阅读说明：本技术 一种大功率组合式正弦波隔离变频电源系统及工作方法 (High-power combined type sine wave isolation variable frequency power supply system and working method ) 是由 李志忠 邵建康 罗建勇 王西香 雷蕾 王晓涛 黄竣峰 王勇 王容 王森 李伟 于 2020-11-30 设计创作，主要内容包括：本发明公开了一种大功率组合式正弦波隔离变频电源系统及工作方法,涉及大功率变频电源系统,尤其涉及大功率组合式正弦波隔离变频电源系统。本发明采用多路独立可控的变频模块,连接多台小容量的隔离变压器,通过体积小,重量轻的多台小容量隔离变压器串联或者并联组合实现大容量的隔离变频电源输出,有效解决传统大功率隔离变频电源系统由于体积大、重量重导致的搬运困难、不易携带和运输困难的问题。(The invention discloses a high-power combined type sine wave isolation variable frequency power supply system and a working method, and relates to a high-power variable frequency power supply system, in particular to a high-power combined type sine wave isolation variable frequency power supply system. The invention adopts a plurality of independent controllable frequency conversion modules to connect a plurality of small-capacity isolation transformers, realizes the output of a large-capacity isolation frequency conversion power supply by combining a plurality of small-capacity isolation transformers with small volume and light weight in series or in parallel, and effectively solves the problems of difficult transportation, difficult carrying and difficult transportation caused by large volume and heavy weight of the traditional high-power isolation frequency conversion power supply system.)

1. A high-power combined sine wave isolation variable frequency power supply system is characterized by comprising a micro control unit, a sine wave generator, a main frequency conversion loop and at least 1 auxiliary frequency conversion loop;

the main frequency conversion loop comprises a main SPWM driving signal generation module, a main frequency conversion module, a main isolation transformer and a main detection module which are sequentially connected;

the slave frequency conversion loop comprises a negative feedback automatic adjusting module, a slave SPWM driving signal generating module, a slave frequency conversion module, a slave isolation transformer and a slave detection module which are sequentially connected in series;

the main isolation transformer and the slave isolation transformer are connected in series or in parallel;

the micro control unit is connected with a sine wave generator, and the sine wave generator is connected with a main SPWM driving signal generation module and a negative feedback automatic adjustment module; the master detection module is connected with the negative feedback automatic adjusting module of each path of slave frequency conversion loop, and the slave detection module is connected with the negative feedback automatic adjusting module of the slave frequency conversion loop.

2. The high-power combined sine wave isolation variable frequency power supply system according to claim 1, wherein the output ends of the master isolation transformer and the slave isolation transformer are connected with filtering modules.

3. The high power combined sine wave isolated variable frequency power supply system according to claim 1, wherein said master and slave detection modules each comprise a voltage transformer and a current transformer.

4. The high power combined sine wave isolated frequency conversion power supply system according to claim 1, wherein the sine wave generator is a DAC sine wave generator.

5. The high power combined sinewave-isolated variable frequency power supply system according to claim 1, wherein the capacities and voltage levels of the master isolation transformer and the slave isolation transformer are the same.

6. The high-power combined sine wave isolated variable frequency power supply system according to claim 1 or 5, wherein the capacities of the master and slave isolation transformers are less than or equal to 20 KVA.

7. The operating method of a high-power combined sine wave isolated variable frequency power supply system as claimed in claim 1, wherein the micro control unit controls the sine wave generator to generate a continuous sine wave input signal and issues a feedback signal selection control command to the negative feedback automatic adjustment module of each slave variable frequency loop;

in a main frequency conversion loop, continuous sine waves generated by a sine wave generator pass through a main SPWM drive signal generation module, a main frequency conversion module and a main isolation transformer to generate current or voltage signals of the main transformer in the main frequency conversion loop;

in the secondary frequency conversion loop, after the feedback signal selection control command is input by the micro control unit, the negative feedback automatic regulation module compares the current or voltage signal of the main transformer with the current or voltage signal of the main transformer, and regulates the data with error with the current or voltage signal of the main transformer, so that the current or voltage signal of the secondary transformer in the secondary circuit is the same as the current or voltage signal of the main transformer.

Technical Field

The invention belongs to the technical field of high-power variable-frequency power supplies, and particularly relates to a high-power combined type sine wave isolation variable-frequency power supply system and a working method.

Background

The variable frequency power supply outputs the alternating current in the commercial power into a pure sine wave through a variable frequency device of alternating current → direct current → alternating current → filtering, and the output frequency and the voltage are adjustable within a certain range. The ideal AC power supply features stable frequency, stable voltage, zero internal resistance and pure sine wave voltage waveform (no distortion). The variable frequency power supply is very close to an ideal alternating current power supply, so that advanced and developed countries increasingly use the variable frequency power supply as a standard power supply so as to provide the most excellent power supply environment for electrical appliances and objectively examine the technical performance of the electrical appliances. The variable frequency power supply can simulate and output power grid indexes of different countries, and provides pure, reliable, low-harmonic-distortion and high-stability voltage and frequency sine wave power supply output for export electrical appliance manufacturers in the applications of design, development, production, detection and the like. For the above reasons, the application of the variable frequency power supply is more and more extensive.

With the use of the variable frequency power supply being wider and wider, the high-power variable frequency power supply also finds a place for the high-power variable frequency power supply to play a role in the current economic society, and the use environment is also wider and wider, wherein the high-power isolated variable frequency power supply is safer, and customers are more willing to select the high-power variable frequency power supply. With the increase of power, the high-power variable frequency power supply has higher requirements on safety and technology: and reducing the volume of the variable frequency power supply. The high power means that an isolation transformer with a large transformation ratio is needed, and a radiator designed for heat dissipation of a power device is larger, so that the high-power variable-frequency power supply system is used as an integrated machine, the whole weight of the high-power variable-frequency power supply system is generally hundreds of kilograms, and the larger the power is, the larger the volume is, the heavier the weight is, and the high-power variable-frequency power supply system is inconvenient to carry, carry and.

In the aspect of safety, the isolation transformer can play a role in protection, lightning protection and filtering, the output end and the input end of the isolation transformer are completely 'open-circuit', and the variable frequency power supply can be safer by adopting the isolation transformer; in the aspect of output, the technology is continuously innovated, the output is guaranteed to be pure sine wave, the waveform distortion rate is small, no interference control is carried out, and the precision is high; aiming at the load, the load-adaptive control circuit can adapt to various output loads, such as resistive load, capacitive load and inductive load, and is suitable for wider environment.

With the increasing use of the variable frequency power supply, the use universality of the high-power isolation variable frequency power supply is gradually increased. The invention of the combined type sine wave isolation variable frequency power supply system has great application value, and the combined type sine wave isolation variable frequency power supply system has small volume, light weight and convenient carrying and portability.

Disclosure of Invention

The invention provides a high-power combined type sine wave isolation variable frequency power supply system and a working method, which can realize the output of a high-power isolation variable frequency power supply, can realize the high-power isolation variable frequency power supply system capable of freely combining different output powers, and can achieve the purposes of convenient transportation and convenient carrying of the high-power isolation variable frequency power supply.

In order to achieve the purpose, the high-power combined sine wave isolation variable frequency power supply system comprises a micro control unit, a sine wave generator, a main frequency conversion loop and at least 1 auxiliary frequency conversion loop; the main frequency conversion loop comprises a main SPWM driving signal generation module, a main frequency conversion module, a main isolation transformer and a main detection module which are sequentially connected; the slave frequency conversion loop comprises a negative feedback automatic adjusting module, a slave SPWM driving signal generating module, a slave frequency conversion module, a slave isolation transformer and a slave detection module which are sequentially connected in series; the main isolation transformer and the slave isolation transformer are connected in series or in parallel; the micro control unit is connected with a sine wave generator, and the sine wave generator is connected with a main SPWM driving signal generation module and a negative feedback automatic adjustment module; the master detection module is connected with the negative feedback automatic adjusting module of each path of slave frequency conversion loop, and the slave detection module is connected with the negative feedback automatic adjusting module of the slave frequency conversion loop.

Furthermore, the output ends of the main isolation transformer and the auxiliary isolation transformer are connected with a filtering module.

Furthermore, the master detection module and the slave detection module respectively comprise a voltage transformer and a current transformer.

Further, the sine wave generator is a DAC sine wave generator.

Further, the capacities and voltage levels of the master isolation transformer and the slave isolation transformer are the same.

Further, the capacity of the main isolation transformer and the slave isolation transformer is less than or equal to 20 KVA.

A working method of a high-power combined sine wave isolation variable frequency power supply system is characterized in that a micro control unit controls a sine wave generator to generate continuous sine wave input signals, and a feedback signal selection control instruction is sent to a negative feedback automatic adjusting module of each slave variable frequency loop;

in a main frequency conversion loop, continuous sine waves generated by a sine wave generator pass through a main SPWM drive signal generation module, a main frequency conversion module and a main isolation transformer to generate current or voltage signals of the main transformer in the main frequency conversion loop;

in the secondary frequency conversion loop, after the feedback signal selection control command is input by the micro control unit, the negative feedback automatic regulation module compares the current or voltage signal of the main transformer with the current or voltage signal of the main transformer, and regulates the data with error with the current or voltage signal of the main transformer, so that the current or voltage signal of the secondary transformer in the secondary circuit is the same as the current or voltage signal of the main transformer.

Compared with the prior art, the invention has at least the following beneficial technical effects:

the invention mainly adopts a plurality of independent controllable frequency conversion modules which are connected with a plurality of small-capacity isolation transformers, realizes the output of a large-capacity isolation frequency conversion power supply by connecting the plurality of small-capacity isolation transformers in series or in parallel, and effectively solves the problems of difficult transportation, difficult carrying and difficult transportation caused by large volume and heavy weight of the traditional high-power isolation frequency conversion power supply system; meanwhile, the invention adopts the design of a plurality of independent controllable variable frequency loops, and can flexibly combine the required voltage, current and capacity.

The single isolation transformer with the capacity of 20KVA or below has small volume and light weight, is easy to move by a single person or two persons on site, and is convenient to combine into a combined variable frequency power supply.

The method of the invention detects the phase difference value of the slave frequency conversion signal source and the master frequency conversion signal source to generate the synchronous signal and is used for controlling the phase synchronization of the sine reference signal, thereby controlling the slave frequency conversion signal source to keep the same frequency and the same phase. The sinusoidal reference is adjusted by detecting the output current or voltage difference value of the slave frequency conversion signal source and the master frequency conversion signal source, so that the output current equalization or voltage equalization among the frequency conversion signal sources is realized, and the electric energy quality of the combined power supply is ensured.

Drawings

Fig. 1 is a diagram of a high-power combined sine wave isolated variable frequency power supply system.

Detailed Description

In order to make the objects and technical solutions of the present invention clearer and easier to understand. The present invention will be described in further detail with reference to the following drawings and examples, wherein the specific examples are provided for illustrative purposes only and are not intended to limit the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, a high-power combined sine wave isolation variable frequency power supply system includes a Micro Controller Unit (MCU), a DAC sine wave generator, a master frequency conversion loop, and a multi-channel slave frequency conversion loop.

The main frequency conversion loop is formed by sequentially connecting a main SPWM drive signal generation module, a main frequency conversion module, a main isolation transformer, a filtering module and a main detection module in series. The main detection module comprises a main voltage transformer and a main current transformer.

The slave frequency conversion loop is formed by sequentially connecting a negative feedback automatic regulation module, a slave SPWM driving signal generation module, a slave frequency conversion module, a slave isolation transformer and filtering module and a slave voltage transformer and current transformer detection module in series. The slave main detection module comprises a slave voltage transformer and a slave current transformer.

The main frequency conversion module and the auxiliary frequency conversion module are used for inverting the direct current into alternating current.

The master detection module is connected with the negative feedback automatic adjusting module of each slave frequency conversion loop, the slave detection voltage transformer slave current transformer module is connected with the negative feedback automatic adjusting module of the slave loop, the MCU is connected with the DAC sine wave generator, the DAC sine wave generator is connected with the master SPWM driving signal generating module which is sequentially connected into the master frequency conversion loop and the negative feedback automatic adjusting modules of all the slave frequency conversion loops, and the MCU is also connected with the negative feedback automatic adjusting module of the slave frequency conversion loop.

The MCU controls the DAC sine wave generator to generate continuous sine wave input signals, and sends feedback signal selection control instructions to the negative feedback automatic adjusting module of each slave frequency conversion loop. When the instrument starts to work, a feedback signal is given to select a control command according to whether the parallel mode or the series mode is selected.

In a main frequency conversion loop, a continuous sine wave generated by a DAC sine wave generator passes through a main SPWM drive signal generation module, a main frequency conversion module, a main isolation transformer and a filtering module, and a main detection module generates a current or voltage signal of a main transformer in the main frequency conversion loop.

In the slave frequency conversion loop, a digital potentiometer is arranged in the negative feedback automatic adjusting module, and can compare current or voltage signals uploaded by the main voltage transformer, the main current transformer, the slave voltage transformer and the slave current transformer after the MCU inputs a feedback signal selection control instruction (current/voltage), finally adjust an input signal generated by the DAC sine wave generator to a correct value and output the input signal.

In the secondary frequency conversion loop, the continuous sine wave generated by the DAC sine wave generator passes through a negative feedback automatic regulating module, a secondary SPWM driving signal generating module, a secondary frequency conversion module, a secondary isolation transformer and a filtering module, a secondary detection module voltage transformer generates a secondary transformer current or voltage signal in the secondary frequency conversion loop from a current transformer, an MCU sends a feedback signal selection control instruction (current/voltage) to the negative feedback automatic regulating module, the negative feedback automatic regulating module simultaneously compares the current or voltage signal of a main transformer transmitted on the main frequency conversion loop with the secondary transformer current or voltage signal generated by the loop in which the MCU is positioned, and the data with errors with the current or voltage signal of the main transformer is adjusted, and finally the current or voltage signal of the slave transformer of the slave frequency conversion loop where the slave frequency conversion loop is located is the same as the current or voltage signal of the main transformer. The voltage of each path is consistent when the multiple paths of small-capacity isolation transformers are connected in series, and the current of each path is consistent when the multiple paths of small-capacity isolation transformers are connected in parallel.

After the current or voltage signals output by each frequency conversion loop are processed, high-power isolated output is realized by connecting small-capacity isolation transformers in series or in parallel. A high-power combined sine wave isolation variable frequency power supply system is characterized in that: the high-power isolation variable frequency power supply system has the advantages of small volume, light weight, convenience in carrying and transportation, and is safe, simple, convenient, efficient and accurate in solution for the convenience of the high-power isolation variable frequency power supply system.

The technical scheme shows that: a high-power combined sine wave isolation variable frequency power supply system comprises an MCU (microprogrammed control Unit), a DAC (digital-to-analog converter) sine wave generator, a main frequency conversion loop and a multi-path slave frequency conversion loop; firstly, a main voltage transformer or a main current transformer collects a phase signal of a main variable frequency signal source, an SPWM driving signal generating module detects a phase difference value of a slave variable frequency signal source and the slave variable frequency signal source to generate a synchronous signal and is used for controlling the phase synchronization of a sinusoidal reference signal, and then the slave variable frequency signal source is controlled to keep the same frequency and the same phase. In addition, the sine reference is adjusted by detecting the difference value of the output current or voltage of the variable frequency signal source and the main variable frequency signal source, so that the output current equalization or voltage equalization among the variable frequency signal sources can be realized.

Example 1

The following description takes a variable frequency power supply system with 50KW (400V, 125A) output of 40Hz-70Hz as an example:

the MCU sends a current feedback signal selection control instruction to the negative feedback automatic adjusting module, and simultaneously sends an instruction for generating a continuous sine wave to the DAC sine wave generator, and the sine wave is respectively input to the main SPWM driving signal generating module of the main frequency conversion loop and the negative feedback automatic adjusting module of the slave frequency conversion loop.

In a main frequency conversion loop, a signal generated by a main SPWM driving signal generation module is amplified and filtered by a main frequency conversion module, a 10KVA main isolation transformer and a filtering module, and then a 10KW (400V, 25A) main frequency conversion loop current signal I is output, and voltage, current and phase signals are fed back to a negative feedback automatic adjustment module of a slave loop through a main detection module.

In the slave frequency conversion loop, the DAC sine wave generator generates sine wave signal, and the slave frequency conversion signal I is generated from the isolation transformer and the filter module through the negative feedback automatic regulation module → the SPWM drive signal generation module → the slave frequency conversion module → 10KVA₁、I₂... In. The up-conversion frequency signals pass through a negative feedback automatic adjusting module which is fed back to the loop where the detection module is positioned, and the negative feedback automatic adjusting module where each slave loop is positioned respectively carries out the current signal I of the main frequency conversion loop and the frequency conversion signal I of the slave loop₁，I₂... In for comparison, if I₁，I₂.., In and I have amplitude difference, starting automatic regulation mode until I₁，I₂... In is identical to I.

5 10KVA isolation transformers are connected into a high-power combined type sine wave isolation variable frequency power supply system, and then the variable frequency power supply with the voltage of 50KW (400V, 125A) and the frequency of 40-70Hz can be obtained after the 5 10KVA isolation transformers are connected in parallel.

Example 2 similarly, a 50KW (2000V, 25A)40-70Hz variable frequency power supply system can be obtained:

the MCU inputs a voltage feedback signal selection control instruction, 5 10KVA isolation transformers are connected into a high-power combined type sine wave isolation variable frequency power supply system, and then the 5 10KVA isolation transformers are connected in series to obtain a variable frequency power supply of 50KW (2000V, 25A) and 40-70 Hz.

The weight of the 50KW all-in-one variable frequency power supply is about hundreds of kilograms, but the weight of the 10KVA isolation transformer is about tens of kilograms, and the 50KW variable frequency power supply can be realized in a high-power combined type sine wave isolation variable frequency power supply system by connecting 5 10KVA isolation transformers in series or in parallel, and the combination is convenient to carry, carry and transport.

Finally, it should be noted that: the above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.