Synchronous rectifier for variable frequency driving of pool or SPA equipment
By employing MOSFET-based synchronous rectifiers, the inefficiencies and reliability issues of traditional diode-based VFDs are addressed, enhancing efficiency and operational stability in pool or spa equipment VFDs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ASTRAL POOL AUSTRALIA
- Filing Date
- 2025-12-04
- Publication Date
- 2026-06-18
Smart Images
Figure IB2025062450_18062026_PF_FP_ABST
Abstract
Description
Attorney Docket No.: 010147-1530053SYNCHRONOUS RECTIFIER FOR VARIABLE FREQUENCY DRIVING OF POOL OR SPA EQUIPMENTTECHNICAL FIELDBACKGROUNDSUMMARYAttorney Docket No.: 010147-1530053
[0005] An example process for driving rotating pool or spa equipment, includes receiving, by a variable frequency drive configured as part of a pool or spa system, an input AC signal and a command to generate an output AC dri ve signal of a particular frequency; outputting, to a synchronous rectifier, the AC signal. The process further includes generating a DC output including switching one or more rectifying elements of the synchronous rectifier using a control circuit. The process further includes smoothing the DC output of the synchronous rectifier using bulk capacitance. The process further includes inverting the smoothed DC output using inverter to generate the AC output signal. The process further includes providing the AC output signal to one or more pieces of rotating equipment.BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG 1 illustrates an example pool or spa system, according to some aspects of the present disclosure.
[0007] FIG. 2 illustrates an example of a synchronous rectifier implementation, according to some aspects of the present disclosure.
[0008] FIG. 3 illustrates a temperature chart comparing a metal-oxide-semiconductor field¬ effect transistor (MOSFET) of a. synchronous rectifier with a diode according to embodiments of the disclosure.
[0009] FIG. 4 illustrates a flowchart of a process for implementing a variable frequency drive (VFD) using a synchronous rectifier for driving of pool or spa equipment, according to some aspects of the present disclosure.
[0010] FIG 5 illustrates a flowchart of a computer-implemented process for operating a VFD using a synchronous rectifier for dri ving of pool or spa equipment, according to some aspects of the present disclosure.
[0011] FIG. 6 shows a block diagram of an example of a computing system usable in concert with a pool automation controller, according to some aspects of the present disclosure.DETAILED DESCRIPTION
[0012] The subject matter of the present embodiments is described herein with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. Hie claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future7Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147- 1530053Existing VFD implementations for rotating pool or spa equipment use analog components such as diodes to rectify the AC input current. However, such components may generate an undesirable amount of heat resulting in a loss of efficiency. Additionally, these analog components can be balky, require significant cooling infrastructure, and may be susceptible to voltage spikes and electromagnetic interference that can reduce their operational lifespan.
[0016] Techniques for implementing a VFD for pool or spa equipment using a synchronous rectifier according to this disclosure can address these challenges. In one example, a pool or spa system may include an AC input connected to an AC power source and a pool automation controller for operating one or more pieces of rotating pool or spa equipment such as pumps, blowers, filters, or other pool or spa equipment with rotating components. The example pool or spa system may include a variable frequency drive for driving the one or more pieces of rotating pool or spa equipment The variable frequency drive may include a synchronous rectifier configured to convert the AC input to a DC output. The synchronous rectifier may include a chipset and one or more switching components such as metal-oxide-semiconductor field-effect transistors (MOSFETs). ’Hie variable frequency drive may also include an inverter configured to convert the DC output to an AC signal at a configured frequency to drive the rotating pool or spa equipment. The pool automation controller can be used to operate the variable frequency drive. For example, the pool automation controller can receive an input for a particular speed to operate a pump at. The pool automation controller can determine the AC frequency needed to operate the pump at the desired speed based on the physical configuration of the pump (e.g., the number of poles in the pump stator). 'Hie pool automation controller can provide a control signal to the variable frequency drive to cause an AC output with the determined frequency.
[0017] The systems and methods according to this disclosure may use semiconductor components, such as MOSFETs, that generate significantly less heat than existing implementations. Additionally, the use of semiconductors such as MOSFETs enable a compact form factor and require significantly less cooling infrastructure than existing implementations. Tire use of semiconductors such as MOSFETs for switching in conjunction with modern integrated circuits can enable precision switching control to reduce voltage spikes and electromagnetic interference.
[0018] FIG. 1 illustrates an example pool or spa system 100, according to some aspects of the present disclosure. 'Die pool or spa system 100 may include equipment associated with operating or maintaining pool or spa 105 For example, the pool or spa system 100 may includeAttorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053120 implementation is shown in FIG 2. The inverter 125 can convert the DC current back to AC, at different frequencies and / or voltage levels using high-speed switching elements such as relays or transistors which can enable precision control over the AC output waveform.
[0027] The VFD 127 may be configured and operated using a user interface provided by the pool automation controller 115 or a standalone user interface. The VFD 127 may be configured to power one or more pieces of rotating equipment 130 such that differen t pieces of rotating equipment 130 can be powered at differing levels of voltage, frequency, waveform, etc. simultaneously.
[0028] For example, a. maintainer or operator of the pool or spa system may input a desired pump speed of 1800 RPM into a user interface provided by the pool automation controller 115 The pool automation controller 115 can determine that a 30 Hz output frequency is required for the pump's four-pole motor and send a con trol signal to the VFD 12? to cause the VFD 127 to generate a 30 Hz AC output, using a 60 HZ AC input signal, causing the pump to operate at the specified speed The incoming 60 Hz AC signal can be rectified by rectifier 120 to a DC signal and then inverted back to AC at 30 Hz by the inverter 125
[0029] FIG 2 illustrates an example of a rectifier 120 implementation, sometimes referred to as a synchronous rectifier 200, according to some aspects of the present disclosure. " Hie synchronous recti fier 200 may include a synchronous rectifier chipset 202, such as an LT4320 chip, which is capable of controlling a synchronous rectification process. Other chips capable of controlling a synchronous rectification process may also be used in addition to or in place of the synchronous rectifier chipset 202. The synchronous rectification process may enable rectification of current from an AC power source 210 to output DC power that can be inverted to generate an AC waveform of a specified voltage, frequency, waveform, etc.
[0030] In some examples, the synchronous rectifier 200 can use metal-oxide-sem iconductor field-effect transistor (‘" MOSFETs”) 225 as switching components. T he MOSFETs 225 can be controlled to turn on and off in sync with the AC input waveform, effectively replacing traditional diodes and reducing conduction losses. Conduction losses can refer generally to the power dissipated as heat when current flows through a forward -biased semiconductor element, such as an activated MOSFET. Operation of MOSFETs 225 can be characterized using certain electrical resistance values relating to the effective resistance presented by the MOSFETs 225 when activated (i.e., when current is flowing through the MOSFET} For example, some MOSFETs 225 can be characterized by their “on-resistance,” sometimes given by RDS(on),Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053frequency, and waveform For example, the inverter 240 may include control circuitry that employs pulse-width modulation (PWM) techniques to synthesize the AC output waveform from the DC output bus of the synchronous rectifier to adjust the switching sequences and duty cycles of the inverter transistors to cause the specified voltage, frequency, and waveform across the AC output of the inverter 240.
[0048] FIG. 6 shows a block diagram of an example of a computing system 602, such as a computing processing device communicatively coupled with the pool automation controller 115 of FIG. 1, usable in concert with the pool automation controller 115, according to some aspects of the present disclosure. In some examples, the components shown in FIG. 6 (e.g., the power source 620, pool automation controller 115, communications interface 622, processor 608, memory 604, and hardware 610) cart be integrated into a single structure. For example, the components can be within a single housing, such as within the housing of the pool automation controller 115 In other examples, the components shown in FIG. 6 can be distributed (e.g., in separate housings) and in electrical communication with each other.
[0049] The computing system 602 can include the processor 608, the memory 604, and a bus 606. The processor 608 can execute one or more operations for operating the computing system 602 The processor 608 can execute instructions stored in the memory 604 to perform foe operations. The processor 608 can include one processing device or multiple processing devices Non-limiting examples of the processor 608 incl a de a Field-Programmable Gate Array (‘ PGA”), an application-specific integrated circuit (“ASIC”), a microprocessor, etc.
[0050] The processor 608 can be communicatively coupled to the memory 604 via the bus 606. The non-volatile memory 604 may include any type of memory device that retains stored information when powered off. Non-limiting examples of the memory 604 include electrically erasable a.ad programmable read-only memory f ‘EEPROM”), flash memory, or any other type of non-volatile memory. In some examples, at least some of the memory 604 can include a non-transitory medium from which the processor 608 can read instructions. A non -transitory computer-readable medium can include electronic, optical, magnetic, or other storage devices capable of providing the processor 608 with computer-readable instructions or other program code. Non-limiting examples of a computer-readable medium include (but are not limited to) magnetic disk(s), memory chip(s). ROM, random -access memory (“RAM”), an ASIC, a configured processor, optical storage, or any other medium from which the processor 608 can read instructions. 'The instructions can include processor-specific instructions generated by aAttorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053General ConsiderationsAttorney Docket No.: 010147-1530053Attorney Docket No.: 010147-1530053to” or “configured to” herein is meant as open and inclusive language that does not foreclose devices adapted to or configured to perform additional tasks or steps. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Additionally, the use of “based on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited Similarly, the use of “based at least part on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based at least in part on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Headings, lists, and numbering included herein are for ease of explanation only and are not meant to be limiting.
[0063] The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within die scope of die present disclosure. In addition, certain method or process blocks may be omitted in some implementations The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described blocks or states may be performed in an order other than that specifically disclosed, or multiple blocks or states may be combined in a single block or state. The example blocks or states may be performed in serial, in parallel, or in some other manner. Blocks or states may be added to or removed from the disclosed examples. Similarly, the example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed examples.
[0064] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
[0065] These examples are not intended to be mutually exclusive, exhaustive, or restrictive in any way, and the disclosure is not limited to these example embodiments but rather encompasses all possible modifications and variations within the scope of any claimsAttorney Docket No.: 010147-1530053
Claims
Attorney Docket No.: 010147-1530053CLAIMSWhat is claimed is:
1. A pool or spa system, comprising:an alternating current (AC) input connected to an AC power source;one or more pieces of rotating pool or spa equipment;a variable frequency drive for driving the one or more pieces of rotating pool or spa equipment, comprising:a synchronous rectifier configured to convert the AC input to a direct current (DC) output, comprising:a chipset; andone or more switching components; andan inverter, configured to convert the DC output to an AC drive signal at a configured frequency.
2. The pool or spa system of claim 1, wherein the one or more switching components are metal -oxide “Semiconductor field-effect transistors (MOSFETs).
3. The pool or spa system of any of claims 1-2, wherein:the synchronous rectifier comprises four MOSFETs; andthe four MOSFETs are connected to the chipset in a bridge configuration.
4. The pool or spa system of any of claims 1-3, wherein the synchronous rectifier further comprises:one or more capacitors connected in parallel across the DC output of the synchronous rectifier.
5. The pool or spa system of any of claims 1-4, wherein the variable frequency drive further comprises:a plurality of synchronous rectifiers and a plurality of respective inverters, each synchronous rectifier and inverter pair being connected to a respective piece of rotating pool or spa equipment.Attorney Docket No.: 010147- 15300536. The pool or spa system of any of claims 1 -5, wherein the one or more pieces of rotating pool or spa equipment comprise at least one of a pump, fan, or blower.
7. The pool or spa system of any of claims 1-6, wherein:the variable frequency drive is connected to a plurality of pieces of pool or spa equipment; andthe variable frequency drive is configured to provide AC power at the configured frequency to the plurality of pieces of pool or spa equipment.
8. The pool or spa system of any of claims 1-7, wherein:the pool or spa system further comprises a pool automation controller; and the pool automation controller comprises a user interface configured to receive a command to generate, by the variable frequency drive, the AC drive signal at a specified frequency.
9. The pool or spa system of any of claims 1-8, further comprising:a network interface configured to receive, from a remote user interface, a command to generate, by the variable frequency drive, the AC drive signal at a specified frequency.
10. A variable frequency drive for driving one or more pieces of rotating pool or spa equipment, comprising:a synchronous rectifier configured to convert an alternating current (AC) input to a direct current (DC) output, comprising:a chipset; andone or more switching components; andan inverter, configured to convert the DC output to an AC drive signal at a configured frequency.
11. The variable frequency drive of claim 10, wherein the one or more switching components are MOSFETs.
12. The variable frequency drive of any of claims 10-11, wherein:the synchronous rectifier comprises four MOSFETs; andthe four MOSFETs are connected to the chipset in bridge configuration.Attorney Docket No.: 010147-153005313. The variable frequency drive of any of claims 10-11, wherein the synchronous rectifier further comprises:one or more capacitors connected in parallel across the DC output of the synchronous rectifier.
14. The variable frequency drive of any of claims 10-11, further comprising:a plurality of synchronous rectifiers and a plurality of respective inverters, each synchronous rectifier and inverter pair being connected to a respective piece of rotating pool or spa equipment.
15. The variable frequency drive of any of claims 10-11, wherein:the variable frequency drive is configured to receive a command to generate, by the variable frequency drive, the AC drive signal at a specified frequency.
16. A method for driving rotating pool or spa equipment, comprising:receiving, by a variable frequency drive configured as part of a pool or spa system, an input AC signal and a command to generate an AC drive signal of a particular frequency; outputting, to a synchronous rectifier, the input AC signal;generating a DC output comprising switching one or more rectifying elements of the synchronous rectifier using a control circuit;smoothing the DC output of the synchronous rectifier using bulk capacitance; inverting the smoothed DC output using inverter to generate the AC drive signal; and providing the AC drive signal to one or more pieces of rotating equipment.
17. The method of claim 16, wherein:the one or more rectifying elements of the synchronous rectifier comprise one or more switching components; andthe synchronous rectifier further comprises a chipset configured to control a synchronous rectification process.
18. The method of any of claims 16-17, wherein the one or more switching components are MOSFETs.Attorney Docket No.: 010147-153005319. The method of any of claims 16-18, wherein:the synchronous rectifier comprises four MOSFETs; andthe four MOSFETs are connected to the chipset in bridge configuration.
20. The method of any of claims 16-19, further comprising:receiving, from a user interface, an indication of a speed for a first piece of pool or spa equipment; anddetermining, based on the indication, the particular frequency.