A current-source type high-isolation auxiliary power supply and its control method

Abstract

This invention discloses a current-source type high-isolation auxiliary power supply and its control method, belonging to the field of power electronics control. The power supply includes a transmitter and multiple receivers, with magnetic coupling between the transmitter and receivers transferring electrical energy. The transmitter employs a soft-switching average current control mode, while the receivers employ an average voltage control mode to supply power to external power electronic equipment. This auxiliary power supply features a simple structure, convenient control, and low static power consumption. Through magnetic coupling, it generates multi-channel isolated auxiliary power supplies, significantly reducing the size of the auxiliary power supply. Each module does not need to bear high common-mode voltage, resulting in high isolation, making it suitable for auxiliary power supply applications in medium- and high-voltage power electronic equipment.

Description

Technical Field

[0001] This invention belongs to the field of power electronic devices and their control technology, specifically relating to a current source type high isolation auxiliary power supply and its control method. Background Technology

[0002] In medium- and high-voltage power electronic conversion systems (such as HVDC transmission, new energy grid-connected converters, and solid-state transformers), the auxiliary power supply system needs to provide isolated power for modules such as controllers and drive circuits. Traditional auxiliary power supply solutions face the following challenges: The contradiction between high isolation requirements and size: Medium- and high-voltage scenarios require power supplies with high isolation withstand voltage (usually several kilovolts), while traditional transformer isolation solutions are bulky and difficult to meet miniaturization design requirements; Common-mode voltage issues with multiple modules: When multiple power supply modules are directly connected in parallel, the high-voltage side common-mode voltage can easily lead to insulation breakdown risk and insufficient reliability; Medium- and high-voltage power electronic conversion systems have high transmission power, and the auxiliary power supply system faces severe electromagnetic interference.

[0003] Therefore, traditional auxiliary power supplies are bulky, difficult to control, and have high static power consumption. Thus, there is an urgent need for a compact, highly isolated, and low-power auxiliary power supply solution. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a current-source type high-isolation auxiliary power supply and its control method.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention discloses a current-source type high-isolation auxiliary power supply, comprising a transmitter and several receivers; the transmitter includes a three-phase rectifier bridge, an input capacitor, a half-bridge circuit, two resonant capacitors, a transmitting magnetic core, and a current controller; the receivers include a receiving magnetic core, a full-bridge rectifier circuit, switching devices, anti-reverse diodes, an output capacitor, and a voltage controller; the transmitting magnetic core and the receiving magnetic core of each receiver are connected by cables to form a magnetic circuit coupling structure; the cables serve as the secondary coils of the transmitting and receiving magnetic cores;

[0007] The AC input port of the three-phase rectifier bridge is used to receive electrical energy from the outside. The positive DC output terminal of the three-phase rectifier bridge is connected to the positive terminal of the input capacitor and the positive DC terminal of the half-bridge circuit, respectively. The negative DC output terminal is connected to the negative terminal of the input capacitor and the negative DC terminal of the half-bridge circuit, respectively. The AC output point of the half-bridge circuit is connected to the positive terminal of the primary coil of the transmitting magnetic core. The negative terminal of the primary coil of the transmitting magnetic core is connected to the negative terminals of two resonant capacitors. The positive terminal of one resonant capacitor is connected to the positive DC terminal of the half-bridge circuit, and the positive terminal of the other resonant capacitor is connected to the negative DC terminal of the half-bridge circuit. The input terminal of the current controller is used to collect the output current of the transmitting end. The output terminal of the current controller is connected to the gate of the two switching devices of the half-bridge circuit, respectively.

[0008] In each receiver, the positive terminal of the primary coil of the receiving magnetic core is connected to the positive input terminal of the full-bridge rectifier circuit, and the negative terminal of the primary coil is connected to the negative input terminal of the full-bridge rectifier circuit. The positive input terminal of the full-bridge rectifier circuit is also connected to the drain or collector of the switching device, and the negative input terminal of the full-bridge rectifier circuit is connected to the source or emitter of the switching device. The positive terminal of the reverse protection diode is connected to the drain or collector of the switching device, and the negative terminal of the reverse protection diode is connected to the positive terminal of the output capacitor. The negative terminal of the output capacitor is connected to the source or emitter of the switching device. The input terminal of the voltage controller is connected to the output terminal of the receiver, and the output terminal of the receiver is used to output electrical energy to the outside. The output terminal of the voltage controller is connected to the gate of the switching device.

[0009] Secondly, the present invention also discloses a control method for the aforementioned current-source type high-isolation auxiliary power supply, comprising:

[0010] 1) Calculate the resonant frequencies of the primary coil and resonant capacitor of the transmitting core; configure the output pulse width of the current controller at the transmitting end to achieve soft switching of the half-bridge circuit;

[0011] 2) Control the three-phase rectifier bridge to receive power from the outside, control the half-bridge circuit to be in a non-working state, connect the receiving end to the power electronic equipment to receive power from the outside; set the target voltage of the voltage controller to the voltage required by the auxiliary power of the power electronic equipment, and start the voltage controller at the receiving end.

[0012] 3) Start the half-bridge circuit at the transmitting end and control the half-bridge circuit to switch at a certain operating frequency. By changing the operating frequency of the half-bridge circuit, measure the average value of the first resonant current of the primary coil of the transmitting core when the output voltage of all receivers is equal to the corresponding target voltage, and record the operating frequency f of the half-bridge circuit at this time. s0 The target current of the current controller is set based on the average value of the first resonant current.

[0013] 4) Set the initial operating frequency of the half-bridge circuit to f. s0The current controller is activated. During each switching cycle of the half-bridge circuit, the current controller detects the average value of the second resonant current of the primary coil of the transmitting magnetic core and controls the operating frequency of the half-bridge circuit to make the average value of the second resonant current equal to the target current, thus completing the power supply to the power electronic equipment that needs to receive power.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] (1) The current source type high isolation auxiliary power supply provided by the present invention achieves high isolation between auxiliary power supplies of multiple power electronic conversion equipment by using a simple resonant circuit and magnetic coupling. The receiving module can be configured independently, supports multiple isolated power supplies, and avoids common-mode voltage risks. At the same time, the circuit is simple to control, small in size, and low in cost.

[0016] (2) The current source type high isolation auxiliary power supply control method provided by the present invention enables the transmitter current controller to easily achieve soft switching of the circuit by adjusting the pulse width, resulting in high efficiency. When the voltage controller at the receiver meets the output voltage requirements, it controls the receiver switching device to conduct without consuming energy, thus exhibiting extremely low static power consumption.

[0017] (3) The current source type high isolation auxiliary power supply provided by the present invention has high flexibility and compatibility. The input supports multiple input modes such as three-phase AC grid, single-phase AC grid, and DC, and can flexibly adapt to different power supply conditions; the number of receiving ends can be flexibly expanded, which is suitable for the needs of multi-channel isolation auxiliary power supply points of various medium and high voltage power electronic conversion equipment, and the current source has strong robustness and strong anti-electromagnetic interference capability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system structure of the current source type high isolation auxiliary power supply of the present invention;

[0019] Figure 2 This is a circuit diagram of the transmitter of the current source type high isolation auxiliary power supply of the present invention;

[0020] Figure 3 This is a circuit diagram of the receiving end of the current source type high isolation auxiliary power supply of the present invention;

[0021] Figure 4 When using the control method of a current source type high isolation auxiliary power supply, the control signal waveform of the receiving end voltage controller and the output voltage waveform of the receiving end are shown.

[0022] Figure 5 When using the control method of a current source type high isolation auxiliary power supply, the waveform diagram of one control signal of the transmitter current controller and the waveform diagram of the transmitter resonant current are shown. Detailed Implementation

[0023] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0024] A specific embodiment of the present invention provides a detailed description of a current-source type high-isolation auxiliary power supply.

[0025] like Figure 1 As shown, the current source type high isolation auxiliary power supply system of the present invention consists of a transmitter, a high voltage insulated cable and N receivers.

[0026] like Figure 2 As shown, the transmitter includes a three-phase rectifier bridge, a half-bridge circuit, an input capacitor, and two resonant capacitors C. r The system consists of a transmitting magnetic core and a current controller. The AC input port of the three-phase rectifier bridge is connected to an external three-phase AC power grid, single-phase AC power grid, or DC power supply to receive electrical energy from the outside. The positive DC output terminal of the three-phase rectifier bridge is connected to the positive terminal of the input capacitor and the positive DC terminal of the half-bridge circuit, respectively. The negative DC output terminal of the three-phase rectifier bridge is connected to the negative terminal of the input capacitor and the negative DC terminal of the half-bridge circuit, respectively. The AC output point of the half-bridge circuit is connected to the positive terminal of the primary coil of the transmitting magnetic core. The negative terminal of the primary coil of the transmitting magnetic core is connected to the negative terminals of two resonant capacitors. The positive terminal of one resonant capacitor is connected to the positive DC terminal of the half-bridge circuit, and the positive terminal of the other resonant capacitor is connected to the negative DC terminal of the half-bridge circuit. The input terminal of the current controller receives the output current of the transmitting end. The current controller uses a current transformer to collect the output current of the transmitting end, which is the resonant current of the primary coil of the transmitting magnetic core. The output terminal of the current controller is connected to the gate of the two switching devices of the half-bridge circuit, respectively.

[0027] When the AC input port of the three-phase rectifier bridge is connected to an external three-phase AC power grid, the three-phase AC power grid is connected to the three AC input ports of the three-phase rectifier bridge; when the AC input port of the three-phase rectifier bridge is connected to an external single-phase AC power grid or DC power supply, the single-phase AC power grid or DC power supply is connected to any two input ports of the three-phase rectifier bridge, and the other input port of the three-phase rectifier bridge is left empty.

[0028] like Figure 3As shown, each receiver includes a receiving magnetic core, a full-bridge rectifier circuit, a switching device, a reverse protection diode, an output capacitor, and a voltage controller. The positive terminal of the primary winding of the receiving magnetic core is connected to the positive input terminal of the full-bridge rectifier circuit, and the negative terminal of the primary winding is connected to the negative input terminal of the full-bridge rectifier circuit. The positive input terminal of the full-bridge rectifier circuit is also connected to the drain or collector of the switching device, and the negative input terminal is connected to the source or emitter of the switching device. The positive terminal of the reverse protection diode is connected to the drain or collector of the switching device, and the negative terminal of the reverse protection diode is connected to the positive terminal of the output capacitor. The negative terminal of the output capacitor is connected to the source or emitter of the switching device. The input terminal of the voltage controller is connected to the output terminal of the receiver, and the output terminal of the receiver is connected to an external power electronic device that receives electrical energy, used to output electrical energy to the outside. The output terminal of the voltage controller is connected to the gate of the switching device.

[0029] In a current-source type high-isolation auxiliary power supply, the high-voltage insulated cable passes sequentially through the transmitting magnetic core at the transmitting end and the receiving magnetic core at each receiving end, magnetically coupling the transmitting and receiving magnetic cores to form a magnetic coupling structure. The input power of the current-source type high-isolation auxiliary power supply is drawn from a three-phase rectifier bridge, and the output power is output from the output terminal of the receiving end, destined for power electronic equipment connected to the receiving end. For example... Figure 1 As shown, both the transmitting and receiving magnetic cores have two sets of coils wound on them. The two sets of coils are the primary coil and the secondary coil, respectively. The secondary coil of the transmitting and receiving magnetic cores is the high-voltage insulated cable. The high-voltage insulated cable has 1 turn wound on both the transmitting and receiving magnetic cores.

[0030] In this invention, the two switching devices in the half-bridge circuit at the transmitting end are fully controllable devices such as MOSFETs or IGBTs; the switching devices at the receiving end are fully controllable devices such as MOSFETs or IGBTs. This invention also provides a control method for a current-source type high-isolation auxiliary power supply. This method includes the following steps:

[0031] 1) Calculate the resonant frequency of the primary coil and resonant capacitor of the transmitting core; obtain the number of current oscillation cycles at the transmitting end, configure the output pulse width of the current controller at the transmitting end, and realize the soft switching of the half-bridge circuit.

[0032] The formula for calculating the resonant frequency of the primary coil and resonant capacitor of the transmitting magnetic core is as follows:

[0033]

[0034] Among them, f r This represents the resonant frequency of the primary coil of the transmitting magnetic core or the resonant frequency of the resonant capacitor. The resonant frequency of the primary coil of the transmitting magnetic core is equal to the resonant frequency of the resonant capacitor; L rC represents the inductance of the primary coil of the transmitting magnetic core. r This represents the resonant capacitor.

[0035] The formula for calculating the output pulse width of the current controller is:

[0036]

[0037] Among them, T p This represents the output pulse width of the current controller; n is the number of current oscillation cycles, which can be an integer between 1 and 5; f r It is the resonant frequency.

[0038] 2) Control the three-phase rectifier bridge to receive power from the outside, control the half-bridge circuit to be in a non-operating state, connect the receiving end to the power electronic equipment to which power is to be received; set the target voltage of the voltage controller to the voltage required by the auxiliary power supply of the power electronic equipment, and start the voltage controller at the receiving end. At this time, the output voltage of the receiving end is 0.

[0039] 3) Start the half-bridge circuit at the transmitting end and control the half-bridge circuit to switch at a certain operating frequency. By changing the operating frequency of the half-bridge circuit, measure the average value of the first resonant current of the primary coil of the transmitting core when the output voltage of all receivers is equal to the corresponding target voltage, and record the operating frequency f of the half-bridge circuit at this time. s0 The target current of the current controller is set based on the average value of the first resonant current.

[0040] The formula for setting the target current of the current controller based on the average value of the first resonant current is:

[0041] I ref =k i *I Lr0

[0042] Among them, I ref Indicates the target current of the current controller; I Lr0 k represents the average value of the first resonant current. i This represents the current margin coefficient, which is generally taken as 1.5 to 2.

[0043] 4) Set the initial operating frequency of the half-bridge circuit to f. s0 The current controller is activated. During each switching cycle of the half-bridge circuit, the current controller detects the average value of the second resonant current of the primary coil of the transmitting core. It controls the operating frequency of the half-bridge circuit to ensure that the average value of the second resonant current is equal to the target current. That is, if the average value of the second resonant current is less than the target current, the operating frequency of the half-bridge circuit at the start of the next switching cycle is increased, so that the operating frequency of the half-bridge circuit at the start of the next switching cycle is (1+k...). f )f sIf the average value of the second resonant current is greater than the target current, reduce the operating frequency of the half-bridge circuit at the beginning of the next switching cycle, so that the operating frequency of the half-bridge circuit at the beginning of the next switching cycle is (1-k). f )f s ′; where k f f represents the frequency conversion coefficient. s ′ represents the operating frequency of the half-bridge circuit at the start of the current switching cycle. When the average value of the second resonant current is equal to the target current, the power supply from the current source type high-isolation auxiliary power supply to the external power electronic equipment to receive electrical energy is completed.

[0044] When the operating frequency of the half-bridge circuit is controlled so that the average value of the second resonant current is equal to the target current, the output voltage of the receiver will also change accordingly. When the output voltage of the receiver is greater than the target voltage, the voltage controller outputs a high level, the switching device at the receiver is turned on, and the output capacitor discharges to the power electronic equipment connected to the receiver. At this time, there is no current consumption at the transmitting end. When the output voltage of the receiver is less than the target voltage, the voltage controller outputs a low level, the switching device at the receiver is turned off, the full-bridge rectifier circuit charges the output capacitor and discharges to the power electronic equipment at the same time.

[0045] In a specific embodiment of the present invention, the selection of the input of the transmitting end, the selection of the inductance of the primary coil of the transmitting magnetic core, the selection of the resonant capacitor, the number of receivers, the output power of the receivers, and the output voltage of the receivers are shown in Table 1. The input of the transmitting end is a 380V three-phase AC power grid.

[0046] Table 1

[0047] Input of current source type high isolation auxiliary power supply 380V three-phase AC power grid Inductance of the primary coil of the transmitting core 27.6uH Resonant capacitor 88nF / set Number of receivers 4 Receiver output power 10W / each Receiver output voltage 28V

[0048] The control method for the current-source type high-isolation auxiliary power supply in this embodiment is as follows:

[0049] Step 1: Calculate the resonant frequency of the primary coil and resonant capacitor of the transmitting magnetic core at the transmitting end.

[0050]

[0051] Select the number of current oscillation periods n=1, and configure the output pulse width of the transmitter current controller to be T. p :

[0052]

[0053] Step 2: Control the three-phase rectifier bridge to receive power from the outside, control the half-bridge circuit to be in a non-operating state, and connect the receiving end to the power electronic equipment that needs to receive power from the outside; set the target voltage of the voltage controller to the voltage required by the auxiliary power supply of the power electronic equipment, that is, set the target voltage of the receiving end voltage controller to be V. ref=28V. Start the voltage controller at the receiving end.

[0054] Step 3: Start the half-bridge circuit at the transmitting end, and control the half-bridge circuit to switch at a certain operating frequency. By changing the operating frequency of the half-bridge circuit, measure the average resonant current I of the primary coil of the transmitting core when all the output voltages of the receiving ends are equal to the corresponding target voltage. Lr0 And record the operating frequency f of the half-bridge circuit at this time. s0 Based on the average value of the resonant current I Lr0 Set the target current I of the current controller ref .

[0055] Average resonant current I Lr0 The current is 3.6A, and the operating frequency f of the half-bridge circuit is... s0 The frequency is 3kHz, the current margin factor is selected as 1.5, and the target current I of the transmitter's current controller is set. ref for:

[0056] I ref =k i *I Lr0 =5.4A

[0057] Step 4: Set the initial operating frequency of the half-bridge circuit to f. s0 The current controller is activated, and at the transmitting end, it detects the average resonant current of the primary coil of the transmitting core once per switching cycle of the half-bridge circuit. The operating frequency of the half-bridge circuit is controlled so that the average resonant current of the primary coil of the transmitting core is close to the target current I. ref Equal, completing the power supply of the power source to the power electronic equipment that needs to receive power from the outside.

[0058] When the average resonant current of the primary coil of the transmitting magnetic core is less than the target current I ref At the same time, increase the operating frequency of the half-bridge circuit at the start of the next switching cycle, and the frequency conversion coefficient k f If 0.1% is selected, the operating frequency is calculated as follows:

[0059] f s "=(1+0.1%)f s ′

[0060] Among them, f s ′ represents the operating frequency of the half-bridge circuit at the start of the current switching cycle; f s "This is the operating frequency of the half-bridge circuit at the start of the next switching cycle."

[0061] When the average resonant current of the primary coil of the transmitting magnetic core is greater than the target current - ref When this happens, the operating frequency of the half-bridge circuit at the start of the next switching cycle is reduced. The frequency calculation method is as follows:

[0062] f s "=(1-0.1%)f s ′

[0063] like Figure 4 As shown, when the output voltage of the receiver is lower than the target voltage, the receiver voltage controller outputs a low level, turning off the switching device. The transmitter, through magnetic coupling, charges the output capacitor of the receiver and supplies power to the power electronic equipment. When the output voltage of the receiver is higher than the target voltage, the receiver voltage controller outputs a high level, turning on the switching device. Power is supplied to the power electronic equipment solely by the output capacitor, and the receiver does not consume power from the transmitter, resulting in very low static losses. The output voltage is consistently maintained near the target voltage of 28V, achieving a stable voltage output.

[0064] like Figure 5 As shown, the output pulse width of the transmitter current controller is configured as follows: p This causes the upper transistor of the half-bridge circuit to be soft-turned on, and the primary coil of the transmitting magnetic core and the resonant capacitor at the transmitting end to resonate. A resonant current of one cycle flows through the high-voltage insulated cable. In the negative half-cycle of the second cycle of the resonant current, the current flows in reverse through the anti-parallel diode of the upper transistor of the half-bridge circuit. At this time, the control signal becomes low level, and the upper transistor of the half-bridge switching circuit is soft-turned off, realizing soft switching.

[0065] This invention relates to a current-source type high-isolation auxiliary power supply, which consists of a transmitter, a receiver, and a high-voltage insulated cable. The transmitter comprises a three-phase rectifier bridge, an input capacitor, a half-bridge circuit, a transmitting magnetic core, a resonant capacitor, and a current controller, drawing power from the power grid. The receiver comprises a receiving magnetic core, a full-bridge rectifier circuit, switching devices, anti-reverse diodes, an output capacitor, and a voltage controller. Power is transferred between the transmitter and receiver using magnetic coupling. The transmitter employs a soft-switching average current control mode, while the output employs an average voltage control mode. This auxiliary power supply is simple in circuitry, small in size, easy to control, low in cost, and allows for flexible configuration of the number of isolated output channels, making it suitable for a wider range of applications. Utilizing the characteristics of a current source, the input is short-circuited by controlling the switching devices at the receiver during static conditions, reducing static power consumption. Each module does not need to bear a high common-mode voltage, resulting in high isolation, making it suitable for auxiliary power supply applications in medium- and high-voltage power electronic equipment.

[0066] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A control method for a current-source type high-isolation auxiliary power supply, characterized in that, The current source type high isolation auxiliary power supply includes a transmitting end and several receiving ends; the transmitting end includes a three-phase rectifier bridge, an input capacitor, a half-bridge circuit, two resonant capacitors, a transmitting magnetic core and a current controller; the receiving end includes a receiving magnetic core, a full-bridge rectifier circuit, a switching device, an anti-reverse diode, an output capacitor and a voltage controller; the transmitting magnetic core is connected to the receiving magnetic core of each receiving end through a cable to form a magnetic circuit coupling structure; the cable serves as the secondary coil of the transmitting magnetic core and the receiving magnetic core. The AC input port of the three-phase rectifier bridge is used to receive electric energy from the outside. The positive DC output terminal of the three-phase rectifier bridge is respectively connected to the positive terminal of the input capacitor and the positive DC terminal of the half-bridge circuit, and the negative DC output terminal is respectively connected to the negative terminal of the input capacitor and the negative DC terminal of the half-bridge circuit. The AC output point of the half-bridge circuit is connected to the positive terminal of the primary coil of the transmitting magnetic core, and the negative terminal of the primary coil of the transmitting magnetic core is connected to the negative terminals of the two resonant capacitors. The positive terminal of one resonant capacitor is connected to the positive DC terminal of the half-bridge circuit, and the positive terminal of the other resonant capacitor is connected to the negative DC terminal of the half-bridge circuit; the input terminal of the current controller is used to collect the output current of the transmitting end, and the output terminal of the current controller is respectively connected to the gates of the two switching devices of the half-bridge circuit. In each receiving end, the positive terminal of the primary coil of the receiving magnetic core is connected to the positive input terminal of the full-bridge rectifier circuit, and the negative terminal of the primary coil is connected to the negative input terminal of the full-bridge rectifier circuit. The positive input terminal of the full-bridge rectifier circuit is also connected to the drain or collector of the switching device, and the negative input terminal of the full-bridge rectifier circuit is connected to the source or emitter of the switching device; the positive terminal of the anti-reverse diode is connected to the drain or collector of the switching device, and the negative terminal of the anti-reverse diode is connected to the positive terminal of the output capacitor. The negative terminal of the output capacitor is connected to the source or emitter of the switching device; the input terminal of the voltage controller is connected to the output terminal of the receiving end. The output terminal of the receiving end is used to output electric energy to the outside, and the output terminal of the voltage controller is connected to the gate of the switching device. The method includes: 1) Calculate the resonant frequencies of the primary coil of the transmitting magnetic core and the resonant capacitors; configure the output pulse width of the current controller at the transmitting end to achieve soft switching of the half-bridge circuit. 2) Control the three-phase rectifier bridge to receive electric energy from the outside, control the half-bridge circuit to be in a non-operating state, and connect the receiving end to the power electronic equipment to be powered from the outside; set the target voltage of the voltage controller to the voltage required for the auxiliary power supply of the power electronic equipment, and start the voltage controller at the receiving end. 3) Start the half-bridge circuit at the transmitting end and control the half-bridge circuit to switch at a certain operating frequency. By changing the operating frequency of the half-bridge circuit, measure the average value of the first resonant current of the primary coil of the transmitting core when the output voltage of all receivers is equal to the corresponding target voltage, and record the operating frequency of the half-bridge circuit at this time. The target current of the current controller is set based on the average value of the first resonant current. 4) Set the initial operating frequency of the half-bridge circuit to be... The current controller is activated. During each switching cycle of the half-bridge circuit, the current controller detects the average value of the second resonant current of the primary coil of the transmitting magnetic core and controls the operating frequency of the half-bridge circuit to make the average value of the second resonant current equal to the target current, thus completing the power supply to the power electronic equipment that needs to receive power.

2. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, The AC input port of the three-phase rectifier bridge is connected to an external three-phase AC power grid, a single-phase AC power grid or a DC power supply; when the AC input port of the three-phase rectifier bridge is connected to an external three-phase AC power grid, the three-phase AC power grid is connected to the three AC input ports of the three-phase rectifier bridge; when the AC input port of the three-phase rectifier bridge is connected to an external single-phase AC power grid or a DC power supply, the single-phase AC power grid or the DC power supply is connected to any two input ports of the three-phase rectifier bridge, and the other input port of the three-phase rectifier bridge is left empty.

3. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, The two switching devices of the half-bridge circuit at the transmitting end are full-controlled devices; the switching device at the receiving end is a full-controlled device; the full-controlled device is a MOSFET or an IGBT.

4. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, In step 1), the formula for calculating the resonance frequency of the primary coil of the transmitting core and the resonance capacitor is: in, This represents the resonant frequency of the primary coil of the transmitting magnetic core or the resonant frequency of the resonant capacitor. The resonant frequency of the primary coil of the transmitting magnetic core is equal to the resonant frequency of the resonant capacitor. This represents the inductance of the primary coil of the transmitting magnetic core; This represents the resonant capacitor.

5. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, In step 1), configuring the output pulse width of the current controller at the transmitting end includes: Obtaining the number of current oscillation periods at the transmitting end, and then calculating the output pulse width of the current controller based on the number of current oscillation periods and the resonance frequency; the calculation formula is: in, Indicates the output pulse width of the current controller; The number of current oscillation cycles; It is the resonant frequency.

6. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, In step 3), the formula for setting the target current of the current controller based on the average value of the first resonance current is: in, Indicates the target current of the current controller; This represents the average value of the first resonant current; This represents the current margin coefficient.

7. The control method for a current-source type high-isolation auxiliary power supply according to claim 1, characterized in that, In step 4), controlling the operating frequency of the half-bridge circuit to make the average value of the second resonance current equal to the target current includes: If the average value of the second resonant current is less than the target current, increase the operating frequency of the half-bridge circuit at the start of the next switching cycle, and make the operating frequency of the half-bridge circuit at the start of the next switching cycle be ; if the average value of the second resonant current is greater than the target current, decrease the operating frequency of the half-bridge circuit at the start of the next switching cycle, and make the operating frequency of the half-bridge circuit at the start of the next switching cycle be ; where represents the frequency conversion coefficient, represents the operating frequency of the half-bridge circuit at the start of the current switching cycle.

Images