Single-phase AC / AC converter

Abstract

The utility model discloses a single-phase AC / AC converter which is used for realizing fine adjustment of output signals of a conversion circuit and improving the precision and stability of output AC signals. The circuit comprises a main control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit. The input end of the first sampling module and the input end of the second sampling module are used for receiving alternating current signals; the main control chip is connected with the output end of the first sampling circuit and the output end of the second sampling circuit; the output end of the main control chip is connected with the input end of the driving chip; the output end of the driving chip is connected with the input end of the conversion circuit, and the output end of the conversion circuit is used for outputting a final alternating current signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of current transformer, in particular to a single-phase AC / AC converter. BACKGROUND

[0002] At present, the main ways to realize AC / AC voltage conversion are direct conversion and indirect conversion. Direct conversion is to connect the input AC power directly with the output through switching devices, and to obtain the required frequency or different frequency output AC power by controlling the on-off of the switching devices. Indirect conversion is to realize AC / AC conversion through intermediate links. Specifically, it is to convert the input AC power into DC power, and then convert the DC power into AC power with the required frequency and amplitude.

[0003] Firstly, from the stability point of view, the AC / AC voltage converter needs to be able to maintain the constant output voltage under various load conditions. However, in actual application, the change of load is often very frequent, such as the start and stop of motor, the switching of lighting device, etc., which will cause the fluctuation of grid voltage. The existing design of AC / AC voltage converter is not optimized, or the control strategy is not flexible enough, which makes it difficult for the AC / AC voltage converter to maintain the stability of output voltage under the condition of load change.

[0004] Secondly, from the accuracy point of view, the AC / AC voltage converter needs to be able to provide high-precision output voltage to meet the needs of various sensitive loads. However, due to the existence of various nonlinear elements and interference factors inside or outside the converter, such as switching loss of switching device, parasitic parameters of filter circuit, control algorithm and sampling accuracy, etc., these will affect the accuracy of output voltage. If the control algorithm is not accurate enough, or the sampling accuracy is not high enough, it will cause the error of output voltage to increase, thereby affecting the performance of various loads connected to the output end of the converter.

[0005] These problems not only affect the overall performance of the converter, but also limit its widespread use and application in various application occasions. CONTENT OF THE INVENTION

[0006] The present application provides a single-phase AC / AC converter, comprising:

[0007] a main control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit;

[0008] The input end of the first sampling module and the input end of the second sampling module are used to receive an AC signal;

[0009] The output end of the first sampling circuit, the output end of the second sampling module and the main control chip are connected;

[0010] The output end of the main control chip is connected with the input end of the driving chip.

[0011] The output end of the driving chip is connected with the input end of the conversion circuit, and the output end of the conversion circuit is used for outputting the final alternating current signal.

[0012] Optionally, the main control chip comprises a first main control chip and a second main control chip.

[0013] The output end of the first main control chip is connected with the output end of the first sampling circuit.

[0014] The output end of the second main control chip is connected with the output end of the second sampling circuit.

[0015] Optionally, the driving chip comprises a first driving chip and a second driving chip.

[0016] The output end of the first main control chip is connected with the input end of the first driving chip.

[0017] The output end of the second main control chip is connected with the input end of the second driving chip.

[0018] Optionally, the conversion circuit comprises a first conversion circuit and a second conversion circuit.

[0019] The output end of the first driving chip is connected with the first input end of the first conversion circuit.

[0020] The output end of the second driving chip is connected with the first input end of the second conversion circuit.

[0021] The first input end of the first conversion circuit is connected with the first input end of the second conversion circuit in series.

[0022] The output end of the first conversion circuit is connected with the output end of the second conversion circuit, and a circuit output end is arranged at the connection position, and the circuit output end is used for outputting the final alternating current signal.

[0023] Optionally, the conversion circuit comprises a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor and a first inductor.

[0024] The drain of the first NMOS tube is connected with one end of the second capacitor, and the gate of the first NMOS tube is connected with one end of the first resistor and one end of the third resistor.

[0025] The source of the first NMOS tube is connected with the source of the second NMOS tube, and a first intersection is arranged at the connection position.

[0026] The other end of the third resistor and one end of the fourth resistor are connected, and a second intersection is arranged at the connection position;

[0027] The first intersection and the second intersection are connected, and a power supply is connected at the same time;

[0028] The gate of the second NMOS tube, the other end of the fourth resistor and one end of the second resistor are connected, the drain of the second NMOS tube, one end of the first inductor and the drain of the third NMOS tube are connected;

[0029] The other end of the first resistor and the other end of the second resistor are connected to drive the chip;

[0030] The gate of the third NMOS tube is connected to one end of the fifth resistor and one end of the seventh resistor;

[0031] The source of the third NMOS tube and the source of the fourth NMOS tube are connected, and a third intersection is arranged at the connection position;

[0032] The other end of the seventh resistor and one end of the eighth resistor are connected, and a fourth intersection is arranged at the connection position;

[0033] The third intersection and the fourth intersection are connected, and a power supply is connected at the same time;

[0034] The gate of the fourth NMOS tube, the other end of the eighth resistor and one end of the sixth resistor are connected, and the drain of the fourth NMOS tube and the other end of the second capacitor and one end of the first capacitor are connected;

[0035] The other end of the first inductor and one end of the first capacitor are connected, and the other end of the fifth resistor and the other end of the sixth resistor are connected to drive the chip;

[0036] The two ends of the second capacitor are connected to an AC signal input end at the same time, and the two ends of the first capacitor are connected to a load.

[0037] Optionally, the first sampling module and the second sampling module are built-in in the main control chip.

[0038] Optionally, the main control chip is an STM32F334C8T6 single-chip microcomputer, and the driving chip is a UCC21520.

[0039] Optionally, the key circuit is further included; the key circuit is connected with the main control chip;

[0040] Optionally, the rectifier circuit is further included, which is used for reducing the harmonic components of the input AC signal;

[0041] The input end of the rectifier circuit is used for receiving an AC signal, and the output end of the rectifier circuit is connected with the main control chip.

[0042] From the above technical solutions, the present application has the following advantages:

[0043] The first sampling module and the second sampling module respectively receive the alternating current signal, the output end of the master control chip is connected with the first sampling module and the second sampling module, and the data obtained by the two sampling modules can be fed back to the master control chip in real time. The master control chip generates corresponding PWM signals according to the sampling data and a preset control strategy. The output end of the master control chip is connected with the input end of the driving chip, and the master control chip can output the PWM signals to the driving chip. The driving chip processes the PWM signals to obtain control signals. The input end of the conversion circuit is connected with the output end of the driving chip, and can receive the control signals. The conversion circuit flexibly adjusts the alternating current signal according to the control signals, and outputs the final alternating current signal through the output end of the conversion circuit.

[0044] Through the series connection of the modules, complete closed-loop control from input sampling to output conversion is realized, which helps to improve the stability and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 FIG. 1 is a structural schematic diagram of a single-phase AC / AC converter according to the present application;

[0046] Figure 2 FIG. 2 is another structural schematic diagram of a single-phase AC / AC converter according to the present application;

[0047] Figure 3 FIG. 3 is a circuit diagram of a conversion circuit in a single-phase AC / AC converter according to the present application. DETAILED DESCRIPTION

[0048] In order to solve the above technical problems, the present application provides a single-phase AC / AC converter for realizing fine adjustment of the output signal of the conversion circuit and improving the precision and stability of the output alternating current signal.

[0049] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to illustrate the relative positional relationship between the components or constituent parts, and do not particularly limit the specific installation orientation of the components or constituent parts.

[0050] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. Those skilled in the art can understand the specific meaning of these terms in the present application according to the specific circumstances.

[0051] In addition, the terms "mounting", "arrangement", "provided with", "connected", "linked" should be interpreted broadly. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood according to the specific circumstances by those skilled in the art.

[0052] In addition, the structures, proportions, sizes, etc. shown in the drawings attached in the present application are only used to cooperate with the disclosed content in the description, to be understood and read by those skilled in the art, and do not have technical significance, and any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose of the present application, should still fall within the scope of the disclosed technical content.

[0053] The technical solutions in the present application will be described clearly and completely in the following with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0054] Please refer to Figure 1 The single-phase AC / AC converter provided by the embodiments of the present application comprises:

[0055] The main control chip, the first sampling module, the second sampling module, the driving chip and the conversion circuit;

[0056] The input end of the first sampling module and the input end of the second sampling module are used for receiving an alternating current signal;

[0057] The output end of the first sampling circuit and the output end of the second sampling module are connected with the main control chip;

[0058] The output end of the main control chip is connected with the input end of the driving chip;

[0059] The output end of the driving chip is connected with the input end of the conversion circuit, and the output end of the conversion circuit is used for outputting a final alternating current signal.

[0060] The components in the embodiments will be described in detail as follows:

[0061] The main control chip is used for receiving circuit data, and analyzing and optimizing the circuit data, and generating corresponding control signals based on the circuit data.

[0062] The first sampling module is configured to collect current data of the input AC signal.

[0063] The second sampling module is configured to collect voltage data of the input AC signal.

[0064] The driving chip is a bridge connecting the main control chip and the conversion circuit. After receiving the PWM signal, the driving chip converts the PWM signal into a signal capable of driving the conversion circuit.

[0065] The electronic devices in the conversion circuit can switch according to the indication of the PWM signal in a specific time sequence, thereby changing the voltage distribution and voltage size in the circuit and realizing accurate adjustment of the AC signal.

[0066] The circuit data of the input AC signal is collected by the first sampling module and the second sampling module, and the circuit data is input into the main control chip. The main control chip analyzes and optimizes the circuit data by using an internal preset algorithm, and obtains optimized circuit data. Based on the optimized circuit data, the main control chip generates a PWM signal and outputs the PWM signal to the driving chip. According to the duty ratio and frequency of the PWM signal, the driving chip controls the conversion circuit to adjust the AC signal, and obtains the final output AC signal, thereby realizing fine adjustment of the output signal of the conversion circuit and further improving the accuracy and stability of the output AC signal.

[0067] Referring to Figure 2 In one specific embodiment, a single-phase AC / AC converter includes:

[0068] The first main control chip, the second main control chip, the first sampling module, the second sampling module, the first driving chip, the second driving chip, the first conversion circuit, and the second conversion circuit.

[0069] The first main control chip is connected to the output end of the first sampling circuit.

[0070] The second main control chip is connected to the output end of the second sampling circuit.

[0071] The output end of the first main control chip is connected to the input end of the first driving chip.

[0072] The output end of the second main control chip is connected to the input end of the second driving chip.

[0073] The output end of the first driving chip is connected to the first input end of the first conversion circuit.

[0074] The output end of the second driving chip is connected to the first input end of the second conversion circuit.

[0075] The first input end of the first conversion circuit is connected in series with the first input end of the second conversion circuit.

[0076] The output end of the first conversion circuit is connected with the output end of the second conversion circuit, and a circuit output end is arranged at the connection position, and the circuit output end is used for outputting the final alternating current signal.

[0077] The first main control chip, the first sampling module, the first driving chip and the first conversion circuit form a loop, the first sampling module collects current data of the input alternating current signal and sends the corresponding control signal to the first main control chip to generate, and the first driving chip controls the first conversion circuit to realize the adjustment of the current parameter of the alternating current signal.

[0078] The second main control chip, the second sampling module, the second driving chip and the second conversion circuit form another loop, the second sampling module collects voltage data of the input alternating current signal and sends the corresponding control signal to the second main control chip to generate, and the second driving chip controls the second conversion circuit to realize the adjustment of the voltage parameter of the alternating current signal.

[0079] The two loops are used for cooperatively adjusting the alternating current signal, and finally output the appropriate alternating current signal to the load.

[0080] Please refer to Figure 3 In a specific embodiment, the conversion circuit in the single-phase AC / AC converter comprises:

[0081] The drain electrode of the first switch tube is connected with one end of the second capacitor, and the gate electrode of the first switch tube is connected with one end of the first resistor and one end of the third resistor.

[0082] The source electrode of the first switch tube is connected with the source electrode of the second switch tube, and a first intersection is arranged at the connection position.

[0083] The other end of the third resistor is connected with one end of the fourth resistor, and a second intersection is arranged at the connection position.

[0084] The first intersection and the second intersection are connected, and a power supply is connected at the same time.

[0085] The gate electrode of the second switch tube, the other end of the fourth resistor and one end of the second resistor are connected, and the drain electrode of the second switch tube, one end of the first inductor and the drain electrode of the third switch tube are connected.

[0086] The other end of the first resistor and the other end of the second resistor are connected with the driving chip.

[0087] The gate electrode of the third switch tube is connected with one end of the fifth resistor and one end of the seventh resistor.

[0088] The gate electrode of the third switch tube is connected with one end of the fifth resistor and one end of the seventh resistor.

[0089] The source of the third switch tube and the source of the fourth switch tube are connected, and a third intersection is arranged at the connection;

[0090] The other end of the seventh resistor and one end of the eighth resistor are connected, and a fourth intersection is arranged at the connection;

[0091] The third intersection and the fourth intersection are connected, and a power supply is connected at the same time;

[0092] The gate of the fourth switch tube, the other end of the eighth resistor and one end of the sixth resistor are connected, and the drain of the fourth switch tube and the other end of the second capacitor and one end of the first capacitor are connected;

[0093] The other end of the first inductor and one end of the first capacitor are connected, and the other end of the fifth resistor and the other end of the sixth resistor are connected to the driving chip;

[0094] The two ends of the second capacitor are connected to an AC signal input end at the same time, and the two ends of the first capacitor are connected to a load at the same time.

[0095] Working principle of the conversion circuit:

[0096] The converter first determines the working state of the switch tube according to the polarity of the input voltage, and controls the effective value and frequency of the output voltage by changing the switching time of the switch tube. The four switch tubes cannot be turned on and turned off at the same time, and the loop will produce an impact current when they are turned on at the same time, which will damage the circuit; when they are turned off at the same time, there is no path for the energy stored in the inductor to be released, which will damage the switch tube.

[0097] When the input voltage polarity is positive, a specific group of switch tubes (for example, the first switch tube and the fourth switch tube) will remain in the on state, while the other group of switch tubes (for example, the second switch tube and the third switch tube) will be modulated by high-frequency PWM (pulse width modulation). When the input voltage polarity is negative, the working state of the switch tube will be reversed, that is, the switch tube that was originally turned on is turned off, and the switch tube that was originally modulated by high-frequency PWM remains in the on state, while the other group of switch tubes is modulated by high-frequency PWM.

[0098] By adjusting the duty cycle of the input PWM signal, the amplitude of the output voltage can be controlled. The larger the duty cycle, the higher the output voltage; the smaller the duty cycle, the lower the output voltage.

[0099] In a specific embodiment, the first sampling module and the second sampling module are built-in in the main control chip.

[0100] In a specific embodiment, the main control chip can use an STM32F334C8T6 single-chip microcomputer, and feedback control is performed through the single-chip microcomputer.

[0101] The switch tube driving chip can select UCC21520. UCC21520 has a source current of 4A and a sink current of 6A, so that the load rising time and falling time of high-frequency switching power supply application are significantly accelerated, such as the rising time of 1.8nF load is 6ns and the falling time is 7ns, thereby reducing the switching loss and improving the power efficiency. It also provides enhanced isolation of 5.7kVRMS, which can effectively isolate high-voltage environments and protect equipment from electric shock and electromagnetic interference.

[0102] In one specific embodiment, a key circuit is further included, and the key circuit includes one or more keys, and the keys are used to step the output AC signal.

[0103] In one specific embodiment, a rectifier circuit is further included, and the rectifier circuit is used to reduce the harmonic components of the input AC signal.

[0104] It should be noted that the above descriptions of the disclosed embodiments enable one of ordinary skill in the art to carry out or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A single phase AC / AC converter, characterized by The application relates to a control chip, a first sampling module, a second sampling module, a driving chip and a conversion circuit. The input end of the first sampling module and the input end of the second sampling module are used for receiving an alternating current signal. The output end of the first sampling circuit and the output end of the second sampling module are connected with the control chip. The output end of the control chip is connected with the input end of the driving chip. The output end of the driving chip is connected with the input end of the conversion circuit, and the output end of the conversion circuit is used for outputting a final alternating current signal. The control chip comprises a first control chip and a second control chip.

2. A single-phase AC / AC converter as defined in claim 1, characterized in that The output end of the first control chip is connected with the output end of the first sampling circuit. The output end of the second control chip is connected with the output end of the second sampling circuit. The driving chip comprises a first driving chip and a second driving chip.

3. A single-phase AC / AC converter as claimed in claim 2, characterized in that The output end of the first control chip is connected with the input end of the first driving chip. The output end of the second control chip is connected with the input end of the second driving chip. The conversion circuit comprises a first conversion circuit and a second conversion circuit.

4. A single-phase AC / AC converter as claimed in claim 3, characterized in that The output end of the first driving chip is connected with the first input end of the first conversion circuit. The output end of the second driving chip is connected with the first input end of the second conversion circuit. The first input end of the first conversion circuit and the first input end of the second conversion circuit are connected in series. The output end of the first conversion circuit and the output end of the second conversion circuit are connected, and a circuit output end is arranged at the connection position, and the circuit output end is used for outputting a final alternating current signal. The conversion circuit comprises a first NMOS tube, a second NMOS tube, a third NMOS tube, a fourth NMOS tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor and a first inductor.

5. A single-phase AC / AC converter as defined in claim 1, characterized in that The drain of the first NMOS tube and one end of the second capacitor are connected, and the gate of the first NMOS tube is connected with one end of the first resistor and one end of the third resistor. The source of the first NMOS tube and the source of the second NMOS tube are connected, and a first intersection is arranged at the connection position. The other end of the third resistor and one end of the fourth resistor are connected, and a second intersection is arranged at the connection position. The first intersection and the second intersection are connected, and a power supply is simultaneously connected. The gate of the second NMOS tube, the other end of the fourth resistor and one end of the second resistor are connected, the drain of the second NMOS tube, one end of the first inductor and the drain of the third NMOS tube are connected. The other end of the first resistor and the other end of the second resistor are connected with the driving chip. The gate of the third NMOS tube is connected with one end of the fifth resistor and one end of the seventh resistor. The source of the third NMOS tube and the source of the fourth NMOS tube are connected, and a third intersection is arranged at the connection position. The other end of the seventh resistor and one end of the eighth resistor are connected, and a fourth intersection is arranged at the connection position. The third intersection and the fourth intersection are connected, and a power supply is simultaneously connected. The gate of the fourth NMOS tube, the other end of the eighth resistor and one end of the sixth resistor are connected, the drain of the fourth NMOS tube and the other end of the second capacitor and one end of the first capacitor are connected. The other end of the first inductor and one end of the first capacitor are connected, and the other end of the fifth resistor and the other end of the sixth resistor are connected with the driving chip. ​ Two ends of the second capacitor are connected with the AC signal input end, and two ends of the first capacitor are connected with the load.

6. A single-phase AC / AC converter as defined in claim 1, characterized in that The first sampling module and the second sampling module are built in the main control chip.

7. The single-phase AC / AC converter according to one of the claims 1-6, characterized in that, The main control chip is an STM32F334C8T6 single-chip microcomputer, and the driving chip is a UCC21520.

8. The single-phase AC / AC converter according to one of the claims 1-7, characterized in that, The key circuit is further included; the key circuit is connected with the main control chip.

9. The single-phase AC / AC converter according to one of the claims 1-7, characterized in that, The single-phase AC / AC converter further includes a rectifier circuit for reducing harmonic components of the input AC signal. An input end of the rectifier circuit is used for receiving an AC signal, and an output end of the rectifier circuit is connected with the main control chip.

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