CN217508348U - Power supply conversion control device - Google Patents

Abstract

The utility model provides a power supply changeover control device, a serial communication port, the device includes: the power supply conversion unit is used for accessing one power supply in a plurality of power supplies; the power state detection unit is used for detecting the voltage zero crossing point of the accessed power supply and sending a zero crossing signal; the control unit is used for sending a power supply switching signal based on the zero-crossing signal, and the switching point from the conducting level to the non-conducting level and/or the switching point from the non-conducting level to the conducting level of the power supply switching signal are/is the voltage zero-crossing points of the accessed power supply; and the switching execution unit comprises an electromagnet and an electronic switch used for controlling whether the electromagnet is electrified, and the electronic switch is switched on or off based on the conversion of the conducting level and the non-conducting level of the power supply switching signal. The device comprises a power state detection unit for detecting the voltage zero crossing point of the accessed power supply, so that the subsequent units can be switched on or off when the voltage zero crossing point exists, and the impact caused by large voltage or current is avoided.

Description

Power supply conversion control device

Technical Field

The present invention relates to switching of a plurality of power sources, and more particularly, to a power conversion control device.

Background

With the increasing demand of critical loads (such as servers and storage devices of a data center) on power supply continuity, the demand on power supply devices such as multiple power supplies (such as dual power supplies) and uninterruptible power supplies is increasing, and multiple power controllers play a key role in bridging, wherein multiple power controllers (such as dual power controllers, for example, Automatic Transfer Switching Equipment (ATSE)) are used for Switching loads to be connected with another power supply in time when one power supply supplying power to the loads fails, so as to continuously supply power to the loads.

The dual power controller is generally applied to critical application occasions such as hospitals, data centers and elevators, so that the switching reliability of the dual power controller, which is a product, is particularly important. Once the switching function is lost, the customer suffers a huge economic loss.

Therefore, a stable and reliable power supply controller is urgently needed.

SUMMERY OF THE UTILITY MODEL

To the above problem, the utility model provides a power supply changeover control device, a serial communication port, power supply changeover control device is including the voltage zero crossing point that is used for detecting the power that inserts and the power state detecting element who sends out the zero signal to the magnitude of voltage of the power that will insert switches on or shuts off dual supply switching circuit for zero, thereby makes the utility model provides a power supply changeover control device can not suffer the impact of big voltage or electric current, has increased the utility model provides a power supply changeover control device's reliability.

The embodiment of the utility model provides a power supply conversion control device, which is characterized in that the power supply conversion control device comprises a power supply conversion unit, a power supply state detection unit, a control unit and a switching execution unit; the power supply conversion unit is connected to the control unit and is used for accessing one of a plurality of power supplies under the control of the control unit; the power state detection unit is connected to the power conversion unit and used for detecting the voltage zero crossing point of the accessed power supply and sending a zero crossing signal to the control unit; the control unit is connected to the power state detection unit and the switching execution unit and used for sending a power switching signal to the switching execution unit based on the zero-crossing signal, wherein a transition point from a conduction level to a non-conduction level and/or a transition point from the non-conduction level to the conduction level of the power switching signal are zero-crossing points of the voltage of the accessed power; and the switching execution unit comprises an electromagnet and an electronic switch used for controlling whether the electromagnet is electrified or not, and the electronic switch is switched on or off based on the conversion of the conduction level and the non-conduction level of the power supply switching signal.

According to the embodiment of the utility model, its characterized in that, power state detection unit includes full-bridge rectifier circuit, current limiting circuit and zero cross detection circuit, wherein, full-bridge rectifier circuit for with the voltage direction conversion of a power is the unidirectional, current limiting circuit for the restriction flows through power state detection unit's electric current, zero cross detection circuit is used for detecting whether the voltage value of the unidirectional of the current-limiting of a power is zero to under the condition for zero, send zero cross signal.

According to the embodiment of the utility model provides a, its characterized in that, full-bridge rectifier circuit includes: the first diode, the second diode, the third diode and the fourth diode, wherein the anode of the first diode is connected with the cathode of the third diode and the anode of the first diode is connected with the first end of the one power supply, the anode of the second diode is connected with the cathode of the fourth diode and the anode of the second diode is connected with the second end of the one power supply.

According to the utility model discloses embodiment, its characterized in that, current-limiting circuit includes: the first end of the first resistor is connected with the cathodes of the first diode and the second diode, the first end of the second resistor is connected with the anodes of the third diode and the fourth diode, and the second end of the second resistor is grounded.

According to the utility model discloses embodiment, its characterized in that, zero cross detection circuit includes: a fifth diode, a third resistor, a fourth resistor, a sixth diode, a capacitor, a PNP triode, and a photoelectric coupler, wherein the photoelectric coupler includes a light emitting diode and an NPN triode, wherein the fifth diode is a voltage regulator diode, a cathode of the fifth diode is connected to the second end of the first resistor and an anode of the fifth diode is grounded, a first end of the third resistor is connected to the second end of the first resistor and a second end of the third resistor is grounded, an anode of the sixth diode is connected to a base of the PNP triode and the second end of the first resistor, a cathode of the sixth diode is connected to an emitter of the PNP triode and the first end of the capacitor, a second end of the capacitor is grounded, an anode of the light emitting diode is connected to a collector of the PNP diode and a cathode of the light emitting diode is grounded, a collector of the NPN triode is connected to the first end of the fourth resistor and the control unit, an emitting electrode of the NPN type triode is grounded, and a second end of the fourth resistor is connected to the preset voltage.

According to the utility model provides a, its characterized in that, a plurality of power are two power.

According to an embodiment of the present invention, the power switching unit comprises a first relay, a second relay, a third relay, a rectifier bridge and a fourth relay, wherein the first relay and the second relay are single-pole single-throw relays, the third relay is a double-pole double-throw relay, and the fourth relay is a single-pole double-throw relay, wherein a first end of the first relay is connected to a first power source of the two power sources, a second end of the first relay is connected to the control unit, a third end of the third relay is connected to a first end of the third relay, a first end of the second relay is connected to a second power source of the two power sources, a second end of the second relay is connected to the control unit, a third end of the third relay is connected to the control unit, a fourth end of the third relay is connected to a first end of the rectifier bridge, a second end of the rectifier bridge is connected to a first end of the fourth relay, the second end of the fourth relay is connected with the control unit, the third end of the fourth relay is connected with the first end of the first electromagnet, and the fourth end of the fourth relay is connected with the first end of the second electromagnet.

According to the utility model discloses, its characterized in that, electronic switch is Insulated Gate Bipolar Transistor (IGBT), the switching execution unit still includes optoelectronic coupler, wherein, optoelectronic coupler includes emitting diode and NPN type triode, emitting diode's positive pole with the control unit is connected and emitting diode's negative pole ground connection, and the projecting pole ground connection of NPN type triode and collecting electrode are connected with IGBT's grid, and IGBT's projecting pole ground connection and collecting electrode are connected with the second end of first electro-magnet and second electro-magnet.

According to the utility model discloses the embodiment, its characterized in that under the condition of the switching point of the conduction level of power switching signal to non-conduction level is the voltage zero crossing of the power of inserting, the control unit includes: a control signal generation unit and a calculation unit, wherein the control signal generation unit is used for receiving the zero-crossing signal, a power switching signal for making the conducting level continue for a preset time is sent out at a first moment so as to control the switching execution unit to conduct the electronic switch and to turn off the electronic switch at the moment when the preset time is over, wherein the first time corresponds to a transition point of a non-conductive level to a conductive level, the time at which the predetermined time ends corresponds to a transition point of a conductive level to a non-conductive level, the calculation unit, for calculating a time difference between the first time and a time at which the zero-crossing signal is received and/or a phase angle of the voltage of the one power supply corresponding to the time difference, to determine the first time from the time difference and/or the phase angle.

According to an embodiment of the present invention, it is characterized in that the calculation unit calculates the time difference and/or the phase angle according to the operating frequency of the one power source and the predetermined time.

Because the utility model provides an above-mentioned power conversion controlling means contains the power state detecting element who detects the voltage zero crossing point that inserts the power, make subsequent switching execution unit switch on or turn-off when the voltage zero crossing point, thereby avoid the impact to components and parts in the power conversion controlling means because of above-mentioned big voltage or electric current bring, the production of higher harmonic has also been avoided simultaneously, and then the harm that the harmonic caused power and other components and parts has been avoided, the life-span of power conversion controlling means has been prolonged, the reliability and the stability of power conversion controlling means product have been improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some exemplary embodiments of the invention, and that other drawings can be derived from these drawings by a person skilled in the art without inventive effort.

Fig. 1 shows a schematic view of a scenario in which a dual power supply supplies power to a load according to an embodiment of the present invention;

fig. 2 shows a schematic diagram of a power conversion control apparatus 200 according to an embodiment of the present invention;

fig. 3 shows an example structure of a voltage device control device 200 according to an embodiment of the present invention;

fig. 4 shows an example circuit diagram of the power state detection unit 220 according to an embodiment of the present invention;

fig. 5 shows a signal timing diagram of a power conversion control apparatus with zero-crossing detection according to an embodiment of the present invention;

fig. 6 is a signal timing comparison diagram showing the operation of the power conversion control device with zero-cross detection and the operation of the power conversion control device without zero-cross detection according to the embodiment of the present invention.

Detailed Description

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention will be combined below to clearly and completely describe the technical solution of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the invention belongs. The use of "first," "second," and similar terms in the description herein do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a," "an," or "the" and similar referents do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

At present, for example, a dual-power two-way power supply system may be an inductive power supply such as a commercial power plus a commercial power or a commercial power plus a generator. Under input power supplies with different frequencies, when the power supply voltage just reaches the maximum value, the dual-power-supply controller is switched (for example, switched on or switched off), so that the dual-power-supply switching circuit is subjected to a large impact current. If the dual power switching loop is more heavily loaded, the shock will be more severe. In addition, if the input power supply is an inductive power supply (such as a generator), when the dual power supply switching loop is turned off, the service life of internal components (such as a relay, an electromagnet and the like) of the dual power supply controller can be influenced or the components can be directly damaged due to impulse voltage caused by reverse electromotive force, so that the service life of the whole product of the dual power supply controller is influenced.

Fig. 1 is an example scene schematic diagram of a dual power supply supplying power to a load according to an embodiment of the present invention. As shown in fig. 1, S1 and S2 are two-way power supplies, which may be three-phase four-wire power supplies (where A, B and C each represent live wire and N represents neutral wire), and the area surrounded by the dashed line is ATSE. In fig. 1, the S1 power supply is supplying power to the load.

In the ATSE, the controller 110 (such as a control Unit (MCU) (MCU/SELV) under a Safety Extra Low Voltage (SELV) as shown in fig. 1) may monitor the states of the two power sources S1 and S2, such as whether the power source is interrupted due to a fault or whether the quality of the power source is poor (such as the Voltage of the power source is unstable), so as to control the switching of the power source connected to the load. The controller 110 may send signals to the relays K1-K4 to control the switching of the relays K1-K4. Without switching the power supply, both K1 and K2 are in the off state, and the switches in K3 and K4 are in the default connection state, as shown in fig. 1, and at this time, the switches in K3 and K4 are in the default connection state with the right line, that is, switch 1 in K3 is in the on state, and switch 1 in K4 is in the on state with the electromagnet 130. The rectifier bridge 160 is used to rectify the alternating current into direct current. The rectifier bridge 160 is typically located in a rectifier and filter unit (not shown) that primarily protects the subsequent components including surge protection varistors (MOVs), rectifier bridge, and filter storage capacitors. After the electromagnet (Solenoid)120 or 130 is powered on, the switch 170 can be controlled by the coil to switch the load communicated with the S1 power supply to be connected with the S2 power supply or switch the load communicated with the S2 power supply to be connected with the S1 power supply. The switch 170 is also referred to as a primary loop unit, and the time for the primary contacts of the primary loop unit to switch from the primary power source (e.g., the S1 power source) to the backup power source (e.g., the S2 power source) may be, for example, 30ms plus an intermediate delay time. The load may be any load, including a capacitive load or an inductive load. The optocoupler 150 is configured to enable the optocoupler 150 to turn on the transistor 140 after receiving a signal from the controller 110. In the example shown in fig. 1, R denotes a reinforcing insulation, and B denotes a basic insulation.

The general power conversion process for ATSE is as follows.

When the S1 power supply is interrupted due to a failure or the controller 110 detects that the voltage of the S1 power supply is unstable in the case where the S1 power supply is supplying power to the load as shown in fig. 1, the controller 110 sends operation signals to K2 to K4 to make K2 in a conductive state, switch 1 in K3 in a conductive state, and switch 1 in K4 in a conductive state with the electromagnet 130. Then, the controller 110 sends a signal to the photo coupler 150 for a predetermined time, so that the photo coupler 150 turns on the transistor 140, thereby turning on a circuit including the S2 power source, K2 to K4, the solenoid 130, the transistor 140, and the ground. In this case, the electromagnet 130 switches the power supply from the S1 path to the S2 path by, for example, the coil control switch 170, and thus the switching of the load from the S1 path to the S2 path is completed, so that the S2 path continues to supply power to the load. After the power switching is completed, at the end of the signal lasting the predetermined time, the transistor 140 becomes the off state, K3 and K4 are restored to the previous default connection state, and K2 is in the off state.

As can be seen from the above ATSE power conversion process, once any one of the power supplies is unavailable, the ATSE will perform power switching, and the phase angle of the S2 power supplies is random when the transistor 140 is turned on or off. Once the phase angle of the S2 power supply is exactly 90 degrees or 270 degrees when the transistor 140 is turned on or off, a large inrush current and voltage are generated in the above-mentioned circuit including the S2 power supply, K2 to K4, the electromagnet 130, the transistor 140, and the ground, which may cause damage to components such as the electromagnet 130 and the relays K2 to K4. If the power supply S2 is inductive, when the phase angle of the input current is just at the 90 degree peak or 270 degree valley position at turn-off, a large back emf, i.e., a surge voltage, is generated with a magnitude L di/dt, where L represents the self-inductance of the winding and di/dt represents the rate of change of current with respect to time. The larger L, the larger the surge voltage.

In order to prevent the breakdown of the components due to voltage or current, the voltage and current levels of the components may be increased, which not only increases the product cost, but also reduces the reliability of the product.

In order to solve the problem, the utility model provides a power supply changeover control device. The utility model provides a power conversion controlling means can detect the voltage zero crossing point of the power of inserting and switch on and/or turn-off the return circuit when the voltage zero crossing point, thereby make the utility model provides a power conversion controlling means can not suffer the impact of big voltage or electric current, has increased the utility model provides a power conversion controlling means's reliability.

The power conversion control device provided by the present invention will now be described in detail with reference to the accompanying drawings.

Fig. 2 shows a schematic diagram of a power conversion control apparatus 200 according to an embodiment of the present invention.

Referring to fig. 2, the power conversion control apparatus 200 may include a power conversion unit 210, a power state detection unit 220, a control unit 230, and a switching execution unit 240.

According to the embodiment of the present invention, the power conversion unit 210 is connected to the control unit 230, and is used for accessing one power source of the plurality of power sources under the control of the control unit 230.

As an example, in the case of two power sources (e.g., S1 power source and S2 power source), when the control unit 230 detects that S1 power source supplying power to the load is unavailable, the control unit 230 may send a signal to the power conversion unit 210 for the relay in the power conversion unit 210, for example, connected to the S2 power source, to be in a conducting state, so that the power conversion unit 210 has access to the S2 power source.

As an example, as shown in fig. 3, the power conversion unit 210 may include a first relay K1, a second relay K2, a third relay K3, a rectifier bridge 160, and a fourth relay K4, wherein the first relay K1 and the second relay K2 are single-pole single-throw relays, the third relay K3 is a double-pole double-throw relay, and the fourth relay K4 is a single-pole double-throw relay.

The first terminal 1 of the first relay K1 is connected to the first power source S1 of the two power sources, the second terminal 2 is connected to the control unit 230, and the third terminal 3 is connected to the first terminal 1 of the third relay K3, wherein the control unit 230 may be the MCU described above.

The first terminal 1 of the second relay K2 is connected to the second power source S2 of the two power sources, the second terminal 2 is connected to the control unit 230, and the third terminal 3 is connected to the second terminal 2 of the third relay K3.

The third terminal 3 of the third relay K3 is connected to the control unit 230 and the fourth terminal 4 is connected to the first terminal 1 of the rectifier bridge 160.

The second terminal 2 of the rectifier bridge 160 is connected to the first terminal 1 of the fourth relay K4.

The second terminal 2 of the fourth relay K4 is connected to the control unit 230, the third terminal 3 is connected to the first terminal 1 of the first electromagnet 120, and the fourth terminal 4 is connected to the first terminal 1 of the second electromagnet 130.

With continued reference to fig. 2, the power state detection unit 220 may be connected to the power conversion unit 210 for detecting a zero-crossing of a voltage of the accessed power and sending a zero-crossing signal to the control unit 230.

As an example, referring to fig. 3, one end of the power state detection unit 220 is connected to the fourth end 4 of the third relay K3 or the first end 1 of the rectifier bridge 160. The other end of the power state detection unit 220 is connected to the control unit 230. Note that although the position of the power state detection unit 220 shown in fig. 3 is within the area surrounded by the power conversion unit 210, the positional relationship of the power state detection unit 220 and the power conversion unit 210 is not necessarily required as long as the above-described connection and the corresponding functions can be achieved.

As an example, referring to fig. 4, the power state detection unit 220 may include a full bridge rectification circuit 410, a current limiting circuit 420, and a zero-crossing detection circuit 430, wherein the full bridge rectification circuit 410 is configured to convert a voltage direction of the one power source (e.g., the S2 power source to be connected) into a single direction, the current limiting circuit 420 is configured to limit a current flowing through the power state detection unit 220, and the zero-crossing detection circuit 430 is configured to detect whether a current-limited single-direction voltage value of the one power source is zero and, in the case of zero, to issue a zero-crossing signal.

The full-bridge rectification circuit 410 may include: a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, wherein an anode of the first diode D1 is connected to a cathode of the third diode D3 and an anode of the first diode D1 is connected to the first terminal 1 of the one power source (e.g., S2 power source), an anode of the second diode D2 is connected to a cathode of the fourth diode D4 and an anode of the second diode D2 is connected to the second terminal 2 of the one power source (e.g., S2 power source).

The current limiting circuit 420 may include: a first resistor R1 and a second resistor R2, wherein a first terminal 1 of the first resistor R1 is connected to cathodes of the first diode D1 and the second diode D2, a first terminal 1 of the second resistor R2 is connected to anodes of the third diode D3 and the fourth diode D4, and a second terminal 2 of the second resistor R2 is grounded.

The zero-crossing detection circuit 430 may include: the light emitting diode device comprises a fifth diode D5, a third resistor R3, a fourth resistor R4, a sixth diode D6, a capacitor C1, a PNP transistor Q1, and a photo-coupler U1, wherein the photo-coupler U1 comprises a light emitting diode D7 and an NPN transistor Q2, and wherein the fifth diode D5 may be a zener diode.

The cathode of the fifth diode D5 is connected to the second terminal 2 of the first resistor R1 and the anode of the fifth diode D5 is connected to ground. The first terminal 1 of the third resistor R3 is connected to the second terminal 2 of the first resistor R1 and the second terminal 2 of the third resistor R3 is connected to ground. The anode of the sixth diode D6 is connected to the base of the PNP transistor Q1 and the second terminal 2 of the first resistor R1. The cathode of the sixth diode D6 is connected to the emitter of the PNP transistor Q1 and the first terminal 1 of the capacitor C1. The second terminal 2 of the capacitor C1 is connected to ground. The anode of the light emitting diode D7 is connected to the collector of the PNP type diode Q1 and the cathode of the light emitting diode D7 is grounded. The collector of the NPN transistor Q2 is connected to the first terminal 1 of the fourth resistor R4 and the control unit 230. The emitter of the NPN transistor Q2 is grounded. The second terminal 2 of the fourth resistor R4 is connected to a preset voltage, wherein the preset voltage may be + 3.3V.

The power state detection unit 220 shown in fig. 4 can accurately detect the zero-crossing point of the voltage. Specifically, for example, after the ac power of the S2 power source passes through the full-bridge rectifier 410 and flows through the current limiting circuit 420 including two resistors R1 and R2, the current limiting circuit 420 may limit the current of the whole loop of the current source state detection unit 220 to protect the components on the side of the photocoupler U1 from breakdown. The input voltage of the zero-crossing detection circuit 430 is regulated to 10V by the zener diode D5, the third resistor R3 forms a first-order inertia element with the capacitor C1 when the sixth diode D6 is turned on, the cut-off frequency is 1/R3C1, wherein R3 is to reduce the bandwidth of the zero-crossing signal, and the magnitude of the R3 resistor determines the charging time of the capacitor C1. During the positive half cycle of the power supply of path S2, the capacitor C1 is charged through the sixth diode D6, and the sixth diode D6 ensures that the PNP transistor Q1 is turned off. When the input voltage is less than or equal to the turn-on voltage of the sixth diode D6 plus the voltage of the capacitor C1, the sixth diode D6 is turned off, and when the input voltage decreases again, the voltage of the capacitor C1 is higher than the input voltage by 0.7V (the voltage drop value of the PNP transistor, which may be different for different PNP transistors), the PNP transistor Q1 is turned on, and at this time, the capacitance of the capacitor C1 determines the time when the zero value of the zero-cross detection circuit 430 occurs. The PNP transistor Q1 is turned on to turn on the led D7 in the photocoupler U1, so that the output terminal of the photocoupler U1 is changed from a high level signal to a low level signal (e.g., 0V). This change from a high signal to a low signal indicates that a zero crossing of the voltage of the power supply, e.g., path S2, is detected and the control unit (e.g., MCU) receives the zero crossing signal. When the input voltage is greater than the on voltage of the sixth diode D6 plus the voltage of the capacitor C1 and higher than 0.7V after the voltage zero crossing point, the sixth diode D6 is turned on to recharge the capacitor C1, and at this time, the PNP transistor Q1 turns off the input terminal of the photocoupler U1 (i.e., the light emitting diode D7 is not turned on), and the low level signal (e.g., 0V) at the output terminal of the U1 becomes a high level signal, which means that the voltage zero crossing point has ended. In addition, the time interval between voltage zero crossings is different due to, for example, the difference in frequency of the S2 power supply. By the aforesaid to the utility model provides a detailed description of power state detecting element 220 can know, the utility model provides a power state detecting element 220 can detect out the voltage zero crossing point that inserts the power (like S2 way power) accurately to send zero crossing signal to the control unit 230, and then make subsequent power conversion operation more accurate.

With continued reference to fig. 2, the control unit 230 is connected to the power state detection unit 220 and the switch execution unit 240, and is configured to send a power switching signal to the switch execution unit 240 based on the zero-crossing signal, where a transition point of a conduction level to a non-conduction level and/or a transition point of a non-conduction level to a conduction level of the power switching signal is a voltage zero-crossing point of the accessed power.

For example, in the case that the transition point of the non-conduction level (e.g., low level) to the conduction level (e.g., high level) of the power switching signal is the zero-crossing point of the voltage of the accessed power, the control unit 230 may immediately issue the power switching signal that makes the conduction level continue for a predetermined time after receiving the zero-crossing signal from the power state detection unit 220 to control the switching execution unit 240 to immediately turn on the electronic switch and turn off the electronic switch at the time point when the predetermined time ends. The instant at which the power switching signal is immediately issued corresponds to a transition point from the non-conductive level to the conductive level, and the instant at which the predetermined time ends corresponds to a transition point from the conductive level to the non-conductive level. In this case, the switching performing unit 240 turns on the electronic switch at the zero crossing point of the voltage. Further, by controlling the predetermined time to be equal to an integer multiple of a half period of the voltage, it is also possible to cause the electronic switch to turn off also at a voltage zero crossing.

For another example, in the case that the transition point from the conducting level to the non-conducting level of the power switching signal is a zero-crossing point of the voltage of the connected power, the control unit 230 may include: a control signal generating unit and a calculating unit, wherein the control signal generating unit is configured to, after receiving the zero-crossing signal, generate a power switching signal that enables an on-level to continue for a predetermined time at a first time to control the switching performing unit 240 to switch the electronic switch at the first time and to switch the electronic switch off at a time when the predetermined time ends. The first time corresponds to a transition point of the non-conductive level to the conductive level and the end of the predetermined time corresponds to a transition point of the conductive level to the non-conductive level. The calculation unit is used for calculating a time difference between the first moment and the moment when the zero-crossing signal is received and/or a phase angle of the voltage of the power supply corresponding to the time difference, so as to determine the first moment according to the time difference and/or the phase angle. The calculation unit calculates the time difference and/or the phase angle from the operating frequency of the one power source and the predetermined time. In this case, the switching execution unit 240 turns off the electronic switch at the zero crossing point of the voltage, and the time for turning on the electronic switch can be calculated according to the time interval requirement from turning on to turning off (i.e. the predetermined time).

For example, the predetermined time may be determined comprehensively according to characteristics of components in the power conversion control device, for example, according to whether the electromagnet in the power conversion control device can complete switching of the power supply within the predetermined time, whether the electronic switch is turned on or off at the start time or the end time of the predetermined time, and the like.

As an example, according to an actual test of the power conversion control apparatus product, the first timing at which the power switching signal for making the conduction level continue for a predetermined time is issued may be determined based on the time difference or the phase angle, or the first timing may be determined integrally based on the time difference and the phase angle.

As an example, the power switching signal may be a Pulse Width Modulation (PWM) signal.

The time difference t1 may be calculated by the following equation (1), and the phase angle a1 may be calculated by the following equation (2):

where T denotes the above predetermined time and the unit is milliseconds (ms), F denotes the operating frequency of the power supply and the unit is hertz (Hz), and INT denotes the rounding operation. As an example, T is 30 ms.

The obtained time difference t1 and the phase angle a1 are different depending on the operating frequency of the power supply, as shown in table 1 below.

TABLE 1

With continued reference to fig. 2, the switching performing unit 240 may include an electromagnet and an electronic switch for controlling whether the electromagnet is energized, the electronic switch being switched on or off based on a transition of a conduction level and a non-conduction level of the power switching signal.

As an example, referring to fig. 3, the switching performing unit 240 may include a first electromagnet 120 and a second electromagnet 130. The electronic switch may be an Insulated Gate Bipolar Transistor (IGBT), and the switching performing unit 240 may further include a photo coupler 150, wherein the photo coupler 150 may include a light emitting diode and an NPN transistor, an anode of the light emitting diode is connected to the control unit 230 and a cathode of the light emitting diode is grounded, an emitter 2 of the NPN transistor is grounded and a collector 1 is connected to the gate 2 of the IGBT 140, an emitter 1 of the IGBT 140 is grounded and a collector 3 is connected to the second end 2 of the first electromagnet 120 and the second end 2 of the second electromagnet 130.

As an example, when the control unit 220 immediately sends out the power switching signal for making the turn-on level (for example, high level) continuously for a predetermined time (for example, 30ms) after receiving the zero-crossing signal, the photocoupler 150 turns on the light emitting diode in the photocoupler 150 when receiving the power switching signal, and further grounds the emitter 2 of the IGBT 140, and the collector of the IGBT 140 is grounded, so that the IGBT 140 is turned on, and the electromagnet 130 starts to operate when being powered on. Under the above condition, the loop including the S2 power source, K2 to K4, the electromagnet 130, the IGBT 140 and the ground is conducted, the electromagnet 130 switches the connection with the S1 power source to the connection with the S2 power source through, for example, the coil control switch 170, and then the switching of the connection of the load with the S1 power source to the connection with the S2 power source is completed, so that the S2 power source continuously supplies power to the load. As can be seen from the above description, when the voltage of the power supply connected to the S2 passes through the zero point, the IGBT 140 is turned on, so that the impact on the components in the power conversion control device caused by the large voltage or current is avoided, the damage to the components is avoided, and the reliability and stability of the power conversion control device product are improved.

As another example, when the MCU generates a power switching signal for making an on level (e.g., high level) continue for a predetermined time (e.g., 30ms) at the first time, the photocoupler 150 receives the power switching signal to turn on the light emitting diode in the photocoupler 150, and further to ground the emitter 2 of the IGBT 140, and the collector of the IGBT 140 is grounded, so that the IGBT 140 is turned on, and the IGBT 140 is turned off at the time when the predetermined time is over, that is, at the voltage zero crossing point of the power. In the above case, at the end of the above predetermined time, the circuit including the S2 power source, K2 to K4, the electromagnet 130, the IGBT 140, and the ground is opened. From the above description, when the voltage of the power supply connected to the S2 path crosses zero, the IGBT 140 is turned off, so that the impact on the components in the power conversion control device caused by the large voltage or current is avoided, the damage to the components is avoided, and the reliability and stability of the power conversion control device product are improved.

As another example, by designing the predetermined time, the IGBT 140 may be turned on and off at a voltage zero crossing point (for example, as in table 1, when the operating frequency of the power supply is 50 Hz), so as to avoid the impact on the components in the power conversion control device caused by the large voltage or current, avoid the damage to the components, and improve the reliability and stability of the power conversion control device product.

The power conversion control device provided by the present invention has been described in detail above with reference to fig. 2 to 4. According to the above, because the utility model provides a power conversion control device contains the power state detecting element who detects the voltage zero crossing point that inserts the power, make subsequent switching execution unit can switch on or turn-off when the voltage zero crossing point, thereby avoid the impact to components and parts in the power conversion control device because of above-mentioned big voltage or electric current bring, the production of higher harmonic has also been avoided simultaneously, and then the harm that the harmonic caused power (for example S1 way power or S2 way power) and other components and parts has been avoided, the life-span of power conversion control device has been prolonged, the reliability and the stability of power conversion control device product have been improved. Furthermore, as can be seen from the above description in conjunction with table 1, the utility model provides a power conversion control device can realize crossing detection and switching on or off of electronic switch when crossing under the different operating frequency of power. In addition, due to the zero point detection and the on or off of the electronic switch at the zero point, the problems of fusion welding, ablation, temperature rise and the like of all relays in the power supply conversion control device are effectively reduced, the existence of a leakage inductance power supply is allowed, and the limitation of the power supply is solved. The utility model provides a zero crossing point that power conversion control device realized detects the precision and can reach zero crossing point moment 50us, has realized the accurate control zero crossing point.

Fig. 5 shows a signal timing diagram of a power conversion control apparatus with zero-cross detection according to an embodiment of the present invention. Fig. 6 is a signal timing comparison diagram showing the operation of the power conversion control device with zero-cross detection and the power conversion control device without zero-cross detection according to the embodiment of the present invention.

Referring to fig. 5 and 6, the direction control relay signal refers to a signal controlling one or more of K1 through K3 in fig. 3, and the source selection relay signal refers to a signal controlling K4 in fig. 3. VBUS refers to the voltage of the second end 2 of the rectifier bridge 160 with respect to ground in fig. 3, the PWM signal (no zero crossing) represents the PWM signal emitted without zero crossing detection, the PWM signal (zero crossing) represents the PWM signal emitted with zero crossing detection, VBUS (no zero crossing) represents the voltage without zero crossing detection, and VBUS (zero crossing) represents the voltage with zero crossing detection. Table 2 below shows the description of the respective time points. In the timing sequence of fig. 5 and 6, the first time the PWM signal is sent is, for example, the switch 170 shown in fig. 3 is switched from communication with the first power source S1 to an intermediate state (e.g., OFF state), and then the second time the PWM signal is sent is such that the switch 170 is switched from the intermediate state to communication with the second power source S2. It should be noted that, according to actual needs, the process of sending two PWM signals may not be performed, but the load connected to the first power supply may be switched to be connected to the second power supply by sending the PWM signal only once.

TABLE 2

Time	Description of the invention	Minimum value	Typical value	Maximum value	Unit of
						T1	Before relay drive	0		65	ms
T2-T1	Direction control relay action time		15		ms
						T3-T2	Source selection relay turn-on and drive voltage setup time			50	ms
T4-T3	First drive PWM		30		ms
						T5-T4	Intermediate bit delay	140			ms
T6-T5	Second drive PWM		30		ms
						T7-T6	Switching loop power down time		10		ms
T8-T7	Source select relay turn-off		15		ms
						T8	Reset time of direction control relay		15		ms

It can also be seen from fig. 5 and fig. 6 and the above table 2 that there is no zero-crossing detection function in the conventional power conversion control device, so that a large power impact (e.g. a steep peak occurs at T4 time VBUS (no zero-crossing)) occurs in the circuit when the IGBT is turned off, thereby causing damage to components in the power conversion control device.

The block diagrams of circuits, units, devices, apparatuses, devices and systems referred to in the present application are provided as illustrative examples only and are not intended to require or imply that they must be connected, arranged or configured in the manner shown in the block diagrams. As will be appreciated by one skilled in the art, these circuits, units, devices, apparatuses, devices, systems may be connected, arranged, configured in any way as long as the desired purpose is achieved. The circuits, units, devices and apparatuses involved in the present invention can be realized in any suitable manner, for example, by using an application specific integrated circuit (asic), a Field Programmable Gate Array (FPGA), etc., and also by using a general purpose processor in combination with a program.

It should be understood by those skilled in the art that the foregoing specific embodiments are merely exemplary and not limiting, and that various modifications, combinations, sub-combinations and substitutions may be made in the embodiments of the invention depending upon design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims (9)

1. A power conversion control device is characterized in that,

the power supply conversion control device comprises a power supply conversion unit, a power supply state detection unit, a control unit and a switching execution unit;

the power supply conversion unit is connected to the control unit and is used for accessing one of a plurality of power supplies under the control of the control unit;

the power state detection unit is connected to the power conversion unit and used for detecting the voltage zero crossing point of the accessed power supply and sending a zero crossing signal to the control unit;

the control unit is connected to the power state detection unit and the switching execution unit and used for sending a power switching signal to the switching execution unit based on the zero-crossing signal, wherein a transition point from a conduction level to a non-conduction level and/or a transition point from the non-conduction level to the conduction level of the power switching signal are zero-crossing points of the voltage of the accessed power; and

the switching execution unit comprises an electromagnet and an electronic switch used for controlling whether the electromagnet is electrified, and the electronic switch is switched on or off based on the conversion of the conducting level and the non-conducting level of the power supply switching signal.

2. The power supply changeover control device according to claim 1, wherein the power supply state detection unit comprises a full bridge rectifier circuit, a current limiting circuit, and a zero-cross detection circuit, wherein,

the full-bridge rectifying circuit for converting a voltage direction of the one power source into a single direction,

the current limiting circuit is used for limiting the current flowing through the power state detection unit,

the zero-crossing detection circuit is used for detecting whether the voltage value of the current-limited single direction of the power supply is zero or not and sending out a zero-crossing signal under the condition of zero.

3. The power supply changeover control device according to claim 2,

the full-bridge rectifier circuit includes: a first diode, a second diode, a third diode, and a fourth diode, wherein,

an anode of the first diode is connected to a cathode of the third diode and an anode of the first diode is connected to a first terminal of the one power source,

an anode of the second diode is connected to a cathode of the fourth diode and an anode of the second diode is connected to the second terminal of the one power source.

4. The power supply changeover control device according to claim 3,

the current limiting circuit includes: a first resistance and a second resistance, wherein,

a first terminal of the first resistor is connected to cathodes of the first diode and the second diode,

the first end of the second resistor is connected with the anodes of the third diode and the fourth diode and the second end of the second resistor is grounded.

5. The power supply changeover control device according to claim 4,

the zero-cross detection circuit includes: a fifth diode, a third resistor, a fourth resistor, a sixth diode, a capacitor, a PNP triode and a photoelectric coupler, wherein the photoelectric coupler comprises a light emitting diode and an NPN triode, the fifth diode is a voltage stabilizing diode,

the cathode of the fifth diode is connected to the second terminal of the first resistor and the anode of the fifth diode is connected to ground,

the first end of the third resistor is connected with the second end of the first resistor and the second end of the third resistor is grounded,

the anode of the sixth diode is connected with the base of the PNP type triode and the second end of the first resistor,

the cathode of the sixth diode is connected with the emitter of the PNP type triode and the first end of the capacitor,

the second terminal of the capacitor is connected to ground,

the anode of the light emitting diode is connected with the collector of the PNP type diode and the cathode of the light emitting diode is grounded,

the collector of the NPN type triode is connected with the first end of the fourth resistor and the control unit,

the emitter of the NPN type triode is grounded,

the second end of the fourth resistor is connected to a preset voltage.

6. The power conversion control device of claim 1, wherein the plurality of power sources is two power sources.

7. The power supply changeover control device according to claim 6,

the power supply conversion unit comprises a first relay, a second relay, a third relay, a rectifier bridge and a fourth relay, wherein the first relay and the second relay are single-pole single-throw relays, the third relay is a double-pole double-throw relay, the fourth relay is a single-pole double-throw relay,

the first end of the first relay is connected with the first power supply of the two power supplies, the second end is connected with the control unit, the third end is connected with the first end of the third relay,

the first end of the second relay is connected with the second power supply of the two power supplies, the second end is connected with the control unit, the third end is connected with the second end of the third relay,

the third end of the third relay is connected with the control unit and the fourth end is connected with the first end of the rectifier bridge,

the second end of the rectifier bridge is connected with the first end of the fourth relay,

the second end of the fourth relay is connected with the control unit, the third end of the fourth relay is connected with the first end of the first electromagnet, and the fourth end of the fourth relay is connected with the first end of the second electromagnet.

8. The power supply changeover control device according to claim 7, wherein the electronic switch is an Insulated Gate Bipolar Transistor (IGBT), and the switching execution unit further comprises a photocoupler, wherein,

the photoelectric coupler comprises a light emitting diode and an NPN type triode,

the anode of the light emitting diode is connected with the control unit and the cathode of the light emitting diode is grounded,

the emitter of the NPN transistor is grounded and the collector is connected to the gate of an Insulated Gate Bipolar Transistor (IGBT),

an emitter of an Insulated Gate Bipolar Transistor (IGBT) is grounded and a collector is connected to second terminals of the first and second electromagnets.

9. The power supply changeover control device according to claim 1, wherein in the case where the changeover point of the conduction level to the non-conduction level of the power supply changeover signal is a zero-crossing point of the voltage of the accessed power supply, the control unit comprises: a control signal generating unit and a calculating unit, wherein,

the control signal generating unit is configured to, after receiving the zero-crossing signal, generate a power switching signal for maintaining a conduction level for a predetermined time at a first time, to control the switching performing unit to turn on the electronic switch and turn off the electronic switch at a time when the predetermined time is over, wherein the first time corresponds to a transition point of a non-conduction level to the conduction level, and the time when the predetermined time is over corresponds to a transition point of the conduction level to the non-conduction level,

the calculation unit is used for calculating a time difference between the first moment and the moment when the zero-crossing signal is received and/or a phase angle of the voltage of the power supply corresponding to the time difference, so as to determine the first moment according to the time difference and/or the phase angle.

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