A power supply module test system for submerged arc furnace

Abstract

The present invention provides a power supply power module test system for an ore-bearing furnace. The test system includes a tested power module, a companion test power module, a three-phase transformer, an inductor L, and a three-phase AC power supply, wherein: the tested power module includes a three-phase uncontrolled input unit 1, a single-phase H-bridge unit 1, and a DC capacitor C1; the DC sides of the three-phase uncontrolled input unit 1 and the single-phase H-bridge unit 1 are connected in parallel with the DC capacitor C1; the test system of the present invention constructs a power module test loop under the condition of unidirectional power flow, greatly reduces the energy consumption level of the function and performance test of the ore-bearing furnace power supply power module, and significantly improves the operating reliability of the ore-bearing furnace power supply converter.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply module testing, and in particular provides a power supply module testing system for a submerged arc furnace. Background Art

[0002] Submerged arc furnaces are core equipment for producing industrial raw materials such as industrial silicon, ferroalloys, and calcium carbide, and play a vital role in the development of the national economy. Existing high-power submerged arc furnaces are generally powered by three single-phase, on-load tap-changing transformers. The secondary windings of these three transformers are angle-connected and connected to the furnace electrodes, with the on-load tap-changing transformers regulating the supply voltage. Existing submerged arc furnaces operate at a 50Hz power supply frequency. Under industrial frequency power supply, the arc ignition point and arc length are irregular, resulting in arc instability, rapid wear and tear of the furnace's bottom electrode, and high energy consumption. For example, a calcium carbide furnace with a rated capacity of 33MVA consumes over 200 million kWh of electricity annually, making it a typical example of high-energy-consuming industrial production equipment.

[0003] To address the high energy consumption of existing submerged arc furnaces, scholars and research institutions at home and abroad have conducted extensive research. They have proposed reducing the furnace's power supply frequency, improving arc stability and heating efficiency, and reducing eddy current losses, thereby increasing energy efficiency and reducing energy consumption. To this end, some scholars have proposed adding a variable-frequency power converter between the furnace's power transformer and the short-circuit grid, providing the furnace with variable-frequency AC power.

[0004] Chinese patents CN 109193655 A and CN 109672172 A propose a back-to-back variable frequency power supply solution that uses a diode-uncontrolled rectifier bridge in the front stage and an active inverter in the back stage. This solution can not only reduce the number of active power semiconductor devices and lower the cost of the variable frequency power supply solution, but also improve power supply efficiency and reliability. Summary of the Invention

[0005] The operating current of the submerged arc furnace is large (over 50kA), and the power supply converter needs to operate under extreme working conditions such as ultra-large current. Therefore, in order to maximize the reliability of power supply, it is necessary to carry out complete functional and performance testing of its power supply power module during the development process of the submerged arc furnace power supply converter. However, since the power module of the submerged arc furnace power supply converter adopts a diode uncontrolled rectifier bridge, power can only flow in one direction, and it is impossible to build a power loop test circuit; and carrying out a single module power test consumes a lot of energy and has poor economic efficiency. At present, the patents for module pair test that have been applied for cannot realize the test of the test module of the diode uncontrolled rectifier bridge type. Therefore, the present invention mainly solves the problem of pair test of the test module of the diode uncontrolled rectifier bridge type.

[0006] The technical task of the present invention is to address the above-mentioned problems and provide a system and method for testing a power supply module for an electric arc furnace.

[0007] The present invention provides a power module testing system for a submerged arc furnace, the testing system comprising a tested power module, a companion test power module, a three-phase transformer, an inductor L and a three-phase AC power supply, wherein:

[0008] The tested power module includes a three-phase uncontrolled input unit 1, a single-phase H-bridge unit 1 and a DC capacitor C1;

[0009] The DC side of the three-phase uncontrolled input unit 1 and the single-phase H-bridge unit 1 is connected in parallel with the DC capacitor C1.

[0010] The accompanying test power module includes a three-phase controllable input unit 2, a single-phase H-bridge unit 2 and a DC capacitor C2;

[0011] The DC side of the three-phase controllable input unit 2 and the single-phase H-bridge unit 2 is connected in parallel with the DC capacitor C2;

[0012] One end of the output of the three-phase AC power supply is connected to the three-phase uncontrolled input unit 1, and the other end is connected to the three-phase controllable input unit 2 through the three-phase transformer;

[0013] The single-phase H-bridge unit 1 and the single-phase H-bridge unit 2 are connected via a wire and an inductor L.

[0014] Furthermore, the structure of the three-phase uncontrolled input unit 1 includes diodes D1, D2, D3, D4, D5, and D6, wherein diodes D1 and D2 are connected in series, diodes D3 and D4 are connected in series, and diodes D5 and D6 are connected in series. Then, the three groups of diodes connected in series are connected in parallel.

[0015] Among them, the connection point between diodes D1 and D2, the connection point between diodes D3 and D4, and the connection point between diodes D5 and D6 serve as AC connection terminals a1, b1, and c1 of the three-phase uncontrolled input unit 1, respectively, and are connected to a three-phase AC power supply.

[0016] Furthermore, the structure of the three-phase controllable input unit 2 includes transistors T1, T2, T3, T4, T5, and T6, wherein transistors T1 and T2 are connected in series, transistors T3 and T4 are connected in series, and transistors T5 and T6 are connected in series. Then, the three sets of transistors connected in series are connected in parallel.

[0017] The connection point between transistors T1 and T2, the connection point between transistors T3 and T4, and the connection point between transistors T5 and T6 serve as AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2, respectively, and are connected to the secondary side of the three-phase transformer.

[0018] The primary side of the three-phase transformer is connected to the three-phase AC power source.

[0019] Furthermore, the structure of the single-phase H-bridge unit 1 includes transistors S1, S2, S3, and S4, wherein transistors S1 and S2 are connected in series, transistors S3 and S4 are connected in series, and then the two groups of transistors connected in series are connected in parallel;

[0020] The connection point between the transistors S1 and S2 and the connection point between the transistors S3 and S4 serve as the AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the tested power module, respectively.

[0021] Furthermore, the structure of the single-phase H-bridge unit 2 includes transistors Q1, Q2, Q3, and Q4, wherein transistors Q1 and Q2 are connected in series, and transistors Q3 and Q4 are connected in series, and then the two groups of transistors connected in series are connected in parallel;

[0022] The connection point between transistors Q1 and Q2 and the connection point between transistors Q3 and Q4 serve as AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the tested power module, respectively.

[0023] Furthermore, the AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the tested power module and the AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the accompanying test power module are connected in parallel via an inductor L, wherein:

[0024] The AC connection terminal x1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal x2 of the single-phase H-bridge unit 2 via the inductor L;

[0025] The AC connection terminal y1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal y2 of the single-phase H-bridge unit 2 through a wire.

[0026] Furthermore, the operation process of the controllable input unit 2 of the three-phase accompanying power module adopts a double closed-loop control method, and the calculation process is as follows:

[0027] Subtract the DC voltage given value from the sampled voltage of the DC capacitor C2, and obtain the AC current reference value through the proportional-integral controller;

[0028] The AC current sampling values ​​of the AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2 are ia2, ib2, and ic2;

[0029] Subtracting the obtained AC current reference value from the AC current sampling values ​​ia2, ib2 and ic2, and obtaining a three-phase AC voltage reference value through a proportional-integral controller;

[0030] The obtained three-phase AC voltage reference value is modulated by sinusoidal pulse width to control the AC side currents ia2, ib2 and ic2 of the three-phase input unit 2 of the test power module to be sinusoidal currents.

[0031] The voltage of the DC capacitor C2 is equal to the voltage of the DC capacitor C1 of the tested power module.

[0032] Furthermore, the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module both adopt an open-loop control method, using unipolar or bipolar sinusoidal pulse width modulation to generate an AC voltage with the same amplitude and frequency, and the single-phase H-bridge unit 1 of the tested power module outputs an AC voltage phase ahead of the single-phase H-bridge unit 2 of the accompanying test power module. By adjusting the phase difference between the output AC voltages of the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module, the operating current of the accompanying test power module reaches the rated current.

[0033] Furthermore, the proportional-integral controller is divided into two calculation channels, one is the proportional calculation channel and the other is the integral calculation channel. The input value of the controller is calculated by the proportional and integral channels respectively, and the calculation results of the two channels are added as the output of the controller.

[0034] Furthermore, the testing process of the system is as follows: by controlling the output voltage phase of the single-phase H-bridge unit of the tested power module to lead the output voltage of the single-phase H-bridge unit of the accompanying test power module, by adjusting the output AC voltage phase difference of the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module, the output power of the tested power module is adjusted, the tested power module is operated at the rated voltage and current state, and a steady-state operating condition test is carried out.

[0035] Compared with the prior art, the power module testing system for a submerged arc furnace of the present invention has the following outstanding beneficial effects:

[0036] The test system of the present invention constructs a power module test loop under the condition of unidirectional power flow, greatly reducing the energy consumption level of the function and performance test of the power module of the submerged arc furnace power supply, and significantly improving the operating reliability of the submerged arc furnace power supply converter.

[0037] By controlling the phase of the output voltage of the single-phase H-bridge unit of the tested power module to lead that of the single-phase H-bridge unit of the companion power module, and adjusting the phase angle difference to regulate active power, the tested power module operates at rated voltage and current, allowing steady-state testing. This method can realistically simulate the operating conditions of a submerged arc furnace power module, significantly reducing energy loss during power module testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the circuit topology of the power supply module test system for the submerged arc furnace of the present invention;

[0039] Figure 2 is the DC voltage of the tested power module;

[0040] Figure 3 Output current of single-phase H-bridge unit 1 of the tested power module;

[0041] Figure 4 It is the DC voltage of the test power module;

[0042] Figure 5 The AC current of the three-phase input unit 2 of the test power module is a sine wave with an effective value of about 520A. DETAILED DESCRIPTION

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0044] like Figure 1 As shown, a power module test system for a submerged arc furnace includes a tested power module, a companion test power module, a three-phase transformer, an inductor L, and a three-phase AC power supply, wherein:

[0045] The tested power module includes a three-phase uncontrolled input unit 1, a single-phase H-bridge unit 1 and a DC capacitor C1;

[0046] The DC side of the three-phase uncontrolled input unit 1 and the single-phase H-bridge unit 1 is connected in parallel with the DC capacitor C1.

[0047] The accompanying test power module includes a three-phase controllable input unit 2, a single-phase H-bridge unit 2 and a DC capacitor C2;

[0048] The DC side of the three-phase controllable input unit 2 and the single-phase H-bridge unit 2 is connected in parallel with the DC capacitor C2;

[0049] One end of the output of the three-phase AC power supply is connected to the three-phase uncontrolled input unit 1, and the other end is connected to the three-phase controllable input unit 2 through the three-phase transformer;

[0050] The single-phase H-bridge unit 1 and the single-phase H-bridge unit 2 are connected via a wire and an inductor L.

[0051] The structure of the three-phase uncontrolled input unit 1 includes diodes D1, D2, D3, D4, D5, and D6, wherein diodes D1 and D2 are connected in series, diodes D3 and D4 are connected in series, and diodes D5 and D6 are connected in series. Then, the three groups of diodes connected in series are connected in parallel.

[0052] Among them, the connection point between diodes D1 and D2, the connection point between diodes D3 and D4, and the connection point between diodes D5 and D6 serve as AC connection terminals a1, b1, and c1 of the three-phase uncontrolled input unit 1, respectively, and are connected to a three-phase AC power supply.

[0053] The structure of the three-phase controllable input unit 2 includes transistors T1, T2, T3, T4, T5, and T6, wherein transistors T1 and T2 are connected in series, transistors T3 and T4 are connected in series, and transistors T5 and T6 are connected in series. Then, the three sets of transistors in series are connected in parallel.

[0054] The connection point between transistors T1 and T2, the connection point between transistors T3 and T4, and the connection point between transistors T5 and T6 serve as AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2, respectively, and are connected to the secondary side of the three-phase transformer.

[0055] The primary side of the three-phase transformer is connected to the three-phase AC power source.

[0056] The structure of the single-phase H-bridge unit 1 includes transistors S1, S2, S3, and S4, wherein transistors S1 and S2 are connected in series, and transistors S3 and S4 are connected in series, and then the two groups of transistors connected in series are connected in parallel;

[0057] The connection point between the transistors S1 and S2 and the connection point between the transistors S3 and S4 serve as the AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the tested power module, respectively.

[0058] The structure of the single-phase H-bridge unit 2 includes transistors Q1, Q2, Q3, and Q4, wherein transistors Q1 and Q2 are connected in series, and transistors Q3 and Q4 are connected in series, and then the two groups of transistors connected in series are connected in parallel;

[0059] The connection point between transistors Q1 and Q2 and the connection point between transistors Q3 and Q4 serve as AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the tested power module, respectively.

[0060] The AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the tested power module and the AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the accompanying test power module are connected in parallel via an inductor L, wherein:

[0061] The AC connection terminal x1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal x2 of the single-phase H-bridge unit 2 via the inductor L;

[0062] The AC connection terminal y1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal y2 of the single-phase H-bridge unit 2 through a wire.

[0063] The operation process of the controllable input unit 2 of the three-phase accompanying power module adopts a double closed-loop control method, and the calculation process is as follows:

[0064] Subtract the DC voltage given value from the sampled voltage of the DC capacitor C2, and obtain the AC current reference value through the proportional-integral controller;

[0065] The AC current sampling values ​​of the AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2 are ia2, ib2, and ic2;

[0066] Subtracting the obtained AC current reference value from the AC current sampling values ​​ia2, ib2 and ic2, and obtaining a three-phase AC voltage reference value through a proportional-integral controller;

[0067] The obtained three-phase AC voltage reference value is modulated by sinusoidal pulse width to control the AC side currents ia2, ib2 and ic2 of the three-phase input unit 2 of the test power module to be sinusoidal currents.

[0068] The voltage of the DC capacitor C2 is equal to the voltage of the DC capacitor C1 of the tested power module.

[0069] The single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module both adopt an open-loop control mode, and use unipolar or bipolar sinusoidal pulse width modulation to generate an AC voltage with the same amplitude and frequency, and the single-phase H-bridge unit 1 of the tested power module outputs an AC voltage phase ahead of the single-phase H-bridge unit 2 of the accompanying test power module. By adjusting the phase difference of the output AC voltages of the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module, the operating current of the accompanying test power module reaches the rated current.

[0070] In one embodiment of the present invention, the parameters of the power supply module for the submerged arc furnace are shown in the following table:

[0071] Circuit parameters

[0072] DC voltage of test and tested power modules [V] 500

[0073] Output AC current of test and tested power modules [A] 6600

[0074] DC capacitance of test and tested power modules [mF] 600

[0075] Switching frequency of single-phase H-bridge unit of the tested and tested power modules [Hz] 400

[0076] Inductance L [μH] 20

[0077] Three-phase AC power supply voltage [V] 330

[0078] Three-phase transformer ratio 3:2

[0079] The power module of the present invention was tested and the test results are as follows:

[0080] like Figure 2 The figure shows the DC voltage of the tested power module. The DC voltage is stable with an amplitude of about 500V. Figure 3 The output current of the single-phase H-bridge unit 1 of the tested power module is about 6600A. Figure 4 To test the DC voltage of the power module, the DC voltage is stable and the amplitude is about 500V; Figure 5 The AC current of the three-phase input unit 2 of the test power module is a sine wave with an effective value of about 520A.

[0081] The embodiments described above are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A power supply module testing system for a submerged arc furnace, characterized in that: The test system includes a tested power module, a companion test power module, a three-phase transformer, an inductor L and a three-phase AC power supply, wherein: The tested power module includes a three-phase uncontrolled input unit 1, a single-phase H-bridge unit 1 and a DC capacitor C1; The DC side of the three-phase uncontrolled input unit 1 and the single-phase H-bridge unit 1 is connected in parallel with the DC capacitor C1. The accompanying test power module includes a three-phase controllable input unit 2, a single-phase H-bridge unit 2 and a DC capacitor C2; The DC side of the three-phase controllable input unit 2 and the single-phase H-bridge unit 2 is connected in parallel with the DC capacitor C2; One end of the output of the three-phase AC power supply is connected to the three-phase uncontrolled input unit 1, and the other end is connected to the three-phase controllable input unit 2 through the three-phase transformer; The single-phase H-bridge unit 1 and the single-phase H-bridge unit 2 are connected via a wire and an inductor L; The structure of the three-phase uncontrolled input unit 1 includes diodes D1, D2, D3, D4, D5, and D6, wherein diodes D1 and D2 are connected in series, diodes D3 and D4 are connected in series, and diodes D5 and D6 are connected in series. Then, the three groups of diodes connected in series are connected in parallel. The connection point between diodes D1 and D2, the connection point between diodes D3 and D4, and the connection point between diodes D5 and D6 serve as AC connection terminals a1, b1, and c1 of the three-phase uncontrolled input unit 1, respectively, and are connected to a three-phase AC power supply. The structure of the three-phase controllable input unit 2 includes transistors T1, T2, T3, T4, T5, and T6, wherein transistors T1 and T2 are connected in series, transistors T3 and T4 are connected in series, and transistors T5 and T6 are connected in series. Then, the three sets of transistors in series are connected in parallel. The connection point between transistors T1 and T2, the connection point between transistors T3 and T4, and the connection point between transistors T5 and T6 serve as AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2, respectively, and are connected to the secondary side of the three-phase transformer. The primary side of the three-phase transformer is connected to the three-phase AC power supply; The structure of the single-phase H-bridge unit 1 includes transistors S1, S2, S3, and S4, wherein transistors S1 and S2 are connected in series, transistors S3 and S4 are connected in series, and then the two groups of transistors connected in series are connected in parallel; The connection point between transistors S1 and S2, and the connection point between transistors S3 and S4 serve as AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the power module under test, respectively. The structure of the single-phase H-bridge unit 2 includes transistors Q1, Q2, Q3, and Q4, wherein transistors Q1 and Q2 are connected in series, and transistors Q3 and Q4 are connected in series, and then the two groups of transistors connected in series are connected in parallel; The connection point between the transistors Q1 and Q2 and the connection point between the transistors Q3 and Q4 serve as the AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the tested power module, respectively.

2. A power supply module testing system for a submerged arc furnace according to claim 1, characterized in that: The AC connection terminals x1 and y1 of the single-phase H-bridge unit 1 of the tested power module and the AC connection terminals x2 and y2 of the single-phase H-bridge unit 2 of the accompanying test power module are connected in parallel via an inductor L, wherein: The AC connection terminal x1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal x2 of the single-phase H-bridge unit 2 via the inductor L; The AC connection terminal y1 of the single-phase H-bridge unit 1 is connected to the AC connection terminal y2 of the single-phase H-bridge unit 2 via a wire.

3. A power supply module testing system for a submerged arc furnace according to claim 2, characterized in that: The operation process of the controllable input unit 2 of the three-phase accompanying power module adopts a double closed-loop control method, and the calculation process is as follows: Subtract the DC voltage given value from the sampled voltage of the DC capacitor C2, and obtain the AC current reference value through the proportional-integral controller; The AC current sampling values ​​of the AC connection terminals a2, b2, and c2 of the three-phase controllable input unit 2 are ia2, ib2, and ic2; Subtracting the obtained AC current reference value from the AC current sampling values ​​ia2, ib2 and ic2, and obtaining a three-phase AC voltage reference value through a proportional-integral controller; The obtained three-phase AC voltage reference value is modulated by sinusoidal pulse width to control the AC side currents ia2, ib2 and ic2 of the three-phase input unit 2 of the test power module to be sinusoidal currents. The voltage of the DC capacitor C2 is equal to the voltage of the DC capacitor C1 of the tested power module.

4. A power supply module testing system for a submerged arc furnace according to claim 3, characterized in that: The single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module both adopt an open-loop control mode, and use unipolar or bipolar sinusoidal pulse width modulation to generate an AC voltage with the same amplitude and frequency, and the single-phase H-bridge unit 1 of the tested power module outputs an AC voltage phase ahead of the single-phase H-bridge unit 2 of the accompanying test power module. By adjusting the phase difference of the output AC voltages of the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module, the operating current of the accompanying test power module reaches the rated current.

5. The power supply module testing system for a submerged arc furnace according to claim 3, characterized in that: The proportional-integral controller is divided into two calculation channels, one is the proportional calculation channel and the other is the integral calculation channel. The input value of the controller is calculated by the proportional and integral channels respectively, and the calculation results of the two channels are added as the output of the controller.

6. A power supply module testing system for a submerged arc furnace according to claim 3 or 4, characterized in that: The testing process of the system is as follows: by controlling the output voltage phase of the single-phase H-bridge unit of the tested power module to lead the output voltage of the single-phase H-bridge unit of the accompanying test power module, by adjusting the output AC voltage phase difference of the single-phase H-bridge unit 1 of the tested power module and the single-phase H-bridge unit 2 of the accompanying test power module, the output power of the tested power module is adjusted, the tested power module is operated at the rated voltage and current state, and a steady-state operating condition test is carried out.

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