Bidirectional inverter circuit

Abstract

The application relates to the technical field of inversion, and discloses a bidirectional inversion circuit, which comprises a step-down rectification circuit, the step-down rectification circuit comprises a group of primary side switch groups, a high-frequency transformer and a group of secondary side switch groups; the high-frequency transformer comprises a primary side coil matched with the primary side switch groups and a secondary side coil matched with the secondary side switch groups, each primary side switch is connected with at least one primary side coil, and each bidirectional switch is connected with each secondary side coil; the bidirectional inversion circuit further comprises a control module which controls the primary side switch groups and the secondary side switch groups; during charging, the control module generates a complementary secondary side PWM signal to control a pair of bidirectional switches to be turned on and turned off, and generates a primary side PWM signal of a switch sequence matched with the secondary side PWM signal to control a pair of primary side switches to be turned on and turned off, so that the step-down rectification circuit outputs a PWM pulse wave. The bidirectional inverter in the prior art needs more devices and has low efficiency, which leads to the problems of high cost and large size of the bidirectional inverter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inverter, in particular to a bidirectional inverter circuit. BACKGROUND

[0002] At present, with the popularization and generalization of vehicle-mounted mobile power supply, portable energy storage equipment and other products, more and more use scenarios need bidirectional energy transfer, which requires the use of bidirectional inverters. Most of the bidirectional inverters on the market are usually composed of bidirectional DC-DC circuits, synchronous rectification and full-bridge conversion. This type of bidirectional inverter converts alternating current into direct current through push-pull circuits or full-bridge and voltage conversion when inverting, and then outputs alternating current after full-bridge conversion and filtering. When charging, the alternating current is boosted through a bridgeless PFC, and then outputted as direct current to charge the battery after full-bridge circuit and transformer voltage reduction and filtering.

[0003] The above bidirectional inverter in the prior art requires many devices and has low efficiency, resulting in high cost and large size of the bidirectional inverter. SUMMARY

[0004] Therefore, the present application provides a bidirectional inverter circuit to solve the problem of the bidirectional inverter in the prior art requiring many devices, having low efficiency, resulting in high cost and large size of the bidirectional inverter.

[0005] In a first aspect, the present application provides a bidirectional inverter circuit, comprising a step-down rectifier circuit, the step-down rectifier circuit comprising a group of primary side switch groups, a high-frequency transformer and a group of secondary side switch groups;

[0006] The primary side switch group comprises a pair of primary side switches located at the low-voltage side of the high-frequency transformer.

[0007] The secondary side switch group comprises a pair of bidirectional switches located at the high-voltage side of the high-frequency transformer.

[0008] The high-frequency transformer comprises a primary side coil adapted to the primary side switch group and a secondary side coil adapted to the secondary side switch group, each of the primary side switches is connected to at least one of the primary side coils, and each of the bidirectional switches is connected to each of the secondary side coils.

[0009] Further comprising a control module for controlling the primary side switch group and the secondary side switch group.

[0010] When charging, the control module generates a complementary secondary side PWM signal to control a pair of bidirectional switches to turn on and off, and generates a primary side PWM signal with a switching sequence adapted to the secondary side PWM signal to control a pair of primary side switches to turn on and off, so that the step-down rectifier circuit outputs a PWM pulse wave.

[0011] In some optional embodiments, during the charging process, when the power frequency alternating current is in the upper half cycle of the sine wave, the control module controls a pair of bidirectional switches in alignment to be alternately turned on with a pair of primary side switches, and outputs a PWM pulse wave.

[0012] When the power frequency alternating current is in the lower half cycle of the sine wave, the control module controls a pair of bidirectional switches in alignment to be alternately turned on with a pair of primary side switches, and outputs a PWM pulse wave.

[0013] In some optional embodiments, the bidirectional inverter circuit further comprises a first filter module;

[0014] The first filter module is located at the output end of the step-down rectifier circuit;

[0015] The first filter module is used to convert the PWM pulse wave into low-voltage direct current after filtering.

[0016] In some optional embodiments, a pair of the primary side switches are configured as a first primary side switch tube and a second primary side switch tube;

[0017] A pair of the bidirectional switches are configured as a first bidirectional switch and a second bidirectional switch;

[0018] The first bidirectional switch comprises a first secondary side switch tube and a second secondary side switch tube;

[0019] The second bidirectional switch comprises a third secondary side switch tube and a fourth secondary side switch tube;

[0020] During the charging process, when the power frequency alternating current is in the upper half cycle of the sine wave, the control module controls the first secondary side switch tube and the second secondary side switch tube to be alternately turned on with the third secondary side switch tube and the fourth secondary side switch tube, and when the first secondary side switch tube and the second secondary side switch tube are turned on, the control module controls the second primary side switch tube to be turned on at the same time, and when the third secondary side switch tube and the fourth secondary side switch tube are turned on, the control module controls the first primary side switch tube to be turned on at the same time;

[0021] When the power frequency alternating current is in the lower half cycle of the sine wave, the control module controls the first secondary side switch tube and the second secondary side switch tube to be alternately turned on with the third secondary side switch tube and the fourth secondary side switch tube, and when the first secondary side switch tube and the second secondary side switch tube are turned on, the control module controls the first primary side switch tube to be turned on at the same time, and when the third secondary side switch tube and the fourth secondary side switch tube are turned on, the control module controls the second primary side switch tube to be turned on at the same time.

[0022] In some optional embodiments, the primary side PWM signal comprises a first primary side PWM signal and a second primary side PWM signal;

[0023] The first primary-side PWM signal is used to control the first primary-side switching transistor;

[0024] The second primary-side PWM signal is used to control the second primary-side switching transistor;

[0025] One pair of secondary-side PWM signals includes a first secondary-side PWM signal and a second secondary-side PWM signal, and another pair of secondary-side PWM signals includes a third secondary-side PWM signal and a fourth secondary-side PWM signal;

[0026] The first secondary-side PWM signal is used to control the first secondary-side switching transistor;

[0027] The second secondary-side PWM signal is used to control the second secondary-side switching transistor;

[0028] The third secondary-side PWM signal is used to control the third secondary-side switching transistor;

[0029] The fourth secondary-side PWM signal is used to control the fourth secondary-side switching transistor.

[0030] In some optional implementations, during charging, when the power frequency AC is in the first half cycle of a sine wave, the second primary-side PWM signal has the same waveform or frequency as the first secondary-side PWM signal and the second secondary-side PWM signal, and the difference in their pulse widths is within a preset range.

[0031] And / or,

[0032] The first primary-side PWM signal has the same waveform or frequency as the third secondary-side PWM signal and the four secondary-side PWM signals, and the difference in their pulse widths is within a preset range.

[0033] When the power frequency AC is in the lower half cycle of a sine wave, the waveform of the first primary PWM signal is consistent with or the frequency of the first secondary PWM signal and the second secondary PWM signal, and the difference in their pulse widths is within a preset range.

[0034] And / or,

[0035] The second primary-side PWM signal has the same waveform or frequency as the third and fourth secondary-side PWM signals, and the difference in their pulse widths is within a preset range.

[0036] In some optional implementations, during charging, the waveforms of the first secondary-side PWM signal and the second secondary-side PWM signal are complementary to the waveforms of the third secondary-side PWM signal and the fourth secondary-side PWM signal.

[0037] In some optional embodiments, the pair of primary-side switches are configured as a first primary-side switch transistor and a second primary-side switch transistor;

[0038] The high-frequency transformer includes a dual-winding primary coil;

[0039] The first primary-side switching transistor is connected to the first lead of the dual-winding primary-side coil;

[0040] The second primary-side switch is connected to the second lead of the dual-winding primary-side coil;

[0041] The middle tap of the primary coil of the dual-winding system is connected to the first filtering module.

[0042] In some optional implementations, a first driving module and a second driving module are also included;

[0043] The first driving module is used to drive the first primary-side switching transistor according to the first primary-side PWM signal issued by the control module, and the second driving module is used to drive the second primary-side switching transistor according to the second primary-side PWM signal issued by the control module.

[0044] The first driving module is configured as a switching transistor driving circuit built from two amplifying transistors; and / or,

[0045] The second driving module is configured as a switching transistor driving circuit consisting of two amplifying transistors.

[0046] In some optional embodiments, the pair of primary-side switches are configured as a first primary-side switch transistor and a second primary-side switch transistor;

[0047] The first primary-side switch includes a first upper primary-side switch and a first lower primary-side switch, and the second primary-side switch includes a second upper primary-side switch and a second lower primary-side switch.

[0048] The high-frequency transformer includes a single-winding primary coil;

[0049] The first upper primary-side switch and the first lower primary-side switch are connected by a first connection line, and the first primary-side lead of the single winding primary-side line is connected to the first connection line.

[0050] The second upper primary-side switch and the second lower primary-side switch are connected by a second connection line, and the second primary-side lead of the single winding primary-side line is connected to the second connection line.

[0051] In some optional implementations, a first driver chip and a second driver chip are also included;

[0052] The first driver chip is used to drive the first upper primary-side switch and the first lower primary-side switch according to the two first primary-side PWM signals issued by the control module, and the second driver chip is used to drive the second upper primary-side switch and the second lower primary-side switch according to the two second primary-side PWM signals issued by the control module.

[0053] In some optional embodiments, the bidirectional inverter circuit further includes a second filter module;

[0054] The pair of bidirectional switches is configured as a first bidirectional switch and a second bidirectional switch;

[0055] The high-frequency transformer includes a dual-winding secondary coil;

[0056] The first bidirectional switch is located on the first secondary lead of the dual-winding secondary coil;

[0057] The second bidirectional switch is located on the second secondary lead of the dual-winding secondary coil;

[0058] The second secondary lead located at the output terminal of the second bidirectional switch is connected to the first secondary lead located at the output terminal of the first bidirectional switch;

[0059] The secondary tap of the dual-winding secondary coil is connected to the second filter module.

[0060] In some optional implementations, during inversion, the control module generates two complementary primary-side SPWM signals and sends them to a pair of primary-side switches, controlling the pair of primary-side switches to turn on and off. Correspondingly, the control module sends two pairs of secondary-side SPWM signals that are adapted to the two primary-side SPWM signals and contain a preset switching sequence to two pairs of secondary-side switches, controlling the two pairs of secondary-side switches to turn on and off to output the boosted high-voltage SPWM pulse wave.

[0061] In some optional embodiments, the second filtering module includes an inductor and a capacitor;

[0062] The inductor and the capacitor together form an LC oscillation circuit to filter the high-voltage SPWM pulse wave.

[0063] In some optional implementations, the second filtering module includes:

[0064] The first inductor has a first end connected to the secondary switch and a second end connected to the first AC terminal.

[0065] A first capacitor, wherein a first terminal of the first capacitor is connected to a first AC terminal, and a second terminal of the first capacitor is connected to a second AC terminal. Attached Figure Description

[0066] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0067] Figure 1 This is a structural diagram of a bidirectional inverter circuit according to an embodiment of the present invention;

[0068] Figure 2 This is a detailed structural diagram of a bidirectional inverter circuit according to an embodiment of the present invention;

[0069] Figure 3 This is another bidirectional inverter circuit structure diagram according to an embodiment of the present invention;

[0070] Figure 4 This is another bidirectional inverter circuit structure diagram according to an embodiment of the present invention;

[0071] Figure 5 This is a schematic diagram of a bidirectional inverter circuit according to an embodiment of the present invention;

[0072] Figure 6 This is a control waveform diagram of the inverter process of a bidirectional inverter circuit according to an embodiment of the present invention;

[0073] Figure 7 This is a control waveform diagram of the inverter process of another bidirectional inverter circuit according to an embodiment of the present invention;

[0074] Figure 8 This is a control waveform diagram of the charging process of a bidirectional inverter circuit according to an embodiment of the present invention;

[0075] Figure 9 This is a control waveform diagram of the charging process of another bidirectional inverter circuit according to an embodiment of the present invention. Detailed Implementation

[0076] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0077] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the module or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0078] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0079] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0080] Currently, with the promotion and popularization of products such as vehicle-mounted power banks and portable energy storage devices, more and more application scenarios require bidirectional energy transfer, which necessitates the use of bidirectional inverters. Most bidirectional inverters on the market typically consist of a bidirectional DC-DC circuit, synchronous rectification, and a full-bridge converter. During inversion, this type of bidirectional inverter uses a push-pull circuit or a full-bridge converter and transformer to boost the voltage and then rectify it into DC. After passing through a full-bridge converter and filtering, it outputs AC. During charging, the AC voltage is boosted through a bridgeless PFC, then stepped down, rectified, and filtered by a full-bridge circuit and transformer before outputting DC to charge the battery.

[0081] As mentioned above, existing bidirectional inverters require more components and have lower efficiency, resulting in higher costs and larger sizes.

[0082] To address this, this embodiment provides a bidirectional inverter circuit, such as... Figure 1 and Figure 5As shown, the bidirectional inverter circuit provided in this embodiment includes a buck rectifier circuit and a control module 40. The buck rectifier circuit includes one or more primary-side switch groups, a high-frequency transformer B, and one or more secondary-side switch groups. The primary-side switch group includes a pair of primary-side switches 10 located on the low-voltage side of the high-frequency transformer B. The secondary-side switch group includes a pair of bidirectional switches located on the high-voltage side of the high-frequency transformer B. The high-frequency transformer B includes a primary-side coil adapted to the primary-side switch group and a secondary-side coil adapted to the secondary-side switch group. Each primary-side switch 10 is connected to at least one of the primary-side coils, and each bidirectional switch is connected to each of the secondary-side coils. The control module 40 is used to control the primary-side switch group and the secondary-side switch group. During charging, the control module 40 generates complementary secondary-side PWM signals to control the switching of a pair of bidirectional switches and generates primary-side PWM signals adapted to the switching sequence of the secondary-side PWM signals to control the switching of a pair of primary-side switches 10, so that the buck rectifier circuit outputs PWM pulse waves.

[0083] Specifically, a pair of bidirectional switches includes a first bidirectional switch 20 and a second bidirectional switch 30. The control module 40 sends two pairs of complementary secondary-side PWM signals to the first bidirectional switch 20 and the second bidirectional switch 30, respectively, so that the first bidirectional switch 20 and the second bidirectional switch 30 are turned on alternately. At the same time, the control module 40 sends primary-side PWM signals adapted to the switching sequence of the secondary-side PWM signals to the two primary-side switches, so that the two primary-side switches are turned on alternately, thereby outputting a stepped-down DC voltage.

[0084] Optionally, the adaptation to the secondary-side PWM signal and the inclusion of a preset switching sequence are the matching sequences of the secondary-side switches according to the conduction sequence of the secondary-side PWM signal, including both the same and opposite sequences.

[0085] refer to Figure 8 The PWM signal is a pulse width modulation signal, and the width of the pulse square wave of the primary-side switch and the secondary-side switch is different at each moment. Within a preset time period, the width of the pulse square wave changes according to a preset rule, which is determined based on the input AC voltage and the output DC voltage. Thus, the rectification purpose is achieved through the cooperation of the primary-side switch group and the secondary-side switch group to output a stepped-down DC voltage.

[0086] Optionally, the bidirectional inverter circuit further includes a first filter module 50, which is located at the output end of the buck rectifier circuit. The first filter module 50 is typically composed of one or more capacitors and is used to filter the PWM pulse wave and convert it into low-voltage DC power.

[0087] For example, refer to Figure 1The high-frequency transformer B includes two primary windings and two secondary windings.

[0088] The bidirectional inverter circuit provided by this invention includes a buck rectifier circuit and a control module 40. The buck rectifier circuit includes one or more primary-side switch groups, a high-frequency transformer B, and one or more secondary-side switch groups. The primary-side switch group includes a pair of primary-side switches 10 located on the low-voltage side of the high-frequency transformer B. The secondary-side switch group includes a pair of bidirectional switches located on the high-voltage side of the high-frequency transformer B. The high-frequency transformer B includes a primary-side coil adapted to the primary-side switch group and a secondary-side coil adapted to the secondary-side switch group. Each primary-side switch 10 is connected to at least one of the primary-side coils, and each bidirectional switch is connected to each of the secondary-side coils. The control module 40 is used to control the primary-side switch group and the secondary-side switch group. During charging, the control module 40 generates complementary secondary-side PWM signals to control the switching of a pair of bidirectional switches and generates primary-side PWM signals adapted to the switching sequence of the secondary-side PWM signals to control the switching of a pair of primary-side switches 10, so that the buck rectifier circuit outputs PWM pulse waves. Compared to traditional bidirectional inverters that consist of push-pull circuits, boost circuits, first rectifier circuits, modulation circuits, and filter circuits, the bidirectional inverter provided in this embodiment omits the first rectifier circuit and modulation circuit, especially the large capacitor. That is, it does not need to convert to AC through a push-pull circuit, boost the voltage, convert it to DC through the first rectifier circuit, and then convert it back to AC through the modulation circuit. Instead, it boosts the voltage and modulates simultaneously. At the same time, the bidirectional inverter provided in this embodiment can also step down the voltage and rectify it simultaneously, outputting a stepped-down DC voltage. This significantly reduces the number of conversion stages, improves conversion efficiency, eliminates a large number of electronic components, and greatly reduces cost, weight, and size.

[0089] In some alternative implementations, during the charging process, when the power frequency AC current is in the upper half-cycle of a sine wave, the control module controls a pair of bidirectional switches and a pair of primary-side switches 10 to alternately conduct, outputting PWM pulse waves. When the power frequency AC current is in the lower half-cycle of a sine wave, the control module controls a pair of bidirectional switches and a pair of primary-side switches 10 to alternately conduct, outputting PWM pulse waves.

[0090] Specifically, during the charging process, when the power frequency AC current is in the upper half-cycle of a sine wave, the control module 40 controls the aligned bidirectional switches and primary-side switches 10 to form a first alignment group and a second alignment group. The first alignment group includes one bidirectional switch and one aligned primary-side switch 10, and the second alignment group includes another bidirectional switch and another aligned primary-side switch 10. The first alignment group and the second alignment group are alternately turned on, outputting the first segment of low-voltage PWM pulse wave corresponding to the upper half-cycle of the power frequency AC current. When the power frequency AC current is in the lower half-cycle of a sine wave, the control module 40 controls the aligned bidirectional switches to form a pair, forming a first alignment group and a second alignment group. The primary-side switch 10 is paired with the secondary-side switch 10 to form a first and a second pair of corresponding switches. The first pair of corresponding switches includes a bidirectional switch and a primary-side switch 10 in the same position. The second pair of corresponding switches includes another bidirectional switch and another primary-side switch 10 in the same position. The first and second pairs of corresponding switches are alternately turned on to output a second low-voltage PWM pulse wave corresponding to the second half-cycle of the power frequency AC current. Under the alternating rectification effect of the corresponding and corresponding switches, the first and second low-voltage PWM pulse waves are rectified into PWM pulse waves in the same direction, no longer presenting the positive and negative voltages of the power frequency AC current, thus laying the foundation for filtering into stable DC current.

[0091] For example, a pair of bidirectional switches are configured as a first bidirectional switch 20 and a second bidirectional switch 30. The first bidirectional switch 20 includes a first secondary switch tube Q5 and a second secondary switch tube Q6, and the second bidirectional switch 30 includes a third secondary switch tube Q7 and a fourth secondary switch tube Q8. That is, the two secondary switch tubes are equivalent to a bidirectional switch, so as to simultaneously turn on and off. Furthermore, the simultaneous conduction of the first secondary-side switch Q5 and the second secondary-side switch Q6 is equivalent to the conduction of the first bidirectional switch; the simultaneous deactivation of the first secondary-side switch Q5 and the second secondary-side switch Q6 is equivalent to the deactivation of the first bidirectional switch. Similarly, the simultaneous conduction of the third secondary-side switch Q7 and the fourth secondary-side switch Q8 is equivalent to the conduction of the second bidirectional switch; and the simultaneous deactivation of the third secondary-side switch Q7 and the fourth secondary-side switch Q8 is equivalent to the deactivation of the second bidirectional switch. In other words, when the power frequency AC current is in the upper half-cycle of a sine wave, the control module 40 controls the aligned first secondary-side switch Q5 and the aligned second secondary-side switch Q6 to pair with the second primary-side switch Q2, forming the first alignment group; and controls the aligned third secondary-side switch Q7 and the aligned fourth secondary-side switch Q8 to pair with the first primary-side switch Q1, forming the second alignment group. The first pair of switches includes a first secondary-side switch Q5 and a second secondary-side switch Q6, and a corresponding second primary-side switch Q2. The second pair of switches includes a third secondary-side switch Q7 and a fourth secondary-side switch Q8, and a corresponding first primary-side switch Q1. The first pair of switches and the second pair of switches are alternately turned on. Specifically, the first secondary-side switch Q5, the second secondary-side switch Q6, and the second primary-side switch Q2 form the first pair of switches, which are simultaneously turned on and off and alternately turned on with the second pair of switches. The third secondary-side switch Q7, the fourth secondary-side switch, and the first primary-side switch Q1 form the second pair of switches, which are simultaneously turned on and off and alternately turned on with the first pair of switches. This is similar to the first segment of low-voltage PWM pulse wave corresponding to the first half-cycle of the power frequency AC current. When the power frequency AC current is in the second half-cycle of the sine wave, the difference is that they are grouped together and output the second segment of low-voltage PWM pulse wave, which will not be described in detail here.

[0092] In some alternative implementations, the bidirectional inverter circuit further includes a first filter module 50;

[0093] The first filter module 50 is located at the output terminal of the buck rectifier circuit;

[0094] The first filtering module 50 is used to filter the PWM pulse wave and convert it into low-voltage DC power.

[0095] Specifically, refer to Figure 2 The first filtering module 50 includes a second capacitor C2 and a third capacitor C3. The second capacitor C2 and the third capacitor C3 smooth the PWM pulse wave and output DC current.

[0096] In some optional implementations, the primary-side PWM signal includes a first primary-side PWM signal and a second primary-side PWM signal;

[0097] The first primary-side PWM signal is used to control the first primary-side switching transistor Q1;

[0098] The second primary-side PWM signal is used to control the second primary-side switching transistor Q2;

[0099] One pair of secondary-side PWM signals includes a first secondary-side PWM signal and a second secondary-side PWM signal, and another pair of secondary-side PWM signals includes a third secondary-side PWM signal and a fourth secondary-side PWM signal;

[0100] The first secondary-side PWM signal is used to control the first secondary-side switching transistor Q5;

[0101] The second secondary-side PWM signal is used to control the second secondary-side switching transistor Q6;

[0102] The third secondary-side PWM signal is used to control the third secondary-side switching transistor Q7;

[0103] The fourth secondary-side PWM signal is used to control the fourth secondary-side switching transistor Q8.

[0104] Specifically, the first primary-side PWM signal is used to control multiple first primary-side switches Q1, the second primary-side PWM signal is used to control multiple second primary-side switches Q2, the first secondary-side PWM signal is used to control multiple first secondary-side switches Q5, the second secondary-side PWM signal is used to control multiple second secondary-side switches Q6, the third secondary-side PWM signal is used to control multiple third secondary-side switches Q7, and the fourth secondary-side PWM signal is used to control multiple fourth secondary-side switches Q8.

[0105] In some optional implementations, during charging, when the power frequency AC is in the first half-cycle of a sine wave, the second primary-side PWM signal has the same waveform or frequency as the first secondary-side PWM signal and the second secondary-side PWM signal, and the difference in their pulse widths is within a preset range.

[0106] And / or,

[0107] The first primary-side PWM signal has the same waveform or frequency as the third secondary-side PWM signal and the four secondary-side PWM signals, and the difference in their pulse widths is within a preset range.

[0108] When the power frequency AC is in the lower half cycle of a sine wave, the waveform of the first primary PWM signal is consistent with or the frequency of the first secondary PWM signal and the second secondary PWM signal, and the difference in their pulse widths is within a preset range.

[0109] And / or,

[0110] The second primary-side PWM signal has the same waveform or frequency as the third and fourth secondary-side PWM signals, and the difference in their pulse widths is within a preset range.

[0111] Specifically, waveform consistency refers to consistent pulse widths and consistent turn-on and turn-off times, or consistent frequencies and the difference between their pulse widths being within a preset range.

[0112] Specifically, waveform consistency means that the pulse width, frequency, and duty cycle of the two waveforms are identical. Narrowing the pulse width within a preset range means that the frequency or period of the two waveforms remains unchanged, the direction of the high and low potentials remains unchanged, and only the pulse width changes. For example, when the waveform of the first primary-side PWM signal is at a high potential, the waveforms of the third and fourth secondary-side PWM signals are also at a high potential. However, the width of the high potential of the secondary-side PWM signal is relatively narrower, that is, the duration of the high potential of the secondary-side PWM signal is shorter than the duration of the high potential of the primary-side PWM signal. Correspondingly, the width of the low potential of the secondary-side PWM signal becomes longer, thereby ensuring that the overall frequency or period remains unchanged. In short, high to high, low to low, only the width changes.

[0113] In some alternative implementations, during charging, the waveforms of the first secondary-side PWM signal and the second secondary-side PWM signal are complementary to the waveforms of the third secondary-side PWM signal and the fourth secondary-side PWM signal.

[0114] Specifically, waveform complementarity refers to complementary turn-on and turn-off times, and complementary pulse widths within one pulse cycle.

[0115] In some alternative implementations, such as Figure 2 As shown, the pair of primary-side switches are configured as a first primary-side switch Q1 and a second primary-side switch Q2;

[0116] The high-frequency transformer includes a dual-winding primary coil;

[0117] The first primary-side switch Q1 is connected to the first lead of the dual-winding primary-side coil;

[0118] The second primary-side switch Q2 is connected to the second lead of the dual-winding primary-side coil;

[0119] The middle tap of the primary winding of the dual-winding coil is connected to the first filter module 50.

[0120] Specifically, refer to Figure 2 The first end of the first filter module 50 is connected to BAT+, the second end of the first filter module 50 is connected to BAT-, and the third end of the first filter module 50 is connected to the middle tap of the primary winding of the double winding.

[0121] In some alternative implementations, the bidirectional inverter circuit further includes a first drive module 60 and a second drive module 70;

[0122] The first driving module 60 is used to drive the first primary-side switch Q1 according to the first primary-side PWM signal issued by the control module 40, and the second driving module 70 is used to drive the second primary-side switch Q2 according to the second primary-side PWM signal issued by the control module 40.

[0123] The first driving module 60 is configured as a switching transistor driving circuit consisting of two amplifying transistors; and / or,

[0124] The second driving module 70 is configured as a switching transistor driving circuit consisting of two amplifying transistors.

[0125] Specifically, the waveform controlled during the charging process is as follows: Figure 8 As shown, this illustrates the situation when the power frequency AC current is in the upper half-cycle of a sine wave (e.g., Figure 8 The first cycle), and when the power frequency AC is in the lower half-cycle of a sine wave (such as... Figure 8 (Second cycle in the sine wave). When the power frequency AC current is in the upper half-cycle of the sine wave, the waveforms of the first primary-side switch Q1, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. The waveforms of the second primary-side switch Q2, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. When the power frequency AC current is in the lower half-cycle of the sine wave, the waveforms of the first primary-side switch Q1, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. The waveforms of the second primary-side switch Q2, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same.

[0126] Specifically, the first secondary-side switch Q5, the second secondary-side switch Q6, the third secondary-side switch Q7, or the fourth secondary-side switch Q8 are MOS (metal-oxide semiconductor field-effect transistor, abbreviated as MOS-FET), IGBT (Insulated Gate Bipolar Transistor), silicon carbide, gallium nitride, and other switching transistors.

[0127] Specifically, such as Figure 3 As shown, the first driving module 60 includes:

[0128] The first amplifier transistor J1 has its control terminal connected to the control module 40. The first terminal of the first amplifier transistor J1 is connected to the preset reference voltage VCC, and the second terminal of the first amplifier transistor J1 is connected to the control terminal of the first primary-side switch transistor Q1.

[0129] The second amplifier tube J2 has its control terminal connected to the control module 40. The first end of the second amplifier tube J2 is connected to the second end of the first amplifier tube J1. The second end of the first amplifier tube J1 is grounded.

[0130] The second drive module 70 includes:

[0131] The third amplifier transistor J3 has its control terminal connected to the control module 40. The first terminal of the third amplifier transistor J3 is connected to the preset reference voltage VCC, and the second terminal of the third amplifier transistor J3 is connected to the control terminal of the second primary-side switch transistor Q2.

[0132] The fourth amplifier tube J4 is connected to the control module 40. The first end of the fourth amplifier tube J4 is connected to the second end of the third amplifier tube J3. The second end of the fourth amplifier tube J4 is grounded.

[0133] Specifically, the amplifying transistor can be a triode or a switching transistor such as a MOS, IGBT, silicon carbide, or gallium nitride.

[0134] Specifically, refer to Figure 3 The first amplifier J1 and the second amplifier J2 amplify the first primary-side PWM signal output from the control module 40 and output it to the first primary-side switch Q1, thereby driving the first primary-side switch Q1. The third amplifier J3 and the fourth amplifier J4 amplify the second primary-side PWM signal output from the control module 40 and output it to the second primary-side switch Q2, thereby driving the second primary-side switch Q2.

[0135] Specifically, the first primary-side switch Q1 or the second primary-side switch Q2 is a MOS (metal-oxide semiconductor field-effect transistor, abbreviated as MOS-FET), IGBT (Insulated Gate Bipolar Transistor), silicon carbide, gallium nitride, or other switching transistors.

[0136] It should be noted that the fifth resistor R5 and the sixth resistor R6 are driving resistors.

[0137] In some alternative implementations, such as Figure 4 As shown, the pair of primary-side switches are configured as a first primary-side switch Q1 and a second primary-side switch Q2;

[0138] The first primary-side switch Q1 includes a first upper primary-side switch K1 and a first lower primary-side switch K2, and the second primary-side switch Q2 includes a second upper primary-side switch K3 and a second lower primary-side switch K4.

[0139] The high-frequency transformer includes a single-winding primary coil;

[0140] The first upper primary-side switch K1 and the first lower primary-side switch K2 are connected by a first connection line, and the first primary-side lead of the single winding primary-side line is connected to the first connection line.

[0141] The second upper primary-side switch K3 and the second lower primary-side switch K4 are connected by a second connection line, and the second primary-side lead of the single winding primary-side line is connected to the second connection line.

[0142] Specifically, the first filtering module 50 is connected to the first primary-side switch K1.

[0143] Specifically, the first upper primary-side switch K1, the first lower primary-side switch K2, the second upper primary-side switch K3, or the second lower primary-side switch K4 are MOS (metal-oxide-semiconductor field-effect transistor), IGBT (Insulated Gate Bipolar Transistor), silicon carbide, gallium nitride, or other switching transistors.

[0144] In some alternative implementations, such as Figure 4 As shown, it also includes a first driver chip U1 and a second driver chip U2;

[0145] The first driver chip U1 is used to drive the first upper primary-side switch K1 and the first lower primary-side switch K2 according to the two first primary-side PWM signals issued by the control module 40. The second driver chip U2 is used to drive the second upper primary-side switch K3 and the second lower primary-side switch K4 according to the two second primary-side PWM signals issued by the control module 40.

[0146] Specifically, the waveform for charging process control is as follows: Figure 9 As shown, this illustrates the situation when the power frequency AC current is in the upper half-cycle of a sine wave (e.g., Figure 9 The first cycle), and when the power frequency AC is in the lower half-cycle of a sine wave (such as... Figure 9(Second cycle in the sine wave). When the power frequency AC current is in the upper half-cycle of the sine wave, the waveforms of the first upper primary-side switch K1, the second lower primary-side switch K4, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. The waveforms of the first lower primary-side switch K2, the second upper primary-side switch K3, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. When the power frequency AC current is in the lower half-cycle of the sine wave, the waveforms of the first upper primary-side switch K1, the second lower primary-side switch K4, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. The waveforms of the first lower primary-side switch K2, the second upper primary-side switch K3, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same.

[0147] Specifically, refer to Figure 4 The first driving module 60 also includes an eighth resistor R8, a first diode D1, a fourth capacitor C4, and a seventh resistor R7. The second driving module 70 also includes a tenth resistor R10, a second diode D2, a fifth capacitor C5, and a ninth resistor R9.

[0148] Specifically, the first upper primary-side switch K1 and the second lower primary-side switch K4 are driven simultaneously by the first driver chip U1 and the second driver chip U2, and the first lower primary-side switch K2 and the second upper primary-side switch K3 are driven simultaneously.

[0149] For example, during the charging process, when the power frequency AC is in the first half-cycle of a sine wave, the first upper primary-side switch K1, the second lower primary-side switch K4, the first secondary-side switch Q5, and the second secondary-side switch Q6, which are in the same position, are simultaneously turned on (at this time, the first lower primary-side switch K2, the second upper primary-side switch K3, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are simultaneously turned off). Then, the first lower primary-side switch K2, the second upper primary-side switch K3, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are simultaneously turned on (at this time, the first upper primary-side switch K1, the second lower primary-side switch K4, the first secondary-side switch Q5, and the second secondary-side switch Q6 are simultaneously turned off), and so on, until the end of the first half-cycle.

[0150] When the power frequency AC is in the second half-cycle of a sine wave, the first upper primary-side switch K1, the second lower primary-side switch K4, the third secondary-side switch Q7, and the fourth secondary-side switch Q8, which are in alignment, are simultaneously turned on (at this time, the first lower primary-side switch K2, the second upper primary-side switch K3, the first secondary-side switch Q5, and the second secondary-side switch Q6 are simultaneously turned off). Then, the first lower primary-side switch K2, the second upper primary-side switch K3, the first secondary-side switch Q5, and the second secondary-side switch Q6 are simultaneously turned on (at this time, the first upper primary-side switch K1, the second lower primary-side switch K4, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are simultaneously turned off). This alternation continues until the end of the second half-cycle.

[0151] In some alternative implementations, the bidirectional inverter circuit further includes a second filter module 80;

[0152] The pair of bidirectional switches is configured as a first bidirectional switch 20 and a second bidirectional switch 30;

[0153] The high-frequency transformer includes a dual-winding secondary coil;

[0154] The first bidirectional switch 20 is located on the first secondary lead of the dual-winding secondary coil;

[0155] The second bidirectional switch 30 is located on the second secondary lead of the dual-winding secondary coil;

[0156] The second secondary side lead located at the output end of the second bidirectional switch 30 is connected to the first secondary side lead located at the output end of the first bidirectional switch 20. That is, the first bidirectional switch 20 and the second bidirectional switch 30 are connected in parallel and alternately conduct through the end of the same lead for input or output.

[0157] The secondary tap of the dual-winding secondary coil is connected to the second filter module 80.

[0158] Specifically, the second filtering module 80 converts the boosted high-voltage PWM pulse wave into power frequency AC power and outputs it. For example, the second filtering module 80 converts the boosted high-voltage PWM pulse wave into a target 50Hz or 60Hz power frequency AC power.

[0159] In some alternative embodiments, during inversion, the control module 40 is connected to each of the primary-side switches and each of the secondary-side switches respectively. The control module is used to send two complementary primary-side SPWM signals to a pair of primary-side switches and control the pair of primary-side switches to turn on and off. Correspondingly, the control module sends two pairs of secondary-side SPWM signals that are adapted to the two primary-side SPWM signals and contain a preset switching sequence to the two pairs of secondary-side switches and controls the two pairs of secondary-side switches to turn on and off to output the boosted high-voltage SPWM pulse wave.

[0160] Specifically, the control module 40 sends complementary primary-side SPWM signals to the two primary-side switches 10, causing the two primary-side switches 10 to conduct alternately. At the same time, the control module 40 sends secondary-side SPWM signals that are adapted to the primary-side SPWM signals and contain a preset switching sequence to the two pairs of secondary-side switches, causing the first bidirectional switch and the second bidirectional switch to conduct alternately, thereby outputting a boosted high-voltage SPWM pulse wave.

[0161] For example, refer to Figure 3 The control waveform during the inverter process is as follows: Figure 6As shown, this illustrates the situation when the power frequency AC current is in the upper half-cycle of a sine wave (e.g., Figure 6 The first cycle), and when the power frequency AC is in the lower half-cycle of a sine wave (such as... Figure 6 (Second cycle in the sine wave). When the power frequency AC current is in the upper half-cycle of the sine wave, the waveforms of the first primary-side switch Q1, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. The waveforms of the second primary-side switch Q2, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. When the power frequency AC current is in the lower half-cycle of the sine wave, the waveforms of the first primary-side switch Q1, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. The waveforms of the second primary-side switch Q2, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same.

[0162] For example, refer to Figure 4 The waveform of the inverter process control is as follows: Figure 7 As shown, this illustrates the situation when the power frequency AC current is in the upper half-cycle of a sine wave (e.g., Figure 7 The first cycle), and when the power frequency AC is in the lower half-cycle of a sine wave (such as... Figure 7 (Second cycle in the sine wave). When the power frequency AC current is in the upper half-cycle of the sine wave, the waveforms of the first upper primary-side switch K1, the second lower primary-side switch K4, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same. The waveforms of the first lower primary-side switch K2, the second upper primary-side switch K3, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. When the power frequency AC current is in the lower half-cycle of the sine wave, the waveforms of the first upper primary-side switch K1, the second lower primary-side switch K4, the third secondary-side switch Q7, and the fourth secondary-side switch Q8 are the same. The waveforms of the first lower primary-side switch K2, the second upper primary-side switch K3, the first secondary-side switch Q5, and the second secondary-side switch Q6 are the same.

[0163] In some alternative embodiments, the second filtering module 80 includes an inductor and a capacitor;

[0164] The inductor and the capacitor together form an LC oscillation circuit to filter the high-voltage SPWM pulse wave.

[0165] In some alternative embodiments, the second filtering module 80 includes:

[0166] The first inductor L1 has its first end connected to the secondary switch and its second end connected to the first AC terminal AC-L.

[0167] A first capacitor C1 is connected to a first AC terminal AC-L at its first end and to a second AC output terminal AC-H at its second end.

[0168] Specifically, an LC filter circuit is constructed based on the first inductor L1 and the first capacitor C1 to convert the sinusoidal wave into power frequency AC power for output. The first inductor L1 can be either a dual inductor or a single inductor.

[0169] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A bidirectional inverter circuit, characterized in that, It includes a step-down rectifier circuit, which includes one or more primary-side switch groups, a high-frequency transformer, and one or more secondary-side switch groups; The primary-side switch group includes a pair of primary-side switches located on the low-voltage side of the high-frequency transformer; The secondary switch group includes a pair of bidirectional switches located on the high-voltage side of the high-frequency transformer; The high-frequency transformer includes a primary coil adapted to the primary-side switch group and a secondary coil adapted to the secondary-side switch group. Each primary-side switch is connected to at least one of the primary-side coils, and each bidirectional switch is connected to each of the secondary-side coils. It also includes a control module for controlling the primary-side switch group and the secondary-side switch group; During charging, the control module generates a complementary secondary-side PWM signal to control a pair of bidirectional switches to turn on and off, and generates a primary-side PWM signal adapted to the switching sequence of the secondary-side PWM signal to control a pair of primary-side switches to turn on and off, so that the buck rectifier circuit outputs PWM pulse waves. During the charging process, when the power frequency AC is in the upper half cycle of the sine wave, the control module controls a pair of bidirectional switches and a pair of primary-side switches to alternately conduct, outputting PWM pulse waves. When the power frequency AC is in the lower half cycle of a sine wave, the control module controls a pair of bidirectional switches and a pair of primary-side switches in the same position to alternately conduct, outputting PWM pulse waves.

2. The bidirectional inverter circuit according to claim 1, characterized in that, The bidirectional inverter circuit also includes a first filter module; The first filter module is located at the output terminal of the step-down rectifier circuit; The first filtering module is used to filter the PWM pulse wave and convert it into low-voltage DC power.

3. The bidirectional inverter circuit according to claim 1, characterized in that, The pair of primary-side switches are configured as a first primary-side switch transistor and a second primary-side switch transistor; The pair of bidirectional switches is configured as a first bidirectional switch and a second bidirectional switch; The first bidirectional switch includes a first secondary-side switch transistor and a second secondary-side switch transistor; The second bidirectional switch includes a third secondary-side switch and a fourth secondary-side switch; During the charging process, when the power frequency AC is in the upper half cycle of a sine wave, the control module controls the first and second secondary side switches to be turned on alternately with the third and fourth secondary side switches. When the first and second secondary side switches are turned on, the control module controls the second primary side switch to be turned on simultaneously. When the third and fourth secondary side switches are turned on, the control module controls the first primary side switch to be turned on simultaneously. When the power frequency AC is in the lower half-cycle of a sine wave, the control module controls the first and second secondary-side switches to conduct alternately with the third and fourth secondary-side switches. When the first and second secondary-side switches are conducting, the control module controls the first primary-side switch to conduct simultaneously. When the third and fourth secondary-side switches are conducting, the control module controls the second primary-side switch to conduct simultaneously.

4. The bidirectional inverter circuit according to claim 3, characterized in that, The primary-side PWM signal includes a first primary-side PWM signal and a second primary-side PWM signal; The first primary-side PWM signal is used to control the first primary-side switching transistor; The second primary-side PWM signal is used to control the second primary-side switching transistor; One pair of secondary-side PWM signals includes a first secondary-side PWM signal and a second secondary-side PWM signal, and another pair of secondary-side PWM signals includes a third secondary-side PWM signal and a fourth secondary-side PWM signal; The first secondary-side PWM signal is used to control the first secondary-side switching transistor; The second secondary-side PWM signal is used to control the second secondary-side switching transistor; The third secondary-side PWM signal is used to control the third secondary-side switching transistor; The fourth secondary-side PWM signal is used to control the fourth secondary-side switching transistor.

5. The bidirectional inverter circuit according to claim 4, characterized in that, During charging, when the power frequency AC is in the upper half cycle of a sine wave, the waveform of the second primary PWM signal is consistent with or the frequency is consistent with the waveform of the first secondary PWM signal and the second secondary PWM signal, and the difference in their pulse widths is within a preset range. And / or, The first primary-side PWM signal has the same waveform or frequency as the third secondary-side PWM signal and the fourth secondary-side PWM signal, and the difference in their pulse widths is within a preset range. When the power frequency AC is in the lower half cycle of a sine wave, the waveform of the first primary PWM signal is consistent with or the frequency of the first secondary PWM signal and the second secondary PWM signal, and the difference in their pulse widths is within a preset range. And / or, The second primary-side PWM signal has the same waveform or frequency as the third and fourth secondary-side PWM signals, and the difference in their pulse widths is within a preset range.

6. The bidirectional inverter circuit according to claim 5, characterized in that, During charging, the waveforms of the first secondary-side PWM signal and the second secondary-side PWM signal are complementary to the waveforms of the third secondary-side PWM signal and the fourth secondary-side PWM signal.

7. The bidirectional inverter circuit according to claim 2, characterized in that, The pair of primary-side switches are configured as a first primary-side switch transistor and a second primary-side switch transistor; The high-frequency transformer includes a dual-winding primary coil; The first primary-side switching transistor is connected to the first lead of the dual-winding primary-side coil; The second primary-side switch is connected to the second lead of the dual-winding primary-side coil; The middle tap of the primary coil of the dual-winding system is connected to the first filtering module.

8. The bidirectional inverter circuit according to claim 7, characterized in that, It also includes a first drive module and a second drive module; The first driving module is used to drive the first primary-side switching transistor according to the first primary-side PWM signal issued by the control module, and the second driving module is used to drive the second primary-side switching transistor according to the second primary-side PWM signal issued by the control module. The first driving module is configured as a switching transistor driving circuit built from two amplifying transistors; and / or, The second driving module is configured as a switching transistor driving circuit consisting of two amplifying transistors.

9. The bidirectional inverter circuit according to claim 2, characterized in that, The pair of primary-side switches are configured as a first primary-side switch transistor and a second primary-side switch transistor; The first primary-side switch includes a first upper primary-side switch and a first lower primary-side switch, and the second primary-side switch includes a second upper primary-side switch and a second lower primary-side switch. The high-frequency transformer includes a single-winding primary coil; The first upper primary-side switch and the first lower primary-side switch are connected by a first connection line, and the first primary-side lead of the single-winding primary-side coil is connected to the first connection line. The second upper primary-side switch and the second lower primary-side switch are connected by a second connection line, and the second primary-side lead of the single-winding primary-side coil is connected to the second connection line.

10. The bidirectional inverter circuit according to claim 9, characterized in that, It also includes a first driver chip and a second driver chip; The first driver chip is used to drive the first upper primary-side switch and the first lower primary-side switch according to the two first primary-side PWM signals issued by the control module, and the second driver chip is used to drive the second upper primary-side switch and the second lower primary-side switch according to the two second primary-side PWM signals issued by the control module.

11. The bidirectional inverter circuit according to any one of claims 8 to 10, characterized in that, The bidirectional inverter circuit also includes a second filtering module; The pair of bidirectional switches is configured as a first bidirectional switch and a second bidirectional switch; The high-frequency transformer includes a dual-winding secondary coil; The first bidirectional switch is located on the first secondary lead of the dual-winding secondary coil; The second bidirectional switch is located on the second secondary lead of the dual-winding secondary coil; The second secondary lead located at the output terminal of the second bidirectional switch is connected to the first secondary lead located at the output terminal of the first bidirectional switch; The secondary tap of the dual-winding secondary coil is connected to the second filter module.

12. The bidirectional inverter circuit according to claim 1, characterized in that, During inversion, the control module generates two complementary primary-side SPWM signals and sends them to a pair of primary-side switches, controlling the pair of primary-side switches to turn on and off. Correspondingly, the control module sends two pairs of secondary-side SPWM signals that are compatible with the two primary-side SPWM signals and contain a preset switching sequence to two pairs of secondary-side switches, controlling the two pairs of secondary-side switches to turn on and off to output the boosted high-voltage SPWM pulse wave.

13. The bidirectional inverter circuit according to claim 11, characterized in that, The second filtering module includes inductors and capacitors; The inductor and the capacitor together form an LC oscillation circuit to filter the high-voltage SPWM pulse wave.

14. The bidirectional inverter circuit according to claim 11, characterized in that, The second filtering module includes: The first inductor has a first end connected to the secondary switch and a second end connected to the first AC terminal. A first capacitor, wherein a first terminal of the first capacitor is connected to a first AC terminal, and a second terminal of the first capacitor is connected to a second AC terminal.

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