Resonant power supply and control method thereof, and non-transitory computer readable storage medium

Abstract

The present application provides a resonant power supply and a control method thereof and a non-transient computer-readable storage medium. The resonant power supply includes a resonant converter and a resonant converter controller, and the resonant converter controller includes a trajectory radius module, a first comparator module, a zero-crossing detection module and a control module. The trajectory radius module is used to obtain a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply; the first comparator module is used to obtain an overcurrent protection trigger signal based on the current of the resonant inductor and the current threshold; the zero-crossing detection module is used to obtain a zero-crossing detection trigger signal based on whether the current of the resonant inductor crosses zero; the control module is used to control the switching of the switch level based on at least one signal among the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal and the clock signal.

Description

Technical Field

[0001] The present invention relates to a resonant power supply, and in particular to a resonant power supply and a control method thereof, and a non-transient computer-readable storage medium. Background Art

[0002] As a type of switching converter, the resonant converter has been used to a certain extent in industrial applications such as communications, medical treatment, welding, etc. Generally, when the resonant converter is in operation, it can adjust and convert the electric energy input from the power supply, and apply the adjusted electric energy to the load for use by the load. The resonant converter generally includes a plurality of switching devices configured in a half-bridge or full-bridge architecture, and the switching devices are turned on or off under the action of the switching signal to perform energy regulation conversion.

[0003] Typically, the resonant converter controller uses an optimal trajectory control algorithm to generate a phase delay between the switching signals acting on the switching device according to the detected state variables of the resonant converter and the command signal, so as to drive the switching of the switches of the switching device. However, typically, the resonant converter controller is implemented by analog circuit control, the analog components in the control loop will have different degrees of differences, and the circuit is complex and difficult to debug, resulting in an unstable no-load output voltage. Summary of the invention

[0004] The present invention provides a resonant power supply and a control method thereof, and a non-transient computer-readable storage medium.

[0005] An exemplary embodiment of the present invention provides a resonant power supply, which includes a resonant converter and a resonant converter controller connected to the resonant converter, wherein the resonant converter includes a switch stage, a resonant inductor, a resonant capacitor and an isolation transformer, and the resonant converter controller includes a trajectory radius module, a first comparator module, a zero-crossing detection module and a control module. The trajectory radius module is configured to obtain a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply; the first comparator module is configured to obtain an overcurrent protection trigger signal based on the current of the resonant inductor and the current threshold; the zero-crossing detection module is configured to obtain a zero-crossing detection trigger signal based on whether the current of the resonant inductor crosses zero; the control module is configured to control the switching of the switch stage based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal and the clock signal.

[0006] An exemplary embodiment of the present invention also provides a control method for a resonant power supply, wherein the resonant power supply includes a resonant converter and a resonant converter controller connected to the resonant converter, the resonant converter includes a switch stage, a resonant inductor, a resonant capacitor and an isolation transformer, wherein the control method includes: obtaining a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply; obtaining an overcurrent protection trigger signal based on the current and current threshold of the resonant inductor; obtaining a zero-crossing detection trigger signal based on whether the current of the resonant inductor passes through zero; and controlling the switching of the switch stage based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal, and a clock signal.

[0007] Exemplary embodiments of the present invention further provide a non-transitory computer-readable storage medium for storing a computer program, wherein the computer program includes instructions for executing the above-mentioned resonant power supply control method.

[0008] Other features and aspects will become apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention may be better understood by describing exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a schematic diagram of a resonant power supply according to some embodiments of the present invention;

[0011] Figure 2 is based on Figure 1 A schematic diagram of a resonant converter controller of a resonant power supply shown;

[0012] Figure 3 is based on Figure 2 A schematic diagram of a control module in a resonant converter controller shown;

[0013] Figure 4 A schematic diagram showing the timing relationship between various waveforms in a resonant power supply is shown;

[0014] Figure 5 Shows Figure 3 A schematic diagram of the control rules of the control module shown; and

[0015] Figure 6 A flow chart showing a method for controlling a resonant power supply according to some embodiments of the present invention is shown. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention will be described below. It should be noted that in the specific description of these embodiments, in order to provide a concise description, it is impossible for this specification to provide a detailed description of all the features of the actual embodiments. It should be understood that in the actual implementation of any embodiment, just as in the process of any engineering project or design project, in order to achieve the specific goals of the developer and to meet system-related or business-related restrictions, various specific decisions are often made, and this will also change from one embodiment to another. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the content disclosed by the present invention, some changes such as design, manufacturing or production based on the technical content disclosed in this disclosure are just conventional technical means, and should not be understood as insufficient content of this disclosure.

[0017] Unless otherwise defined, the technical or scientific terms used in the claims and the specification shall have the usual meaning understood by persons with ordinary skills in the technical field to which the invention belongs. The words "first", "second" and similar words used in the patent application specification and the claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. "Include" or "comprises" and other similar words mean that the elements or objects appearing before "include" or "comprises" include the elements or objects listed after "include" or "comprises" and their equivalent elements, and do not exclude other elements or objects. "Connected" or "connected" and other similar words are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0018] In some embodiments, in a magnetic resonance imaging system (MRI), a resonant power supply can be used to receive electric energy input from an external power supply, and adjust and transform the input electric energy into output electric energy to provide to a gradient amplifier, so that the gradient amplifier can drive one or more gradient coils (e.g., gradient coils for three axes of X, Y and Z) to generate a gradient magnetic field for magnetic resonance imaging. It should be pointed out that, from the perspective of ordinary technicians in this field or related fields, such a description should not be understood as limiting the present invention to magnetic resonance imaging systems. In fact, the resonant power supply described herein can be reasonably applied to other related occasions, such as communications, medical treatment, and welding, etc.

[0019] Figure 1 FIG. 1 is a schematic diagram of a resonant power supply 100 according to some embodiments of the present invention. Figure 1As shown, the resonant power supply 100 includes a resonant converter 101 and a resonant converter controller 140 . The resonant converter 101 includes a switch stage 110 , a resonant circuit 120 , an isolation transformer 136 and an output stage 130 .

[0020] The switch stage 110 receives an input DC voltage (V dc ) 102, and selectively provides a DC voltage (V dc ) 102 to the resonant circuit 120. In some embodiments, the switch stage 110 is configured as a full-bridge architecture, which includes a first bridge arm 111 and a second bridge arm 121, the first bridge arm 111 includes a first switch 108 and a second switch 112 connected in series, and the second bridge arm 121 includes a third switch 114 and a fourth switch 116 connected in series, wherein the connection point between the first switch 108 and the second switch 112 is a first node 109, and the connection point between the third switch 114 and the fourth switch 116 is a second node 115. The switch elements 108, 112, 114, 116 can be any suitable solid-state semiconductor switch devices, such as insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistors (MOSFETs). The switch stage 110 further includes diodes 118, 122, 124 and 126, and the diodes 118, 122, 124 and 126 are respectively connected to the switch elements 108, 112, 114, 116 in an anti-parallel manner. Taking the connection between the first switch 108 and the diode 118 as an example, the collector of the first switch 108 is connected to the cathode of the diode 118, and the emitter of the first switch 108 is connected to the anode of the diode 118. In some embodiments, the first switch 108 and the second switch 112 in the first bridge arm 111 operate in a complementary manner, that is, when the first switch 108 is turned on, the second switch 112 is turned off. Similarly, the third switch 114 and the fourth switch 116 in the second bridge arm 121 also operate in a complementary manner. In other embodiments, the switch stage 110 can also adopt a half-bridge architecture and any other suitable topology architecture known to ordinary technicians in the field.

[0021] The isolation transformer 136 is used to electrically isolate the resonant circuit 120 from the output stage 130. The isolation transformer 136 includes a primary winding 138 and a secondary winding 142. The resonant circuit 120 may include a resonant inductor 132 and a resonant capacitor 134. The resonant inductor 132 and the resonant capacitor 134 are sequentially connected in series between the first node 109 and one end (e.g., the positive end) of the primary winding 138 of the isolation transformer 136, and the other end (e.g., the negative end) of the primary winding 138 is connected to the second node 115.

[0022] The output stage 130 outputs a regulated DC voltage (V0) 157 via two output ports 152 and 154 to apply it to a load 156. The output stage 130 includes a rectifier 144 formed by a diode device. The rectifier 144 is connected to the secondary winding 142 of the isolation transformer 136 and is configured to rectify the voltage generated by the secondary winding 142. In some embodiments, the output stage 130 further includes an output capacitor 146 connected in parallel with the rectifier 144, which has the function of a low-pass filter to filter out the fluctuation signal in the DC voltage generated by the rectifier 144. It can be understood that in other embodiments, the output stage 130 can also omit the output capacitor 146 in specific implementation.

[0023] The resonant converter controller 140 is connected to a plurality of signal detectors or sensors for detecting and monitoring a plurality of state variables of the resonant converter 101, in particular the resonant circuit 120. In some embodiments, the state variables include the resonant inductor current I flowing through the resonant inductor 132. _Lr , the resonant capacitor voltage V at the resonant capacitor 134 _Cr , the primary voltage V at the primary winding 138 of the isolation transformer 136 _pri , and the output voltage V at the secondary winding 142 _load . Resonant inductor current I _Lr The resonant capacitor voltage V _Cr The primary voltage V _pri The output voltage V _load The voltage can be detected by the third voltage sensor 158, which can provide a corresponding signal to the resonant converter controller 140. The converter controller 140 further receives a voltage command signal V _cmd To control the operation of the resonant converter 101.

[0024] In some embodiments, the resonant converter controller 140 is further connected to the switch stage 110, and provides a first switch signal 182 to control the switching of the first switch 108, provides a second switch signal 184 to control the switching of the second switch 112, provides a third switch signal 186 to control the switching of the third switch 114, and provides a fourth switch signal 188 to control the switching of the fourth switch 116. In other embodiments, the resonant converter controller 140 is further connected to the switch stage 110, provides a switch signal to control the first switch 108 and the second switch 112 in the first bridge arm 111, and provides another switch signal to control the third switch 114 and the fourth switch 116 in the second bridge arm 121. In still other embodiments, the resonant converter controller 140 is connected to the switch stage 110 to control the switching of the switches in the switch stage 110 in other control modes.

[0025] Figure 2 Shows Figure 1 Schematic diagrams of some embodiments of the resonant converter controller 140 in the resonant power supply 100 shown in FIG. Figure 2 As shown, the resonant converter controller 140 includes a trajectory radius module 210, a first comparator module 220, a zero-crossing detection module 230, and a control module 240. The trajectory radius module 210 is configured to determine the current I based on the resonant inductor. _Lr , the voltage of the resonant capacitor V _Cr , the primary voltage V at the primary winding of the isolation transformer _pri and the output voltage V at the secondary winding _load At least one signal in the output voltage command signal V _cmd Get the trajectory radius trigger signal R _trig The first comparator module 220 is configured to determine the resonant inductor current I _Lr With the current threshold T a Get overcurrent protection trigger signal I _trig The zero-crossing detection module 230 is configured to detect the resonant inductor current I _Lr Whether it is zero crossing or not, get zero crossing detection trigger signal I _zero The control module 240 is configured to trigger the signal R based on the trajectory radius. _trig , overcurrent protection trigger signal I _trig , zero-crossing detection trigger signal I _zero and at least one of the clock signals Timer controls the switch stage 110 (eg Figure 1 shown).

[0026] In some embodiments, the trajectory radius module 210 includes an adjustment module 211, a trajectory radius calculation module 212, and a second comparator module 213. The adjustment module 211 is configured to calculate the trajectory radius based on the output voltage V_load With the voltage command signal V _cmd The difference V _err Output trajectory radius command signal R _cmd In some embodiments, the regulating module 211 may include a proportional-integral (PI) regulating module. In other embodiments, the regulating module 211 may include a proportional-integral-derivative (PID) regulating module, a fuzzy control regulating module, or other process control regulating modules.

[0027] The trajectory radius calculation module 212 is configured to calculate the real-time current I based on the resonant inductor. _Lr , the real-time voltage of the resonant capacitor V _Cr , and the real-time voltage V at the primary winding of the isolation transformer _pri Calculate the trajectory radius feedback signal R _fed In some embodiments, the trajectory radius feedback signal R _fed It can be calculated by the following formula:

[0028]

[0029] Where, Z0 is the characteristic impedance of the resonant inductor and capacitor, I _Lr is the real-time current of the resonant inductor, V _Cr is the real-time voltage of the resonant capacitor, V _pri is the real-time voltage at the primary winding of the isolation transformer, R _fed is the trajectory radius feedback signal.

[0030] In some other embodiments, the trajectory radius calculation module 212 is configured to calculate the real-time current I based on the resonant inductor. _Lr , the real-time voltage of the resonant capacitor V _Cr , and the real-time output voltage V _load Calculate the trajectory radius feedback signal R _fed For example, the trajectory radius feedback signal R _fed It can be calculated by the following formula:

[0031] For I _Lr >0

[0032] For I _Lr <0

[0033] Where, Z0 is the characteristic impedance of the resonant inductor and capacitor, I _Lr is the real-time current of the resonant inductor, V _Cr is the real-time voltage of the resonant capacitor, V _load is the real-time output voltage at the secondary winding of the isolation transformer, N is the turns ratio between the primary winding and the secondary winding of the isolation transformer, R _fed is the trajectory radius feedback signal.

[0034] The second comparator module 213 is configured to convert the trajectory radius instruction signal R _cmd and trajectory radius feedback signal R _fed Compare and output trajectory radius trigger signal R _trig In some embodiments, when the trajectory radius feedback signal R _fed Greater than the trajectory radius command signal R _cmd When the output is logic high, for example, the trajectory radius trigger signal R _trig =1, when the trajectory radius feedback signal R _fed Not greater than the trajectory radius command signal R _cmd When the output is logic low, for example, the trajectory radius trigger signal R _trig =0.

[0035] In some embodiments, when the resonant inductor current I _Lr Greater than the current threshold T a When the first comparator module 220 outputs a logic high level, for example, an overcurrent protection trigger signal I _trig =1, when the current of the resonant inductor I _Lr Not greater than the current threshold T a When the first comparator module 220 outputs a logic low level, for example, the overcurrent protection trigger signal I _trig =0.

[0036] In some embodiments, when the resonant inductor current I _Lr When the zero-crossing detection module 230 is equal to zero, the zero-crossing detection module 230 outputs a logic high level, for example, the zero-crossing detection trigger signal I _zero =1, when the current of the resonant inductor I _Lr When it is not equal to zero, the zero-crossing detection module 230 outputs a logic low level, for example, the zero-crossing detection trigger signal I _zero =0.

[0037] In some embodiments, in the resonant converter controller 140, the trajectory radius calculation module 212 is implemented in the form of hardware, for example, by analog circuit modules such as analog multipliers and analog adders, while the adjustment module 211, the second comparator module 213, the first comparator module 220, the zero-crossing detection module 230 and the control module 240 can be implemented in the form of software, for example, by a digital control module. By implementing the trajectory radius calculation module through hardware, a real-time trajectory radius feedback signal can be calculated based on real-time state variables (for example, the current of the resonant inductor, the voltage of the resonant capacitor, the voltage at the primary winding of the isolation transformer, etc.), so as to facilitate more timely and efficient control of the switching between the switch levels, and by implementing other modules through a digital control module, the power consumption and disturbance effects of the analog components can be reduced, and the working efficiency of the resonant converter can be improved.

[0038] Figure 3 Shows Figure 2 Schematic diagram of some embodiments of the control module 240 in the resonant converter controller 140 shown in FIG. Figure 3 As shown, the control module 240 includes a first bridge arm control unit 242, and the first bridge arm control unit 242 is used to trigger the zero-crossing detection signal I _zero Control the switching between the first switch 108 and the second switch 112 in the first bridge arm 111. In some embodiments, the first bridge arm control unit 242 is configured to _zero =1, the first switch signal 182 and the second switch signal 184 are used to control the switching of the first switch 108 and the second switch 112. For example, in a certain mode, the first switch 108 is in the on state and the second switch 112 is in the off state. When the zero-crossing detection trigger signal I is detected _zero =1, the first bridge arm control unit can control the first switch 108 to be turned off and the second switch 112 to be turned on.

[0039] In some embodiments, the control module 240 may include a mode selection unit 241, which is connected to the adjustment module 211 and is configured to adjust the trajectory radius based on the command signal R _cmd Select the light load mode unit 281 or the heavy load mode unit 282 to control the switching between the third switch 114 and the fourth switch 116. In some embodiments, when the trajectory radius command signal R _cmd Not greater than the radius threshold T R When the resonant power supply 100 operates in the light load mode, the mode selection unit 241 selects the light load mode unit 281 to control the switching between the third switch 114 and the fourth switch 116. _cmd Greater than the radius threshold T RWhen the resonant power supply 100 operates in the heavy load mode, the mode selection unit 241 selects the heavy load mode. The unit 282 can control the switching between the third switch 114 and the fourth switch 116 through the third switch signal 186 and the fourth switch signal 188.

[0040] In some embodiments, the light load mode unit 281 includes a third comparator module 243 and a light load mode control unit 244. The third comparator module 243 is used to output a light load mode trigger signal T based on the clock signal Timer and the first threshold T1. 1_trig The light load mode control unit 244 is used to trigger the light load mode based on the light load mode trigger signal T 1_trig Control switching between the third switch 114 and the fourth switch 116. In some embodiments, the first threshold T1 is the minimum duty cycle of the full-bridge output of the switch stage 110, and the minimum duty cycle of the full-bridge output of the switch stage is the minimum quotient of the time when the switch stage output is a positive voltage and a cycle time, for example, Figure 4 As shown, the minimum duty cycle of the switch stage output is the minimum quotient of the time α of mode 1 and the entire cycle time T from mode 1 to mode 4. In some embodiments, when the clock signal Timer is not greater than the first threshold T1, the light load mode trigger signal T is output. 1_trig =0, when the clock signal Timer is greater than the first threshold T1, the light load mode trigger signal T 1_trig =1, when the third comparator module 243 outputs the light load mode trigger signal T 1_trig =1, the light-load mode control unit 244 controls the switching between the third switch 114 and the fourth switch 116 through the third switch signal 186 and the fourth switch signal 188 .

[0041] In some embodiments, the reload mode unit 282 includes a fourth comparator module 245 and a reload mode control unit 246. The fourth comparator module 245 is used to output a reload mode trigger signal T based on the clock signal Timer and the second threshold T2. 2_trig The overload mode control unit 246 is used to trigger the overload mode signal T based on 2_trig , trajectory radius trigger signal R _trig and overcurrent protection trigger signal I _trig One of them controls the switching between the third switch 114 and the fourth switch 116. In some embodiments, the second threshold T2 is the maximum on-time of any switch in the switch stage 110. Usually, each switch element in the switch stage 110 has an operating frequency range, for example, 17KHZ-37KHZ, that is, each switch element has a maximum on-time and a minimum on-time, and the second threshold is the maximum on-time of any switch element. In some embodiments, when the clock signal Timer is not greater than the second threshold T2, the overload mode trigger signal T is output.2_trig =0, when the clock signal Timer is greater than the second threshold T2, the reload mode trigger signal T 2_trig =1, when the heavy load mode trigger signal T 2_trig , trajectory radius trigger signal R _trig , and the overcurrent protection trigger signal I _trig When one of the signals is equal to 1, the heavy-load mode control unit 246 can control the switching between the third switch 114 and the fourth switch 116 through the third switch signal 186 and the fourth switch signal 188 .

[0042] Figure 4 A schematic diagram 190 showing the timing relationship between various waveforms in some embodiments of the resonant power supply 100 is shown. Figure 5 Shows Figure 3 FIG. 2 is a schematic diagram of a control rule 300 of the control module 240. Figure 4-5 As shown, the first waveform 182 and the second waveform 184 are the switching signal waveforms of the first switch 108 and the second switch 112 in the first bridge arm, the third waveform 186 and the fourth waveform 188 are the switching signal waveforms of the third switch 114 and the fourth switch 116 in the second bridge arm 121, and the current waveform 192 is the resonant current I flowing through the resonant inductor 132. _Lr The voltage waveform diagram 194 shows the voltage U between the first node 109 and the second node 115. 12 .

[0043] In some embodiments, when the resonant power supply 100 starts to operate, the switch stage 110 first operates in mode 1, that is, the first switch 108 and the fourth switch 116 are in the on state.

[0044] In mode 1, the first switch 108 and the fourth switch 116 are in the on state. Since the first switch 108 and the second switch 112 are in a complementary relationship, the third switch 114 and the fourth switch 116 are in a complementary relationship, the second switch 112 and the third switch 114 are in the off state, and the voltage U 12 is positive, the resonant current I _Lr The control module 240 can select the light load mode or the heavy load mode to control the switching between the third switch 114 and the fourth switch 116. In the light load mode, when the trigger condition 301 satisfies the clock signal Timer greater than the first threshold T1 (i.e., the light load mode trigger signal T 1_trig=1), the control module 240 controls the switching between the third switch 114 and the fourth switch 116, that is, the control module 240 controls the fourth switch 116 to be turned off and the third switch 114 to be turned on. At this time, the diode 124 connected in anti-parallel to the third switch 114 is in a conducting state, that is, the switch stage 110 works in mode 2. In the heavy load mode, when the trigger condition 301 satisfies one of the following three conditions: when the clock signal Timer is greater than the second threshold value T2 (that is, the heavy load mode trigger signal T 2_trig =1), trajectory radius trigger signal R _trig =1, and the overcurrent protection trigger signal I _trig =1, the control module 240 controls the switching between the third switch 114 and the fourth switch 116, that is, the control module 240 controls the fourth switch 116 to be turned off and the third switch 114 to be turned on. At this time, the diode 124 anti-parallel to the third switch 114 is in the on state, that is, the switch stage 110 works in mode 2.

[0045] In mode 2, the first switch 108 and the third switch 114 are in the on state, while the second switch 112 and the fourth switch 116 are in the off state, and the voltage U 12 is zero, the resonant current I _Lr When the trigger condition 302 satisfies the zero-crossing detection trigger signal I _zero =1, the control module 240 controls the switching between the first switch 108 and the second switch 112 , that is, the control module 240 controls the first switch 108 to be turned off and the second switch 112 to be turned on, and the switch stage 110 operates in mode 3.

[0046] In mode 3, the second switch 112 and the third switch 114 are in the on state, while the first switch 108 and the fourth switch 116 are in the off state, and the voltage U 12 is negative, the resonant current I _Lr The control module 240 selects the light load mode or the heavy load mode to control the switching between the third switch 114 and the fourth switch 116. In the light load mode, when the trigger condition 303 satisfies the clock signal Timer greater than the first threshold T1 (i.e., the light load mode trigger signal T 1_trig =1), the control module 240 controls the switching between the third switch 114 and the fourth switch 116, that is, the control module 240 controls the third switch 114 to be turned off and the fourth switch 116 to be turned on. At this time, the diode 126 connected in anti-parallel to the fourth switch 116 is in a conducting state, that is, the switch stage 110 works in mode 4. In the heavy load mode, when the trigger condition 303 satisfies one of the following three conditions: when the clock signal Timer is greater than the second threshold value T2 (that is, the heavy load mode trigger signal T 2_trig =1), trajectory radius trigger signal R _trig=1, and the overcurrent protection trigger signal I _trig =1, the control module 240 controls the switching between the third switch 114 and the fourth switch 116, that is, the control module 240 controls the third switch 114 to be turned off and the fourth switch 116 to be turned on. At this time, the diode 126 anti-parallel to the fourth switch 116 is in the on state, that is, the switch stage 110 works in mode 4.

[0047] In mode 4, the second switch 112 and the fourth switch 116 are in the on state, while the first switch 108 and the third switch 114 are in the off state, and the voltage U 12 is zero, the resonant current I _Lr When the trigger condition 304 satisfies the zero-crossing detection trigger signal I _zero =1, the control module 240 controls the switching between the first switch 108 and the second switch 112, that is, the control module 240 controls the second switch 112 to be turned off and the first switch 108 to be turned on, and the switch stage 110 works in mode 1, and so on.

[0048] Figure 6 FIG. 4 is a flow chart showing a control method 400 of a resonant power supply 100 according to some embodiments of the present invention. Figure 6 As shown, the control method 400 of the resonant power supply includes the following steps.

[0049] In step 410, a trajectory radius trigger signal is obtained based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply. In some embodiments, step 410 includes the following steps:

[0050] In step 411, a trajectory radius command signal is output based on the difference between the secondary side voltage of the isolation transformer and the voltage command signal.

[0051] In step 412, a trajectory radius feedback signal is calculated based on the real-time current of the resonant inductor, the real-time voltage of the resonant capacitor, and the real-time voltage of the primary side of the isolation transformer. In some embodiments, the trajectory radius feedback signal can be calculated using the following formula:

[0052]

[0053] Where, Z0 is the characteristic impedance of the resonant inductor and capacitor, I _Lr is the real-time current of the resonant inductor, V _Cr is the real-time voltage of the resonant capacitor, V _pri is the real-time voltage on the primary side of the isolation transformer, R _fed is the trajectory radius feedback signal.

[0054] In other embodiments, the trajectory radius feedback signal can also be calculated based on the real-time current of the resonant inductor, the real-time voltage of the resonant capacitor, and the real-time output voltage of the secondary side of the isolation transformer. For example, the trajectory radius feedback signal can be calculated using the following formula:

[0055] For I _Lr >0

[0056] For I _Lr <0

[0057] Where, Z0 is the characteristic impedance of the resonant inductor and capacitor, I _Lr is the real-time current of the resonant inductor, V _Cr is the real-time voltage of the resonant capacitor, V _load is the real-time output voltage on the secondary side of the isolation transformer, N is the turns ratio between the primary and secondary windings of the isolation transformer, R _fed is the trajectory radius feedback signal.

[0058] In step 413, the trajectory radius command signal and the trajectory radius feedback signal are compared and a trajectory radius trigger signal is output. In some embodiments, when the trajectory radius feedback signal is greater than the trajectory radius command signal, a logic high level is output, and when the trajectory radius feedback signal is not greater than the trajectory radius command signal, a logic low level is output.

[0059] In some embodiments, the control method 400 further includes step 420, selecting a light load mode or a heavy load mode based on the trajectory radius command signal to control the switching between the third switch and the fourth switch. In some embodiments, when the trajectory radius command signal is not greater than the radius threshold, the resonant power supply operates in the light load mode, and when the trajectory radius command signal is greater than the radius threshold, the resonant power supply operates in the heavy load mode.

[0060] In step 430, an overcurrent protection trigger signal is obtained based on the current of the resonant inductor and the current threshold. In some embodiments, when the current of the resonant inductor is greater than the current threshold, the overcurrent protection trigger signal is a logic high level, and when the current of the resonant inductor is not greater than the current threshold, the overcurrent protection trigger signal is a logic low level.

[0061] In step 440, a zero-crossing detection trigger signal is obtained based on whether the current of the resonant inductor crosses zero. When the current of the resonant inductor is zero, the zero-crossing detection trigger signal is a logic high level, and when the current of the resonant inductor is not zero, the zero-crossing detection trigger signal is a logic low level.

[0062] In step 450, the switching of the switch stage is controlled based on at least one of a trajectory radius trigger signal, an overcurrent protection trigger signal, a zero-crossing detection trigger signal, and a clock signal. In some embodiments, the switching between the first switch and the second switch is controlled based on the zero-crossing detection trigger signal. In some embodiments, when the resonant power supply operates in a light load mode, a light load mode trigger signal is output based on the clock signal and the first threshold, and the switching between the third switch and the fourth switch is controlled based on the light load mode trigger signal. In some embodiments, when the resonant power supply operates in a heavy load mode, a heavy load mode trigger signal is output based on the clock signal and the second threshold, and the switching between the third switch and the fourth switch is controlled based on one of the trajectory radius trigger signal, the overcurrent protection trigger signal, and the heavy load mode trigger signal.

[0063] The control method of the resonant power supply proposed in the present invention realizes the combination of hardware and software, that is, the control mode of combining analog and digital, on the basis of the optimal trajectory control algorithm, so that the resonant power supply can reduce the power consumption and disturbance influence of analog components by reducing the number of analog components in the resonant converter on the basis of retaining the advantages of the existing soft switch, and on the other hand, the trajectory radius calculation module is realized by hardware, so that the real-time trajectory radius feedback signal can be calculated according to the real-time state variable, so as to control the switching between the switch levels more timely and efficiently. In addition, by judging whether the resonant power supply is in light load mode or heavy load mode, different signals are selected to control the switching of the switch level, which eliminates low-frequency disturbances, improves the stability of control in light load mode, realizes more efficient control, and achieves higher output efficiency of the power supply. Moreover, the resonant converter controller is realized by software control, the number of analog components is reduced, the cost is reduced, and subsequent maintenance or service is more convenient.

[0064] The present invention may also provide a non-transitory computer-readable storage medium for storing an instruction set and / or a computer program, which, when running on a resonant power supply, uses the above-mentioned control method to control the resonant power supply. In some embodiments, the non-transitory computer-readable storage medium may be a device such as a floppy disk, a CD-ROM, or a digital versatile disk (DVD) that enables a computer or other machine to read instructions or data therefrom. It should be understood that there are other suitable machine-readable memory types (such as rewritable optical disks and flash memories), and this document does not exclude any of them. In other embodiments, a computer program for executing a resonant power supply control method may be programmed in a computer processor installed in a magnetic resonance imaging system, and the program may be executed by a computer of the magnetic resonance imaging system to achieve control of the resonant power supply. In other embodiments, the above-mentioned resonant power supply control method may also be executed by other related machines.

[0065] Specifically, the set of instructions and / or computer program, when executed by a computer, causes the computer to:

[0066] Obtaining a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply;

[0067] An over-current protection trigger signal is obtained based on the current and current threshold of the resonant inductor;

[0068] Obtaining a zero-crossing detection trigger signal based on whether the current of the resonant inductor crosses zero; and

[0069] The switching of the switch stage is controlled based on at least one of a trajectory radius trigger signal, an overcurrent protection trigger signal, a zero-crossing detection trigger signal, and a clock signal.

[0070] In some embodiments, any two or more instructions in the above instructions can be combined into one instruction for execution. In other embodiments, any instruction in the above instructions can also be split into multiple instructions for execution, and in addition, it is not limited to the execution order of the above instructions.

[0071] In some embodiments, the set of instructions and / or the computer program further causes the computer to:

[0072] A light load mode or a heavy load mode is selected based on the trajectory radius command signal to control switching between the third switch and the fourth switch.

[0073] In some embodiments, obtaining a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply includes:

[0074] Outputting a trajectory radius command signal based on a difference between a secondary side voltage of the isolation transformer and a voltage command signal;

[0075] receiving a trajectory radius feedback signal calculated by the hardware module; and

[0076] The trajectory radius command signal and the trajectory radius feedback signal are compared and a trajectory radius trigger signal is output.

[0077] In some embodiments, controlling the switching of the switch stage based on at least one of a trajectory radius trigger signal, an overcurrent protection trigger signal, a zero-crossing detection trigger signal, and a clock signal comprises:

[0078] Control switching between the first switch and the second switch based on the zero-crossing detection trigger signal;

[0079] outputting a light-load mode trigger signal based on the clock signal and the first threshold, and controlling switching between the third switch and the fourth switch based on the light-load mode trigger signal; and

[0080] A heavy load mode trigger signal is output based on the clock signal and the second threshold, and switching between the third switch and the fourth switch is controlled based on the trajectory radius trigger signal, the overcurrent protection trigger signal, and one of the heavy load mode trigger signal.

[0081] As used herein, the term "computer" or "module" may include any processor-based or microprocessor-based system, including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuits or processors capable of performing the functions described herein. The above examples are merely exemplary, and are not intended to limit the definition and / or meaning of the term "computer" or "module" in any way.

[0082] The instruction set may include various commands that instruct a computer or processor as a processing machine to perform specific operations, such as the methods and processes of various embodiments. The instruction set may take the form of a software program that may form part of one or more tangible non-transitory computer-readable media. The software may take various forms such as system software or application software. In addition, the software may take the form of a collection of independent programs or modules, a program module within a larger program, or a portion of a program module. The software may also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to operator commands, or in response to previous processing results, or in response to a request made by another processing machine.

[0083] Some exemplary embodiments have been described above, however, it should be understood that various modifications may be made. For example, if the described techniques are performed in a different order and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents, suitable results may be achieved. Accordingly, other implementations also fall within the scope of protection of the claims.

Claims

1. A resonant power supply, comprising: A resonant converter including a switching stage, a resonant inductor, a resonant capacitor and an isolation transformer; as well as A resonant converter controller connected to the resonant converter, and the converter controller comprises: A trajectory radius module, configured to obtain a trajectory radius trigger signal based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply; A first comparator module, configured to obtain an overcurrent protection trigger signal based on the current of the resonant inductor and a current threshold; a zero-crossing detection module, configured to obtain a zero-crossing detection trigger signal based on whether the current of the resonant inductor crosses zero; and A control module, configured to control the switching of the switch stage based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal and the clock signal; wherein: The switch stage includes a first switch and a second switch located in a first bridge arm, and a third switch and a fourth switch located in a second bridge arm, a connection point between the first switch and the second switch is a first node, a connection point between the third switch and the fourth switch is a second node, the resonant inductor and the resonant capacitor are connected in series between the first node and one end of the primary winding of the isolation transformer, and the other end of the primary winding of the isolation transformer is connected to the second node; The trajectory radius module includes: a regulating module configured to output a trajectory radius command signal based on a difference between a secondary side voltage of the isolation transformer and the voltage command signal; a trajectory radius calculation module, configured to calculate a trajectory radius feedback signal based on the real-time current of the resonant inductor, the real-time voltage of the resonant capacitor, and the real-time voltage of the primary side of the isolation transformer; and a second comparator module, configured to compare the trajectory radius command signal with the trajectory radius feedback signal and output the trajectory radius trigger signal; The control module includes a mode selection unit, which is connected to the adjustment module and is configured to select a light load mode unit or a heavy load mode unit based on the trajectory radius instruction signal to control the switching between the third switch and the fourth switch, wherein when the light load mode unit is selected, a light load mode trigger signal is output based on the clock signal and the minimum duty cycle output by the switch stage to control the switching between the third switch and the fourth switch, and when the heavy load mode unit is selected, a heavy load mode trigger signal is generated based on the clock signal and the maximum on-time of any switch from the first switch to the fourth switch, and the switching between the third switch and the fourth switch is controlled based on the heavy load mode trigger signal, the trajectory radius trigger signal and one of the overcurrent protection trigger signal.

2. The resonant power supply according to claim 1, wherein: The control module includes a first bridge arm control unit configured to control switching between the first switch and the second switch based on the zero-crossing detection trigger signal.

3. The resonant power supply according to claim 1, wherein: When the trajectory radius command signal is not greater than the radius threshold, the resonant power supply operates in a light load mode, and the mode selection unit selects the light load mode unit. When the trajectory radius command signal is greater than the radius threshold, the resonant power supply operates in a heavy load mode, and the mode selection unit selects the heavy load mode unit.

4. The resonant power supply according to claim 1, wherein: The light load mode unit comprises: A third comparator module, configured to output the light load mode trigger signal based on the clock signal and the minimum duty cycle; A light load mode control unit is configured to control switching between the third switch and the fourth switch based on the light load mode trigger signal.

5. The resonant power supply according to claim 1, wherein: The heavy load mode unit comprises: a fourth comparator module, configured to output the heavy load mode trigger signal based on the clock signal and the maximum on-time; A heavy-load mode control unit is configured to control switching between the third switch and the fourth switch based on one of the heavy-load mode trigger signal, the trajectory radius trigger signal and the overcurrent protection trigger signal.

6. A control method for a resonant power supply, the resonant power supply comprising a resonant converter and a resonant converter controller connected to the resonant converter, the resonant converter comprising a switch stage, a resonant inductor, a resonant capacitor and an isolation transformer, the switch stage comprising: A first switch and a second switch are located in the first bridge arm, and a third switch and a fourth switch are located in the second bridge arm, the connection point between the first switch and the second switch is a first node, the connection point between the third switch and the fourth switch is a second node, the resonant inductor and the resonant capacitor are connected in series between the first node and one end of the primary winding of the isolation transformer, and the other end of the primary winding of the isolation transformer is connected to the second node, Wherein, the control method comprises: A trajectory radius trigger signal is obtained based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply, including: Outputting a trajectory radius command signal based on a difference between a secondary side voltage of the isolation transformer and the voltage command signal; Calculating a trajectory radius feedback signal based on the real-time current of the resonant inductor, the real-time voltage of the resonant capacitor, and the real-time voltage of the primary side of the isolation transformer; and Compare the trajectory radius command signal with the trajectory radius feedback signal and output the trajectory radius trigger signal; Obtaining an overcurrent protection trigger signal based on the current and current threshold of the resonant inductor; Obtaining a zero-crossing detection trigger signal based on whether the current of the resonant inductor crosses zero; and The switching of the switch stage is controlled based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal, and the clock signal, including: Based on the trajectory radius command signal, a light load mode or a heavy load mode is selected to control the switching between the third switch and the fourth switch, wherein, when the light load mode is selected, a light load mode trigger signal is output based on the clock signal and the minimum duty cycle output by the switch stage to control the switching between the third switch and the fourth switch, and when the heavy load mode is selected, a heavy load mode trigger signal is generated based on the clock signal and the maximum on-time of any switch from the first switch to the fourth switch, and based on one of the heavy load mode trigger signal, the trajectory radius trigger signal and the overcurrent protection trigger signal, the switching between the third switch and the fourth switch is controlled.

7. The control method according to claim 6, wherein: The controlling the switching of the switch stage based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal, and the clock signal comprises: Switching between the first switch and the second switch is controlled based on the zero-crossing detection trigger signal.

8. A non-transitory computer-readable storage medium for storing a computer program, wherein when the computer executes the control method of a resonant power supply, the computer program causes the computer to: A trajectory radius trigger signal is obtained based on the current of the resonant inductor, the voltage of the resonant capacitor, at least one of the primary side voltage and the secondary side voltage of the isolation transformer, and the voltage command signal expected to be output by the resonant power supply, including: Outputting a trajectory radius command signal based on a difference between a secondary side voltage of the isolation transformer and the voltage command signal; A trajectory radius feedback signal is calculated based on the real-time current of the resonant inductor, the real-time voltage of the resonant capacitor, and the real-time voltage of the primary side of the isolation transformer; as well as Compare the trajectory radius command signal with the trajectory radius feedback signal and output the trajectory radius trigger signal; Obtaining an overcurrent protection trigger signal based on the current and current threshold of the resonant inductor; Obtaining a zero-crossing detection trigger signal based on whether the current of the resonant inductor passes through zero; as well as Based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero-crossing detection trigger signal, and the clock signal, the switching of the switch stage is controlled, wherein the switch stage includes a first switch and a second switch located in a first bridge arm, and a third switch and a fourth switch located in a second bridge arm, the connection point between the first switch and the second switch is a first node, the connection point between the third switch and the fourth switch is a second node, the resonant inductor and the resonant capacitor are connected in series between the first node and one end of the primary winding of the isolation transformer, and the other end of the primary winding of the isolation transformer is connected to the second node; the switching of the control switch stage includes: A light load mode or a heavy load mode is selected based on the trajectory radius command signal, wherein, when the light load mode is selected, a light load mode trigger signal is output based on the clock signal and the minimum duty cycle output by the switch stage to control the switching between the third switch and the fourth switch, and when the heavy load mode is selected, a heavy load mode trigger signal is generated based on the clock signal and the maximum on-time of any switch from the first switch to the fourth switch, and the switching between the third switch and the fourth switch is controlled based on one of the heavy load mode trigger signal, the trajectory radius trigger signal and the overcurrent protection trigger signal.

9. The non-transitory computer-readable storage medium of claim 8, wherein: Controlling the switching of the switch stage based on at least one of the trajectory radius trigger signal, the overcurrent protection trigger signal, the zero crossing detection trigger signal, and the clock signal includes: Switching between the first switch and the second switch of the switching stage is controlled based on the zero-crossing detection trigger signal.

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