unit and output it to the first waveform control conversion unit; The first waveform control conversion unit is further used to convert the second direct current signal into a fourth alternating current signal under the control of the control unit, change the current waveform of the fourth alternating current signal and the angle between the voltage waveform and the current waveform of the fourth alternating current signal, filter the fourth alternating current signal and output it to the device under test, so as to realize bidirectional power flow and control the active power and reactive power of the device under test; The first waveform control conversion unit includes a first filter network and a first totem pole network; The first filter network is electrically connected to the first totem pole network, and the first totem pole network is electrically connected to the high-frequency isolated bidirectional power converter; The first filter network is used to be electrically connected to the device under test, and to filter the first AC signal output by the device under test and then output it to the first totem pole network; The first totem pole network is used to be electrically connected to the control unit, and under the control of the control unit, change the current waveform of the first alternating current signal and the angle between the voltage waveform and the current waveform of the first alternating current signal, convert the first alternating current signal into a first direct current signal and output it to the high-frequency isolated bidirectional power converter; and is also used to, under the control of the control unit, convert the second direct current signal into a fourth alternating current signal, change the current waveform of the fourth alternating current signal and the angle between the voltage waveform and the current waveform of the fourth alternating current signal, and output it to the first filtering network; The first filtering network is also used to filter the fourth alternating current signal and then output it to the device under test; The first filter network includes a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, a sixth inductor, a first capacitor, a second capacitor and a third capacitor; One end of the first inductor, the second inductor and the third inductor is respectively used to be electrically connected to the device under test; the other ends of the first inductor, the second inductor and the third inductor are respectively electrically connected to one end of the fourth inductor to the sixth inductor in a one-to-one correspondence; The other ends of the fourth inductor, the fifth inductor and the sixth inductor respectively constitute the first connection end, the second connection end and the third connection end of the first filter network, and are respectively electrically connected to the first connection end, the second connection end and the third connection end of the first totem pole network in a one-to-one correspondence; One end of the first capacitor is electrically connected to the other end of the first inductor and one end of the fourth inductor, and the other end of the first capacitor is electrically connected to the other end of the second inductor and one end of the fifth inductor; One end of the second capacitor is electrically connected to the other end of the third inductor and one end of the fifth inductor, and the other end of the second capacitor is electrically connected to the other end of the third inductor and one end of the sixth inductor; One end of the third capacitor is electrically connected to the other end of the first inductor and one end of the fourth inductor, and the other end of the third capacitor is electrically connected to the other end of the third inductor and one end of the sixth inductor; The first totem pole network includes a first electronic switch tube, a second electronic switch tube, a third electronic switch tube, a fourth electronic switch tube, a fifth electronic switch tube and a sixth electronic switch tube; The output end of the first electronic switch tube and the input end of the second electronic switch tube are electrically connected to form a first connection end of the first totem pole network, which is used to be electrically connected to the first connection end of the first filter network; The output end of the third electronic switch tube and the input end of the fourth electronic switch tube are electrically connected to form a second connection end of the first totem pole network, which is used to be electrically connected to the second connection end of the first filter network; The output end of the fifth electronic switch tube and the input end of the sixth electronic switch tube are electrically connected to form a third connection end of the first totem pole network, which is used to be electrically connected to the third connection end of the first filter network; The input ends of the first electronic switch tube, the third electronic switch tube and the fifth electronic switch tube are electrically connected to form a first connection end of the first waveform control conversion unit, which is used to be electrically connected to the first connection end of the high-frequency isolation bidirectional power converter; The output ends of the second electronic switch tube, the fourth electronic switch tube and the sixth electronic switch tube are electrically connected to form a second connection end of the first waveform control conversion unit, which is used to be electrically connected to the second connection end of the high-frequency isolation bidirectional power converter; The second waveform control conversion unit includes a second filter network and a second totem pole network; The second filter network is electrically connected to the second totem pole network, and the second totem pole network is electrically connected to the high frequency isolated bidirectional power converter; The second totem pole network is used to be electrically connected to the control unit, and under the control of the control unit, convert the first DC signal into a second AC signal and output it to the second filter network; The second filter network is used to be electrically connected to the power grid, filter the second AC power signal and output it to the power grid; and is also used to filter the third AC power signal output by the power grid and output it to the second totem pole network; The second totem pole network is also used to convert the third AC power signal into a second DC power signal under the control of the control unit and output it to the high-frequency isolated bidirectional power converter; The second filter network includes a seventh inductor, an eighth inductor, a ninth inductor, a sixth capacitor, a seventh capacitor and an eighth capacitor; One end of the seventh inductor, the eighth inductor and the ninth inductor is respectively used to be electrically connected to the power grid; The other ends of the seventh inductor, the eighth inductor and the ninth inductor respectively constitute the first connection end, the second connection end and the third connection end of the second filtering network, and are used to be electrically connected to the first connection end, the second connection end and the third connection end of the second totem pole network in a one-to-one correspondence; The sixth capacitor is electrically connected between one end of the seventh inductor and one end of the eighth inductor; The seventh capacitor is electrically connected between one end of the eighth inductor and one end of the ninth inductor; The eighth capacitor is electrically connected between one end of the seventh inductor and one end of the ninth inductor; The second totem pole network includes a fifteenth electronic switch tube, a sixteenth electronic switch tube, a seventeenth electronic switch tube, an eighteenth electronic switch tube, a nineteenth electronic switch tube and a twentieth electronic switch tube; The output end of the nineteenth electronic switch tube and the input end of the twentieth electronic switch tube are electrically connected to form a first connection end of the second totem pole network, which is used to be electrically connected to the first connection end of the second filter network; The output end of the seventeenth electronic switch tube and the input end of the eighteenth electronic switch tube are electrically connected to form a second connection end of the second totem pole network, which is used to be electrically connected to the second connection end of the second filter network; The output end of the fifteenth electronic switch tube and the input end of the sixteenth electronic switch tube are electrically connected to form a third connection end of the second totem pole network, which is used to be electrically connected to the third connection end of the second filter network; The input ends of the fifteenth electronic switch tube, the seventeenth electronic switch tube and the nineteenth electronic switch tube are electrically connected to form a first connection end of the second waveform control conversion unit, which is used to be electrically connected to the third connection end of the high-frequency isolation bidirectional power converter; The output ends of the sixteenth electronic switch tube, the eighteenth electronic switch tube and the twentieth electronic switch tube are electrically connected to form the second connection end of the second waveform control conversion unit, which is used to be electrically connected to the fourth connection end of the high-frequency isolation bidirectional power converter.

2. The electronic load circuit according to claim 1, It is characterized in that The high-frequency isolated bidirectional power converter comprises a first conversion circuit, a second conversion circuit and a high-frequency transformer; The first conversion circuit is electrically connected to the first waveform control conversion unit and the primary side of the high-frequency transformer, and the second conversion circuit is electrically connected to the secondary side of the high-frequency transformer and the second waveform control conversion unit; The first conversion circuit is used to be electrically connected to the control unit, and to chop the first DC signal and then output it to the primary side of the high-frequency transformer; The high-frequency transformer is used to change the voltage of the first direct current signal and output it to the second conversion circuit; The second conversion circuit is used to be electrically connected to the control unit, chop the first DC signal and output it to the second waveform control conversion unit; and is also used to chop the second DC signal and output it to the secondary side of the high-frequency transformer; The high-frequency transformer is also used to change the voltage of the second DC signal and output it to the first conversion circuit; The first conversion circuit is further used for chopping the second DC signal and outputting the signal to the first waveform control conversion unit.

3. The electronic load circuit according to claim 2, It is characterized in that The first conversion circuit and the second conversion circuit are full-bridge circuits, half-bridge circuits, push-pull circuits or flyback circuits.

4. An electronic load device, It is characterized in that The electronic load circuit comprises a control unit and any one of claims 1 to 3, and is used for testing a device under test.

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