{ "node": { "id": "term:buck-boost-converter", "type": "Term", "label": "Buck and boost converters", "properties": { "id": "buck-boost-converter", "name": "Buck and boost converters", "aka": [ "buck converter", "boost converter", "step-down converter", "step-up converter", "bidirectional DC/DC converter" ], "section": "topic-data", "definition": "Switch-mode circuits that step a DC voltage down (buck) or up (boost) using a fast switch, an inductor and a capacitor, often above 95% efficient. With transistors in place of diodes the same circuit runs both ways, charging a battery from a bus or discharging into it, as in stationary storage and on-board boosters that let 800 V cars use 400 V chargers.", "related": [ "dc-dc-converter", "pulse-width-modulation", "mosfet", "active-balancing", "split-pack" ], "url": "https://lemonergy.com/learn/glossary/buck-boost-converter/", "mentions": [ "stationary-storage", "capacitor" ] } }, "edges": [ { "id": "edge:5260", "source": "term:buck-boost-converter", "target": "topic:topic-data", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:5261", "source": "term:buck-boost-converter", "target": "term:dc-dc-converter", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5262", "source": "term:buck-boost-converter", "target": "term:pulse-width-modulation", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5263", "source": "term:buck-boost-converter", "target": "term:mosfet", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5264", "source": "term:buck-boost-converter", "target": "term:active-balancing", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5265", "source": "term:buck-boost-converter", "target": "term:split-pack", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/buck-boost-converter/stationary-storage", "source": "term:buck-boost-converter", "target": "term:stationary-storage", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:mentions/buck-boost-converter/capacitor", "source": "term:buck-boost-converter", "target": "term:capacitor", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:5268", "source": "term:buck-boost-converter", "target": "visual:pwm", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-data", "type": "Topic", "label": "Data, communication and electronics", "properties": { "id": "topic-data", "name": "Data, communication and electronics", "lede": "The control units, chips, protocols and file formats through which a battery is measured, controlled and logged.", "context": "Separate quantities from encoding and transport.", "example": "2500 in a log might mean 25.00 °C, 2.5 V or raw counts. Units and scale must accompany the value.", "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-basics/", "lesson_label": "Open battery basics" } }, { "id": "term:dc-dc-converter", "type": "Term", "label": "DC/DC converter", "properties": { "id": "dc-dc-converter", "name": "DC/DC converter", "section": "topic-pack", "definition": "The power electronics that step the high-voltage pack down to 12 V or 48 V for the auxiliary systems, replacing the alternator of a combustion car. 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The instantaneous signal remains a 0/12 V waveform; a real converter also depends on topology and filtering." }, "url": "https://lemonergy.com/learn/glossary/pulse-width-modulation/", "mentions": [ "charger", "contactor" ] } }, { "id": "term:mosfet", "type": "Term", "label": "MOSFET", "properties": { "id": "mosfet", "name": "MOSFET", "aka": [ "metal–oxide–semiconductor field-effect transistor", "power MOSFET" ], "section": "topic-data", "definition": "A transistor switched by the voltage on its gate, with an on-resistance of milliohms or less in power parts. 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Switched capacitors shuttle charge between neighbours; inductors or transformers carry it further; isolated converters exchange it between one cell and the whole string; bypass switches take a cell out of the string. Currents reach amperes, at the cost of more parts.", "related": [ "cell-balancing", "buck-boost-converter", "bms", "cell-to-cell-variation", "mosfet" ], "url": "https://lemonergy.com/learn/glossary/active-balancing/", "mentions": [] } }, { "id": "term:split-pack", "type": "Term", "label": "Split pack", "properties": { "id": "split-pack", "name": "Split pack", "aka": [ "switchable pack", "reconfigurable pack", "400/800 V switching" ], "section": "topic-pack", "definition": "A pack built as two halves that contactors can connect in series or in parallel, so the same battery works at two voltages. GM’s Hummer EV drives at 400 V with its halves in parallel and switches them to series for 800 V fast charging; other designs split an 800 V pack to use 400 V chargers.", "related": [ "pack-voltage", "contactor", "series-parallel", "dc-fast-charging", "battery-disconnect-unit", "split-pack-charging" ], "url": "https://lemonergy.com/learn/glossary/split-pack/", "mentions": [ "fast-charging" ] } }, { "id": "term:stationary-storage", "type": "Term", "label": "Stationary storage", "properties": { "id": "stationary-storage", "name": "Stationary storage", "abbr": "BESS", "aka": [ "battery energy storage system", "ESS" ], "section": "topic-applications", "definition": "Batteries installed in a fixed place — a container at a solar farm, a cabinet in a home — to shift energy in time or support the grid. LFP cells dominate because cost per cycle and safety matter more than mass.", "related": [ "lfp", "energy-management-system", "inverter", "energy-arbitrage", "long-duration-storage", "ul-9540a" ], "url": "https://lemonergy.com/learn/glossary/stationary-storage/", "mentions": [] } }, { "id": "term:capacitor", "type": "Term", "label": "Capacitor", "properties": { "id": "capacitor", "name": "Capacitor", "section": "topic-units", "definition": "A component that stores energy as charge on two conducting plates separated by an insulator; its voltage rises in proportion to the charge, unlike a battery’s nearly flat curve. The large DC-link capacitors at an inverter’s input draw a huge inrush current when connected to a pack, which is why a pre-charge circuit fills them first.", "formula": "Q = C·V; E = ½·C·V²", "unit": "F (farad)", "related": [ "pre-charge", "inverter", "supercapacitor", "double-layer", "contactor" ], "example": { "title": "Calculate stored charge and energy", "text": "An ideal 100 F capacitor charged to 2 V stores 200 C and 200 J. Doubling voltage quadruples its stored energy when capacitance remains constant." }, "url": "https://lemonergy.com/learn/glossary/capacitor/", "mentions": [ "inrush-current" ] } }, { "id": "visual:pwm", "type": "Visual", "label": "Duty cycle controls average voltage", "properties": { "title": "Duty cycle controls average voltage", "summary": "An ideal pulse train alternates between zero and the supply voltage.", "readout": "50% of 12 V gives a 6 V time average.", "formula": "V_average = D V_supply", "note": "Unfiltered ideal waveform; actual output depends on the converter circuit and control.", "software": { "status": "reference", "label": "Reference concept", "body": "This shows V_avg = duty × V_supply for a pulse train. A real converter also requires topology, filtering, switching losses and control.", "href": "../chapter-1/" }, "html": "
Ideal 12 V pulse train
Ideal 12 V pulse trainTime (switching periods) versus Voltage (V). Switched voltage; Time average. Interpretation follows the graphs.003.517210.53144Time (switching periods)Voltage (V)
Switched voltageTime average (dashed)
" } } ] }