Test tool for driving bus power supply of industrial frequency converter

Abstract

The invention 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 invention 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 invention relates to the field of testing technology, and in particular to a testing tool for industrial frequency converter driven bus power supply. Background Art

[0002] As we all know, industrial inverters are essentially AC power conversion devices that convert three-phase electricity from the public power grid (rated voltage 380V, rated frequency 50Hz) into three-phase electricity with a specific frequency and voltage. For AC motors, the three-phase electricity (i.e., UVW three-phase electricity) with a specific frequency and voltage received from the output end of the industrial inverter directly determines the size of its actual operating power, speed, and torque. The UVW three-phase electricity at the output end of the inverter is directly affected by its internal drive bus voltage, that is, the size of the drive bus voltage can determine the size of the inverter UVW three-phase output voltage and current to a certain extent, thereby affecting the actual operating power, speed, and torque of the motor. Under the condition that the output frequency of the inverter remains unchanged, there is a corresponding proportional relationship between its UVW three-phase output voltage value and the internal drive bus voltage value, that is, the higher the ratio of the UVW three-phase voltage to the drive bus voltage, the greater the power, speed, and torque that the motor can achieve in actual operation. However, too high a drive bus voltage will also cause overvoltage damage to the power conversion device inside the inverter, so the drive bus voltage cannot be increased blindly.

[0003] This requires a lot of testing in the early design stage of the inverter through test fixtures to verify the UVW three-phase voltage and current value range under different drive bus voltages. Finally, according to the UVW three-phase output voltage and current value to be achieved by the design, the internal drive bus voltage is reasonably selected to achieve the best control effect.

[0004] Currently, the market only uses a simple test fixture consisting of "air switch, rectifier bridge, drive bus capacitor, and current equalizing resistor". This test fixture requires a 380V public power grid, and the output drive bus voltage cannot be adjusted. It has the defects of high usage requirements and narrow applicable scenarios. Summary of the invention

[0005] The object of the present invention is to provide a test fixture for industrial inverter driven bus power supply, so as to overcome the defects of the prior art in that the use requirements are high and the application scenarios are narrow.

[0006] To achieve this object, the present invention adopts the following technical solutions: A test fixture for industrial inverter driven bus power supply, comprising: 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.

[0007] Optionally, the input terminal of the single-phase contact voltage regulator is connected to a 220V public grid power supply line through a main switch.

[0008] Optionally, the single-phase contact voltage regulator includes an input winding and an output winding that are electrically isolated.

[0009] Optionally, the driving bus capacitor includes six capacitors, and the six capacitors are connected in parallel between the driving bus power supply positive line and the driving bus power supply negative line in three paths, and each path includes two capacitors with the same capacitance and withstand voltage connected in series.

[0010] Optionally, 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.

[0011] Optionally, a discharge resistor is further connected between the drive bus power supply positive line and the drive bus power supply negative line.

[0012] Optionally, a discharge switch connected in series with a discharge resistor is further connected between the drive bus power supply positive line and the drive bus power supply negative line.

[0013] Optionally, 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.

[0014] Optionally, it also includes a voltage display; the voltage display is connected in parallel to the 220V public grid power supply line and the drive bus voltage power supply line.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Unlike the simple test fixtures on the market, the test fixture of the embodiment of the present invention only needs 220V public power grid power supply, not 380V public power grid power supply, with lower usage requirements and wider application scenarios. In addition, the single-phase contact voltage regulator knob inside the test fixture can be used to adjust the drive bus voltage value (0VDC~560VDC) output by the fixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 An electrical schematic diagram of a test fixture provided by an embodiment of the present invention; Figure 2 This is an internal schematic diagram of a single-phase contact voltage regulator provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Different from the simple test fixture on the market that only uses "air switch, rectifier bridge, drive bus capacitor, current sharing resistor" without overload protection and output drive bus voltage cannot be adjusted, the embodiment of the present invention provides a test fixture, which 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 fixture, a current display for monitoring the output current of the fixture, and a discharge resistor for safety protection".

[0020] Unlike other simple test fixtures on the market, this test fixture only requires 220V public power grid power supply, and does not require 380V public power grid power supply. It has lower usage requirements and a wider range of applicable scenarios. In addition, the drive bus voltage value (0VDC~560VDC) output by the fixture can be adjusted through the single-phase contact voltage regulator knob inside the test fixture. In addition to low usage requirements and adjustable output drive bus voltage value, this fixture also realizes real-time monitoring of the input and output voltage values ​​and output current values ​​of the fixture operation through voltage displays and current displays, and realizes safety protection for the personnel using the fixture through discharge resistors.

[0021] Specifically, the electrical schematic diagram of this test fixture is as follows: Figure 1The core invention of the tooling is the integration of four parts: "single-phase contact voltage regulator T1", "control transformer T2", "discharge resistor RP", "current display A1 and voltage display UD1", so as to realize the functions of 220V public grid power supply, input overload protection, and adjustable output drive bus voltage.

[0022] The power supply of the test tool is controlled by the main switch D1. When D1 is disconnected, the power supply inside the tool can be cut off, so that the user can inspect and repair the tool. Conversely, when the main switch D1 is closed, the 220V power supply from the public 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. Its internal principle is as follows Figure 2 As shown, the 220V public grid power supply is connected to the input terminals A and X, and 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 internal brush of 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 the spring pressure. By turning the knob of the voltage regulator T1, the turns ratio of the primary and secondary sides of the voltage regulator can be changed to adjust the output voltage of T1 within the range of 0 to 250V, and thus achieve the purpose of adjusting the driving bus supply voltage of the tooling output within the range of 0 to 560V. In addition, as the electrical principle of the tooling Figure 1 As shown, the single-phase contact voltage regulator T1 also integrates a fuse RL to achieve overload protection function. If the input current exceeds the fuse rating (12A), the fuse can quickly blow to disconnect the front-stage public grid power supply from the rear-stage circuit to prevent overcurrent from damaging other rear-stage devices.

[0023] T2 is a control transformer that performs isolation and voltage boosting functions. Compared with the single-phase contact voltage regulator T1, which has only one winding on the internal magnetic core, the control transformer T2 has two electrically isolated windings (i.e., input winding and output winding). The two electrically isolated windings can achieve electrical isolation between the 220V public grid input of the front stage of the tooling and the output of the drive bus voltage of the back stage of the tooling, thereby reducing the interference that may exist on the 220V public grid to the output voltage of the tooling and improving the stability of the power supply of the drive bus voltage of the test tooling. In addition, the setting of the turns ratio of the input winding to the output winding inside the control transformer also enables it to play a role of voltage boosting to a certain extent, thereby increasing the maximum drive bus voltage that the tooling can achieve.

[0024] D2 is a rectifier bridge, whose main function is to rectify the AC voltage output by the front-stage control transformer into a DC drive bus voltage, and output it to the rear-stage drive bus capacitors C1~C6, which plays the role of charging the drive bus capacitors. Considering the need to reduce the total cost of tooling while ensuring the total capacity of the drive bus capacitors, the drive bus capacitors C1~C6 are connected in three parallel paths, and each path is connected in series with two capacitors with the same capacitance and withstand voltage. In order to eliminate the charging and discharging differences between the capacitors under the above-mentioned drive bus capacitor connection method and ensure the same life of each capacitor, this tooling uses equalizing resistors R1 and R2 to ensure the same voltage on each capacitor, thereby ensuring that each capacitor is charged and discharged synchronously.

[0025] K2 is the discharge switch and RL is the discharge resistor, which together form the drive bus capacitor discharge circuit. This discharge circuit is not always connected in parallel to the drive bus capacitor line. The discharge switch K2 controls whether to connect the discharge resistor in parallel to the drive bus. This can effectively prevent the tool user from being shocked by the residual electricity in the bus capacitor without affecting the basic function of the tool, which is the power supply of the drive bus, and improve the safety of the tool.

[0026] The current display A1 and the voltage display UD1 are integrated into the display module to reduce the total size of the tooling. The current display is connected in series to the positive power supply line (P+) of the drive bus to monitor the tooling drive bus power supply current in real time, and the voltage display is connected in parallel to the 220V public power grid and the drive bus voltage supply line of the tooling to monitor the voltage value of the input and output terminals of the tooling in real time.

[0027] As mentioned above, compared with the traditional simple test tool, this drive bus power supply test tool can realize the basic function of 560V drive bus power supply. By integrating single-phase contact adjustable transformer, control transformer, discharge resistor, current display and voltage display, it further realizes a series of functions such as use under 220V public power grid conditions, electrical isolation between public power grid and tool drive bus power supply, input overload protection, adjustable output drive bus voltage DC0~560V, discharge protection, and real-time monitoring of tool input and output voltage and output current. It facilitates the test process of industrial inverter drive bus power supply voltage and improves the safety and operability of tool use.

[0028] As described above, the above embodiments 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 thereof may be replaced by equivalents. However, these 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.

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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