Power supply circuit, power supply method and power supply system of refrigerator car

Abstract

The invention discloses a power supply circuit, a power supply method and a power supply system of a refrigerator car, and relates to the field of power supplies. If alternating current output by an alternating current power supply is received, direct current obtained by rectifying the alternating current through a rectifying circuit is used for supplying power to target equipment; and when no alternating current output by the alternating current power supply exists, the original power supply of the target equipment is used for supplying power. Meanwhile, the alternating current power supply is input into the rectifying circuit after passing through the reactor, so that harmonic interference in a power grid can be effectively avoided, stable operation of target equipment is facilitated, and the utilization rate of electric energy is improved; the original power supply serves as the main power supply, the alternating current output by the alternating current power supply serves as the standby power supply, automatic switching of the main power mode and the standby power mode is achieved, and the new energy refrigerator car can directly use the mains supply to supply power to the refrigerating unit under the condition that the mains supply is connected. The situation that the original power supply of the new energy refrigerator car needs to supply power to the refrigerating unit while being charged is avoided, and the charging rate of the original power supply in the new energy refrigerator car is increased.

Description

Technical Field

[0001] The present invention relates to the field of power supplies, and in particular to a power supply circuit, a power supply method and a power supply system for a refrigerated truck. Background Art

[0002] With the development of new energy, refrigerated trucks based on new energy have also developed rapidly. Refrigerated trucks can be used for the transportation of frozen foods, vegetables, vaccines and medicines, and are widely used. New energy refrigerated trucks carry batteries to power the entire vehicle. The operation of the entire vehicle and the refrigeration of the air conditioner (or refrigeration unit, referred to as the refrigeration machine) in the refrigerated truck depend on the power of the battery it carries. Therefore, if the transportation time of the goods is relatively long, the battery power may not be able to support the new energy refrigerated truck to reach the destination, especially for some goods with high refrigeration requirements. The refrigeration machine needs to be turned on throughout the transportation process for refrigeration, which will consume a lot of battery power. Therefore, the new energy refrigerated truck will charge the battery during transportation to ensure the normal operation of the vehicle and the air conditioner.

[0003] In the process of implementing the present invention, the inventors found that there are at least the following problems in the prior art:

[0004] In order to ensure the refrigeration requirements of the goods, new energy refrigerated trucks often charge the battery while turning on the refrigeration unit for cooling, but this will affect the charging rate and significantly increase the time to fully charge. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a power supply circuit, a power supply method and a power supply system for a refrigerated vehicle, which can improve the charging rate.

[0006] In order to effectively solve the above technical problems, the present invention provides a power supply circuit, comprising:

[0007] A reactor, a first end of which is used to be connected to an AC power source;

[0008] A rectifier circuit, the AC end of which is connected to the second end of the reactor, for rectifying the AC power output by the AC power supply into DC power;

[0009] A controllable switch, wherein a first input end is connected to an original power source of a target device, a second input end is connected to an output end of the rectifier circuit, and an output end is connected to the target device;

[0010] A control module, the output end of which is connected to the control end of the controllable switch, is used to control the first input end and the output end of the controllable switch to be connected when there is no AC input power supply circuit, so as to use the original power supply to power the target device; when there is an AC input power supply circuit, control the second input end and the output end of the controllable switch to be connected, so as to use the AC power supply to power the target device.

[0011] Optionally, also include:

[0012] The energy storage capacitor is arranged between the DC bus positive terminal and the DC bus negative terminal of the DC end of the rectifier circuit and is used to store the DC power output by the rectifier circuit.

[0013] Optionally, also include:

[0014] A current limiting resistor, a first end of which is connected to the positive end of the DC bus of the rectifier circuit, and a second end of which is connected to the first end of the energy storage capacitor;

[0015] The pre-charging control switch is connected in parallel at both ends of the current limiting resistor, and the control end is connected to the output end of the control module, and is used for being turned on when the duration of the rectifier circuit outputting direct current reaches a preset duration.

[0016] Optionally, also include:

[0017] A filter, connected in series between the AC power supply and the first end of the reactor;

[0018] and / or,

[0019] A lightning protection board, the input end of which is respectively connected to the output end of the filter and the first end of the reactor.

[0020] Optionally, the reactor includes a first sub-reactor connected to a first phase of the AC power supply, a second sub-reactor connected to a second phase of the AC power supply, and a third sub-reactor connected to a third phase of the AC power supply;

[0021] The rectifier circuit comprises:

[0022] A first switch device, a first end of which serves as a first output end of the rectifier circuit;

[0023] a second switching device, a first end of which is respectively connected to the second end of the first sub-reactor and the second end of the first switching device, and a second end of which serves as a second output end of the rectifier circuit;

[0024] a third switching device, a first end of which is connected to the first end of the first switching device;

[0025] a fourth switching device, a first end of which is respectively connected to the second end of the second sub-reactor and the second end of the third switching device, and a second end of which is connected to the second end of the second switching device;

[0026] a fifth switching device, a first end of which is connected to the first end of the first switching device;

[0027] A sixth switching device has a first end connected to the second end of the third sub-reactor and the second end of the fifth switching device respectively, and a second end connected to the second end of the second switching device.

[0028] Optionally, the controllable switch includes:

[0029] A first controllable sub-switch, connected in series between the output end of the original power supply of the target device and the target device, and configured to be turned on under the control of the control module when there is no AC input power supply circuit;

[0030] A second controllable sub-switch is connected in series between the output end of the rectifier circuit and the target device, and is used for being turned on under the control of the control module when there is an AC input power supply circuit.

[0031] Optionally, the control module includes:

[0032] A voltage detection circuit, the input ends of which are respectively connected to the three-phase outputs of the AC power supply, and is used to detect whether the AC power supply outputs AC power to the power supply circuit;

[0033] A processor, the input end of which is connected to the output end of the voltage detection circuit, and the output end of which is connected to the input end of the backup power control board, for outputting a power switching signal to the backup power control board when there is an AC input power supply circuit;

[0034] The backup power control board, whose output end is connected to the control end of the second controllable sub-switch and whose signal end is connected to the signal end of the main control board, is used to forward the power switching signal to the main control board when receiving the power switching signal, and control the second controllable sub-switch to be turned on when the target device allows backup power access;

[0035] The main control board has an output end connected to the control end of the first controllable sub-switch, and is used to control the first controllable sub-switch to turn off when the power switching signal is received and the target device allows the main power to be disconnected.

[0036] Optionally, the output end of the main control board is also connected to the electric control system of the target device;

[0037] The main control board is further used for controlling the target device to stop working when receiving the power switching signal, and determining that the target device allows the main power to be disconnected after the target device stops working for a first preset time.

[0038] Optionally, the main control board is further used to send a shutdown signal to the backup power control board when controlling the first controllable sub-switch to be turned off;

[0039] The backup power control board is further used to determine that the target device allows backup power access after receiving the shutdown signal for a second preset time period.

[0040] In order to effectively solve the above technical problems, the present invention also provides a power supply system for a refrigerated truck, including a refrigeration unit, an electronic control system and a power supply circuit as described above, wherein the output end of the power supply circuit is connected to the refrigeration unit through the electronic control system.

[0041] In order to effectively solve the above technical problems, the present invention further provides a power supply method, which is applied to the power supply circuit as described above, and the power supply method comprises:

[0042] When there is no AC input power supply circuit, controlling the first input terminal and the output terminal of the controllable switch of the power supply circuit to be connected, so as to use the original power supply to power the target device;

[0043] When there is an AC input power supply circuit, the second input terminal and the output terminal of the controllable switch are controlled to be connected, so as to use the AC power supply to power the target device.

[0044] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects:

[0045] The present invention provides a power supply circuit, including a reactor, a rectifier circuit, a controllable switch and a control module. When the power supply circuit receives the alternating current output by the alternating current power supply, the rectifier circuit is first used to rectify the alternating current, and then the direct current obtained by the rectification is used to power the target device; when there is no alternating current output by the alternating current power supply, the original power supply of the target device itself is used for power supply. At the same time, since the alternating current power supply is first input into the rectifier circuit through the reactor, the harmonic interference in the power grid can be effectively avoided, which is conducive to the stable operation of the target device and improves the utilization rate of electric energy; the original power supply is used as the main power supply, and the alternating current output by the alternating current power supply is used as the backup power supply, which realizes the automatic switching of the main and backup power modes of the power supply of the target device, so that the new energy refrigeration vehicle can directly use the main power supply as the backup power supply to power the refrigeration unit when connected to the main power supply, effectively reducing or even avoiding the situation that the original power supply of the new energy refrigeration vehicle needs to power the refrigeration unit while being charged, and improving the charging rate of the original power supply in the new energy refrigeration vehicle.

[0046] The present invention also provides a power supply system for a refrigerated truck, which has the same beneficial effects as the above power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the prior art and the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 A schematic diagram of the structure of a power supply circuit provided by the present invention;

[0049] Figure 2 A schematic diagram of the structure of a backup power circuit provided by the present invention;

[0050] Figure 3 A schematic diagram of the structure of another power supply circuit provided by the present invention;

[0051] Figure 4 A schematic diagram of a specific circuit structure of a power supply circuit provided by the present invention;

[0052] Figure 5 A schematic diagram of a control flow of a power supply circuit provided by the present invention. DETAILED DESCRIPTION

[0053] The core of the present invention is to provide a power supply circuit, a power supply method and a power supply system for a refrigerated truck. The original power supply is used as the main power supply, and the AC power output by the AC power supply is used as the backup power supply, thereby realizing the automatic switching of the main and backup power modes of the power supply of the target device, so that the new energy refrigerated truck can directly use the AC power as the backup power supply to power the refrigeration unit when connected to the AC power supply, so as to reduce or even avoid the situation where the original power supply of the new energy refrigerated truck needs to power the refrigeration unit while being charged, thereby improving the charging rate of the original power supply in the new energy refrigerated truck.

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] Please refer to Figure 1 , Figure 1 A schematic diagram of a power supply circuit provided by the present invention; please refer to Figure 2 , Figure 2 A schematic diagram of a backup power circuit provided by the present invention; To effectively solve the above technical problems, the present invention provides a power supply circuit, including:

[0056] Reactor 1, a first end of which is used to be connected to an AC power source;

[0057] A rectifier circuit 2, the AC end of which is connected to the second end of the reactor 1, and is used to rectify the AC power output by the AC power supply into DC power;

[0058] A controllable switch 3, wherein a first input terminal is connected to the original power supply of the target device, a second input terminal is connected to the output terminal of the rectifier circuit 2, and an output terminal is connected to the target device;

[0059] The control module 4 has an output end connected to the control end of the controllable switch 3, and is used to control the first input end and the output end of the controllable switch 3 to be connected when there is no AC input power supply circuit, so as to use the original power supply to power the target device; when there is an AC input power supply circuit, control the second input end and the output end of the controllable switch 3 to be connected, so as to use the AC power supply to power the target device.

[0060] It can be understood that in order to speed up the charging speed of the power system of the target device and shorten the charging time, the present invention provides a power supply circuit to simultaneously utilize the original power supply in the power system of the target device and the external AC power supply to power the target device. The AC power supply is the power supply for charging the power system of the target device. When the AC power supply does not output AC power to the power supply circuit, it means that the power supply system of the target device is not charging at this time. At this time, the first input end and the output end of the controllable switch 3 are directly turned on, so that the original power supply of the target device can be output to the target device through the first input end and the output end of the controllable switch 3 that are turned on, and the target device is powered. At this time, the second input end and the output end of the controllable switch 3 are disconnected; when the AC power supply outputs AC power to the power supply circuit, it means that the power supply system of the target device is charging at this time. In order to avoid the low charging efficiency caused by the power supply system supplying power to the target device while charging, the control module 4 will control the second input end and the output end of the controllable switch 3 to be turned on. The AC power output by the AC power supply can be output to the target device through the second input end and the output end of the controllable switch 3 that are turned on after passing through the reactor 1 and the rectifier circuit 2 in sequence, and the target device is powered. At the same time, the first input end and the output end of the controllable switch 3 are disconnected, and the original power supply of the target device only needs to receive the AC power supply to perform an independent charging process, thereby realizing the independence of the charging process of the power supply system and the power supply process of the target device by using the controllable switch 3.

[0061] It is not difficult to understand that when the AC power supply supplies power to the target device through the power supply circuit, the harmonic current in the AC power supply is first processed by the reactor 1, and the reactor 1 can also filter out the high-frequency signal generated by the power switch in the rectifier circuit 2 when it is in action to prevent pollution to the AC power supply. By setting the reactor 1, the harmonics in the AC power supply can be effectively avoided from interfering with the power supply process of the target device. In particular, when the AC power supply is directly implemented by the power grid, the reactor 1 can filter out the harmonics and other interference signals in the power grid. At the same time, the reactor 1 can also suppress the impact current at the input end of the power supply circuit to avoid damage to the rear-end rectifier circuit 2 and the target device. The AC power output by the reactor 1 is then rectified and filtered by the rectifier circuit 2, and finally the DC power is output to power the target device. Please refer to Figure 3 , Figure 3 A schematic diagram of the structure of another power supply circuit provided by the present invention; specifically, an AFE (Active Front End) module can be used to implement a backup power supply circuit. The AFE module itself has a rectification function, and can also effectively eliminate high-order harmonics, improve the power factor, and effectively avoid the impact of grid fluctuations on the output voltage. Therefore, when using an AC power supply to power the target device during charging, the AC power supply can be harmonically controlled and the power factor can be adjusted, so that the utilization rate of the connected AC power supply is improved and harmonic interference in the grid is suppressed. While realizing the backup power supply, the accuracy and reliability of the backup power supply process for the target device are ensured.

[0062] It should be noted that the specific types and implementation methods of the reactor 1, the rectifier circuit 2, the controllable switch 3 and the control module 4 are not specifically limited in this application. The controllable switch 3 can be implemented by a contactor or the like, and the control module 4 can be implemented by a control board or the like. The specific types and implementation methods of the AC power supply, the original power supply of the target device and the target device are not specifically limited in this application. The AC power supply can generally be directly implemented by the mains. The original power supply is the circuit when the original power supply of the target device is powered by the original power. The original power can be a power battery from a new energy refrigeration vehicle. The target device can be a refrigeration unit in a new energy refrigeration vehicle, referred to as a refrigeration unit, or an air conditioning system. During the charging process of the new energy refrigeration vehicle, a separate mains power supply can be provided to power the refrigeration unit, so that the refrigeration unit can work. In this way, the charging time of the whole vehicle will be greatly reduced, that is, the charging rate can be greatly improved, thereby improving the transportation efficiency of the new energy refrigeration vehicle. By setting the reactor 1 and using the AFE module to implement the rectifier circuit 2, the harmonics in the power grid can be effectively processed and the power factor can be improved, and control interference caused by harmonics can be avoided, thereby ensuring the normal operation of the unit, effectively improving the energy utilization rate of the AC power supply, and reducing losses.

[0063] As a specific embodiment, the power supply circuit includes a main circuit in which the original power supply is supplied through the first input end and the output end of the controllable switch 3, and a backup power circuit in which the AC power supply is supplied through the inductor 1, the rectifier circuit 2, and the second input end and the output end of the controllable switch 3 in sequence. Taking the controllable switch 3 using a contactor as an example, when the AC power supply is not connected to the backup power circuit, the main circuit remains unblocked and the backup power circuit does not work; when the backup power circuit is connected to the AC power supply, the backup power detection module first performs a backup power detection to determine whether there is AC power output by the AC power supply in the backup power circuit. If the backup power detection module detects the backup power, the contactor corresponding to the backup power circuit is turned on, the backup power circuit is controlled to be turned on, and the contactor corresponding to the main circuit is turned off to cut off the power supply of the main circuit; the control module 4 will continue to detect the backup power circuit. If the AC power supply in the backup power circuit is disconnected, the contactor corresponding to the main circuit will be controlled to be turned on to restore power to the main circuit, and the contactor of the backup power circuit will be disconnected to cut off the backup power circuit.

[0064] It can be understood that, based on the power supply circuit provided by the present invention, an electrical solution for circuit switching suitable for new energy refrigerated trucks can be realized, and the process of automatic switching between the main and standby power can be used to realize different power supply modes of the refrigeration unit. The AFE module is used at the front end of the standby power circuit for rectification. The AFE module mainly plays a rectifying role, and can also have the function of filtering grid harmonics. When the city power is connected, the harmonics in the grid are filtered through the AFE module and the reactor 1, which improves the efficiency of the grid and can effectively avoid the interference of harmonics in the grid with some low-voltage devices. At the same time, the AFE module also has the function of adjusting the power factor, which can increase the power factor to 0.98, greatly improving the utilization rate of electric energy. The standby power circuit can better improve the power factor of the grid with the cooperation of the reactor 1 and the rectifier circuit 2, and control the harmonics in the grid, which is conducive to the stable operation of the refrigeration unit and the improvement of the utilization rate of the electric energy of the refrigeration unit; the main and standby power modes are automatically switched, and no manual operation is required, which is convenient and fast. In the automatic switching of main and backup power control, the backup power circuit and the main circuit can directly share an existing electronic control system in the new energy refrigerated truck to operate the unit. The entire power supply circuit is implemented with DC devices, which meets the electronic control requirements of new energy vehicles and improves the reliability of the circuit.

[0065] The present invention provides a power supply circuit, including a reactor 1, a rectifier circuit 2, a controllable switch 3 and a control module 4. When the power supply circuit receives the alternating current output by the alternating current power supply, the rectifier circuit 2 is first used to rectify the alternating current, and then the direct current obtained by the rectification is used to power the target device; when there is no alternating current output by the alternating current power supply, the original power supply of the target device itself is used for power supply. At the same time, since the alternating current power supply is first input into the rectifier circuit 2 through the reactor 1, the harmonic interference in the power grid can be effectively avoided, which is conducive to the stable operation of the target device and improves the utilization rate of electric energy; the original power supply is used as the main power supply, and the alternating current output by the alternating current power supply is used as the backup power supply, which realizes the automatic switching of the main and backup power modes of the power supply of the target device, so that the new energy refrigeration vehicle can directly use the main power supply as the backup power supply to power the refrigeration unit when connected to the main power supply, effectively reducing or even avoiding the situation that the original power supply of the new energy refrigeration vehicle needs to power the refrigeration unit while being charged, thereby improving the charging rate of the original power supply in the new energy refrigeration vehicle.

[0066] Based on the above embodiments:

[0067] As an optional embodiment, it also includes:

[0068] The energy storage capacitor C0 is arranged between the DC bus positive terminal and the DC bus negative terminal of the DC end of the rectifier circuit 2 and is used to store the DC power output by the rectifier circuit 2 .

[0069] It is not difficult to understand that an energy storage capacitor C0 connected in parallel between the two output ends of the rectifier circuit 2 can be added at the output end of the rectifier circuit 2. After the rectifier circuit 2 converts the AC power into DC power, the energy storage capacitor C0 can be charged, and the energy storage capacitor C0 is filtered to form a target DC voltage on the energy storage capacitor C0 to power the target device. The specific type and implementation method of the energy storage capacitor C0 are not particularly limited in this application.

[0070] Specifically, by adding the energy storage capacitor C0, the DC power output by the rectifier circuit 2 can be further filtered, the output DC power can be smoothed, interference can be eliminated, and the accuracy and reliability of the DC power finally output to the target device can be improved. At the same time, the energy storage capacitor C0 can store a certain amount of electrical energy and can still maintain DC power output for a period of time after the AC power supply is cut off.

[0071] As an optional embodiment, it also includes:

[0072] A current limiting resistor R0, a first end of which is connected to the positive end of the DC bus of the rectifier circuit 2, and a second end of which is connected to the first end of the energy storage capacitor C0;

[0073] The pre-charging control switch K0 is connected in parallel to both ends of the current limiting resistor R0, and the control end is connected to the output end of the control module 4, and is used to be turned on when the duration of the rectifier circuit 2 outputting direct current reaches a preset duration.

[0074] It is understandable that, in order to further protect the circuit, a pre-charge circuit in series can be added on the output side of the rectifier circuit 2, and the pre-charge circuit includes a current limiting resistor R0 and a pre-charge control switch K0. When the rectifier circuit 2 is powered on, the pre-charge control switch K0 is in a disconnected state for a period of time before the backup power supply circuit is powered on. At this time, the AC power supply charges the energy storage capacitor C0 through the current limiting resistor R0, and the current limiting resistor R0 can effectively limit the size of the charging current to avoid the damage caused to the energy storage capacitor C0 and the target device by the large impact current in the power supply circuit. After the energy storage capacitor C0 is charged to a certain extent, the pre-charge control switch K0 is closed and the charging current is no longer limited. When the voltage at both ends of the energy storage capacitor C0 reaches a set value, the pre-charge control switch K0 can be controlled to close, or the pre-charge control switch K0 can be controlled to close after the rectifier circuit 2 is powered on for a set time. The specific type and implementation of the current limiting resistor R0 and the pre-charge control switch K0 are not particularly limited in this application.

[0075] Specifically, by setting a pre-charging circuit connected in series on the output side of the rectifier circuit 2, the output current of the rectifier circuit 2 can be controlled by controlling the pre-charging control switch K0, so that the energy storage capacitor C0 is first charged to a certain extent by controlling the current to avoid damage to the target device caused by instantaneous overload of the DC power output by the rectifier circuit 2, thereby achieving stable power supply to the target device and improving the reliability and safety of the entire power supply circuit.

[0076] As an optional embodiment, it also includes:

[0077] A filter, used to be connected in series between the AC power supply and the first end of the reactor 1;

[0078] and / or,

[0079] The lightning protection board has an input end connected to the output end of the filter and the first end of the reactor 1 respectively.

[0080] It is not difficult to understand that in order to improve the stability and reliability of the power supply process of the target device, a filter and / or a lightning protection board can be further set at the front end of the power supply circuit. By setting the filter, the AC power output by the AC power supply can be filtered, and the interference signal generated by the rear-end rectifier circuit 2 and the target device can be filtered to avoid the adverse effects of the interference signal on the rectifier circuit 2 and other devices in the power grid, and effectively improve the power supply safety. A lightning protection board can also be added between the filter and the reactor 1. The lightning protection board is provided with a power supply lightning arrester. By adding a lightning protection board at the front end of the rectifier circuit 2, it can effectively prevent the damage caused by lightning strikes, surges and other impacts to the rectifier circuit 2, effectively avoid the phenomenon of abnormal operation of the rectifier circuit 2 and affecting the operation of the whole machine, thereby effectively avoiding the generation of significant economic losses. Specifically, the three external terminals of the lightning protection board are respectively connected to the three-phase output terminals of the AC power supply, effectively avoiding the situation where the power supply circuit cannot be used normally due to self-damage. The specific types and implementation methods of the filter and the lightning protection board are not particularly limited in this application.

[0081] Specifically, by adding a filter and / or a lightning protection board at the front end of the power supply circuit, the power supply safety of the entire power supply circuit can be effectively improved, mutual interference between other devices connected to the AC power supply and the target device can be avoided, and the accuracy and reliability of the power supply process can be improved; the filter cooperates with the inductor 1 to filter out harmonics and interference in the power grid.

[0082] As an optional embodiment, the reactor 1 includes a first sub-reactor 1 connected to a first phase of the AC power supply, a second sub-reactor 1 connected to a second phase of the AC power supply, and a third sub-reactor 1 connected to a third phase of the AC power supply;

[0083] The rectifier circuit 2 comprises:

[0084] A first switch device Q1, a first end of which serves as a first output end of the rectifier circuit 2;

[0085] A second switching device Q2, a first end of which is respectively connected to the second end of the first sub-reactor 1 and the second end of the first switching device Q1, and a second end of which serves as a second output end of the rectifier circuit 2;

[0086] A third switching device Q3, a first end of which is connected to the first end of the first switching device Q1;

[0087] A fourth switching device Q4, a first end of which is respectively connected to the second end of the second sub-reactor 1 and the second end of the third switching device Q3, and a second end of which is connected to the second end of the second switching device Q2;

[0088] a fifth switch device Q5, a first end of which is connected to the first end of the first switch device Q1;

[0089] The sixth switching device Q6 has a first end connected to the second end of the third sub-reactor 1 and the second end of the fifth switching device Q5 , and a second end connected to the second end of the second switching device Q2 .

[0090] It can be understood that the AC power supply is specifically a three-phase AC power supply, so the reactor 1 specifically includes a first sub-reactor 1, a second sub-reactor 1, and a third sub-reactor 1 corresponding to the A, B, and C phases of the three-phase AC power supply, respectively. The rectifier circuit 2 is specifically implemented by a rectifier bridge composed of 6 switching devices, and the rectifier circuit 2 controls the on and off of each switching device through the PWM provided by the control module 4, so as to rectify the three-phase AC power. When the three-phase power is connected to the circuit, since the triggering and opening time of the IGBT will be inconsistent, it is necessary to ensure that two switching devices are turned on at each moment, so as to rectify the three-phase power into pulsating direct current, and then the pulsating direct current is processed into standard direct current through the energy storage capacitor C0. The specific types and implementation methods of the first switching device Q1, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, and the sixth switching device Q6 are not particularly limited in this application, and can be implemented by switching devices such as IGBT (Insulated Gate Bipolar Transistor).

[0091] It is not difficult to understand that the backup power circuit is realized by using the AFE module to process the harmonics of the input mains power. At the same time, the self-shutoff device IGBT is used as the power device in the AFE module, and the pulse width modulation technology of the sine wave is adopted. Since the voltage and current waveforms at the front end of the rectifier circuit 2 have been filtered into sine waveforms under the action of the filter and the reactor 1, the phase difference angle between the voltage and current sine waveforms can be set within a certain range as needed, so the power factor is adjustable. By adjusting the internal parameters of the rectifier circuit 2, the phase angle of the input current and the input voltage of the backup power supply circuit can be adjusted, thereby realizing the process of suppressing the harmonic current in the power supply circuit and correcting the power factor to the required value. For example, the phase of the input voltage and the input current is adjusted to be the same, so as to adjust the power factor to more than 95%.

[0092] Further, three current detection resistors R1, R2, and R3 respectively connected in series with the second switch device Q2, the fourth switch device Q4, and the sixth switch device Q6 can be added. The current detection resistors are connected in series in the rectifier circuit 2, and the currents of each phase in the rectifier circuit 2 can be respectively collected. The sampled current signals can be output to the control module 4 so that the control module 4 performs overcurrent protection. There is no need to use a complex current transformer to collect the input current, the circuit structure is simple, the functional integration is high, and the volume is small. In order to ensure the safety and reliability of the entire rectifier circuit 2, a cooling fan can also be set inside the rectifier circuit 2 to dissipate heat for the rectifier circuit 2 and the entire AFE module to avoid overheating and damage of the highly integrated AFE module during operation, thereby affecting the normal power supply to the target device. Specifically, in order to facilitate improving the integration of the power supply circuit, an auxiliary power supply integrated in the AFE module can also be set to power the cooling fan. The auxiliary power supply converts the DC voltage at the DC bus positive terminal DC+ of the PWM rectifier unit into the power supply voltage of the cooling fan. A temperature sensor is also integrated inside the AFE module to sense the temperature inside the AFE module and send the detected temperature to the MCU (Microcontroller Unit) of the AFE module for detection. When the MCU detects that the temperature of the AFE module reaches a preset temperature, it outputs a fan power supply control signal to control the power supply circuit between the auxiliary power supply and the cooling fan to be turned on, so that the auxiliary power supply outputs a corresponding power supply voltage to the cooling fan.

[0093] Specifically, the rectifier circuit 2 can be directly implemented using an AFE module based on IGBT technology. The AFE module has a high switching frequency and a shorter opening and closing time, which can reduce switching losses and help reduce harmonics. By adjusting the conduction time of each switching device, the power factor of the backup power supply circuit can also be adjusted to improve the utilization rate of electric energy.

[0094] Please refer to Figure 4 , Figure 4 A schematic diagram of a specific circuit structure of a power supply circuit provided by the present invention; as an optional embodiment, the controllable switch 3 includes:

[0095] A first controllable sub-switch is connected in series between the output end of the original power supply of the target device and the target device, and is used to be turned on under the control of the control module 4 when there is no AC input power supply circuit;

[0096] The second controllable sub-switch is connected in series between the output end of the rectifier circuit 2 and the target device, and is used to be turned on under the control of the control module 4 when there is an AC input power supply circuit.

[0097] It is not difficult to understand that, considering that the power supply circuit is divided into a main circuit and a backup circuit, in order to realize independent control of the main circuit and the backup circuit, the controllable switch 3 is respectively provided with a first controllable sub-switch connected in series in the main circuit and a second controllable sub-switch connected in series in the backup circuit. When the power supply circuit is not connected to an AC power source, the first controllable sub-switch is turned on, the second controllable sub-switch is turned off, and the main circuit remains turned on to supply power to the target device; when the power supply circuit is connected to an AC power source, the first controllable sub-switch is turned off, the second controllable sub-switch is turned on, and the backup circuit remains turned on to supply power to the target device. The specific types and implementation methods of the first controllable sub-switch and the second controllable sub-switch are not particularly limited in this application, and can be implemented by relays and the like, such as Figure 4 As shown, the first controllable sub-switch is implemented by contactors KM1 and KM2, and the second controllable sub-switch is implemented by contactors KM3 and KM4.

[0098] Specifically, for the convenience of control, the controllable switch 3 specifically includes a first controllable sub-switch and a second controllable sub-switch. The first controllable sub-switch realizes independent control of the main circuit, and the second controllable sub-switch realizes independent control of the backup circuit, thereby avoiding mutual interference between the main circuit and the backup circuit and improving the accuracy and reliability of the power supply process of the target device.

[0099] As an optional embodiment, the control module 4 includes:

[0100] A voltage detection circuit, the input ends of which are respectively connected to the three-phase outputs of the AC power supply, and is used to detect whether the AC power supply outputs AC power to the power supply circuit;

[0101] A processor, an input end of which is connected to an output end of a voltage detection circuit, and an output end of which is connected to an input end of a backup power control board, for outputting a power switching signal to the backup power control board when an AC power input power supply circuit is present;

[0102] A backup power control board, whose output end is connected to the control end of the second controllable sub-switch and whose signal end is connected to the signal end of the main control board, is used to forward the power switching signal to the main control board when receiving the power switching signal, and control the second controllable sub-switch to be turned on when the target device allows backup power access;

[0103] The main control board has an output end connected to the control end of the first controllable sub-switch, and is used to control the first controllable sub-switch to turn off when a power switching signal is received and the target device allows the main power to be disconnected.

[0104] It is understandable that when switching between the main and standby power supplies, it is necessary to determine whether to switch based on the real-time situation of the AC power input to the power supply circuit. Therefore, a voltage detection circuit needs to be set in the power supply circuit to detect the input situation of the AC power supply in real time, and a processor is set to receive the detection result of the voltage detection circuit. If it is detected that there is an AC input power supply circuit, it is necessary to switch the power supply circuit of the target device from the main circuit to the standby circuit. At this time, the processor can output a power switching signal to control the switching process. If the AC input power supply circuit is not detected, it is necessary to keep the power supply circuit of the target device in the main circuit or restore it from the standby circuit to the main circuit. Considering that there is an MCU that controls the switching device in the AFE module itself, and the voltage detection circuit will be connected to the input side of the AFE module, the processor can directly reuse the MCU in the AFE module itself. The specific type and implementation method of the voltage detection module and the processor are not particularly limited in this application.

[0105] Furthermore, after the processor outputs the power switching signal, the control module 4 needs to further control the first controllable sub-switch and the second controllable sub-switch to switch the main and standby power. The control of whether the main circuit is on or not and the control of whether the standby circuit is on or not need to be linked to each other. Therefore, in order to avoid the AI ​​and DI ports of a single control board receiving signals being insufficient, and also for the convenience of control, a main control board corresponding to the first controllable sub-switch and a standby power control board corresponding to the second controllable sub-switch are also provided. Considering the special situation of charging a new energy refrigerated truck, the power supply circuit provided by the present invention will preferentially use the standby circuit to power the target device when there is an AC power input in the standby circuit. Therefore, the power switching signal output by the processor will be output to the standby power control board first. In order to ensure the normal application of the target device, when switching the main and standby power, it is also necessary to consider whether the current state of the target device is running to switch the power. Therefore, the standby power control board will open the standby power circuit to power the target device when receiving the power switching signal and the target device allows the standby power to be connected. At the same time, the main control board also needs to disconnect the main circuit when receiving the power switching signal and the target device allows the main power to be disconnected. This application does not make any special restrictions on the specific conditions for accessing the backup power supply to the target device and allowing the main power supply to be disconnected.

[0106] It should be noted that the backup power control board can be an extended PLC board, which can communicate with the AFE module to detect the working condition of the AFE module. When the mains power is connected, the DO port on the MCU of the AFE module will output a digital quantity, and this digital quantity signal will be given to the backup power control board. The backup power control board will send a signal to the main control board, and the main circuit will be switched to the backup power circuit. The main control board has a control port for the contactor in the main circuit, and the backup power control board has a control port for the contactor in the backup power circuit. The two control boards can cooperate with each other through CAN (Controller Area Network) communication and other methods to achieve main and backup power switching. This application does not make any special restrictions on the specific types and implementation methods of the main control board and the backup power control board.

[0107] It is not difficult to understand that, considering that both the main control board and the backup power control board need power supply to work, an AC / DC circuit can be added to the power supply circuit to convert the AC power into a low voltage to power the main control board and the backup power control board. When there is AC power input, there is no need to use the original power supply of the target device to control the control board. In order to ensure the normal operation of the main control board and the backup power control board, in addition to the power provided by the AC / DC (alternating current / direct current) circuit, the original power supply of the target device can also be used, that is, the vehicle power supply (battery) of the new energy refrigeration vehicle can also be used to power the main control board and the backup power control board at the same time. Considering that there is a DC / DC (direct current / direct current) module in the power system of the new energy refrigeration vehicle that powers the refrigeration unit, this DC / DC module can also be directly used to power the main control board and the backup power control board. The main control board and the backup power control board can have up to three power supplies. This application does not make any special restrictions on the specific implementation methods and voltage levels of each power supply. Generally, the power supply of the new energy refrigerated truck is 24V, the DC-DC module is 400-540V DC input, the output power supply is a 27.5V circuit, and the output power supply of the AC / DC circuit is 24V. At the same time, considering that during transportation, the new energy refrigerated truck may be directly turned off when the driver is resting or in other situations, and the original power supply of the new energy refrigerated truck no longer has power output when the engine is turned off, it is possible to further increase the three-phase rectifier bridge ED2 connected to the output end of the AC / DC circuit. When the vehicle is turned off but there is AC power input, the AC / DC circuit and the three-phase rectifier bridge ED2 can be directly used to ensure the normal operation of the refrigeration machine during charging.

[0108] Specifically, in order to facilitate control and realize switching between the main circuit and the backup power circuit, a main control board and a backup power control board are respectively provided in the control module 4 to realize independent control of the main circuit and independent control of the backup power circuit respectively. At the same time, in cooperation with the processor in the AFE module, it can realize the control of the main and backup power switching according to the AC power supply of the input power supply circuit, which is simple, effective and easy to implement.

[0109] As an optional embodiment, the output end of the main control board is also connected to the electric control system of the target device;

[0110] The main control board is also used to control the target device to stop working when receiving the power switching signal, and determine that the target device allows the main power to be disconnected after the target device stops working for a first preset time.

[0111] It is not difficult to understand that in order to ensure that the switching of the main power supply and the standby power supply will not affect the normal operation of the target device, the main control board can control the target device to stop working when receiving the power switching signal, so as to avoid safety problems caused by unstable voltage during the power switching process. At the same time, considering that it takes a certain amount of time to shut down the device, when the instruction to control the target device to stop working reaches the first preset time, the main control board will determine that the target device allows the main power supply to be disconnected, and then control the main power supply to be disconnected. The specific value of the first preset time is not particularly limited in this application, and can be set according to the actual shutdown time of the target device, which cannot be too large or too small.

[0112] Specifically, by controlling the target device to stop working and using a delayed control method when controlling the main power to be disconnected, it is ensured that the main power is disconnected only after the target device completely stops working, thereby avoiding safety problems caused by direct disconnection of the main power when the target device is working and abnormal operation of the target device, thereby ensuring the normal operation of the target device.

[0113] As an optional embodiment, the main control board is further used to send a shutdown signal to the backup power control board when controlling the first controllable sub-switch to be turned off;

[0114] The backup power control board is further used to determine whether the target device allows backup power access after receiving the shutdown signal for a second preset time period.

[0115] It is understandable that, accordingly, the backup power control board also needs to connect to the backup circuit immediately after the main power supply is cut off after ensuring that the target device completely stops working, so as to realize the switching process between the main and backup power. In order to facilitate the backup power control board to connect to the backup circuit in time, the main control board can also set a shutdown signal to inform the main control board of the disconnection of the main power supply. The specific type and implementation method of the shutdown signal and the specific value of the first preset duration are not particularly limited in this application.

[0116] As a specific embodiment, please refer to Figure 5 , Figure 5 A control flow diagram of a power supply circuit provided by the present invention. The power supply circuit includes an AFE module, a backup power detection module, the prime mover of the new energy refrigerated truck itself, and the electric control system of the new energy refrigerated truck itself. The power supply required by the refrigeration unit needs to be processed by the electric control system before being output to the refrigeration unit. When the whole vehicle is connected to the mains, the AFE module starts to work. The AFE module has a DO output port for detecting whether there is voltage on the AC bus. If there is voltage, a signal will be sent to the DI port of the backup power control board. The DI port of the backup power control board is used as a backup power detection module. Whether the backup power circuit is connected is determined by whether the DI port of the backup power control board receives a signal. If the backup power circuit needs to be connected, the CAN communication between the backup power control board and the main control board is used to control the output end of the AFE module and the DC contactor connected in series as the second controllable sub-switch between the electronic control system to be connected after a certain delay, so that the refrigeration machine continues to work and the backup power supply is executed first; at the same time, the contactor of the main circuit connected in series as the first controllable sub-switch between the prime mover and the electronic control system is controlled to be disconnected after a certain delay. Since the AFE module is added when the AC power is converted into DC power, the power factor can be improved through this module, and the harmonics in the AC power can be suppressed. The reliability of the entire circuit is improved. At the same time, the devices used are all DC devices, which are relatively simple and easy to maintain.

[0117] Specifically, the main control board sends a shutdown signal to inform the backup power control board that the target device has stopped working and the main power has been cut off. At the same time, the backup power control board also uses a delayed control method when controlling the access of the backup circuit to ensure that the backup circuit will not be connected until the target device has completely stopped working, avoiding safety problems such as surges caused by direct connection of the backup circuit when the target device is working, thereby ensuring the normal operation of the target device.

[0118] In order to effectively solve the above technical problems, the present invention also provides a power supply system for a refrigerated truck, including a refrigeration unit, an electric control system and a power supply circuit as described above, wherein the output end of the power supply circuit is connected to the refrigeration unit through the electric control system.

[0119] It should be noted that the electronic control system is composed of the original vehicle-mounted circuit, and the main circuit and the backup power circuit in the power supply circuit share a set of electronic control systems. This application does not make any special restrictions on the specific type and implementation method of the electronic control system, which usually includes filter boards, inverters, DC / DC modules and other circuits.

[0120] For an introduction to a power supply system for a refrigerated vehicle provided by the present invention, please refer to the above-mentioned embodiment of the power supply circuit, and the present invention will not be described in detail here.

[0121] In order to effectively solve the above technical problems, the present invention further provides a power supply method, which is applied to the power supply circuit as described above. The power supply method comprises:

[0122] When there is no AC input power supply circuit, the first input terminal and the output terminal of the controllable switch of the power supply circuit are controlled to be connected, so as to use the original power supply to power the target device;

[0123] When there is an AC input power supply circuit, the second input terminal and the output terminal of the controllable switch are controlled to be connected, so as to use the AC power supply to power the target device.

[0124] For an introduction to a power supply method provided by the present invention, please refer to the embodiment of the above-mentioned power supply circuit, and the present invention will not be described in detail here.

[0125] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. It should also be noted that in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0126] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power supply circuit, characterized in that: include: A reactor, a first end of which is used to be connected to an AC power source; A rectifier circuit, the AC end of which is connected to the second end of the reactor, for rectifying the AC power output by the AC power supply into DC power; A controllable switch, wherein a first input end is connected to an original power source of a target device, a second input end is connected to an output end of the rectifier circuit, and an output end is connected to the target device; A control module, the output end of which is connected to the control end of the controllable switch, is used to control the first input end and the output end of the controllable switch to be connected when there is no AC input power supply circuit, so as to use the original power supply to power the target device; when there is an AC input power supply circuit, control the second input end and the output end of the controllable switch to be connected, so as to use the AC power supply to power the target device.

2. The power supply circuit according to claim 1, characterized in that: Also includes: The energy storage capacitor is arranged between the DC bus positive terminal and the DC bus negative terminal of the DC end of the rectifier circuit and is used to store the DC power output by the rectifier circuit.

3. The power supply circuit according to claim 2, characterized in that: Also includes: A current limiting resistor, a first end of which is connected to the positive end of the DC bus of the rectifier circuit, and a second end of which is connected to the first end of the energy storage capacitor; The pre-charging control switch is connected in parallel at both ends of the current limiting resistor, and the control end is connected to the output end of the control module, and is used for being turned on when the duration of the rectifier circuit outputting direct current reaches a preset duration.

4. The power supply circuit according to claim 1, characterized in that: Also includes: A filter, connected in series between the AC power supply and the first end of the reactor; and / or, A lightning protection board, the input end of which is respectively connected to the output end of the filter and the first end of the reactor.

5. The power supply circuit according to claim 1, characterized in that: The reactor comprises a first sub-reactor connected to a first phase of the AC power supply, a second sub-reactor connected to a second phase of the AC power supply, and a third sub-reactor connected to a third phase of the AC power supply; The rectifier circuit comprises: A first switch device, a first end of which serves as a first output end of the rectifier circuit; a second switching device, a first end of which is respectively connected to the second end of the first sub-reactor and the second end of the first switching device, and a second end of which serves as a second output end of the rectifier circuit; a third switching device, a first end of which is connected to the first end of the first switching device; a fourth switching device, a first end of which is respectively connected to the second end of the second sub-reactor and the second end of the third switching device, and a second end of which is connected to the second end of the second switching device; a fifth switching device, a first end of which is connected to the first end of the first switching device; A sixth switching device has a first end connected to the second end of the third sub-reactor and the second end of the fifth switching device respectively, and a second end connected to the second end of the second switching device.

6. The power supply circuit according to any one of claims 1 to 5, characterized in that: The controllable switch comprises: A first controllable sub-switch, connected in series between the output end of the original power supply of the target device and the target device, and configured to be turned on under the control of the control module when there is no AC input power supply circuit; A second controllable sub-switch is connected in series between the output end of the rectifier circuit and the target device, and is used for being turned on under the control of the control module when there is an AC input power supply circuit.

7. The power supply circuit according to claim 6, characterized in that: The control module comprises: A voltage detection circuit, the input ends of which are respectively connected to the three-phase outputs of the AC power supply, and is used to detect whether the AC power supply outputs AC power to the power supply circuit; A processor, the input end of which is connected to the output end of the voltage detection circuit, and the output end of which is connected to the input end of the backup power control board, for outputting a power switching signal to the backup power control board when there is an AC input power supply circuit; The backup power control board, whose output end is connected to the control end of the second controllable sub-switch and whose signal end is connected to the signal end of the main control board, is used to forward the power switching signal to the main control board when receiving the power switching signal, and control the second controllable sub-switch to be turned on when the target device allows backup power access; The main control board has an output end connected to the control end of the first controllable sub-switch, and is used to control the first controllable sub-switch to turn off when the power switching signal is received and the target device allows the main power to be disconnected.

8. The power supply circuit according to claim 7, characterized in that: The output end of the main control board is also connected to the electric control system of the target device; The main control board is further used for controlling the target device to stop working when receiving the power switching signal, and determining that the target device allows the main power to be disconnected after the target device stops working for a first preset time.

9. The power supply circuit according to claim 8, characterized in that: The main control board is also used to send a shutdown signal to the backup power control board when controlling the first controllable sub-switch to be turned off; The backup power control board is further used to determine that the target device allows backup power access after receiving the shutdown signal for a second preset time period.

10. A power supply system for a refrigerated vehicle, characterized in that: It comprises a refrigeration unit, an electric control system and a power supply circuit as claimed in any one of claims 1 to 9, wherein the output end of the power supply circuit is connected to the refrigeration unit through the electric control system.

11. A power supply method, characterized in that: Applied to the power supply circuit according to any one of claims 1 to 9, the power supply method comprises: When there is no AC input power supply circuit, controlling the first input terminal and the output terminal of the controllable switch of the power supply circuit to be connected, so as to use the original power supply to power the target device; When there is an AC input power supply circuit, the second input terminal and the output terminal of the controllable switch are controlled to be connected, so as to use the AC power supply to power the target device.

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