An input switching method, device and power supply device compatible with AC and DC power sources

Abstract

The application provides an input switching method and device compatible with AC / DC power supply and a power supply device. The switching device comprises an input voltage detection circuit, a rectifier, an energy storage capacitor, an output voltage detection circuit, a relay, a sampling resistor and a controller. The controller is connected with the output end of the input voltage detection circuit, the output end of the output voltage detection circuit and the second switch end of the relay, respectively, for controlling the relay to be disconnected according to the received power supply switching signal, and for controlling the relay to be attracted when the difference between the voltage value output by the input voltage detection circuit and the voltage value output by the output voltage detection circuit is less than or equal to a preset threshold. The application can realize stable and fast switching of the input AC / DC power supply of the servo drive and the frequency conversion device, prevent the load from being impacted by current, and ensure the reliable operation of the load when the external input power supply supplies power to the load after the AC / DC power supply is switched and the input voltage and the output voltage are relatively stable.

Description

Technical Field

[0001] This invention relates to the field of power switching control technology, and in particular to an input switching method, apparatus, and power supply device compatible with AC and DC power supplies. Background Technology

[0002] With the promotion and technological development of new energy sources, various servo drive products and frequency converters have begun to use new energy sources for power supply. The storage of new energy sources such as wind and solar power to power servo drives and frequency converters has been widely implemented. However, new energy sources are affected by unstable factors such as sunlight and wind, and their energy storage is limited. To ensure the continuous and reliable operation of servo drives and frequency converters, power supply methods compatible with both AC and DC power have broad application prospects.

[0003] However, servo drives and frequency converters that are compatible with AC and DC power inputs are capacitive loads. During power-on and power switching, the imbalance of input voltage can cause the power grid, energy storage devices, relays, and thyristors to be subjected to large current surges, which can cause problems such as power grid harmonic pollution and reduced device reliability. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the input switching method, device and power supply device of the present invention that are compatible with AC and DC power supply solves the problem that the switching of AC and DC power supply in the prior art will cause the circuit to be subjected to current surge, which will affect the reliability of the device.

[0005] In a first aspect, the present invention provides an input switching device compatible with AC / DC power supplies. The switching device includes: an input voltage detection circuit, a rectifier, an energy storage capacitor, an output voltage detection circuit, a relay, a sampling resistor, and a controller. The input terminal of the input voltage detection circuit is connected to the live wire of an external input power supply, the input terminal of the rectifier is connected to the external input power supply, the energy storage capacitor is connected to the output terminal of the rectifier, and the input terminal of the output voltage detection circuit is connected to the energy storage capacitor. The first coil terminal of the relay is connected to the controller, the second coil terminal of the relay is connected to the power supply, the first switch terminal of the relay is connected to the live wire of the external input power supply, and the second switch terminal of the relay is connected to the live wire of the external input power supply through the sampling resistor. The controller is also connected to the output terminals of the input voltage detection circuit, the output terminal of the output voltage detection circuit, and the second switch terminal of the relay, and is used to control the relay to disconnect according to a received power switching signal, and to control the relay to engage when the difference between the voltage value output by the input voltage detection circuit and the voltage value output by the output voltage detection circuit is less than or equal to a preset threshold.

[0006] Optionally, the switching device further includes a filter circuit, the input terminal of which is connected to the external input power supply, and the output terminal of which is connected to the input terminal of the rectifier.

[0007] Optionally, the input voltage detection circuit includes: a first resistor, a diode, and a second resistor; the first end of the first resistor is connected to the live wire of the external input power supply, the second end of the first resistor is connected to the anode of the diode, the cathode of the diode is connected to the first end of the second resistor, the first end of the second resistor is also connected to the controller, and the second end of the second resistor is grounded.

[0008] Optionally, the output voltage detection circuit includes a third resistor and a fourth resistor; the first end of the third resistor is connected to the positive terminal of the energy storage capacitor, the second end of the third resistor is grounded through the fourth resistor, and the second end of the third resistor is also connected to the controller.

[0009] Optionally, the switching device further includes a fifth resistor, the first end of which is connected to the first terminal of the switch of the relay, and the second end of which is connected to the first terminal of the sampling resistor.

[0010] Optionally, the filter circuit includes: a first differential-mode inductor, a second differential-mode inductor, and a common-mode inductor; a first terminal of the first differential-mode inductor is connected to the neutral terminal of the external input power supply, a second terminal of the first differential-mode inductor is connected to the first input terminal of the common-mode inductor, a first terminal of the second differential-mode inductor is connected to the live terminal of the external input power supply, a second terminal of the second differential-mode inductor is connected to the second input terminal of the common-mode inductor, and an output terminal of the common-mode inductor is connected to the output terminal of the rectifier.

[0011] Optionally, the filter circuit further includes: a first inter-line capacitor and a bleeder resistor; a first terminal of the first inter-line capacitor is connected to a first terminal of the first differential mode inductor, and a second terminal of the first inter-line capacitor is connected to a first terminal of the second differential mode inductor; a first terminal of the bleeder resistor is connected to a first terminal of the first inter-line capacitor, and a second terminal of the bleeder resistor is connected to a second terminal of the first inter-line capacitor.

[0012] Optionally, the filter circuit further includes: a second line-to-line capacitor, a first-to-ground capacitor, and a second-to-ground capacitor; the first terminal of the second line-to-line capacitor is connected to the first output terminal of the common-mode inductor, the second terminal of the second line-to-line capacitor is connected to the second output terminal of the common-mode inductor, the first terminal of the first-to-ground capacitor is connected to the first output terminal of the common-mode inductor, the second terminal of the first-to-ground capacitor is grounded, the first terminal of the second-to-ground capacitor is connected to the second output terminal of the common-mode inductor, and the second terminal of the second-to-ground capacitor is grounded.

[0013] Secondly, the present invention provides an input switching method compatible with AC and DC power supplies. The switching method includes: when the controller receives a first power switching signal, controlling the relay to disconnect and obtaining the current input current value through the sampling resistor; when the current input current value is equal to a preset current value, the controller sends a second power switching signal, causing an external switching device to switch between AC and DC power inputs according to the second power switching signal; the controller calculates a real-time voltage difference based on the voltage value output by the input voltage detection circuit and the voltage value output by the output voltage detection circuit; when the real-time voltage difference is less than or equal to a preset threshold, controlling the relay to engage.

[0014] Thirdly, the present invention provides a power supply device, which includes the aforementioned input switching device compatible with AC and DC power supplies, switching equipment, AC power supply, and DC power supply.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention first controls a relay to disconnect, cutting off the path between the external input power supply and the switching device. When the input current is detected to be zero, it controls the switching between the external AC power supply and the DC power supply. When the current external input voltage is comparable to the output voltage of the switching device, the controller then controls the relay to engage, allowing the input power supply after the AC / DC power supply switch to power the subsequent load through the switching device. Therefore, this invention enables the external input power supply to power the subsequent load only after the AC / DC power supply switch is completed and the input and output voltages are relatively stable. This allows for stable and rapid switching of AC / DC power inputs for servo drives and frequency converters, preventing current surges to the load and ensuring reliable operation of the load. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The diagram shown is a structural schematic of an input switching device compatible with AC / DC power supply provided in an embodiment of the present invention.

[0020] Figure 2The diagram shown is a circuit diagram of a filter circuit provided in an embodiment of the present invention;

[0021] Figure 3 The diagram shown is a flowchart illustrating an input switching method compatible with AC / DC power supplies provided in an embodiment of the present invention.

[0022] Figure 4 The diagram shown is a timing control schematic provided by an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Functional units with the same reference numerals in the examples of this invention have the same and similar structures and functions.

[0024] Example 1

[0025] Figure 1 The diagram shown is a structural schematic of an input switching device compatible with AC / DC power supplies provided in an embodiment of the present invention. Figure 1 As shown, the switching device includes:

[0026] Input voltage detection circuit 110, rectifier VC, energy storage capacitor C1, output voltage detection circuit 120, relay K1, sampling resistor R0 and controller U1;

[0027] The input terminal of the input voltage detection circuit 110 is connected to the live wire terminal of the external input power supply, the input terminal of the rectifier VC is connected to the external input power supply, the energy storage capacitor C1 is connected to the output terminal of the rectifier VC, and the input terminal of the output voltage detection circuit 120 is connected to the energy storage capacitor C1.

[0028] The first end of the coil of relay K1 is connected to the controller U1, the second end of the coil of relay K1 is connected to the power supply, the first end of the switch of relay K1 is connected to the live wire of the external input power supply, and the second end of the switch of relay K1 is connected to the live wire of the external input power supply through the sampling resistor R0.

[0029] The controller U1 is also connected to the output terminal of the input voltage detection circuit 110, the output terminal of the output voltage detection circuit 120, and the second switch terminal of the relay K1. It is used to control the relay K1 to open according to the received power switching signal, and to control the relay K1 to close when the difference between the voltage value output by the input voltage detection circuit 110 and the voltage value output by the output voltage detection circuit 120 is less than or equal to a preset threshold.

[0030] It should be noted that in this embodiment, the input voltage detection circuit is used to detect the voltage value input by the external power supply, the rectifier is used to convert the input AC power into DC power, the energy storage capacitor is used to store the DC power output by the rectifier, the output voltage detection circuit is used to detect the voltage value output by the energy storage capacitor, the relay is used to control whether the voltage input by the external power supply is input into the rectifier, the sampling resistor is used to detect whether the relay is completely open, and the controller is used to control the opening and closing of the relay. The external power supply includes both DC and AC power, and only one of them is connected to the input switching device in this embodiment at any given time.

[0031] The working principle of the switching device in this embodiment is as follows: When the controller receives a power switching signal, it detects the input current value. When the input current value is zero, it determines that the system needs to switch the input power. At this time, the relay or thyristor controlling the servo drive and frequency converter disconnects the power input port, and at the same time sends a switching ready signal to the external switching device. After the external switching device completes the AC / DC switching of the input power, it detects the voltage difference between the voltage value output by the output voltage detection circuit and the voltage value output by the input voltage detection circuit. When the voltage difference is less than the preset threshold ΔV1, the relay or thyristor is activated, and the servo drive and frequency converter start to operate normally.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention first controls a relay to disconnect, cutting off the path between the external input power supply and the switching device. When the input current is detected to be zero, it controls the switching between the external AC power supply and the DC power supply. When the current external input voltage is comparable to the output voltage of the switching device, the controller then controls the relay to engage, allowing the input power supply after the AC / DC power supply switch to power the subsequent load through the switching device. Therefore, this invention enables the external input power supply to power the subsequent load only after the AC / DC power supply switch is completed and the input and output voltages are relatively stable. This allows for stable and rapid switching of AC / DC power inputs for servo drives and frequency converters, preventing current surges to the load and ensuring reliable operation of the load.

[0034] In one embodiment, the switching device further includes a filter circuit, the input terminal of which is connected to the external input power supply, and the output terminal of which is connected to the input terminal of the rectifier; used to filter the voltage signal input from the external input power supply.

[0035] like Figure 2 As shown, the filter circuit includes: a first differential mode inductor L1, a second differential mode inductor L2, and a common mode inductor L3; the first end of the first differential mode inductor L1 is connected to the neutral terminal of the external input power supply, the second end of the first differential mode inductor L1 is connected to the first input terminal of the common mode inductor L3, the first end of the second differential mode inductor L2 is connected to the live terminal of the external input power supply, the second end of the second differential mode inductor L2 is connected to the second input terminal of the common mode inductor L3, and the output terminal of the common mode inductor L3 is connected to the output terminal of the rectifier.

[0036] Furthermore, the filter circuit further includes: a first inter-line capacitor C2 and a bleeder resistor R6; the first end of the first inter-line capacitor C2 is connected to the first end of the first differential mode inductor L1, and the second end of the first inter-line capacitor C2 is connected to the first end of the second differential mode inductor L2; the first end of the bleeder resistor R6 is connected to the first end of the first inter-line capacitor C2, and the second end of the bleeder resistor R6 is connected to the second end of the first inter-line capacitor C2.

[0037] Furthermore, the filter circuit further includes: a second line-to-line capacitor C3, a first ground capacitor C4, and a second ground capacitor C5; the first end of the second line-to-line capacitor C3 is connected to the first output terminal of the common-mode inductor L3, the second end of the second line-to-line capacitor C3 is connected to the second output terminal of the common-mode inductor L3, the first end of the first ground capacitor C4 is connected to the first output terminal of the common-mode inductor L3, the second end of the first ground capacitor C4 is grounded, the first end of the second ground capacitor C5 is connected to the second output terminal of the common-mode inductor L3, and the second end of the second ground capacitor C5 is grounded.

[0038] In this embodiment, the input voltage detection circuit includes: a first resistor R1, a diode D1, and a second resistor R2; the first end of the first resistor R1 is connected to the live wire of the external input power supply, the second end of the first resistor R1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the first end of the second resistor R2, the first end of the second resistor R2 is also connected to the controller, and the second end of the second resistor R2 is grounded.

[0039] It should be noted that in this embodiment, the voltage input from the external power supply is divided by the first resistor R1 and the second resistor R2 and then output to the controller for detection; wherein, the first resistor R1 can be a resistor with a large resistance value, or it can be composed of multiple resistors with small resistance values ​​connected in series; the diode D1 in this embodiment has the function of preventing reverse connection, preventing the live wire and neutral wire of the external power supply from being connected in reverse.

[0040] In this embodiment, the output voltage detection circuit includes a third resistor R3 and a fourth resistor R4; the first end of the third resistor R3 is connected to the positive terminal of the energy storage capacitor, the second end of the third resistor R3 is grounded through the fourth resistor R4, and the second end of the third resistor R3 is also connected to the controller.

[0041] It should be noted that in this embodiment, the voltage output by the energy storage capacitor is divided by the third resistor R3 and the fourth resistor R4 and then output to the controller for detection; wherein, the third resistor R3 can be a resistor with a large resistance value, or it can be composed of multiple resistors with small resistance values ​​connected in series.

[0042] In this embodiment, the switching device further includes a fifth resistor R5, the first end of which is connected to the first terminal of the relay switch, and the second end of which is connected to the first terminal of the sampling resistor; wherein, the fifth resistor R5 is a variable resistor and serves to limit current.

[0043] Example 2

[0044] Figure 3 The diagram shown is a flowchart illustrating an input switching method compatible with AC / DC power supplies provided in an embodiment of the present invention. Figure 3 As shown, the switching method specifically includes the following steps:

[0045] Step S101: When the controller receives the first power switching signal, it controls the relay to disconnect and obtains the current input current value through the sampling resistor;

[0046] Step S102: When the current input current value is equal to the preset current value, the controller sends a second power switching signal, causing the external switching device to switch between AC power and DC power input according to the second power switching signal.

[0047] Step S103: The controller calculates the real-time voltage difference based on the voltage value output by the input voltage detection circuit and the voltage value output by the output voltage detection circuit;

[0048] Step S104: When the real-time differential pressure is less than or equal to a preset threshold, control the relay to engage.

[0049] It should be noted that, in combination Figure 3 and Figure 4 It can be seen that after the downstream load is powered on and running, when the controller receives the first power switching signal A, it will disconnect the relay K1 at time T0. After the relay K1 is disconnected, the input current value is detected by the sampling resistor R0. When the input current value Iin = 0, it ensures that the relay K1 is completely disconnected. The controller sends the second power switching signal B, which is ready for switching, to the external switching device for switching AC power and DC power.

[0050] After receiving signal B, the external switching device performs AC / DC power switching at time T1. Simultaneously, it detects the input voltage value Vin through the input voltage detection circuit and the DC bus voltage Vdc on the energy storage capacitor C1 through the output voltage detection circuit, calculating Vin - Vdc = ΔV. When ΔV is less than the preset threshold ΔV1, the controller activates relay K1 by controlling the KIN signal at time T2. The resulting power switching inrush current is within an acceptable range, and the servo drive and frequency converter operate normally. Similarly, when the controller receives the first power switching signal A again, it repeats steps S101 to S104. The preset threshold ΔV1 is an error range value. Theoretically, switching when Vin - Vdc = 0 is ideal, but in practical applications, an error range needs to be set. Switching can be achieved when the difference between Vin and Vdc is within this error range. The value of the error range can be set according to the actual application scenario. Therefore, by disconnecting and engaging K1, the present invention can greatly reduce the impact of grid / power supply current caused by capacitive loads, and ensure the continuous and reliable operation of servo drive and frequency converter during AC / DC power switching.

[0051] In another embodiment of the present invention, a power supply device is provided, the power supply device including the input switching device, switching equipment, AC power supply and DC power supply compatible with the above embodiments.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An input switching device compatible with AC / DC power supplies, characterized in that, The switching device includes: Input voltage detection circuit, rectifier, energy storage capacitor, output voltage detection circuit, relay, sampling resistor and controller; The input terminal of the input voltage detection circuit is connected to the live wire of the external input power supply, the input terminal of the rectifier is connected to the external input power supply, the energy storage capacitor is connected to the output terminal of the rectifier, and the input terminal of the output voltage detection circuit is connected to the energy storage capacitor. The first end of the relay coil is connected to the controller, the second end of the relay coil is connected to the power supply, the first end of the relay switch is connected to the live wire of the external input power supply, and the second end of the relay switch is connected to the live wire of the external input power supply through the sampling resistor. The controller is also connected to the output terminal of the input voltage detection circuit, the output terminal of the output voltage detection circuit, and the second terminal of the relay switch. When the controller receives the first power switching signal, it controls the relay to disconnect and obtains the current input current value through the sampling resistor. When the current input current value is equal to the preset current value, the controller sends a second power switching signal, causing the external switching device to switch between AC power and DC power input according to the second power switching signal. The controller calculates the real-time voltage difference based on the voltage values ​​output by the input voltage detection circuit and the output voltage detection circuit. When the real-time differential pressure is less than or equal to a preset threshold, the relay is controlled to engage.

2. The input switching device compatible with AC / DC power supply as described in claim 1, characterized in that, The switching device further includes: A filter circuit, wherein the input terminal of the filter circuit is connected to the external input power supply, and the output terminal of the filter circuit is connected to the input terminal of the rectifier.

3. The input switching device compatible with AC / DC power supply as described in claim 1, characterized in that, The input voltage detection circuit includes: First resistor, diode, and second resistor; The first end of the first resistor is connected to the live wire of the external input power supply, the second end of the first resistor is connected to the anode of the diode, the cathode of the diode is connected to the first end of the second resistor, the first end of the second resistor is also connected to the controller, and the second end of the second resistor is grounded.

4. The input switching device compatible with AC / DC power supply as described in claim 1, characterized in that, The output voltage detection circuit includes: The third and fourth resistors; The first end of the third resistor is connected to the positive terminal of the energy storage capacitor, the second end of the third resistor is grounded through the fourth resistor, and the second end of the third resistor is also connected to the controller.

5. The input switching device compatible with AC / DC power supply as described in claim 2, characterized in that, The switching device further includes: The fifth resistor has its first end connected to the first terminal of the relay switch, and its second end connected to the first end of the sampling resistor.

6. The input switching device compatible with AC / DC power supply as described in claim 2, characterized in that, The filtering circuit includes: First differential-mode inductor, second differential-mode inductor, and common-mode inductor; The first terminal of the first differential mode inductor is connected to the neutral terminal of the external input power supply, the second terminal of the first differential mode inductor is connected to the first input terminal of the common mode inductor, the first terminal of the second differential mode inductor is connected to the live terminal of the external input power supply, the second terminal of the second differential mode inductor is connected to the second input terminal of the common mode inductor, and the output terminal of the common mode inductor is connected to the output terminal of the rectifier.

7. The input switching device compatible with AC / DC power supply as described in claim 6, characterized in that, The filtering circuit also includes: First line-to-line capacitance and bleed resistor; The first terminal of the first inter-line capacitor is connected to the first terminal of the first differential mode inductor, and the second terminal of the first inter-line capacitor is connected to the first terminal of the second differential mode inductor; the first terminal of the bleed resistor is connected to the first terminal of the first inter-line capacitor, and the second terminal of the bleed resistor is connected to the second terminal of the first inter-line capacitor.

8. The input switching device compatible with AC / DC power supply as described in claim 6, characterized in that, The filtering circuit also includes: Second line-to-line capacitor, first pair-to-ground capacitor, and second pair-to-ground capacitor; The first end of the second line-to-line capacitor is connected to the first output terminal of the common-mode inductor, the second end of the second line-to-line capacitor is connected to the second output terminal of the common-mode inductor, the first end of the first pair of ground capacitor is connected to the first output terminal of the common-mode inductor, the second end of the first pair of ground capacitor is grounded, the first end of the second pair of ground capacitor is connected to the second output terminal of the common-mode inductor, and the second end of the second pair of ground capacitor is grounded.

9. A power supply device, characterized in that, The power supply device includes the input switching device, switching equipment, AC power supply and DC power supply compatible with any one of claims 1-8.

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