Power supply device of high-efficiency electric furnace and control method thereof

Abstract

The invention discloses a power supply device of a high-efficiency electric furnace, which comprises an input power receiving part for receiving first power in an alternating-current voltage form; an input power conversion unit that converts the first power into second power in a DC voltage form; an output power conversion unit that converts the second power into third power in a DC or AC voltage form according to at least one preset heat generation region of the electric furnace and outputs the third power; and a control unit for controlling the output of the third power according to a preset temperature formula for the electric furnace. The control method comprises the following steps: an input power receiving step: receiving first power in an alternating voltage form; an input power conversion step of converting the input power into second power in a DC voltage form; an output power conversion step of converting the second power into third power in a direct-current or alternating-current voltage form according to at least one preset heating area of the electric furnace and outputting the third power; and a control step of controlling the output of the third power according to a preset temperature formula for the electric furnace.

Description

TECHNICAL FIELD

[0001] The present invention relates to a high-efficiency electric furnace power supply device and a control method thereof, and more particularly, to a technology for efficiently controlling the temperature of an electric furnace to a desired reaction temperature. BACKGROUND

[0002] Generally, vacuum furnaces are widely used in various high-temperature processes such as high-temperature heat treatment, thermal decomposition, high-purification, smelting, and coating, and one of the core technologies thereof is a heating system capable of precise temperature control. Although such a heating system has been diversified according to the material, structure, shape, and the like of a heating element, a power supply device for power supply has remained in a conventional manner. Most of the power supply methods for the heating element require a large current, and thus a unipolar phase control method based on a silicon controlled rectifier (SCR) or the like is commonly used.

[0003] However, such a power supply device has many limitations in terms of power efficiency, power factor, and power quality. A power supply device using a phase control method can cause harmonic noise and a decrease in power factor, and in order to compensate for these defects, auxiliary devices such as a power factor compensator or a filter are additionally required. This not only increases the cost and installation space of the power supply device, but also limits the fundamental performance improvement. In particular, in the fields of manufacturing high-purity semiconductor materials or high-temperature chemical vapor deposition equipment requiring precise processes, the limitations of such a power supply device are more prominent.

[0004] In addition, the conventional unipolar phase control power supply device cannot effectively cope with power quality problems such as voltage sag, instantaneous interruption, and voltage swell, which can cause problems such as production interruption or product defects in batch processes. In particular, in the case of an emergency such as an emergency stop, the control response speed is slow, and the abnormal state is maintained for a long time, which makes it difficult to protect the equipment.

[0005] In addition, in order to achieve uniform heating of the heating element, it is necessary to independently control the zones composed of a plurality of heaters, and thus it is required to provide each zone with an independent power supply device. However, the conventional phase control power supply device is difficult to adapt to such a structure, and thus a plurality of power supply devices must be additionally installed, which increases the complexity and cost of the power equipment. Ultimately, the conventional power supply device has problems of additional equipment costs and process cost increases due to an increase in power consumption, and thus there is a need to develop a new power supply technology capable of achieving high efficiency and high integration.

[0006] (Patent Document 1) KR 10-1626088 B1 SUMMARY

[0007] The technical problem to be solved by the present application is to provide an efficient electric furnace power supply device and a control method thereof, which utilizes a bipolar device to actively respond to changes in load output current through an on-off switching mode while maintaining a high power factor.

[0008] The present application aims to provide an efficient electric furnace power supply device and a control method thereof, which can provide power output to multiple hot zones through a single power supply device.

[0009] The present application aims to provide an efficient electric furnace power supply device and a control method thereof, which can generate a required power supply formula in real time according to a temperature rising formula set based on design conditions of an electric furnace, process operation conditions, and characteristics of a heating body, thereby controlling heating of the electric furnace without relying on internal temperature sensors of the electric furnace.

[0010] In addition, the present application aims to provide an efficient electric furnace power supply device and a control method thereof, which can significantly reduce the generation of harmonic noise, thereby reducing the risk of failure to other components of a power supply device.

[0011] In addition, the present application aims to provide an efficient electric furnace power supply device and a control method thereof, which can provide stable power supply to electric furnace equipment used in batch processes such as chemical vapor deposition (CVD), coating, purification furnaces, and low-pressure vacuum furnaces.

[0012] The technical solution of the present application is: the efficient electric furnace power supply device according to the embodiment of the present application comprises: an input power receiving part for receiving a first power of an alternating voltage; an input power conversion part for converting the first power into a second power of a direct current voltage; an output power conversion part for converting the second power into a third power of a direct current voltage or an alternating voltage and outputting according to at least one heating zone preset for an electric furnace; and a control part for controlling the output of the third power according to a temperature formula preset for the electric furnace.

[0013] In addition, the input power receiving part comprises: a power input part for supplying the first power to the input power conversion part through a power switch; a charging circuit part for smoothly charging the first power after completing initial charging of the input power conversion part by controlling a charging current; and a filter part for reducing electromagnetic interference (EMI) and harmonic distortion corresponding to the first power.

[0014] Further, the input power conversion section includes a first conversion section adjusting a voltage amplitude by adjusting a duty ratio according to a switching control action of the first power, a first DC link storing the second power output from the first conversion section, and a first conversion control section adjusting a phase according to a control signal applied from the control section to minimize a switching loss.

[0015] Further, the output power conversion section can include a second DC link for storing the second power supplied from the input power conversion section, a second conversion section converting the second power stored in the second DC link into an AC voltage or a DC voltage and outputting the third power, and a second conversion control section adjusting a phase according to a control signal applied from the control section to minimize a switching loss.

[0016] Further, the filter section can include a first filter for blocking electromagnetic interference (EMI) corresponding to the first power, and a second filter for reducing harmonic distortion in the first power processed through the first filter.

[0017] In addition, the input power conversion section performs a switching action according to a preset duty ratio according to a switching control action of the first power, and provides a PWM or SPWM signal through linkage with a high harmonic filter, i.e., a second filter, of the input power receiving section, thereby being able to improve a power factor regardless of a load condition.

[0018] Further, the input power conversion section performs a switching action according to a preset duty ratio according to a switching control action of the first power, and the control section provides a PWM or SPWM signal through linkage with a high harmonic filter, i.e., a second filter, of the input power receiving section, thereby being able to improve a power factor regardless of a load condition or minimize a total harmonic distortion (THD).

[0019] In addition, a control power supply section for uninterruptedly supplying power to the control section in response to a transient voltage fluctuation occurring in the electric furnace can be further included.

[0020] A power supply method of a high-efficiency electric furnace power supply device according to another embodiment of the present application includes an input power receiving step of receiving a first power of an AC voltage, an input power conversion step of converting the first power into a second power of a DC voltage, an output power conversion step of converting the second power into a third power of a DC voltage or an AC voltage according to at least one heating region preset for the electric furnace and outputting the third power, and a control step of controlling output of the third power according to a temperature recipe preset for the electric furnace.

[0021] The beneficial technical effects of the present application are: Therefore, by using the bipolar device for switching operation, the load output current can be actively responded while maintaining a high power factor.

[0022] In addition, a single power supply device can provide output to multiple hot zones.

[0023] In addition, the heating-up formula can be generated in real time according to the design conditions of the electric furnace, process operation conditions, and heating body characteristics, etc. set, so that the electric furnace heating can be controlled without relying on the internal temperature sensor of the electric furnace.

[0024] In addition, the scheme can reduce the generation of harmonic noise, which not only ensures the stability of the power supply device control signal, but also reduces the probability of failure of other equipment connected to the power receiving part.

[0025] In addition, it can also provide a stable and reliable power supply for electric furnaces used in chemical vapor deposition (CVD), coating, purification furnace, and low-pressure vacuum furnace batch processing processes. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a configuration diagram of the power supply device of the high-efficiency electric furnace of the embodiment of the present application; Figure 2 is Figure 1 a flowchart of the power supply method of the power supply device of the high-efficiency electric furnace shown in Figure 3 is an example diagram for explaining that the power supply device of the high-efficiency electric furnace receives three-phase power and supplies power to multiple heating areas in the electric furnace; Figure 4 and Figure 5 is Figure 3 a detailed configuration diagram of the input power receiving part in the power supply device of the high-efficiency electric furnace shown in Figure 6 is Figure 3 a detailed configuration diagram of the input power conversion part in the power supply device of the high-efficiency electric furnace shown in Figure 7 is Figure 3 a detailed configuration diagram of the output power conversion part in the power supply device of the high-efficiency electric furnace shown in Figure 8 is Figure 3 a detailed configuration diagram of the control part in the power supply device of the high-efficiency electric furnace shown in Figure 9 is Figure 3FIG. 1 is a detailed configuration diagram of a power supply unit of a high-efficiency electric furnace. Figure 10 FIG. 2 is a waveform diagram of an AC system voltage and an AC system current before and after a load of the power supply unit of the high-efficiency electric furnace.

[0027] Reference numerals are as follows: 100: power supply device 110: input power receiving unit 111: power input unit 111-1: power switch 111-2: power protection unit 111-3: first voltage sensor 112: charging circuit unit 112-1: charging resistor 112-2: first contactor 112-3: second contactor 113: filter unit 113-1: first filter 113-2: second filter 113-21: filter inductor 113-22: filter capacitor 113-3: first current sensor 120: input power conversion unit 121: first conversion unit 121-1: first switch 121-2: second switch 121-3: first gate driver 121-4: first buffer circuit 121-5: first temperature sensor 121-6: second temperature sensor 122: first direct current link (DC Link) 122-1: first capacitor 122-2: balancing resistor 123: first conversion control unit 123-1: first gate interface 123-2: first cooling unit 123-3: first cooling control unit 124: second voltage sensor 130: output power conversion unit 131: second direct current link (DC Link) 131-1: second capacitor 132: second conversion unit 132-1: third switch 132-2: fourth switch 132-3: second gate driver 132-4: second buffer circuit 132-5: third temperature sensor 132-6: fourth temperature sensor 132-7: second current sensor 132-8: output protection unit 133: second conversion control unit 133-1: second gate interface 133-2: second cooling unit 133-3: second cooling control section 134: voltage conversion section 134-1: third voltage sensor 134-2: third current sensor 140: control section 141: power control processor 142: interface module 143: operation section 150: control power supply section 151: uninterruptible unit 152: control power conversion section 152-1: multi-winding transformer 152-2: first SMPS (switching mode power supply) 152-3: indicator lamp (Lamp) 152-4: third contactor 152-5: third cooling unit 152-6: cooling fan 10: electric arc furnace 11: heat generating region DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings. The terms used are terms selected on the basis of functions in the embodiments, and the meanings of the terms can be different according to the intention or custom of the user, operator, etc. Therefore, unless otherwise specifically defined in the specification, the meanings of the terms used in the following embodiments should be interpreted as the meanings commonly understood by those skilled in the art. If there is a specific definition, it is defined as it is.

[0029] Figure 1 is a configuration diagram of a power supply device of a high-efficiency electric furnace according to an embodiment of the present application. Figure 2 is Figure 1 is a flowchart of a power supply method of the power supply device of the high-efficiency electric furnace shown in Figure 3 is an example diagram for explaining that the power supply device of the high-efficiency electric furnace receives three-phase power and supplies power to a plurality of heat generating regions in the electric furnace. Figure 4 and Figure 5 is Figure 3 is a detailed configuration diagram of an input power receiving section in the power supply device of the high-efficiency electric furnace shown in Figure 6 is Figure 3 is a detailed configuration diagram of an input power conversion section in the power supply device of the high-efficiency electric furnace shown in Figure 7 is Figure 3 is a detailed configuration diagram of an output power conversion section in the power supply device of the high-efficiency electric furnace shown in Figure 8 is Figure 3 is a detailed configuration diagram of a control section in the power supply device of the high-efficiency electric furnace shown in Figure 9 is Figure 3 is a detailed configuration diagram of a control power supply section in the power supply device of the high-efficiency electric furnace shown in is

[0030] Referring to Figures 1 to 9 The power supply device (100) of the high-efficiency electric furnace according to the embodiment of the present application comprises an input power receiving unit (110), an input power conversion unit (120), an output power conversion unit (130) and a control unit (140).

[0031] The input power receiving unit (110) receives the first power (S110) in the form of alternating voltage. As the first stage of the power supply device (100), the input power receiving unit (110) receives the power in the form of alternating voltage supplied from the outside. Its function is to stabilize the reception of the alternating voltage first power supplied from the public power grid and to pass it to the subsequent stage, the input power conversion unit (120). In this case, the first power supplied to the input power receiving unit (110) can apply single-phase or three-phase alternating voltage according to the distribution panel configuration, and the single-phase can use 220V, and the three-phase can use 220V, 380V or 440V voltage.

[0032] More specifically, the input power receiving unit (110) comprises a power input unit (111), a charging circuit unit (112) and a filter unit (113). The power input unit (111) comprises a power switch (111-1), a power protection unit (111-2) and a first voltage sensor (111-3).

[0033] The power switch (111-1) is formed at the input side, and its function is to perform on-off control during the process of supplying the first power to the input power conversion unit (120), and the power switch (111-1) is equivalent to a kind of main switch. The power protection unit (111-2) is used to protect the first power from lightning or surge impact, which can be realized by using a surge protection relay (SPD). The first voltage sensor (111-3) is used to detect the voltage of the first power.

[0034] The charging circuit unit (112) is a circuit for controlling the charging current to the input power conversion unit (120). The charging circuit unit (112) comprises a charging resistor (112-1), a first contactor (112-2) and a second contactor (112-3). The charging resistor (112-1) is used to prevent excessive current from flowing into the input power conversion unit (120) at a moment. The first contactor (112-2) makes the first power supplied through the charging resistor (112-1). The second contactor (112-3) makes the first power supplied directly after the input power conversion unit (120) completes the initial charging.

[0035] The filter unit (113) is configured to reduce electromagnetic interference or harmonic distortion contained in the first power supplied by the charging circuit unit (112). The filter unit (113) includes a first filter (113-1), a second filter (113-2), and a first current sensor (113-3). The first filter (113-1) functions to block or suppress electromagnetic interference (EMI) in the first power supplied by the charging circuit unit (112).

[0036] The second filter (113-2) is connected to the first filter (113-1) and plays an important role in reducing harmonic distortion of the first power. The second filter (113-2) cooperates with the first capacitor (122-1) of the first DC link (122) to perform power factor compensation through an LC circuit according to the operating state of the input power conversion unit (120). The second filter (113-2) can be implemented by a combination of an inductor and a capacitor, and its outstanding feature is that it can ensure that the system maintains a stable power factor of more than 95% whether the input power conversion unit (120) is in boost mode or buck mode. Through the cooperation of the first filter (113-1) and the second filter (113-2), the power supply quality and operational stability of the first power are effectively improved.

[0037] The first current sensor (113-3) is arranged between the first filter (113-1) and the second filter (113-2) and is configured to accurately measure the current parameters of the first power. The sensor has a harmonic detection function and can measure the harmonic distortion of the first power processed by the first filter (113-1). The first current sensor (113-3) system can adopt a multi-sensor configuration scheme, that is, a current sensor can also be added at the output end of the second filter (113-2) to monitor the output current. The data collected by the first current sensor (113-3) is mainly used in two aspects: one is to analyze the overall power quality of the first power, and the other is to provide data support for system operational state diagnosis.

[0038] Meanwhile, the input power conversion unit (120) is connected to the input power receiving unit (110) and converts the first power of alternating voltage received by the input power receiving unit (110) into second power of direct current voltage (S120). The input power conversion unit (120) performs energy storage processing on the converted direct current voltage second power to ensure stable power supply. The main purpose is to provide a direct current power supply with stable voltage for the subsequent output power conversion unit (130). In this process, it is crucial to maximize power conversion efficiency and minimize energy consumption.

[0039] Specifically, the input power conversion unit (120) comprises a first conversion unit (121), a first DC link (122) and a first conversion control unit (123). For example, the first conversion unit (121) can be implemented by a full converter composed of bipolar power semiconductor devices (e.g. IGBT). In this configuration, the output DC voltage second power can be regulated in amplitude by adjusting the duty ratio according to the switching control action of the full converter. Compared with the fixed voltage of 1.414 times the effective value of the output of the ordinary rectifier circuit, the input power conversion unit of the present application can obtain an adjustable DC voltage that is both lower and higher than the preset reference value by using a full converter.

[0040] In addition, when a three-phase power supply is used, the first conversion unit (121) comprises a plurality of first switches (121-1), a plurality of second switches (121-2), a plurality of first gate drivers (121-3), a plurality of first buffer circuits (121-4), a first temperature sensor (121-5) and a second temperature sensor (121-6).

[0041] The plurality of first switches (121-1) are bipolar power semiconductor devices corresponding to each phase voltage, which are used to implement the upper bridge arm (+) of the positive power supply input. The plurality of second switches (121-2) are also bipolar power semiconductor devices corresponding to each phase voltage, which are used to implement the lower bridge arm (-) of the negative power supply input. The first switches (121-1) and the second switches (121-2) can be arranged in a configuration of two per phase. In this case, the first switches (121-1) and the second switches (121-2) can be arranged on a heat dissipation substrate, thereby effectively reducing the heat generated by the switching loss.

[0042] The plurality of first gate drivers (121-3) perform the important function of precise driving: precisely controlling the isolated gate of the bipolar power semiconductor devices (e.g. IGBT or MOSFET) used in the first conversion unit (121) through an insulated trigger signal. The plurality of first gate drivers (121-3) perform on-off operation according to the preset duty ratio according to the switching control action of the first switches (121-1) and the second switches (121-2). In this process, by cooperating with the second filter (113-2) of the harmonic filter of the input power receiving unit (110), PWM or SPWM signals are provided, thereby effectively improving the power factor under any load condition.

[0043] The first plurality of snubber circuits (121-4) are composed of a circuit structure containing a capacitor, which can effectively suppress the voltage spikes generated by the first switch (121-1) and the second switch (121-2) during operation.

[0044] The first plurality of temperature sensors (121-5) are used to monitor the operating temperature of the first switch (121-1) and the second switch (121-2) in each phase circuit, and the core function is to detect the heating state of these switch devices in real time. The second temperature sensor (121-6) is a thermosensitive element specially used to detect the temperature of the heat sink of the first conversion unit (121). The temperature data collected by the first temperature sensor (121-5) and the second temperature sensor (121-6) will be used as the basis for decision-making for the operation control of the first cooling unit (123-2).

[0045] The first DC link (122) is connected to the output of the first conversion unit (121) and is used to store the second power. Specifically, the first DC link (122) contains a plurality of first capacitors (122-1) and a balancing resistor (122-2). The first capacitor (122-1) is used to store the DC voltage second power converted and output by the first conversion unit (121). The balancing resistor (122-2) is used to balance the second power.

[0046] The first conversion control unit (123) includes a first gate interface (123-1), a first cooling unit (123-2), and a first cooling control unit (123-3). The first gate interface (123-1) is a phase shift type gate drive circuit based on the PWM control signal of the control unit (140), and the core function is to effectively reduce the switching loss through the phase shift technology.

[0047] The first cooling unit (123-2) is responsible for forced cooling of the heat sink that absorbs the heat of the first switch (121-1) and the second switch (121-2). The first cooling unit (123-2) is composed of a multi-fan array structure, and the operation of the first cooling unit (123-2) is driven and controlled by the first cooling control unit (123-3).

[0048] The first cooling control unit (123-3) receives the temperature data of the first temperature sensor (121-5) and the second temperature sensor (121-6) to perform closed-loop control on the operation of the first cooling unit (123-2). The first cooling control unit (123-3) monitors the operation state of the first cooling unit (123-2) in real time, and uploads the temperature data collected by the first temperature sensor (121-5) and the second temperature sensor (121-6) and the cooling unit operation parameters to the control unit (140), so as to realize abnormal state detection and intelligent regulation based on switching loss analysis.

[0049] In addition, the input power conversion unit (120) can also be additionally provided with a second voltage sensor (124). The sensor is connected across the balancing resistor (122-2), and the system monitoring is realized by measuring the voltage amplitude of the second power. The core function of the second voltage sensor (124) is to accurately monitor the voltage of the second power, and to ensure that the required DC voltage is provided to the load side.

[0050] At the same time, the output power conversion unit (130) converts the DC voltage second power converted by the input power conversion unit (120) into third power in the form of DC or AC voltage according to the different needs of the multiple heating areas (11), and outputs (S130). For example, when the output end needs DC voltage, the output power conversion unit (130) can use a DC-DC converter to realize. When the output end needs AC voltage, a DC-AC inverter or a step-down transformer can be used to realize, but the implementation manner is not limited to the above scheme.

[0051] In addition, the amplitude and frequency of the third power output by the output power conversion unit (130) are converted by the accurate regulation of the control unit (140). The third power will be converted into a power supply form with different characteristics according to the different needs of the multiple heating areas (11) preset by the electric furnace (10). In this process, the power characteristics (including voltage, frequency, phase and other parameters) required by each heating area (11) can be different. The output power conversion unit (130) can accurately convert and supply power according to these diversified needs. The conversion process is usually realized by an inverter circuit, and a precise control strategy needs to be used to ensure that the optimal power supply is provided for each heating area (11).

[0052] Specifically, the output power conversion unit (130) includes a second DC link (131), a second conversion unit (132), and a second conversion control unit (133).

[0053] The second DC link (131) is used to store the second power delivered from the first DC link (122). The second power from the first DC link (122) will be distributed in a voltage division manner to the plurality of second DC links (131) aiming to provide independent stable power supply for each heating area (11) of the electric furnace (10). In practice, the second DC link (131) can realize the energy storage function through a plurality of second capacitors (131-1), and the output end thereof is directly connected with the second conversion unit (132).

[0054] The second conversion unit (132) converts the second power stored in the second DC link (131) into third power through DC-AC conversion or DC-DC conversion. For example, the second conversion unit (132) can be realized by using an inverter of DC-AC conversion type or a converter of DC-DC conversion type. When the electric furnace (10) has a plurality of heating areas (11), a single power supply device system can be constructed by configuring a plurality of second conversion units (132). This integrated design scheme not only can simplify the device structure and reduce the installation space, but also can significantly improve the cost economic benefits.

[0055] In the present application, the scheme that the second conversion unit (132) is realized by using an inverter of DC-AC conversion type is taken as an embodiment for description. Specifically, when a three-phase power supply is used, the second conversion unit (132) comprises a plurality of third switches (132-1), a plurality of fourth switches (132-2), a plurality of second gate drivers (132-3), a plurality of second buffer circuits (132-4), a third temperature sensor (132-5) and a fourth temperature sensor (132-6).

[0056] The plurality of third switches (132-1) are realized by using bipolar power semiconductor devices corresponding to each phase voltage, and are used as the upper bridge arm (Upper Arm) of the positive (+) power supply input. The plurality of fourth switches (132-2) are realized by using bipolar power semiconductor devices corresponding to each phase voltage, and constitute the lower bridge arm (Lower Arm) of the negative (-) power supply input. The third switches (132-1) and the fourth switches (132-2) can be realized by using bipolar semiconductor devices, including transistors, MOSFETs, IGBTs and other elements used in half-wave rectification (Half Bridge) and full-wave rectification (Full Bridge) switching circuits.

[0057] The third switch (132-1) and the fourth switch (132-2) are controlled by the gate signal of the second gate driver (132-3) to perform ON / OFF operation. The third switch (132-1) and the fourth switch (132-2) can be arranged in a configuration of two per phase, and are usually arranged on a heat dissipation substrate to effectively reduce the heat generated by the switch loss. The third switch (132-1) and the fourth switch (132-2) work together to convert the second power of the second DC link (131) and achieve pulse width modulation output by adjusting the duty cycle.

[0058] The second gate driver (132-3) has a precise driving function: it precisely controls the isolated gate of the bipolar power semiconductor device such as IGBT or MOSFET used in the second conversion unit (132) through an insulated trigger signal. In a three-phase system, the second gate driver (132-3) is independently configured for U phase, V phase, and W phase. The second gate driver (132-3) generates a pulse width modulation (PWM) control signal by alternately driving the third switch (132-1) and the fourth switch (132-2) according to the target square wave pulse width requirement. In this process, the gate drive signal of each switch uses electrical isolation technology to effectively prevent short circuit accidents.

[0059] The second buffer circuit (132-4) is independently configured for U phase, V phase, and W phase in a three-phase system. The buffer circuit is composed of a circuit structure containing a capacitor, which can effectively suppress the voltage spikes generated during the operation of the third switch (132-1) and the fourth switch (132-2).

[0060] The third temperature sensor (132-5) is independently configured for U phase, V phase, and W phase in a three-phase system. These sensors are used to monitor the operating temperature of the third switch (132-1) and the fourth switch (132-2) in each phase circuit, aiming to detect the heating state of the switch device in real time. The fourth temperature sensor (132-6) is used to detect the temperature of the heat dissipation substrate of the second conversion unit (132). The temperature data collected by the third temperature sensor (132-5) and the fourth temperature sensor (132-6) will be an important basis for the operation control of the second cooling unit (133-2).

[0061] In addition, the second conversion unit (132) can also be provided with a second current sensor (132-7). The sensor is used to detect the output current, and in a three-phase system, it is configured independently according to the U phase, V phase, and W phase. At the same time, the second conversion unit (132) can also include an output protection unit (132-8), which is used to protect against lightning strikes or surges that may invade the second power. This can be achieved through a surge protection relay (SPD; Surge Protection Device).

[0062] In addition, the second conversion unit (132) can also be provided with a current limiting reactor (Current Limit Reactor). When the load device requires arc discharge protection or needs to suppress the short-circuit current of the internal heater of the electric furnace (10), the reactor can achieve the short-circuit protection function by limiting the current.

[0063] The second conversion control unit (133) includes a second gate interface (133-1), a second cooling unit (133-2), and a second cooling control unit (133-3). The second gate interface (133-1) is a phase shift type gate interface circuit based on the PWM (Pulse Width Modulation) control signal of the control unit (140), and the design purpose is to maximize the reduction of switching loss through phase shift technology.

[0064] The second cooling unit (133-2) is responsible for forced cooling of the heat dissipation substrate that absorbs the heat of the third switch (132-1) and the fourth switch (132-2). The cooling unit adopts a multi-fan array structure, and its operation is driven and controlled by the second cooling control unit (133-3).

[0065] The second cooling control unit (133-3) implements precise driving control of the second cooling unit (133-2) by receiving temperature data from the third temperature sensor (132-5) and the fourth temperature sensor (132-6). The second cooling control unit (133-3) monitors the operating state of the second cooling unit (133-2) in real time, and uploads the data collected by the third temperature sensor (132-5) and the fourth temperature sensor (132-6) and the operating parameters of the second cooling unit (133-2) to the control unit (140), thereby realizing abnormal state detection and intelligent regulation based on switching loss analysis.

[0066] Meanwhile, the output power conversion unit (130) can be additionally provided with a voltage conversion unit (134). The voltage conversion unit (134) is responsible for the voltage conversion function of the direct current or alternating current third power, and can perform step-up or step-down processing on the third power according to the load demand of the heating area (11) of the electric furnace (10). The voltage conversion unit (134) can be provided with a plurality of third voltage sensors (134-1) and third current sensors (134-2) corresponding to the R, S, and T three-phase, which are used to detect abnormal states of the system by monitoring the third power parameters (voltage / current) processed by the voltage conversion unit (134).

[0067] The control unit (140) accurately controls the output of the third power according to the temperature formula preset for the electric furnace (10) (S140). The so-called temperature formula refers to the temperature control curve varying with time defined for each heating area (11) of the electric furnace (10). The control unit (140) adjusts the characteristic parameters of the third power generated by the output power conversion unit (130) in real time according to the formula. Such a temperature formula can be automatically generated based on the design parameters of the electric furnace (10) (such as process-required heat capacity, heating rate, and other process conditions) and the heating body characteristic information.

[0068] The control unit (140) calculates the heat value required for the electric furnace (10) to reach the preset temperature in real time according to the temperature formula, and accurately outputs the third power accordingly. Through this control mode, there is no need to additionally install temperature sensors inside the electric furnace for temperature control. This not only saves the cost of replacing the expensive thermocouple periodically, but also realizes stable control of the process temperature through the temperature formula. In this configuration, the control unit (140) is integrated with a real-time clock (RTC; Real Time Clock) module, and can be provided with a storage memory for real-time backup of the running state data of the electric furnace (10).

[0069] The control unit (140) controls the first power received by the input power receiving unit (110) to be converted into the second power and stored in the first direct current link (DC Link) (122) of the input power conversion unit. In this process, the control unit (140) drives and controls the first conversion unit (121) of the input power conversion unit (120). By generating a PWM control signal of a specific capacity, the control unit (140) realizes high power factor and high efficiency power conversion during the charging process of the second power in the first direct current link (DC Link) (122). At the same time, the control unit (140) also continuously monitors the temperature state of the first conversion unit (121), performs closed-loop control on the charging circuit unit (112), and monitors the running parameters of the entire system.

[0070] In the process, the control unit (140) can also work with the second filter (113-2) of the input power receiving unit (110) in harmony, and provide PWM or SPWM control signals to achieve the improvement of power factor or the minimization of total harmonic distortion (THD) under any load condition. At this time, the control unit (140) can accurately control the first switch (121-1) and the second switch (121-2) by driving the first gate driver (121-3).

[0071] In addition, the control unit (140) can also independently provide the required third power for each hot zone (11) of the electric furnace (10) as needed. To this end, the control unit (140) drives and controls the second conversion unit (132) of the output power conversion unit (130). In the process, the control unit (140) continuously measures and monitors various data required for the driving control of the second conversion unit (132), while monitoring the power parameters supplied to the hot zone (11) of the electric furnace (10). The control unit (140) also monitors the temperature state of the second conversion unit (132) in real time, and comprehensively monitors the operating parameters of the entire system.

[0072] Specifically, the control unit (140) can include a power control processor (141), an interface module (142), and an operation unit (143). The power control processor (141) is designed with a digital signal processor (DSP) architecture, which can process complex power conversion algorithms generated according to a preset temperature formula in real time, and can provide microsecond (μs) level switching control accuracy.

[0073] The interface module (142) is connected with the first gate interface (123-1) and the second gate interface (133-1), and serves as a communication bridge between the input power conversion unit (120) and the output power conversion unit (130) and various sensors and external interfaces.

[0074] The operation unit (143) is an interactive unit designed for users to confirm and operate the running state of the power supply device (100). For example, the operation unit (143) can maximize user convenience by integrating an LCD panel and touch screen functions, while providing real-time running data graphical display, event recording, and alarm functions.

[0075] At the same time, the high-efficiency electric furnace power supply device (100) of the embodiment of the present application can also be additionally provided with a control power supply unit (150).

[0076] The control power supply unit (150) is responsible for providing stable power supply to the control unit (140). The control power supply unit (150) is capable of delivering power to the control unit (140) in an uninterrupted manner. Although the control unit (140) can also obtain control power from the DC voltage stored in the first DC link (DC Link) (122) through an independent power converter (not shown in the figure), the uninterrupted power supply solution implemented by the control power supply unit (150) often has better efficiency.

[0077] Specifically, the control power supply unit (150) can include an uninterrupted unit (151) and a control power conversion unit (152). The uninterrupted unit (151) ensures that the stable supply of control power can be maintained even in the event of power failure. Through this unit, the current is distributed to multiple power branch points. The uninterrupted unit (151) receives power input through the main circuit breaker and is equipped with a surge protection unit, which can effectively block surge voltage caused by lightning strikes or switch malfunctions.

[0078] The control power conversion unit (152) is connected with the uninterrupted unit (151) and is responsible for electrical isolation. After electrical isolation (Isolation) is achieved through a multi-winding isolation transformer (152-1), a stable control power is provided through a switch mode power supply (SMPS) (152-2). This design can ensure that a pure and noise-free power supply is provided to precision circuits such as the control unit (140). In this configuration, the control power conversion unit (152) can be connected with state indicator lamps (152-3) and a third contactor (152-4): the state lamps are used to display the working state of the power supply, and the third contactor controls the power supply path through the switching function. At the same time, the control power conversion unit (152) can also work with the SMPS (152-2) through a third cooling unit (152-5), and the switching power supply is responsible for stably supplying DC control power to each load. In addition, the system is also equipped with a cooling fan (152-6) for thermal management.

[0079] In summary, the control power supply unit (150) can effectively deal with voltage transient variation problems such as instantaneous interruption, voltage sag, and instantaneous swell caused by voltage fluctuations due to abnormal power supply quality of the input power receiving unit (110). According to the requirements of the load device and the preset derating curve (Derating Curve) setting, the power supply device (100) can maintain continuous output during the longest 30-cycle (600ms) transient voltage fluctuation period without power failure.

[0080] Figure 10 is an example diagram for illustrating the AC system voltage and AC system current waveform before and after the load in the power supply device of the high-efficiency electric furnace of the present application.

[0081] Referring to Figure 10 It can be known that the power supply device (100) of the high-efficiency electric furnace has a current of nearly zero and a flat straight waveform in the no-load state, and the AC system voltage and the current waveform are almost completely coincident in the load state. This shows that the system has excellent power factor characteristics in the load state. The advantage is derived from the fact that the device obtains pure power with minimized electromagnetic interference and harmonic distortion through the input power conversion unit (120) and the output power conversion unit (130), and the precise synchronization of the current phase and the voltage is realized by using the PWM or SPWM control mode. Even if the load system changes, the real-time optimization of the input current through the dynamic control algorithm can also ensure the stable maintenance of the power factor, thereby effectively reducing the power loss, improving the load response characteristics, and providing protection for the surrounding equipment and the power grid system.

[0082] The above description of the application is based on the best embodiment described with reference to the accompanying drawings, but is not limited thereto. Therefore, the application should be explained according to the description of the patent claim, and the scope is intended to cover all obvious modifications derived from the described embodiments.

Claims

1. A power supply device for a high-efficiency electric furnace, characterized in that, Includes an input power receiving unit that receives first power in the form of AC voltage; The input power conversion unit converts the first power into a second power in the form of DC voltage. The output power conversion unit converts the second power into a third power in the form of DC or AC voltage according to at least one preset heating zone of the electric furnace and outputs it. And a control unit that controls the output of the third power source according to a temperature formula preset for the electric furnace.

2. The power supply device for the high-efficiency electric furnace according to claim 1, characterized in that, The input power receiving unit includes: The power input unit supplies the first power to the input power conversion unit via a power switch; The charging circuit section controls the charging current to enable the input power conversion section to complete initial charging and then connect to the first power source; and The filter section is used to reduce electromagnetic interference and harmonic distortion in the first power supply.

3. The power supply device for the high-efficiency electric furnace according to claim 1, characterized in that, The input power conversion unit includes: The first conversion unit adjusts the duty cycle according to the switching control action of the first power supply, thereby adjusting the output voltage amplitude; A first DC link stores the second power output from the first converter; and The first switching control unit adjusts the phase according to the control signal applied from the control unit to minimize switching losses.

4. The power supply device for the high-efficiency electric furnace according to claim 1, characterized in that, The output power conversion unit includes: The second DC link stores the second power supplied from the input power conversion unit; The second conversion unit converts the second power stored in the second DC link into a third power in the form of AC voltage or DC voltage and outputs it; and The second switching control unit adjusts the phase according to the control signal applied from the control unit to minimize switching losses.

5. The power supply device for the high-efficiency electric furnace according to claim 1, characterized in that, The control unit is configured as follows: The temperature formula generated based on the design parameters of the electric furnace and the characteristic information of the heating element is used to calculate the heat value required to reach the preset temperature of the electric furnace in real time, and to control the output of the third power source accordingly.

6. The power supply device for the high-efficiency electric furnace according to claim 2, characterized in that, The filtering unit includes: A first filter is used to block electromagnetic interference in the first power supply; and The second filter is used to reduce harmonic distortion in the first power after it has been processed by the first filter.

7. The power supply device for the high-efficiency electric furnace according to claim 2, characterized in that, The input power conversion unit is configured as follows: Based on the switching control action of the first power supply, the on / off operation is performed according to the preset duty cycle; The control unit is configured as follows: By providing a PWM or SPWM signal that is interlocked with a second filter of the harmonic filter of the input power receiver, the power factor can be improved or the total harmonic distortion minimized under any load conditions.

8. The power supply device for the high-efficiency electric furnace according to claim 4, characterized in that, The output power conversion unit includes: The transformer section is connected to the second conversion section and is used to step up or step down the voltage of the third power supply.

9. The power supply device for the high-efficiency electric furnace according to any one of claims 1-8, characterized in that, It also includes a power supply control unit for providing uninterrupted power to the control unit in response to instantaneous voltage fluctuations occurring in the electric arc furnace.

10. A control method for a power supply device of a high-efficiency electric furnace, characterized in that, This includes the input power receiving step, receiving the first power in the form of AC voltage; The input power conversion step converts the input power into a second power in the form of DC voltage. The output power conversion step converts the second power into a third power in the form of DC or AC voltage according to at least one preset heating area of ​​the electric furnace and outputs it. as well as The control step involves controlling the output of the third power source according to a preset temperature formula for the electric furnace.

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