Single-phase inverter electrical performance test device, test cabinet and test method

Abstract

The invention provides a single-phase inverter electrical performance testing device and a testing cabinet, and belongs to the technical field of AC power supply testing, the device comprises a resistance wire, a plurality of taps are distributed between two ends of the resistance wire, and each tap is electrically connected with a single-phase inverter through an independent switch; the data acquisition module is electrically connected with the single-phase inverter and is used for acquiring output data of the single-phase inverter in the process of adjusting the load power, and the output data comprises a voltage waveform, a current waveform and frequency; and the USB acquisition card is electrically connected with the data acquisition module and the switch, is in communication connection with the upper computer, and is used for controlling the switch corresponding to the target tap to be closed according to an instruction sent by the upper computer, and transmitting output data acquired by the data acquisition module after the switch is closed to the upper computer so as to carry out an electrical performance test. The method effectively solves the technical problem that the prior art cannot be widely applied to performance testing on a working site due to hardware limitation.

Description

Technical Field

[0001] The present invention relates to the technical field of AC power testing, and particularly relates to a single-phase inverter electrical performance testing device and a testing cabinet. Background Art

[0002] In the field operations of some industries such as petroleum, power, and exploration, operators often use a special type of off-grid single-phase inverter power supply. Such a power supply is powered by several 12V automotive batteries connected in series or an external on-site AC power supply, and outputs stable 230V / 50Hz power with an output power of 1 - 2kW.

[0003] The electrical characteristics of the inverters provided by the prior art are generally detected in accordance with the relevant standards of diesel generator sets. However, due to the small power of the power supply, most of the commercially available related finished product test systems are secondarily developed based on 10kW-class diesel generator set testing cabinets, with high product costs, large volume and mass, and cannot be widely used for performance testing at the operation site, especially in the field. Summary of the Invention

[0004] In view of this, it is necessary to provide a single-phase inverter electrical performance testing device and a testing cabinet to solve the technical problem that the prior art cannot be widely used for performance testing at the operation site due to hardware limitations.

[0005] To solve the above technical problem, in a first aspect, the present invention provides a single-phase inverter electrical performance testing device, including: A resistance wire with several taps distributed between its two ends, and each tap is electrically connected to the single-phase inverter through an independent switch; A data acquisition module, electrically connected to the single-phase inverter, for acquiring the output data of the single-phase inverter during the process of adjusting the load power, where the output data includes: voltage waveform, current waveform, and frequency; A USB acquisition card, electrically connected to the data acquisition module and the switch, and communicatively connected to the upper computer, for controlling the closing of the switch corresponding to the target tap according to the instruction sent by the upper computer, and transmitting the output data acquired by the data acquisition module after the switch is closed to the upper computer for electrical performance testing.

[0006] In some embodiments of the present invention, the USB acquisition card includes: An analog IO port, electrically connected to the data acquisition module, for acquiring the output data; A digital IO port, electrically connected to the power level module, for turning on any single power level module in the power level module; A USB interface, communicatively connected to the upper computer, for receiving the instruction sent by the upper computer and transmitting the output data to the upper computer; The MCU is electrically connected to the analog IO port, digital IO port, and USB interface, and is used to receive and store the output data obtained by the analog IO port, transmit it to the host computer through the USB interface, and control the digital quantity output by the digital IO port according to the instructions received by the USB interface.

[0007] In some embodiments of the present invention, the single-phase inverter electrical performance test device further includes: The first power supply module is electrically connected to the external power supply and the switch, and is used to convert the alternating current input by the external power supply into direct current of a preset voltage level and provide it to the switch; The second power supply module is electrically connected to the external power supply and the switch, and is used to convert the direct current input by the external power supply into direct current of a preset voltage level and provide it to the switch.

[0008] In some embodiments of the present invention, the switch includes: a intermediate relay and a single-phase AC contactor that are electrically connected in sequence; The first power supply module includes: A first air switch and an AC-DC converter that are electrically connected in sequence. One end of the first air switch is electrically connected to the external AC power supply, and the other end is electrically connected to the input end of the AC-DC converter. The output end of the AC-DC converter is electrically connected to the intermediate relay and the single-phase AC contactor; The second power supply module includes: A second air switch, a third air switch, and a DC-DC converter. One end of the second air switch is electrically connected to the vehicle battery, and the other end is electrically connected to the input end of the DC-DC converter. One end of the third air switch is electrically connected to the vehicle cigarette lighter, and the other end is also electrically connected to the input end of the DC-DC converter. The output end of the DC-DC converter is electrically connected to the intermediate relay and the single-phase AC contactor.

[0009] In some embodiments of the present invention, the single-phase inverter electrical performance test device further includes: A resistance wire cooling fan, which is electrically connected to the AC-DC converter and the DC-DC converter, and the air outlet is arranged facing the resistance wire.

[0010] In some embodiments of the present invention, the AC-DC converter is electrically connected to the resistance wire cooling fan, the intermediate relay, and the single-phase AC contactor through a first diode; The second air switch is electrically connected to the DC-DC converter through a second diode; The third air switch is electrically connected to the DC-DC converter through a third diode; The DC-DC converter is electrically connected to the resistance wire cooling fan, the intermediate relay, and the single-phase AC contactor through a fourth diode.

[0011] In a second aspect, the present invention further provides a test cabinet, including: The single-phase inverter electrical performance test device as described in any one of the above device items and a rectangular housing for receiving the single-phase inverter electrical performance test device; Wherein, the rectangular housing is composed of a lightweight plastic plate with a metal coating. A recess is designed on one side of the rectangular housing and extends into the interior. A control panel is installed at the end of the recess. The control panel is provided with: an inverter input interface, which is electrically connected to the data acquisition module and the single-phase AC contactor, and is used for accessing a single-phase inverter; An AC input interface, which is electrically connected to a first air switch and is used for accessing an external AC power supply to supply power to the test cabinet; A battery input interface, which is electrically connected to a second air switch and is used for accessing an automotive battery to supply power to the test cabinet; A vehicle cigarette lighter interface, which is electrically connected to a third air switch and is used for accessing a vehicle cigarette lighter to supply power to the test cabinet; A USB interface, which is electrically connected to the MCU of the USB acquisition card and is used for accessing a host computer for data exchange; Air outlet louvers are installed on two opposite sides of the rectangular housing adjacent to the side with the recess. Handles are installed in the middle of the two sides. Air inlet louvers are installed at the lower part of the two sides and are staggered from the air outlet louvers in the vertical direction; Four rollers with locking devices are installed on the side of the rectangular housing facing the ground.

[0012] In a third aspect, the present invention further provides a method for testing the electrical performance of a single-phase inverter, which is applied to the single-phase inverter electrical performance test device as described in any one of the above device items, including: Sending an instruction to the USB acquisition card based on a preset load power-time curve to control the closing of the switch corresponding to the target tap; Starting the data acquisition module to collect the output data of the single-phase inverter during the process of adjusting the load power, where the output data includes: voltage waveform, current waveform, and frequency; Obtaining the output data collected by the USB acquisition card; Determining the load active power, sinusoidal distortion rate, steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, voltage waveform sinusoidal distortion rate, transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time, and frequency stabilization time based on a preset calculation program and the output data.

[0013] In some embodiments of the present invention, sending an instruction to the USB acquisition card based on a preset load power-time curve and controlling the switch corresponding to the target tap to close includes: Adjusting the output signal of the digital IO port of the USB acquisition card based on a preset first load power-time curve to control the plurality of switches to connect to the corresponding taps, and controlling the load power of the resistance wire to increase stepwise from 0% to 100% and then decrease to 0% of the maximum load power of the resistance wire based on a preset step and duration. Adjusting the output signal of the digital IO port of the USB acquisition card based on a preset second load power-time curve to control the plurality of switches to connect to the corresponding taps, and controlling the load power of the resistance wire to instantaneously load from 0% to 100% and then instantaneously unload to 0% of the maximum load power of the resistance wire continuously for several times according to a preset loading duration and loading time interval.

[0014] In some embodiments of the present invention, determining the test result of the electrical performance test based on the preset calculation program and the output data includes: Calculating the load active power and sinusoidal distortion rate under the first load power-time curve and the second load power-time curve based on the voltage waveform and current waveform. Respectively plotting the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the first load power-time curve and the second load power-time curve based on the voltage waveform, current waveform, and frequency. Calculating the steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, and voltage waveform sinusoidal distortion rate based on the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the first load power-time curve, and calculating the transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time, and frequency stabilization time based on the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the second load power-time curve.

[0015] The beneficial effects of the present invention are as follows: The present invention provides a single-phase inverter electrical performance testing device. By sending instructions from the host computer to the USB acquisition card, the corresponding switch is controlled to connect to the tap of the resistance wire, thereby adjusting the load power. At the same time, the USB acquisition card collects the output data of the single-phase inverter under test during the process of adjusting the load power obtained by the data acquisition module and hands it over to the host computer for performance testing. Without the need for a dedicated measurement and acquisition circuit based on MCU, DSP or FPGA and developing a control and communication module based on PLC, only through the data exchange between the USB acquisition card and the host computer, signal acquisition and load power control can be completed, reducing the requirements for hardware configuration and making the electrical performance testing device easy to be carried to the target operation site, thus solving the technical problem that performance testing cannot be widely used in the operation site due to hardware limitations. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 FIG. 8 is a schematic structural diagram of an embodiment of the single-phase inverter electrical performance testing device provided by the present invention; Figure 2 FIG. 11 is a schematic structural diagram of an embodiment of the resistance wire and the switch provided by the present invention; Figure 3 FIG. 14 is a schematic structural diagram of an embodiment of the USB acquisition card provided by the present invention; Figure 4 FIG. 17 is a schematic structural diagram of an embodiment of the power supply module provided by the present invention; Figure 5 FIG. 20 is a schematic structural diagram of an embodiment of the power supply module provided by the present invention, which is provided with a diode and a resistance wire cooling fan; Figure 6 FIG. 23 is a schematic structural diagram of an embodiment of the single-phase inverter electrical performance testing cabinet provided by the present invention; Figure 7 FIG. 26 is a front view of the single-phase inverter electrical performance testing cabinet provided by the present invention; Figure 8 FIG. 29 is a side view of the single-phase inverter electrical performance testing cabinet provided by the present invention; Figure 9 FIG. 32 is a schematic flowchart of an embodiment of the single-phase inverter electrical performance testing method provided by the present invention; Figure 10 FIG. 35 is a curve graph of the load power during the static 4-item test provided by the present invention; Figure 11The curve diagram of the load power during the dynamic four-item test provided by the present invention; Figure 12 The schematic flow diagram of the MATLAB calculation program provided by the present invention; Figure 13 The schematic flow diagram of the MATLAB calculation program when calculating the static four-item indicators provided by the present invention; Figure 14 The schematic flow diagram of the MATLAB calculation program when calculating the dynamic four-item indicators provided by the present invention. Specific embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0018] In the description of the embodiments of the present invention, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example: A and / or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone these three situations.

[0019] The descriptions such as "first" and "second" involved in the embodiments of the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Therefore, the technical features defined with "first" and "second" may explicitly or implicitly include at least one such feature.

[0020] Referring to "embodiment" in this article means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present invention. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0021] Before presenting the embodiments, the following terms will be explained first.

[0022] Dynamic four items: Refer to the indicators that mainly evaluate the response ability and stability of the inverter under dynamic conditions such as load changes or input voltage changes, mainly including: transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time, and frequency stabilization time.

[0023] Static four items: These refer to the indicators mainly used to evaluate the output characteristics and accuracy of the inverter during steady-state operation, mainly including: steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, and voltage waveform sine distortion rate.

[0024] The present invention provides a single-phase inverter electrical performance test device and a test cabinet, which will be described separately below.

[0025] Figure 1 It is a schematic structural diagram of an embodiment of the single-phase inverter electrical performance test device provided by the present invention. As Figure 1 shown, in combination with Figure 2 and Figure 3 , the single-phase inverter electrical performance test device 10 includes: A resistance wire 110, with several taps distributed between its two ends, and each tap is electrically connected to the single-phase inverter through an independent switch 120.

[0026] As Figure 2 , in some embodiments of the present invention, the switch 120 includes: a intermediate relay 121 and a single-phase AC contactor 122 that are electrically connected in sequence.

[0027] It can be understood that different switches are connected to different taps on the resistance wire, so turning on different switches can change the load actually connected to the inverter circuit by the resistance wire, thereby achieving the technical effect of changing the load power.

[0028] Preferably, in this embodiment, a total of 4 taps are provided on the resistance wire. When the input voltage is 230V, the load powers that can be provided are 250W, 500W, 750W, and 1000W in sequence.

[0029] A data acquisition module 130, which is electrically connected to the single-phase inverter 20 and is used to collect the output data of the single-phase inverter during the process of adjusting the load power. Among them, the output data includes: voltage waveform, current waveform, and frequency.

[0030] Among them, the output data includes: voltage, current, and frequency.

[0031] Preferably, the data acquisition module 110 includes a voltage sensor, a current sensor, and a voltage-frequency conversion circuit to respectively collect the above output data. Among them, the voltage sensor is of the electrical isolation type, with a maximum AC input voltage of 300V and a response frequency band of 50 - 10kHz; the current sensor is of the electrical isolation type, with a maximum AC input current of 10A and a response frequency band of 10 - 100kHz; the voltage-frequency conversion circuit is used to convert the AC voltage of the single-phase inverter to be measured into a cluster of square waves with an amplitude of 3 - 5V, a duty cycle of 50%, and an oscillation frequency of 10kHz.

[0032] Further, the voltage sensor is directly connected across the two ends of the inverter input interface 1, reducing the amplitude of the output voltage waveform of the inverter to within ±5V and providing a voltage signal to the voltage-frequency conversion circuit. The voltage-frequency conversion circuit converts the voltage into a cluster of square waves with an amplitude of 3 - 5V, a duty cycle of 50%, and an oscillation frequency of 10kHz. The current sensor is clamped on the phase line of the output cable connected to the inverter, converting the load current into a voltage signal within ±5V. It should be noted that different power level modules are connected to different taps on the resistance wire. Thus, turning on different power level modules can change the load actually connected to the inverter circuit by the resistance wire, thereby achieving the technical effect of changing the output power of the inverter by changing the load power.

[0033] Such as Figure 3 , the USB acquisition card 140 is electrically connected to the data acquisition module 130 and the switch 120, and is communicatively connected to the host computer 30, and is configured to control the closing of the switch 120 corresponding to the target tap according to an instruction sent by the host computer 30, and transmit the output data acquired by the data acquisition module 130 after the switch 120 is closed to the host computer 30 for electrical performance testing.

[0034] In some embodiments of the present invention, the USB acquisition card 140 includes: An analog IO port 141, electrically connected to the data acquisition module, for acquiring output data; A digital IO port 142, electrically connected to the power level module, for turning on any single power level module in the power level module; A USB interface 143, communicatively connected to the host computer, for receiving an instruction sent by the host computer and transmitting the output data to the host computer; An MCU 144, electrically connected to the analog IO port 141, the digital IO port 142, and the USB interface 143, for receiving and storing the output data acquired by the analog IO port 141, transmitting the output data to the host computer 30 through the USB interface 143, and controlling the digital quantity output by the digital IO port 142 according to an instruction received by the USB interface 143.

[0035] In summary, the single-phase inverter electrical performance testing device 10 provided by the present invention is constructed around the USB acquisition card 130. Its specific working process is as follows: Inside the power access device of the inverter under test, it is connected to the taps of different power levels of the resistance wire through a single-phase AC contactor. Connecting these taps can change the output power of the inverter. The USB acquisition card collects the output voltage waveforms of the voltage sensor, current sensor, and voltage-frequency conversion circuit through the internal analog I / O port, and uploads them to the host computer (usually a laptop) via the USB bus for off-line calculation. At the same time, the host computer will send a load gear switching instruction to the USB acquisition card via the USB bus. The switching signal is output through the digital I / O port and drives the corresponding single-phase AC contactor by the intermediate relay to connect the taps corresponding to different power levels of the resistance wire, thereby realizing the transformation of the output power of the inverter under test.

[0036] Compared with the prior art, a single-phase inverter electrical performance testing device provided by the present invention sends instructions from the host computer to the USB acquisition card to control the corresponding switch to connect the resistance wire tap, thereby adjusting the load power. At the same time, the USB acquisition card collects the output data of the single-phase inverter under test during the process of adjusting the load power obtained by the data acquisition module and hands it over to the host computer for performance testing. Without the need for a dedicated measurement and acquisition circuit based on MCU, DSP, or FPGA and developing a control and communication module based on PLC, only data exchange between the USB acquisition card and the host computer can complete signal acquisition and load power control, reducing the requirements for hardware configuration and making the electrical performance testing device easy to be carried to the target operation site, thus solving the technical problem that it cannot be widely used in the operation site for performance testing due to hardware limitations.

[0037] Such as Figure 4 , to provide stable electric energy for the testing device to ensure the stability of the testing process. At the same time, to expand the versatility of the testing device so that it can be used in combination with both DC power supplies and AC power supplies. In some embodiments of the present invention, the single-phase inverter electrical performance testing device 10 further includes: A first power module 150, electrically connected to an external power supply and a switch 120, for converting the alternating current input by the external power supply into direct current of a preset voltage level and providing it to the switch; A second power module 160, electrically connected to an external power supply and a switch 120, for converting the direct current input by the external power supply into direct current of a preset voltage level and providing it to the switch.

[0038] In some embodiments of the present invention, the switch 120 includes: an intermediate relay 121 and a single-phase AC contactor 122 that are electrically connected in sequence; The first power module 150 includes: A first air switch 151 and an AC-DC converter 152 that are electrically connected in sequence. One end of the first air switch 151 is electrically connected to an external AC power supply, and the other end is electrically connected to the input end of the AC-DC converter 152. The output end of the AC-DC converter 152 is electrically connected to an intermediate relay 121 and a single-phase AC contactor 122; The second power supply module 160 includes: A second air switch 161, a third air switch 162, and a DC-DC converter 163. Among them, one end of the second air switch 161 is electrically connected to the vehicle battery, and the other end is electrically connected to the input end of the DC-DC converter 163. One end of the third air switch 162 is electrically connected to the vehicle cigarette lighter, and the other end is also electrically connected to the input end of the DC-DC converter 163. The output end of the DC-DC converter 163 is electrically connected to the intermediate relay 121 and the single-phase AC contactor 122.

[0039] It should be noted that the three air switches are mainly used to control the access of the power supply and achieve short-circuit protection. The AC-DC converter connected to the first air switch is used to convert the input alternating current into 24V direct current. The second air switch and the third air switch are connected in parallel to the DC-DC power supply, and the function of the DC-DC power supply is to convert the input direct current into 24V direct current. In addition, the vehicle battery and cigarette lighter can provide continuous and stable direct current, ensuring the acquisition of continuous and stable power in the field scenario, further enhancing the versatility of the present invention.

[0040] Such as Figure 5 , since the resistance wire generates heat during operation, and when the temperature is too high, the actual resistance of the resistance wire will also change. To reduce the influence of the overheating of the resistance wire on the test results, in some embodiments of the present invention, the single-phase inverter electrical performance test device 10 further includes: A resistance wire cooling fan 170, which is electrically connected to the AC-DC converter 152 and the DC-DC converter 163, and the air outlet is arranged facing the resistance wire 110.

[0041] In addition, since a large circulating current appears between the power supplies due to the voltage difference inside after multiple input power supplies are connected in parallel, which may burn out the power supplies. To improve the safety of the test device, such as Figure 6 , in some embodiments of the present invention, the AC-DC converter 152 is electrically connected to the resistance wire cooling fan 170, the intermediate relay 121, and the single-phase AC contactor 122 through a first diode D1; The second air switch 161 is electrically connected to the DC-DC converter 163 through a second diode D2; The third air switch 162 is electrically connected to the DC-DC converter 163 through a third diode D3; The DC-DC converter 163 is electrically connected to the resistance wire cooling fan 170, the intermediate relay 121, and the single-phase AC contactor 122 through the fourth diode D4.

[0042] It should be noted that the functions of diodes D2 and D3 are to prevent a large circulating current and power source burnout between the input DC power sources due to a voltage difference when they are directly paralleled. The AC-DC converter 152 and the DC-DC converter 163 are paralleled through diodes D1 and D4 to supply power to the coils of the intermediate relay and the single-phase AC contactor. The functions of diodes D1 and D4 are the same as those of diodes D2 and D3.

[0043] In the second aspect, as Figure 6 , the present invention further provides a test cabinet 40, including: The single-phase inverter electrical performance test device 10 as described in any one of the above device items and the rectangular housing 410 for receiving the single-phase inverter electrical performance test device 10; Among them, further, to improve the portability of the test cabinet and make it convenient to carry, while preventing damage to the test cabinet caused by rain, snow, and heat generated during operation, the rectangular housing 410 is made of a lightweight plastic plate with a metal coating. A recess is designed on one side of the rectangular housing 410 and extends into the interior, and a control panel is installed at the end of the recess. The control panel is provided with: An inverter input interface 411, which is electrically connected to the data acquisition module 130 and the single-phase AC contactor 122, and is used to connect the single-phase inverter 20; An AC input interface 412, which is electrically connected to the first air switch 151 and is used to connect an external AC power source to supply power to the test cabinet; A battery input interface 413, which is electrically connected to the second air switch 161 and is used to connect an automotive battery to supply power to the test cabinet; A vehicle cigarette lighter interface 414, which is electrically connected to the third air switch 162 and is used to connect a vehicle cigarette lighter to supply power to the test cabinet.

[0044] The AC input interface 412 is used to connect to different types of commercial power around the world and 115V / 400Hz single-phase AC power on aircraft. The battery input interface 413 is a 2-core aviation socket and can be connected to a cable with 2 alligator clips. One or two series-connected automotive batteries can be connected through the cable with alligator clips. The vehicle cigarette lighter interface 414 is a standard vehicle cigarette lighter interface and can be connected to the cigarette lighter in the vehicle cab through a cable to connect to the 12V or 24V power supply of the vehicle.

[0045] A USB interface 133, which is electrically connected to the MCU 144 of the USB acquisition card 140 and is used to connect to the host computer 30 for data exchange.

[0046] Preferably, in a specific embodiment, such as Figure 7 , the front size of the test cabinet is 300 mm wide and 300 mm high (excluding the rollers). A notch 420 that is recessed 100 mm inward is machined on the front. The test cabinet wiring and operation panel are embedded at the end of the channel. The concave design of the panel can prevent rainwater from wetting the interface panel in light rain weather. From top to bottom on the left side of the interface panel are the AC input interface 412, the battery input interface 413, the vehicle cigarette lighter interface 414, and the corresponding power-on indicator lights 430, 440, 450. From left to right in the upper part on the right side of the interface panel are the first air switch 1411, the second air switch 1421, and the third air switch 1422. On the right side is the Type B interface 133 of the USB acquisition card. Below the lower right of the operation panel is the inverter input interface 411. At the lower right of the front is the M4-sized bolt 460 with a cross slot. The AC input interface 412 is used to access mains power of different systems around the world and 115V / 400Hz single-phase AC power on aircraft. The battery input interface 413 is a 2-core aviation socket, which can be connected to a cable with two alligator clips. One or two series-connected automotive batteries can be accessed through the cable with alligator clips. The vehicle cigarette lighter interface 414 is a standard vehicle cigarette lighter interface, which can be connected to the cigarette lighter in the vehicle cab through a cable to access the 12V or 24V power of the vehicle. The USB interface uses the more versatile Type B interface.

[0047] On the two opposite sides of the rectangular housing 410 adjacent to the side with the notch, air outlet louvers are installed. Handles are installed in the middle of the two sides. Air inlet louvers are installed at the lower part of the two sides and are offset from the air outlet louvers in the vertical direction. Four rollers with locking devices are installed on the side of the rectangular housing facing the ground.

[0048] In a specific embodiment, such as Figure 8 , the side size of the test cabinet is 300 mm wide and 300 mm high (excluding the rollers). Above the side is the plastic exhaust louver 1 that slopes downward, and its back is coated with a metal layer to enhance the electromagnetic shielding effect. In the middle is the housing opening 2 that is recessed inward and upward, which serves as a handle for convenient user handling. Below is the plastic intake louver 3 that slopes downward, and its back is coated with a metal layer to enhance the electromagnetic shielding effect. The installation position is offset from the upper exhaust louver in the vertical direction to prevent the intake of high-temperature air flowing obliquely downward.

[0049] Such as Figure 9 , thirdly, the present invention also provides a method for testing the electrical performance of a single-phase inverter, which is applied to the single-phase inverter electrical performance testing device 10 described in any one of the above device items, and includes: S901. Send an instruction to the USB acquisition card based on a preset load power-time curve to control the closing of the switch corresponding to the target tap.

[0050] In some embodiments of the present invention, step S901 includes: Based on a preset first load power-time curve, adjust the output signal of the digital IO port of the USB acquisition card to control the plurality of switches to connect to the corresponding taps, and control the load power of the resistance wire to increase stepwise from 0% to 100% and then decrease to 0% of the maximum load power of the resistance wire based on a preset step and duration; Based on a preset second load power-time curve, adjust the output signal of the digital IO port of the USB acquisition card to control the plurality of switches to connect to the corresponding taps, and control the load power of the resistance wire to instantaneously load from 0% to 100% and then instantaneously unload to 0% of the maximum load power of the resistance wire continuously for several times according to a preset loading duration and loading time interval.

[0051] It should be noted that adjusting the load power based on the first load power-time curve is essentially to obtain the output data during the static four-item test of the single-phase inverter, and adjusting the load power based on the second load power-time curve is to obtain the output data during the dynamic four-item test of the single-phase inverter. S902. Start the data acquisition module to acquire the output data of the single-phase inverter during the process of adjusting the load power, where the output data includes: voltage waveform, current waveform, and frequency; S903. Obtain the output data acquired by the USB acquisition card; S904. Determine the load active power, sinusoidal distortion rate, steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, voltage waveform sinusoidal distortion rate, transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time, and frequency stabilization time based on a preset calculation program and the output data.

[0052] In some embodiments of the present invention, step S904 includes: Calculate the load active power and sinusoidal distortion rate under the first load power-time curve and the second load power-time curve based on the voltage waveform and current waveform; Respectively plot the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the first load power-time curve and the second load power-time curve based on the voltage waveform, current waveform, and frequency; Calculate the steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, and voltage waveform sinusoidal distortion rate based on the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the first load power-time curve. Calculate the transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time, and frequency stabilization time based on the current effective value-time curve, voltage effective value-time curve, and frequency effective value-time curve under the second load power-time curve.

[0053] Preferably, the host computer software for implementing the above method consists of a LabVIEW control and recording program and a MATLAB calculation program; Please refer to Figure 10 . In an embodiment, when the LabVIEW control and recording program is started, the program first enters the static four-index test mode. The program controls the load to increase from 0% to 100% and then decrease to 0% in a stepped manner with a 25% step by adjusting the output signal of the digital IO port of the acquisition card. The step duration is 2 minutes. The specific load power changes are 0%, 100%, 25%, 50%, 75%, 100%, 75%, 50%, 25%, 0%, 100%, 0%. The rated output power of the measured single-phase inverter is 1 kVA, so the corresponding load power changes are 0 W, 1 kW, 250 W, 500 W, 750 W, 1 kW, 750 W, 500 W, 250 W, 0 W, 1 kW, 0 kW. The model of the acquisition card used is NI USB 6009, and the highest sampling rate is 10 kS / s. Therefore, the program records the real-time curves of voltage and current during the whole process at a rate of 10 kS / s.

[0054] Please refer to Figure 11 . In an embodiment, after the static four-index test is completed, the LabVIEW control and recording program enters the dynamic four-index test mode, and controls the load to be instantaneously loaded from 0% to 100% and then instantaneously unloaded to 0% three times continuously. The duration of each load is 60 s, and the interval between two loads is 60 s. The specific load power changes are 0%, 100%, 0%, 100%, 0%, 100%, 0%. The rated output power of the measured single-phase inverter is 1 kVA, so the corresponding load power changes are 0 W, 1 kW, 0 W, 1 kW, 0 W, 1 kW, 0 W. The model of the acquisition card used is NI USB 6009, and the highest sampling rate is 10 kS / s. Therefore, the program records the real-time curves of voltage and current during the whole process at a rate of 10 kS / s.

[0055] When calculating the four static indicators, the MATLAB calculation program is used to calculate the voltage sine distortion rate of the inverter under test based on the no-load voltage waveform that appears for the second time, calculate the active power of the inverter under test based on the integration of the voltage and current waveforms, calculate the effective value-time curves and frequency-time curves of the voltage and current based on the zero-crossing points of the current waveform. On this basis, the load change moment is determined based on the mutation points of the current effective value, and the voltage effective value-time curve and frequency-time curve between 50 and 110 s after the load change are selected to calculate the voltage maximum value sequence and frequency maximum value sequence, and finally the steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, and frequency fluctuation rate indicators are obtained.

[0056] Specifically, please refer to Figure 12 , in an embodiment, the tester starts the MATLAB calculation program and manually specifies the static four-item test waveform record file X.csv and the dynamic four-item test waveform record file XX.csv. After the calculation program reads them in respectively, it performs calculations according to the predetermined calculation program. For the static four-item test waveforms, the program first obtains the zero-crossing moments of the current waveform, such as t1, t2, t3, t4 in sequence, and then calculates the effective value I1 of the current waveform in the first cycle according to the following formula: (1) where i(t) is the recorded current waveform; then replace t1 with t2 and t2 with t4 to obtain I2, and so on to obtain the current effective value-time curve. Similarly, the voltage effective value-time curve and frequency-time curve are obtained. For the power effective value-time curve, P1 is calculated according to the following formula, and the remaining steps are the same as those for calculating the current effective value-time curve: (2) where u(t) is the recorded voltage waveform and i(t) is the recorded current waveform. At the same time, the program also intercepts the voltage waveform from 240 to 360 s, and obtains the fundamental component amplitude U F and harmonic component amplitude U H (i), i = 2 to 40, and calculates the voltage sine distortion rate k according to the following formula M : (3) Finally, based on the previously obtained voltage effective value-time curve, current effective value-time curve and frequency-time curve, the values of the four static indicators are further calculated. Similarly, the values of the four dynamic indicators are calculated. Finally, the program summarizes the calculation results and writes them into the user-specified excel file in a certain layout.

[0057] Furthermore, please refer to Figure 13, in one embodiment, the MATLAB calculation program calculates four static indicators according to the following logic. First, traverse the effective current-time curve, use the ischange instruction to mark all current mutation points, and record the corresponding time points as ic(n), where n = 1 to 12. Starting from ic(n) + 50 s and ending at ic(n) + 110 s, intercept the effective voltage-time curve and frequency-time curve within the corresponding time period. Then, find the maximum and minimum values of each segment of the effective voltage-time curve and frequency-time curve, respectively, to form a voltage maximum value sequence, a voltage minimum value sequence, a frequency maximum value sequence, and a frequency minimum value sequence. Then, find the maximum and minimum values of these sequences in turn to obtain the maximum voltage U S max, the minimum voltage U S min, the maximum frequency f S max and the minimum frequency f S min, and obtain the steady-state voltage regulation rate ΔU S +, ΔU S -, the voltage fluctuation rate ΔU B , the steady-state frequency regulation rate Δ f S +, Δ f S -, the frequency fluctuation rate Δ f B : (4) (5) (6) (7) (8) (9) When calculating the four dynamic indicators, the MATLAB calculation program is also used to calculate the effective voltage-time curve, current-time curve, and frequency-time curve based on the zero-crossing points of the current waveform. On this basis, the load change moment is determined based on the effective current mutation points, the voltage and frequency stability moments are determined based on the relationship between the difference between the maximum and minimum values within the sliding window and the predetermined threshold, and the voltage stability time sequence and frequency stability time sequence are calculated. Select the effective voltage-time curve from the load change to the voltage stability moment, and calculate the voltage maximum and minimum value sequence; select the frequency-time curve from the load change to the frequency stability moment, and calculate the frequency maximum and minimum value sequence. Finally, the transient voltage regulation rate, transient frequency regulation rate, voltage stability time, and frequency stability time are obtained.

[0058] Specifically, please refer toFigure 14 In one embodiment, the MATLAB calculation program calculates the four dynamic indicators according to the following logic. First, the current effective value-time curve is traversed, and all current mutation points are marked using the ischange instruction. The corresponding time point is recorded as ic(n), where n=1~12. Then, a sliding window with a length of 5 is used to slide the voltage effective value-time curve and the frequency-time curve backward from ic(n), and the maximum value wmax and the minimum value wmin in the window are obtained. If (wmax-wmin) <ws(ws为阈值),则认定电压或频率达到稳定,记对应时间点为ius(n)及ifs(n),n=1~12。在本实施例中,电压阈值wsu=0.05V、频率阈值wsf=0.01Hz。截取ic(n)~ ius(n)范围内的电压有效值-时间曲线和ic(n)~ ifs(n)范围内的频率-时间曲线,参考静态4项参数的稳态电压调整率、稳态频率调整率,计算得到瞬态电压调整率ΔU T +, ΔU T -, and transient frequency regulation rate Δ f T +, Δ f T -. Finally, calculate (ius(n) - ic(n)) to get the voltage stabilization time series, calculate (ifs(n) - ic(n)) to get the frequency stabilization time series, and take the maximum values ​​of these two series to get the voltage stabilization time and frequency stabilization time.

[0059] Finally, the MATLAB calculation program is also used to generate a fixed-format Excel report output from the final calculation results.

[0060] The single-phase inverter electrical performance test device and test cabinet provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A single-phase inverter electrical performance test device, characterized in that: include: The resistor wire has a plurality of taps distributed between the two ends, and each tap is electrically connected to the single-phase inverter through an independent switch; A data acquisition module is electrically connected to the single-phase inverter and is used to collect output data of the single-phase inverter during the process of adjusting the load power, wherein the output data includes: voltage waveform, current waveform and frequency; The USB acquisition card is electrically connected to the data acquisition module and the switch, and is communicatively connected to the host computer. It is used to control the closure of the switch corresponding to the target tap according to the instruction sent by the host computer, and transmit the output data collected by the data acquisition module after the switch is closed to the host computer for electrical performance testing.

2. The single-phase inverter electrical performance test device according to claim 1, characterized in that: The USB acquisition card includes: An analog IO port, electrically connected to the data acquisition module, for acquiring the output data; A digital IO port, electrically connected to the power gear module, for connecting any single power gear module in the power gear module; A USB interface is connected to a host computer for receiving instructions from the host computer and transmitting the output data to the host computer; The MCU is electrically connected to the analog IO port, the digital IO port and the USB interface, and is used to receive and store the output data obtained by the analog IO port and transmit it to the host computer through the USB interface, and control the switching value output by the digital IO port according to the instructions received by the USB interface.

3. The single-phase inverter electrical performance test device according to claim 1, characterized in that: The single-phase inverter electrical performance testing device also includes: A first power supply module, electrically connected to an external power supply and a switch, and configured to convert the AC power inputted from the external power supply into a DC power of a preset voltage level and provide the DC power to the switch; The second power supply module is electrically connected to the external power supply and the switch, and is used to convert the direct current power input from the external power supply into direct current power of a preset voltage level and provide it to the switch.

4. The single-phase inverter electrical performance test device according to claim 3, characterized in that: The switch comprises: an intermediate relay and a single-phase AC contactor electrically connected in sequence; The first power module comprises: A first air switch and an AC-DC converter electrically connected in sequence, wherein one end of the first air switch is electrically connected to an external AC power supply, and the other end is electrically connected to an input end of the AC-DC converter, and an output end of the AC-DC converter is electrically connected to the intermediate relay and a single-phase AC contactor; The second power supply module comprises: A second air switch, a third air switch and a DC-DC converter, wherein one end of the second air switch is electrically connected to the vehicle battery, and the other end is electrically connected to the input end of the DC-DC converter, one end of the third air switch is electrically connected to the vehicle cigarette lighter, and the other end is also electrically connected to the input end of the DC-DC converter, and the output end of the DC-DC converter is electrically connected to the intermediate relay and the single-phase AC contactor.

5. The single-phase inverter electrical performance test device according to claim 4, characterized in that: The single-phase inverter electrical performance testing device also includes: The resistance wire cooling fan is electrically connected to the AC-DC converter and the DC-DC converter, and the air outlet is arranged facing the resistance wire.

6. The single-phase inverter electrical performance test device according to claim 5, characterized in that: The AC-DC converter is electrically connected to the resistance wire cooling fan, the intermediate relay and the single-phase AC contactor through a first diode; The second air switch is electrically connected to the DC-DC converter via a second diode; The third air switch is electrically connected to the DC-DC converter via a third diode; The DC-DC converter is electrically connected to the resistance wire cooling fan, the intermediate relay and the single-phase AC contactor through a fourth diode.

7. A test cabinet, characterized in that: include: The single-phase inverter electrical performance test device as claimed in any one of claims 1 to 6, and a rectangular housing receiving the single-phase inverter electrical performance test device; The rectangular shell is composed of a lightweight plastic plate with a metal coating, one side of the rectangular shell is designed with a recessed recess, and a control panel is installed at the end of the recess, and the control panel is provided with: an inverter input interface, which is electrically connected to the data acquisition module and the single-phase AC contactor and is used to access the single-phase inverter; An AC input interface, electrically connected to the first air switch, for connecting to an external AC power supply to power the test cabinet; The battery input interface is electrically connected to the second air switch and is used to connect to the car battery to power the test cabinet; The vehicle cigarette lighter interface is electrically connected to the third air switch and is used to connect to the vehicle cigarette lighter to power the test cabinet; USB interface, electrically connected to the MCU of the USB acquisition card, used to access the host computer for data exchange; The rectangular shell is provided with air outlet louvers on two sides adjacent to the side with the notch and opposite to each other, a handle is provided in the middle of the two sides, and air inlet louvers are provided at the lower part of the two sides and are staggered with the air outlet louvers in the vertical direction; Four rollers with locking devices are installed on one side of the rectangular shell facing the ground.

8. A method for testing the electrical performance of a single-phase inverter, characterized in that: The single-phase inverter electrical performance test device applied to any one of claims 1 to 6 above comprises: Sending instructions to the USB acquisition card based on a preset load power-time curve to control the switch corresponding to the target tap to close; Starting the data acquisition module to acquire output data of the single-phase inverter during the process of adjusting the load power, wherein the output data includes: voltage waveform, current waveform and frequency; Obtain output data collected by the USB acquisition card; Based on the preset calculation program and the output data, the load active power, sinusoidal distortion rate, steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate, voltage waveform sinusoidal distortion rate, transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time and frequency stabilization time are determined.

9. The single-phase inverter electrical performance testing method according to claim 8, characterized in that: The sending of instructions to the USB acquisition card based on a preset load power-time curve to control the closing of a switch corresponding to a target tap includes: Based on a preset first load power-time curve, the output signal of the digital IO port of the USB acquisition card is adjusted to control the plurality of switches to connect corresponding taps, and the load power of the resistance wire is controlled to increase from 0% to 100% of the maximum load power of the resistance wire and then decrease to 0% in a step-by-step manner based on a preset step and duration; Based on the preset second load power-time curve, the output signal of the digital IO port of the USB acquisition card is adjusted to control the several switches to connect the corresponding taps, and the load power of the resistance wire is controlled to be instantly loaded from 0% of the maximum load power of the resistance wire to 100% and then instantly unloaded to 0% several times according to the preset loading duration and loading time interval.

10. The single-phase inverter electrical performance testing method according to claim 9, characterized in that: The step of determining the test result of the electrical performance test based on a preset calculation program and the output data comprises: Calculate the load active power and sinusoidal distortion rate under the first load power-time curve and the second load power-time curve based on the voltage waveform and the current waveform; Based on the voltage waveform, current waveform and frequency, respectively draw a current effective value-time curve, a voltage effective value-time curve and a frequency effective value-time curve under the first load power-time curve and the second load power-time curve; The steady-state voltage regulation rate, steady-state frequency regulation rate, voltage fluctuation rate and voltage waveform sinusoidal distortion rate are calculated based on the current effective value-time curve, voltage effective value-time curve and frequency effective value-time curve under the first load power-time curve; the transient voltage regulation rate, transient frequency regulation rate, voltage stabilization time and frequency stabilization time are calculated based on the current effective value-time curve, voltage effective value-time curve and frequency effective value-time curve under the second load power-time curve.

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