Test tool for driving bus power supply of industrial frequency converter

Abstract

The utility model relates to the technical field of testing, and discloses a testing tool for driving bus power supply of an industrial frequency converter. The test tool comprises a single-phase contact voltage regulator, an input terminal of which is connected to a 220V public power grid power supply line and is used for regulating a driving bus voltage value output by the test tool; the two ends of the control transformer are connected with the single-phase contact voltage regulators and the rectifier bridges respectively, and the control transformer is used for achieving the electric isolation and boosting effects between the front-stage single-phase contact voltage regulator and the rear-stage rectifier bridge; and two ends of the rectifier bridge are respectively connected with the control transformer and the driving bus capacitor, and the rectifier bridge is used for rectifying the alternating-current voltage output by the control transformer into direct-current driving bus voltage and outputting the direct-current driving bus voltage to a post-stage. The test tool provided by the embodiment of the utility model can be used only by being powered by a 220V public power grid, the use requirement is lower, and the application scene is wider; in addition, a driving bus voltage value output by the tool can be adjusted through a single-phase contact voltage regulator knob in the testing tool.

Description

Technical Field

[0001] The utility model relates to the technical field of testing, in particular to a testing tool for power supply of a driving bus of an industrial frequency converter. Background Technique

[0002] As is well known, an industrial frequency converter is essentially an AC power conversion device that converts three-phase power of a public power grid (rated voltage 380V, rated frequency 50Hz) into three-phase power of a specific frequency and specific voltage. For an AC motor, the three-phase power of a specific frequency and specific voltage (i.e., UVW three-phase power) received from the output end of the industrial frequency converter directly determines the actual operating power, speed, and torque of the motor. The UVW three-phase power at the output end of the frequency converter is directly affected by the voltage of its internal driving bus, that is, the magnitude of the driving bus voltage can, to a certain extent, determine the magnitudes of the UVW three-phase output voltage and current of the frequency converter, thereby affecting the actual operating power, speed, and torque of the motor. Under the condition that the output frequency of the frequency converter remains unchanged, there is a corresponding proportional relationship between the values of the UVW three-phase output voltage and the internal driving bus voltage, that is, the higher the ratio of the UVW three-phase voltage to the driving bus voltage, the greater the power, speed, and torque that the motor can actually reach during operation. However, too high a driving bus voltage will also cause overvoltage damage to the power conversion devices inside the frequency converter, so the driving bus voltage cannot be blindly increased.

[0003] This requires a large number of tests to be carried out through a testing tool during the preliminary design stage of the frequency converter to verify the ranges of the UVW three-phase voltage values and current values output under different driving bus voltages. Finally, based on the UVW three-phase output voltage and current values to be achieved in the design, the internal driving bus voltage is reasonably selected to achieve the best control effect.

[0004] Currently, only a simple testing tool composed of "air switch, rectifier bridge, driving bus capacitor, and current sharing resistor" is used on the market. This testing tool requires power supply from a 380V public power grid, and the output driving bus voltage is not adjustable, having the defects of high usage requirements and narrow applicable scenarios. Summary of the Invention

[0005] The purpose of the utility model is to provide a testing tool for power supply of a driving bus of an industrial frequency converter to overcome the defects of high usage requirements and narrow applicable scenarios existing in the prior art.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A testing tool for power supply of a driving bus of an industrial frequency converter includes:

[0008] A single-phase contact voltage regulator, whose input terminals are connected to a 220V public power grid supply line, for adjusting the value of the driving bus voltage output by the testing tool;

[0009] A control transformer, with its two ends respectively connected to a single-phase contact voltage regulator and a rectifier bridge, is used to achieve electrical isolation and boost the voltage between the single-phase contact voltage regulator in its front stage and the rectifier bridge in its rear stage;

[0010] A rectifier bridge, with its two ends respectively connected to the control transformer and the drive bus capacitor, is used to rectify the AC voltage output by the control transformer in the front stage into a DC drive bus voltage and output it to the drive bus capacitor in the rear stage.

[0011] Optionally, the input terminals of the single-phase contact voltage regulator are connected to the 220V public power grid supply line through a main switch.

[0012] Optionally, the single-phase contact voltage regulator includes an input winding and an output winding that are electrically isolated.

[0013] Optionally, the drive bus capacitor includes six capacitors. The six capacitors are divided into three parallel paths between the drive bus power supply positive line and the drive bus power supply negative line, and each path includes two capacitors of the same capacitance and the same withstand voltage connected in series.

[0014] Optionally, two equalizing resistors connected in series are also connected between the drive bus power supply positive line and the drive bus power supply negative line.

[0015] Optionally, a discharge resistor is also connected between the drive bus power supply positive line and the drive bus power supply negative line.

[0016] Optionally, a discharge switch connected in series with the discharge resistor is also connected between the drive bus power supply positive line and the drive bus power supply negative line.

[0017] Optionally, it further includes a current display; the current display is connected in series on the drive bus power supply positive line of the drive bus capacitor and is used to monitor the drive bus power supply current of the test tooling in real time.

[0018] Optionally, it further includes a voltage display; the voltage display is connected in parallel to the 220V public power grid supply line and the drive bus voltage supply line.

[0019] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0020] Different from the simple test tooling on the market, the test tooling of the embodiment of the present utility model can be used only by being powered by the 220V public power grid, without the need for 380V public power grid power supply. The usage requirements are lower and the applicable scenarios are wider. In addition, the drive bus voltage value (0VDC - 560VDC) output by the tooling can be adjusted through the single-phase contact voltage regulator knob inside the test tooling. Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the electrical schematic diagram of the test tooling provided by the embodiment of the present invention;

[0023] Figure 2 It is the internal schematic diagram of the single-phase contact voltage regulator provided by the embodiment of the present invention. Specific embodiments

[0024] To make the utility model objectives, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] Different from the simple test tooling on the market that only consists of "air switch, rectifier bridge, drive bus capacitor, and current-sharing resistor" without overload protection and with an uncontrollable output drive bus voltage, the embodiment of the present invention provides a test tooling that also integrates "a single-phase contact voltage regulator with overload protection function, a control transformer for isolation / boosting, a voltage display for monitoring the input and output voltage values of the tooling, a current display for monitoring the output current of the tooling, and a discharge resistor for safety protection" inside.

[0026] Different from the other simple test tooling on the market, this test tooling can be used only with a 220V public power grid supply, without the need for a 380V public power grid supply, with lower usage requirements and a wider range of applicable scenarios. In addition, the drive bus voltage value (0VDC - 560VDC) output by the tooling can be adjusted through the knob of the single-phase contact voltage regulator inside the test tooling. In addition to low usage requirements and an adjustable output drive bus voltage value, this tooling also realizes real-time monitoring of the input and output voltage values and output current value during the operation of the tooling through the voltage display and current display, and realizes safety protection for the users of the tooling through the discharge resistor.

[0027] Specifically, the electrical schematic diagram of this test tooling is as Figure 1As shown. The core utility model points of the tooling are the integration of four major parts: "single-phase contact voltage regulator T1", "control transformer T2", "discharge resistor RP", and "current display A1 and voltage display UD1" to achieve functions such as 220V public power grid power supply, input overload protection, and adjustable output drive bus voltage.

[0028] The overall power-on and power-off of this test tooling is controlled by the main switch D1. After D1 is disconnected, it can ensure that the inside of the tooling is in a power-off state, so that the user can repair the tooling. On the contrary, after the main switch D1 is closed, the 220V power supply of the public power grid can flow through the input switch K1 and be transmitted to the single-phase contact voltage regulator T1. T1 is a single-phase contact voltage regulator with overload protection function, and its internal principle is as follows Figure 2 As shown, the 220V public power grid power supply is connected through the input terminals A and X. After voltage regulation, it is output to the subsequent circuit through the output terminals a and x. Among them, the output terminal a is connected to the brush inside the voltage regulator T1. The brush is in close contact with the polished surface of the coil on the internal magnetic core under the action of spring pressure. By turning the knob of the voltage regulator T1, the turns ratio of the primary side and the secondary side of the voltage regulator can be changed, so as to adjust the output voltage of T1 in the range of 0-250V, and thus achieve the purpose of adjusting the drive bus power supply voltage output by the tooling in the range of 0-560V. In addition, as shown in the electrical principle of the tooling Figure 1 As shown, a fuse RL is also integrated in the single-phase contact voltage regulator T1 to achieve the overload protection function. If the input current exceeds the rated value of the fuse (12A), the fuse can quickly fuse to disconnect the power supply of the front-stage public power grid from the subsequent circuit to prevent overcurrent from damaging the remaining devices in the subsequent stage.

[0029] T2 is a control transformer that plays an isolation and boosting role. Compared with the single-phase contact voltage regulator T1 with only one winding on the internal magnetic core, the control transformer T2 has two electrically isolated windings (i.e., the input winding and the output winding) inside. Through the two electrically isolated windings, the electrical isolation between the 220V public power grid input in the front stage of the tooling and the drive bus voltage output in the subsequent stage of the tooling can be realized, thereby reducing the possible interference to the output voltage of the tooling on the 220V public power grid and improving the stability of the drive bus voltage power supply of the test tooling. In addition, the setting of the turns ratio between the input winding and the output winding inside the control transformer also makes it play a boosting role to a certain extent, thereby increasing the maximum value of the drive bus voltage that the tooling can reach.

[0030] D2 is a rectifier bridge, whose main function is to rectify the AC voltage output by the pre-stage control transformer into a DC drive bus voltage and output it to the post-stage drive bus capacitors C1 - C6, serving to charge the drive bus capacitors. Considering the need to reduce the total cost of tooling production while ensuring the total capacitance of the drive bus capacitors, the drive bus capacitors C1 - C6 are connected in three parallel branches, and each branch is connected in series with two capacitors of the same capacitance and withstand voltage. Also, to eliminate the charge and discharge differences among the capacitors in the above drive bus capacitor connection method and ensure the same lifespan for each capacitor, equalizing resistors R1 and R2 are used inside this tooling to ensure the same voltage across each capacitor, thereby ensuring that each capacitor charges and discharges synchronously.

[0031] K2 is a discharge switch and RL is a discharge resistor, and the two together form a drive bus capacitor discharge circuit. This discharge circuit is not always connected in parallel to the drive bus capacitor line. It controls whether to connect the discharge resistor in parallel to the drive bus through the discharge switch K2. Thus, it can effectively prevent the tooling users from being shocked by the residual electricity inside the bus capacitor without affecting the basic function of the tooling's drive bus power supply, improving the safety of tooling use.

[0032] The current display A1 and the voltage display UD1 are integrated inside the display module together to reduce the overall volume of the tooling. Among them, the current display is connected in series on the positive line (P+) of the drive bus power supply to monitor the drive bus power supply current of the tooling in real time, and the voltage display is connected in parallel to the 220V public power grid power supply line and the drive bus voltage power supply line of the tooling respectively to monitor the voltage values at the input and output ends of the tooling in real time.

[0033] As described above, compared with the traditional simple test tooling, in addition to being able to achieve the basic function of 560V drive bus power supply, this drive bus power supply test tooling further realizes a series of functions such as being used under the condition of 220V public power grid power supply, electrical isolation between the public power grid power supply and the tooling's drive bus power supply, input overload protection, adjustable output drive bus voltage from DC0 to 560V, with discharge protection, and real-time monitoring of the input and output voltages and currents of the tooling by integrating a single-phase contact adjustable transformer, a control transformer, a discharge resistor, a current display, and a voltage display. It facilitates the test process of the drive bus power supply voltage of industrial frequency converters and improves the safety and operability of tooling use.

[0034] As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test fixture for industrial inverter driven bus power supply, characterized in that: include: Single-phase contact voltage regulator, whose input terminal is connected to the 220V public power grid power supply line, is used to adjust the drive bus voltage value output by the test fixture; A control transformer, with two ends connected to a single-phase contact voltage regulator and a rectifier bridge respectively, for achieving electrical isolation and voltage boosting between the single-phase contact voltage regulator at the front stage and the rectifier bridge at the rear stage; The rectifier bridge has two ends connected to the control transformer and the drive bus capacitor respectively, and is used to rectify the AC voltage output by the control transformer of the previous stage into a DC drive bus voltage and output it to the drive bus capacitor of the subsequent stage.

2. The test fixture for industrial inverter driven bus power supply according to claim 1, characterized in that: The input terminal of the single-phase contact voltage regulator is connected to the 220V public power grid power supply line through a main switch.

3. The test fixture for industrial inverter driven bus power supply according to claim 1, characterized in that: The single-phase contact voltage regulator includes an input winding and an output winding which are electrically isolated.

4. The test fixture for industrial inverter drive bus power supply according to claim 1, characterized in that: The driving bus capacitor includes six capacitors, which are divided into three paths and connected in parallel between the driving bus power supply positive line and the driving bus power supply negative line, and each path includes two capacitors with the same capacitance and withstand voltage connected in series.

5. The test fixture for industrial inverter driven bus power supply according to claim 4, characterized in that: Two voltage-equalizing resistors connected in series are further connected between the driving bus power supply positive line and the driving bus power supply negative line.

6. The test fixture for industrial inverter drive bus power supply according to claim 4, characterized in that: A discharge resistor is also connected between the driving bus power supply positive line and the driving bus power supply negative line.

7. The test fixture for industrial inverter driven bus power supply according to claim 6, characterized in that: A discharge switch connected in series with the discharge resistor is also connected between the drive bus power supply positive line and the drive bus power supply negative line.

8. The test fixture for industrial inverter drive bus power supply according to claim 1, characterized in that: It also includes a current display; the current display is connected in series to the driving bus power supply positive line of the driving bus capacitor, and is used to monitor the driving bus power supply current of the test tooling in real time.

9. The test fixture for industrial inverter drive bus power supply according to claim 1, characterized in that: It also includes a voltage display; the voltage display is connected in parallel to the 220V public power grid power supply line and the drive bus voltage power supply line.

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